:" x" I? »\i, "i ” U f 2— Recent Surface Movements In the Baldwin Hills, 35;»? ' L05 Angeles County, California ‘GEOLOGICAL SURVEY jPROFESSIONAL PAPER 882 ‘F 1.. UOCUMtNTS GEF’ARTMENT SEP8 1975 LIFT“ Uigsygmm 515‘ng WGRNM r- ,- ”N a I a ‘ .1 l \4 ‘ P‘lmt ‘ v ,_, l RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Oblique aerial view Asouth—southeastward across the Baldwin Hills. (A) trace of the Inglewood fault; (B) Stocker StreeteLa Brea Avenue«0verhill Drive intersection; (C) highest point in the Baldwin Hills; (D) surface projection of structural high east of the Inglewood fault on surface 50 feet above Vickers-Machado zone of the Inglewood oil field (the Inglewood fault dips westward here); (E) surface projection of structural high west of the Inglewood fault on surface 50 feet above Vickers-Machado zone of the In- glewood oil field; (F) approximate location of bench mark Hol- lywood E—11; (G) approximate center of subsidence in the Baldwin Hills area as shown by Los Angeles Department of Water and Power leveling surveys conducted since 1950; (H) Baldwin Hills Reservoir. Photograph by Spence Air Photos, November 1952. Recent Surface Movements In the Baldwin Hills, Los Angeles County, California By ROBERT O. CASTLE and ROBERT F. YERKES GEOLOGICAL SURVEY PROFESSIONAL PAPER 882 A study of surface deformation associated with oil-field operations UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1976 UNITED STATES DEPARTMENT OF THE INTERIOR THOMAS S. KLEPPE, St‘l'r‘r‘lrn)‘ GEOLOGICAL SURVEY V. E. McKelvey, Dirwtm‘ Library of Congress catalog~card No. 76—20775 For sale by the Superintendent of Documents, Us. Government Printing Office Washington, DC. 20402 Stock Number 024-001—02849—2 CONTENTS Abstract ________________________________________________ Introduction ______________________________________________ Acknowledgments ____________________________________ Geology ______________________________________________ Seismicity Regional elevation changes ____________________________ Elevation changes along control lines through the Baldwin Hills and environs __________________________________ Elevation changes —--—-———--. _____________________________ Subsidence at PBM 67 and PBM 68 ____________________ Maximum subsidence during the period 1911—63 ________ General pattern of elevation changes __________________ Initiation of subsidence Horizontal movements ____________________________________ Earth cracks and contemporary fault displacements ________ Causes of the surface movements __________________________ Movements attributable to oil-field operations __________ Development of the Inglewood oil field ____________ Subsidence ______________________________________ Subsidence in other oil fields __________________ Comparison with the Wilmington oil field ______ Physical relations ____________________________ Theoretical and experimental bases ________ Relations between reservoir pressure decline and subsidence Relations between liquid production and subsidence Compaction ______________________________ Conclusion __________________________________ Horizontal movements ____________________________ Horizontal movements in the Wilmington and Buena Vista oil fields ______________________ Mechanical basis Conclusion __________________________________ Earth cracks and contemporary fault displacements Faulting in other oil fields ____________________ Mechanical basis Conclusion __________________________________ Movements attributable to changes in ground-water regimen __________________________________________ Ground-water development in the Baldwin Hills area Subsidence ______________________________________ Horizontal movements ____________________________ Earth cracks and contemporary fault displacements Movements attributable to surface loading ____________ Subsidence ______________________________________ Horizontal movements ____________________________ 15 16 19 20 25 26 30 38 39 39 43 50 50 55 55 57 62 63 64 64 65 65 66 66 67 72 78 78 78 80 81 81 82 82 82 Causes of the surface movements—Continued Movements attributable to surface loading—Continued Earth cracks and contemporary fault displacements Movements attributable to tectonic activity ____________ Subsidence ______________________________________ Horizontal movements ____________________________ Earth cracks and contemporary fault displacements Summary and conclusions ________________________________ Geologic framework __________________________________ Elevation changes ____________________________________ Horizontal movements ________________________________ Earth cracks and contemporary fault displacements ____ Causes of the surface movements ______________________ Movements attributable to oil-field operations ______ Subsidence __________________________________ Horizontal movements ________________________ Earth cracks and contemporary fault displace- ments Movements attributable to other causes ____________ Changes in ground-water regimen ____________ Changes in surface loading ____________________ Tectonic activity ______________________________ Conclusion __________________________________________ References cited __________________________________________ Appendix A—Survey history and adjustments of level lines A, B, and C ______________________________________________ Appendix B—Location of PBM 68 (identified alternatively as DD) Appendix C—Derivation of November 1911 elevations of PBM 68 and Hollywood E—11 ________________________________ Appendix D—Determinations of subsidence of PBM 68 with respect to Hollywood E—ll Appendix E—Determination of subsidence of PBM 68 with respect to PBM 58 ______________________________________ Appendix F—Derivation of J une—J uly 1910 elevations of PBM 68 and PBM 67 with respect to 8—32 ____________________ Appendix G—Determination of subsidence of PBM 67 with respect to Hollywood E—11 ______________________________ Appendix H—Calculation of maximum subsidence in the northern Baldwin Hills since 191 1 with respect to Hollywood E— 1 1 __________________________________________________ Appendix I—Comparative 1910 and 1917 elevations within the area of differential subsidence centering in the northern Baldwin Hills ___________________________________________ Appendix J——Calculations of average increase in effective pressure in an unlayered equivalent of the Vickers zone __ Appendix K—Estimates of compaction of the Vickers zone __ Page 82 84 84 85 86 87 87 88 88 89 89 89 89 90 90 91 91 91 92 92 92 98 99 100 114 115 117 117 119 122 123 VI FRONTISPIECE. PLATE FIGURE 1 2. 3. 4 P‘PWN!‘ F” 10. 11. 12. 13. 14. 15. 16. 17. 18—21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. CONTENTS ILLUSTRATIONS [Plates are in pocket] Oblique aerial photograph of the Baldwin Hills. Generalized geologic column through the Inglewood oil field. Map of northern Baldwin Hills showing faults, joints, and earth cracks as of February 1964. Map showing earthquake epicenters in the Los Angeles basin area, January 1, 1934—March 31, 1963. Map of northern Baldwin Hills showing approximate pattern of average annual elevation changes, horizontal move- ments, and distribution of earth cracks during various periods, 1934—63. Map showing location of the Baldwin Hills and major faults and physiographic features in the Los Angeles basin" Generalized geologic section through the northern Baldwin Hills ______________________________________________ Map showing structure contours drawn on top of “Gyroidina” zone, Inglewood oil field __________________________ Map showing structure contours drawn on surface 50 feet above Vickers-Machado zone, Inglewood oil field ________ Map showing average annual rates of elevation change of parts of the Los Angeles basin with respect to BM 37—54—26 for various periods _______________________________________________________________________________________ Map showing average annual rates of elevation change of parts of the Los Angeles basin with respect to Los Angeles Bureau of Engineering datum, 1949—55 __________________________________________________________________ Map showing contours on the base of freshwater-bearing deposits near Salt Lake oil field and average annual rates of elevation change in the La Cienega Boulevard area for various periods between 1925 and 1938 ______________ Map showing approximate routes of level surveys A, B, and C __________________________________________________ Graph showing changes in elevation along level survey A, 1935—43 ________-__________-______________.- _________ Graph showing changes in elevation along level survey B, 1933—43 ____________________________________________ Graph showing changes in elevation along level survey C, 1939—62 ____________________________________________ Graph showing alternative derivations of the subsidence of PBM 68 ____________________________________________ Graph showing subsidence of PBM 68 with respect to PBM 58 since 1911 ______________________________________ Map of north-central part of Baldwin Hills showing earth cracks and approximate pattern of average annual eleva- tion changes relative to Hollywood E—ll, 1958—60 ________________________________________________________ Map of north-central part of Baldwin Hills showing earth cracks and reinterpreted approximate pattern of average annual elevation changes relative to Hollywood E—Il, 1958—60 ____________________________________________ Graphs showing repeated interstation measurements and calculated horizontal strain along selected traverses within the Baldwin Hills subsidence field ________________________________________________________________________ Graph showing average rate of subsidence at PBM 68 versus average rate of horizontal movement at four triangula— tion points ______________________________________________________________________________________________ Photographs showing: 18. Patching along earth crack I ________________________________________________________________________ 19. Earth crack II ______________________________________________________________________________________ 20. Damaged wall intersected by earth crack I ____________________________________________________________ 21. Displacement along earth crack IX __________________________________________________________________ Map of Baldwin Hills Reservoir showing traces of earth cracks IX and X and locations of California Department of Water Resources excavation 2, inlet line tunnel, circulator lines, and drainage inspection chamber __________ Drawing of north face of excavation 2, intersecting earth crack IX ______________________________________________ Schematic diagram illustrating possible horizontal offset of rigid structure intersected by fault __________________ Graph showing subsidence at bench mark BHBM 128 ________________________________________________________ Graph‘showin'g strain—gage measurements across crack in concrete liner of inspection chamber of Baldwin Hills Reservoir ___________________________________________ I ___________________________________________________ Graph showing elevation changes along inlet tunnel and drainage inspection chamber of the Baldwin Hills Reser- v01r ____________________________________________________________________________________________________ Graph showing annual oil, net water, and net liquid production from the Inglewood oil field through 1963 ________ Graph showing cumulative net liquid and cumulative gas production from the Inglewood oil field through 1963 -_ Graph showing gas:oil ratios for the Inglewood oil field and the Vickers zone of the Inglewood oil field ____________ Graph showing ratio of oil production to net water production for the Vickers zone of the Inglewood oil field ______ Graph showing cumulative net liquid and cumulative gas production from the Vickers zone of the Inglewood oil field through 1963 __________________________________________________________________________________________ Graph showing fluid-pressure decline at -1,330 feet in the Vickers East zone, 1925—63 __________________________ Graph showing calculated fluid-pressure decline midway through the central Vickers zone, 1925—63 ———-——————4——:, Graph showing liquid production from the Inglewood oil field and Vickers zone versus subsidence at PBM 68 since 1911-- Graph showing rate of subsidence versus rates of net liquid production from the Inglewood oil field and Vickers zone, 1926—62 ________________________________________________________________________________________________ 9 11 12 13 I3 14 18 19 22 23 28 30 31 31 31 32 33 34 35 36 37 39 41 41 42 42 43 43 43 45 46 FIGURE TABLE 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. S99°flg°WPP°E°H H 53 CONTENTS VII Page Graph showing liquid production from the Inglewood oil field and Vickers zone versus cumulative volume of subsidence since 1911 ______________________________________________________________________________________________ 49 Graph showing cumulative subsidence at PBM 68 versus cumulative pressure decline in the Vickers zone, 1926—62 49 Graph showing annual average subsidence at PBM 68 and annual average pressure decline in the Vickers zone plotted against time ____________________________________________________________________________________________ 49 Graph showing annual oil, net water, and net liquid production from the Wilmington oil field through 1961 ______ 52 Graph showing cumulative net liquid production and gas production from the Wilmington oil field through 1961, and cumulative maximum subsidence within the Wilmington oil field subsidence bowl, 1928—60 __________________ 52 Graph showing liquid production from the Wilmington field versus maximum subsidence, 1928—60 ______________ 53 Graph showing cumulative maximum subsidence versus cumulative measured pressure decline in the Ranger and Upper Terminal zones of the Wilmington oil field ________________________________________________________ 55 Graph showing void ratio as a function of applied pressure for two Bolivar Coast samples ________________________ 56 Graph showing calculated horizontal displacement and horizontal extension along sections through the Baldwin Hills subsidence bowl, 1954—58 ________________________________________________________________________________ 66 Photograph of “fracture” on Hog Island, Goose Creek oil field, Texas ____________________________________________ 67 Map showing contours of equal subsidence around the Goose Creek oil field, Texas ______________________________ 67 Map of part of Buena Vista Hills area showing parts of the Buena Vista, Midway-Sunset, and Elk Hills oil fields; surface trace of active fault along south flank of the Buena Vista Hills; record elevation changes in the Buena Vista Hills area; and horizontal movements, 1932—59 ________________________________________________________________ 69 Map of part of the western Los Angeles basin showing the Dominguez and Rosecrans oil fields; location at depth of faults along which subsurface displacements are reported to have occurred during historic time; and elevation changes in the Dominguez oil field, 1945/46—60, and the Rosecrans oil field, 1953—60 __________________________________ 71 Mohr diagram showing hypothetical states of stress at depth __________________________________________________ 72 Idealized profile showing elastic rebound of block located along the periphery of differential subsidence bowl ______ 73 Part of original triangulation net of the Los Angeles Investment Co. in the northern Baldwin Hills ______________ 100 Assumed e-log—p curves for the Vickers zone of the Inglewood oil field __________________________________________ 125 TABLES Page Petroleum production statistics for the Inglewood oil field by zone through December 31, 1963 ____________________ 40 Fluid production and waterfiooding statistics for the Inglewood oil field by year ________________________________ 40 Fluid production and waterflooding statistics for the Vickers zone of the Inglewood oil field by year ______________ 42 Subsidence and production data for the Inglewood oil field ____________________________________________________ 47 Subsidence and production data for the Vickers zone of the Inglewood oil field __________________________________ 48 Fluid production and waterfiooding statistics for the Wilmington oil field by year ________________________________ 51 Subsidence and production data for the Wilmington oil field ____________________________________________________ 54 Measured reservoir-pressure decline in selected zones of the Wilmington oil field ________________________________ 60 Casing collar surveys of compaction in upper three producing zones of the Wilmington oil field over two selected time intervals ______________________________________________________________________________________________ 60 Calculations of the average increase in effective pressure attributed to decompression and liquid-level decline through an unlayered equivalent of the Vickers zone of the Inglewood oil field ______________________________________ 124 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS AN GELES COUNTY, CALIFORNIA By ROBERT O. CASTLE and ROBERT F. YERKES ABSTRACT The Baldwin Hills comprise one of several isolated groups of hills extending along the Newport-Inglewood zone of folds and faults, a northwest-trending structural lineament identified with a series of highly productive oil fields. Surface deformation in the Baldwin Hills has been closely monitored since 1939. This deformation, which includes differential subsidence, horizontal displacements, and surface rupturing, is attributed virtually entirely to the exploitation of the spatially associated Inglewood oil field, located in the northern part of the hills. The hills are underlain by gently to moderately arched and conspicuously faulted Cenozoic sedimentary and volcanic rocks that overlie crystalline basement at a depth ofmore than 10,000 feet. They are transected diagonally by the Inglewood fault, a major feature of the Newport-Inglewood zone. Evidence of recent and apparently continuing deformation is seen in the seismicity and elevation changes that characterize both the hills and their environs. A well-defined, northwest-trending subsidence bowl enbracing the northwest part of the Baldwin Hills has been revealed through repeated levelings. Selected level lines have been reconstructed with respect to a common, relatively stable control point located at the edge of the subsidence bowl, in order to assess the subsidence since 1910 and 1911 at two points near the center ofthe bowl. Bench mark PBM 67 is estimated to have subsided 4.324 feet between June 1910 and February 1963; bench mark PBM 68 (the only one within the subsidence bowl that was leveled prior to 1926 and has been repeatedly leveled since) subsided 3.846 feet between November 1911 and June 1962. PBM 122, which has remained very close to the center of subsidence since at least 1950, is calculated to have subsided 5.67 feet between 1911 and 1963. Horizontal displacements (with respect to an external base line) of six triangulation points within the subsidence bowl have been measured for various periods between 1934 and 1963. Displacements have been generally toward the center of subsidence and almost precisely perpendicular to the immediately adjacent isobases of equal elevation change. Maximum movement has been recorded at triangulation point Baldwin Aux, which was displaced 2.21 feet between 1934 and 1961; horizontal displacements of three other points ranged from 0.95 foot to 1.85 feet between 1936 and 1961. Displacements of 0.10—0.29 foot were recorded at all six monuments during the period 1961~63. Remeasurement of earlier survey traverses has shown that the peripheral part of the subsidence bowl is identified with radially oriented extensional horizontal strain and that the central part is associated with contractional or compressional horizontal strain. "Earth cracks” and surficial fault displacements were recognized in the Baldwin Hills at least as early as 1957. The cracks are relatively straight, generally continuous fractures confined almost exclusively to the structural block east of the Inglewood fault; they are concentrated in two areas centering on (1) the Baldwin Hills Reservoir and (2) the Stocker Street—LaBrea Avenue—Overhill Drive intersec- tion. The cracks trend north to north-northeast, are nearly everywhere parallel to or coincident with minor faults and joints, and are generally orthogonal to radii emanating from the center of subsidence. Differential movement along the cracks has been almost entirely dip slip along steep to nearly vertical surfaces, and generally down toward the center of subsidence. Cumulative displacements have been as much as 6 or 7 inches. Rates of displacement have varied widely, and the movement has generally occurred as creep or small discrete jumps. A probable exception is the several inches of differential movement that is believed to have occurred along a crack through the floor of the Baldwin Hills Reservoir on or about December 14, 1963. Possible explanations for the contemporary surface movements include: (1) exploitation of the Inglewood oil field, (2) changes in the ground-water regimen, (3) compaction of sedimentary materials in response to surface loading, (4) tectonic activity, or (5) some combination of these. The following considerations indicate that the differential subsid- ence is attributable largely or entirely to oil-field exploitation: ( 1) the coincidence among the centers of the oil field, the producing structure, and the subsidence bowl, (2) the general correspondence between the pattern of subsidence and the outlines of the oil field, (3) the approximate coincidence between the onset of production and the onset of subsidence, (4) the generally linear relations between various measures of subsidence and liquid production from both the field as a whole and the exceptionally prolific Vickers zone in particular, (5) the coincidence between the sharp deceleration of subsidence in the east block of the field and the beginning of full-scale waterflooding there, (6) the many other examples of spatial and temporal associations between oil-field production and subsidence, (7) the many similarities between the subsidence-production relations in the Inglewood field and those in the Wilmington field where a causal relation between oil-field operations and subsidence has been clearly documented, and (8) the recognized relation between subsidence or a tendency toward subsidence and declining reservoir pressure associated with under- ground fluid extraction. Consideration of various possible explanations for the increasing rate of subsidence with respect to reservoir fluid pressure decline suggests that measured or calculated down-hole reservoir fluid pressure decline is unrepresentative of average or real fluid pressure decline away from producing wells. The near-linear relations between net liquid production and subsidence are explained by analogy with a tightly confined artesian system of infinite areal extent, where production must derive from liquid expansion and (or) reservoir 2 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA compaction. Test data from compaction studies in two other oil fields yield estimates of ultimate compaction of the Vickers zone resulting from a total loss of fluid pressure; the best estimate, based on these data and considerations of late Cenozoic history in the Baldwin Hills area, is about 10 feet. The centripetally directed horizontal displacements and associated horizontal strain are also attributable to exploitation of the Inglewood oil field owing to: (1) their well-defined spatial and symmetrical associations with the differential subsidence, (2) the similarities between these associations and those developed in and around other subsiding oil fields, and (3) the mechanical compatibility of these movements with subsidence induced by the extraction of subsurface materials. The earth cracks and surficial fault displacements are attributable largely or entirely to the exploitation of the Inglewood oil field owing to: (1) their spatial and temporal relations to both oil-field operations and the differential subsidence, (2) the similarities of these cracks and displacements to those generated in and around other oil fields and areas from which subsurface materials have been extracted, and (3) surface strain patterns deduced from the measured vertical and horizontal surface movements. The cracks and displacements are explained by a differential compaction model consistent with radially oriented extensional strain and elastic compression of the sedimen- tary section around the periphery of the subsidence bowl. Analysis of the history of ground—water extraction within and around the Baldwin Hills and subsidence associated with water-level declines in sediments comparable with those in the Baldwin Hills indicates that the surface movements can be no more than incidentally attributed to changes in ground-water conditions. Similarly, analysis of the history of natural and artificial changes in surface loading indicates that these movements cannot be associated with changes in surface loading. Considerations of local geologic history and various tectonic associations indicate that it is very unlikely that the differential subsidence and horizontal movements are due to tectonic downwarp- ing. Although there exists a far stronger prima facie argument for tectonic involvement in the earth cracking and associated fault displacements, this argument is disputed by: (1) the spatial and temporal relations of the earth cracks to and their mechanical compatibility with the nontectonic differential subsidence, (2) the absence of displacements on the Inglewood fault in conjunction with those along the earth cracks, (3) the probability that branch or conjugate faulting would be characterized by strike- or oblique-slip displacements, (4) the incompatibility of postulated extensional faulting with contractional strain in the central part of the subsidence bowl, and (5) the absence of any clear temporal relation between crack growth and local seismicity. Because as much as about 10 percent of the local isobase gradient may be unexplained by oil-field exploita- tion, a small fraction of this gradient, and thus the displacements among the southern group of cracks, may have resulted from tectonic activity. However, this fraction could not have been significant in the absence of the strain pattern produced by nontectonic compaction of the underlying oil measures. Because nearly all the described surface movements can be fully explained as the products of oil-field operations, yet can be no more than incidentally attributed to changes in ground-water conditions, surface loading, or tectonic activity, we conclude that these movements should be attributed largely or entirely to the exploitation of the Inglewood oil field. INTRODUCTION The Baldwin Hills occur within the northwestern part of the Los Angeles basin near the north end of the northwest-trending Newport-Inglewood zone (fig. 1). They occupy about 10 square miles and are roughly equidimensional in plan. Rising gently from the south and east and relatively steeply from the north and west, they stand about 350—400 feet above the surrounding basin lowland. The youthful physiographic character of the hills is clearly evident in their slight to moderate dissection and from the well-defined scarp of the Inglewood fault (frontispiece). This report describes and analyzes historic surface deformation in the Baldwin Hills that had occurred through 1963. The described deformation includes well-defined differential subsidence centering on the Inglewood oil field, horizontal displacements directed toward the center of subsidence, and earth cracks and associated surficial fault displacements along the eastern margin of the subsidence bowl. Because these movements have been recorded in exceptional detail over a very long period, they comprise one of the most definitive and revealing examples of oil-field-associated surface deformation recognized to date. The nature and magnitude of the continuing vertical movements have been defined by numerous repeated levelings, which were begun at least as early as 1910. Intelligent use of the resulting data, however, has required a reevaluation of the various datums and adjustments employed in the derivation of the many utilized elevations. Although knowledge of the horizon- tal movements and earth cracks is less detailed, both can be shown to be spatially and mechanically related to the differential subsidence. Each of the recognized types of surface movement, moreover, is clearly associated in space with operations in the Inglewood oil field. A temporal association with these operations, however, is less well defined, and the possible effects of ground- water extraction, surface loading, and tectonic activity have greatly complicated this analysis. Abundant circumstantial evidence and various theoretical considerations indicate that both the differ- ential subsidence and the horizontal displacements are due to withdrawal of fluids from the underlying Inglewood oil field. Neither the actual changes in ground-water and loading conditions nor their maximum conceivable effects can explain more than a very small fraction of the differential subsidence. Tectonic activity is considered an equally implausible explanation of the observed subsidence. Comparisons with similar examples elsewhere, limited circumstan- tial evidence, and mechanical compatibility with both the measured and deduced horizontal strain indicate that the earth cracks and associated fault displace— ments are also due largely to oil-field operations. The surface deformation in the Baldwin Hills is compared in detail with that associated with the INTRODUCTION 340161890' 118°00’ 117°45' ....r\» 1 ..l SAN , GABRIEL MTS I “Iv/“N I ll'” H \~ ‘ (Nun/ll: “>300 II’I/I H U“ / I‘m“ :“ \\\‘ / HIIII'HIIHIZ‘MQIMillioxfil i/K ' :17/ ’7,“ H \\‘ 3/1], \“/’ ll|\\\\\\ ,, 1 . W I, .I 7 \C SANTA MON'CA MTS . EL //’/ .:::::\.< H IIIIII 'I“ " x V SAN BERNARDINO \ Q ' A II\\"/: “In“ Illllll"‘\\\ :3 [/‘d [if LLEY 3““ 7);,” VALLEY \\\l|\\\\\\\\\\ ’2 : ’/ /// \\\ I\\\ \ / :\“\\\ x H?“ ”U / Y m “x; \ \. 0 WT“ W 1;; >°,~: INGLEWOOD\ “ LOS'IANGELES ;“H"":\S~? 5V3: sum“: OIL FIELD \ ”‘““‘/ x’/ : T’LlyIIw/I..m,, 3 , t 3 34°00' / _ ’5: \ \ ’H‘ “0“ 3‘ — :: 3\\I”III|”/,/ \ouu / 72 \ ‘v\* BALDWIN HILLS / ”Inf 2 NGLEWOOD / x K 2/] 1141/77.] 7“ m‘ / Inn/I 0/ \\ .’ I/ ZIHHI\\\\;IIHI|I\H/// ,’ 4,1,” ¢ v / % PUENTE HILLS 62, /‘"‘ " 2 /,ll I I! E I . . u, U _ $29)\ 4 (I \ AHIIIHC \\\\‘I'H\: ”HUN" ’57- :— \ \ OS ----- --.._,.’l f NO \\"’/./’//,,, H \qituioo‘ / l - ----- /II\ \ \ —.’//III I‘n'Wn‘ 0‘“ 46A : " / NORWA..'."‘ Zn“ II“—"'\’|.|'I'I/$ ( ’ / LK p'"... N ,"$\"/$/’llll" \ 6‘1» / 054$. / 400%. /“ ‘ ’ ' y: SANTA ANA MTS \ , / 0046‘} ' ”W \ U 4 / ,/ 1 R <4W )7../” %/I15 ‘ ¥_‘ 0” SII’IL \ 45' _ o a}: 2 k _ ( SANTA ANA ””2. / 0”"; , :71; 5701‘; ' E\\\\\|l'/,/q\\H/H\Ul,l/UH”, GUI/2 ‘ E. s NEWPORT BEACH 5 44ldo a EXPLANATION .1 400/ 2% ,,,I\\\ ...... E 4/5, Fault : 44,9 I Dotted where concealed / or inferred LAGUNA BEACH , Area of I map < 33°30’ — 4 0 4 8 MILES 4 0 4 8 KILOMETRES l l l FIGURE 1.—Map of the Los Angeles basin showing location of the Baldwin Hills and major faults and physiographic features. Crosshatched area is shown on plates 2 and 4. Also shown are the approximate locations of the Inglewood and Wilmington oil fields. Modified after Woodford, Schoellhamer, Vedder, and Yerkes (1954, p. 66). operation of other oil fields in order to evaluate the significance of the association in the Baldwin Hills. This report thus provides a comprehensive review of surface deformation associated with oil-field operations gener- ally. This paper supersedes an earlier version released as an open-file report (Castle and Yerkes, 1969). It differs from the earlier version chiefly in the presentation of data unavailable to us at the time of the open-file release and because it discusses studies of the problem published since 1969. ACKNOWLEDGMENTS The generous assistance of the several organizations and many individuals that have contributed to the as 4.: Q mm 3 2s: In 0% q; f2> (D Lu~l Lu it? s ._,_, \ $0) 0 WEST S 2000'1 Holocene alluvium Top of “Gyroidina” zone . ". >v' So-called Pico Formation v" (Pliocene and Pleislooene(?)) I I I / 2000’ — // / // / So-called Repetio Formation / (Pliocene) / Undivided Pleistocene deposits RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA E 4 a 2 s u; < < in J: < x (I) lu 0 2 n: B E m to Q 5 EAST Holocene alluvium Undivided Pleistocene deposits -\)___.__ 1000 0 2500 1000 2000 FEET 250 500 METRES FIGURE 2,—Generalized geologic section of the northern Baldwin Hills normal to trend of the Inglewood fault. Based chiefly on surface mapping by Castle (1960); approximate location of top of "Gyroidina” zone, stratigraphic contacts, and major faults at depth projected from sections by Driver (1943, p. 307). preparation of this report is gratefully acknowledged. Particular thanks are extended to the Department of Water and Power of the City of Los Angeles, especially to H. B. Hemborg and W. J. Simon, for permission to incorporate the results of leveling surveys carried out under the supervision of S. A. Hayes and F. J. Walley. R. R. Wilson of the Department of Water and Power has contributed background geologic data, and L. M. Charles of the same department has provided an analysis of a Bureau of Water Works and Supply level survey. Compilation of leveling data and measurements of horizontal movements undertaken by the Depart- ment of County Engineer, County of Los Angeles, were carried out under the direction of I. H. Alexander. D. R. Brown, formerly Supervising Civil Engineer, Depart- ment of County Engineer, has aided in the preparation of the report both in supplying data on local surface cracking and through discussion of the problems. Professor C. R. Allen of the California Institute of Technology has provided tabulations of seismic data used in the preparation of a map showing the local seismicity. The Standard Oil Co. of California has permitted use of a detailed, composite lithologic log through the center of the Inglewood oil field. Lastly, we thank B. E. Lofgren, D. S. McCulloch, J. F. Poland, H. W. Olsen, F. S. Riley, D. J. Varnes, and T. L. Youd of the Geological Survey for many helpful suggestions. We are especially indebted to D. S. McCulloch and D. J. Varnes for their meticulous review of the manuscript. The investigation has been supported in part by the Division of Reactor Development and Technology, US. Atomic Energy Commission. GEOLOGY The stratigraphic section underlying the Baldwin Hills is comprised of Tertiary and Quaternary sedimen- tary rocks and Tertiary volcanic rocks (pl. 1). The crystalline basement complex on which these rest lies more than 10,000 feet beneath the surface (Yerkes and others, 1965, p. A4, pl. 4). Units exposed at the surface consist entirely of Quaternary to uppermost Tertiary(?) sedimentary rocks (fig. 2). The oldest rocks cropping out in the Baldwin Hills are assigned to the so-called Pico Formation of Pliocene and Pleistocene(?) age. They consist chiefly of poorly consolidatedmarine silts and very fine sands together with local lenses of coarser sand and pebbly materials. This sequence is locally rich in clay, particularly along the northwest flank of the hills, and much of it is thinly laminated; dips exceed 35° locally but average considerably less. Overlying this INTRODUCTION 5 silty unit, at least in part unconformably, is a pre- dominantly marine sequence of Pleistocene age that is composed of unconsolidated, locally pebbly to cobbly, coarse to medium sand. This unit is characterized by relatively shallow dips of up to no more than 12°. A variety of upper Pleistocene and younger terrestrial deposits unconformably overlies all of these units. These younger deposits consist chiefly of unconsolidated to well indurated, very poorly sorted silts, sands, and gravels. Deformation in the Baldwin Hills area may have begun during middle Miocene time (Reed and Hollister, 1936, p. 131; Yerkes and others, 1965, p. A48) or even earlier. It has continued at least intermittently through Quaternary time, as indicated especially by prominent fault scarps across the conspicuously arched upper Pleistocene units and the youthful dissection of the hills. The hills resemble a gently arched, north-northwest- trending dome that has been bisected and offset along the line of the Inglewood fault (frontispiece). The summit of the eastern dome or block is about 2,500 feet south-southwest of bench-mark Hollywood E—11 (fron- tispiece); a broad, wedge-shaped area lying largely within 5 or 10 feet of the summit elevation extends for about 3,000 feet north and northwest from this highest point. This broad topographic apex is roughly coincident with the structural crest defined by several well- developed stratigraphic horizons of Pleistocene age. The structural crest that is defined by the upper Pliocene stratigraphic horizons is shown in figures 3 and 4; it lies about 5,000 feet south of the Pleistocene crest, and from 3,000 to 5,500 feet south of the physiographic summit area. Similar relations are shown in the western block as well. Hence, we infer that the fold crest may have migrated northward during a late Tertiary—early Quaternary interval. The pattern of faults and joints developed at the surface (pl. 2) differs in detail from that inferred for the subsurface (figs. 3 and 4). The only difference between the two subsurface interpretations occurs in the southeastern part of the area where subsurface data from recently developed parts of the Inglewood oil field may have aided in the California Division of Oil and Gas interpretation (fig. 4). Significant differences exist, however, between the subsurface interpretations of both Driver (fig. 3) and the Division of Oil and Gas (fig. 4), and the fault pattern mapped at the surface (pl. 2). For example, the Inglewood fault is shown in the subsurface (figs. 3 and 4) as a relatively straight, throughgoing feature, whereas surface mapping (pl. 2) indicates a good deal of structural complexity in the vicinity of the La Brea Avenue—Stocker Street—Overhill Drive intersection. Other discrepancies may be only apparent and may be due simply to inclination of fault surfaces or generalization of the structure at depth. Displacements of thousands of feet have occurred along the major north-northwest-trending faults in the Baldwin Hills area, whereas displacements on many of the shorter, north to north-northeast-trending sub- sidiary faults may have been no more than a few feet. Major lateral displacements have been postulated along both the Inglewood fault (Driver, 1943, p. 308) and the Newport-Inglewood fault zone (Hill, 1954, p. 10). Driver has observed that the attitudes of striae in many drill cores indicate a larger component of horizontal than vertical movement, and Hill has deduced right-lateral movement of several miles along the Newport- Inglewood zone on the basis of electric log correlations. Right-lateral displacement along the Inglewood fault of at least 3,000—4,000 feet since middle or late Pliocene time is indicated by the apparent offset of the structural crests on both the top of the “Gyroidina” zone (fig. 3) and the nearly stratigraphically equivalent horizon con- toured in figure 4. Right-lateral displacement of 1,500—2,000 feet during Quaternary time is suggested by the apparent topographic offset of the hills along the Inglewood fault (frontispiece). In spite of the fairly abundant evidence of lateral displacements on the Inglewood fault during the geologic past, positive indications of very recent lateral movements have not yet been adduced. Moreover, relatively recent vertical separations of up to at least 200 feet, indicated both by offsets of Pleistocene deposits (Castle, 1960) and the well-developed scarp along the Inglewood fault (frontispiece), imply a possible change in the sense of movement during latest Quaternary time. Right-lateral displacements of 100—150 feet are suggested, however, by offset stream channels along the trace of the Inglewood fault, about 1 mile south of the north edge of the hills. Because the offset stream channels are well incised within the fault scarp, it is likely that right-lateral movements have postdated or accompanied the scarp-forming displacements (whether predominantly dip slip or not). The only other information bearing on the sense of recent movement along the Newport-Inglewood zone derives from exami— nation of seismograms produced by the Dominguez Hills earthquake of 1944 (Martner, 1948). According to Martner (1948, p. 118), “study of the compressions and dilatations of first motion at the various stations* * * is in perfect agreement with the general movement of the region, namely, a differential movement in a northwest direction on the west side and southeast on the east side of the main Inglewood fault zone.” Thus, although the data are inconclusive, it is likely that the style of movement along the Newport-Inglewood zone has remained essentially right lateral. 6 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 1 18°22’30” 34°00’ — SLAUSON AVE val 100 feet W— Fault g ___________ 53‘ Oil-field production boundary (Division of Oil and Gas) RODEO RD _ __ ._ _ EXPLANATION 1000 Structure contour Drawn on top of “Gyroidina” zone. Contours given in feet below sea level; contour inter. Oil-field production boundary (Department of Water Resources) Vickers zone production boundary 1000 0 1000 2000 FEET 250 0 250 500 M ETR ES 4?; Hollywood E—11 ‘ FIGURE 3,—Structure contour map on top of the ”Gyroidina” zone of the Inglewood oil field (Driver, 1943, p. 307). Oil-field production boundaries after California Division of Oil and Gas (1961, p. 576) and SEISMICITY Although the relation between seismicity and geologic structure in the area of the Los Angeles basin seems to be poorly developed (Allen and others, 1965, p. 769—772, pl. 1), there exists at least one exception to this generalization. Thus, the association between the Newport-Inglewood zone and the seismicity within the Los Angeles basin for the period January 1, 1934— March 31, 1963 is fairly clearly defined, particularly California Department of Water Resources (1964, pl. 8); Vickers zone production boundary after California Department of Water Resources (1964, pl. 16). along the southern projection of this zone (pl. 3). Furthermore, of the four largest earthquakes known to have originated in this area prior to 1934 (that is, the 1769 “Olive,” the 1812 San Juan Capistrano, the 1920 Inglewood, and the 1933 Long Beach shocks), all but perhaps the “Olive” probably were generated along the Newport—Inglewood zone (Richter, 1958, p. 67, 466, 469, and 472). Hence, the epicenters shown on plate 3, coupled with the distribution of the pre-1934 major earthquakes, identify a band of seismicity that coin- INTRODUCTION 7 1 18°22’30” | EXPLANATION — 1000— Structure contour g Drawn on surface 50 feet above top of the q Vickers-Machado zone. Contours given in m feet below sea level; contour interval 100 RODEO RD fee’ LVD *t B 53 Fault Q 5’ 1000 o 1000 2000 FEET 250 0 250 500 METRES 34°00’ — SLAUSON AVE 7 q?’ FIGURE 4.—Structure contour map on surface 50 feet above the Vickers-Machado zone of the Inglewood oil field (California Division of Oil and Gas, 1961, p. 576). (Note: Several obvious errors occur near the crest of the structure where contours are either miss- cides roughly with the Newport-Inglewood zone and attests to continuing tectonic activity along this zone. The Inglewood earthquake of June 21, 1920, probably was the largest earthquake to have originated in the Baldwin Hills area during historic time. Field investi- gation by Taber (1920, p. 133) indicated that this shock had an intensity of about “eight and one-half on the Rossi-Forel scale,” and its magnitude has been esti- mated by C. F. Richter (written commun., 1966) at M ing or numbered incorrectly or where a fault has been represented improperly. No attempt has been made to investigate the source of these errors since they do not affect the general presentation.) 5—51/2. The epicenter was located in the Inglewood area (Taber, 1920, p. 137), and the shock has been attributed to movement on a major fault within the Newport- Inglewood zone, about 1 mile east of the center of Inglewood (Kew, 1923, p. 158). Richter (1958, p. 67, 474), on the other hand, has attributed the earthquake simply to movement on the "Inglewood fault,” or what we identify here as the N ewport-Inglewood zone. Taber (1920, p. 137) discovered no evidence of surficial fault 118°30’ SANTA MONICA MOUNTAINS 34°oo' PACIFIC OCEAN EXPLANATION LLLLLLLLI +001 .LLLL .I.u.L Isobase line Showing average annual elevation change, in feet. Contour interval 0.01 foot per year. Dashed where approximately located. H achured on low side where low side is de- terminable O 2 MILES 1 0 1 2K|LOMETRES RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 22’30” 118°15’ HOLLYWOOD BLVD Center I Baldwin Hills IMPERIAL FIGURE 5.—-Average annual rates of elevation change of parts of the Los Angeles basin with respect to BM 37—54—26; based on data collected between 1925 and 1938. Modified after Grant and Sheppard (1939). Box shows area of plates 2 and 4. displacements, nor are there any other reports of surface cracks, mole tracks, or similar ground effects developed during this earthquake. Thus, the most important tectonic event associated with the northern part of the Newport-Inglewood zone during historic time apparently was unaccompanied by surficial fault- ing or other ground effects that might have simulated faulting. REGIONAL ELEVATION CHANGES The historic pattern of vertical movements over large sections of the Los Angeles basin has been described by several writers.1 Grant and Sheppard (1939), working ‘The measured elevation changes considered in this paper derive from levelings employing conventional instruments and techniques, All the level lines are assumed to have been surveyed with equal precision We have made no attempt to evaluate the accuracy of the actual field measurements, despite the fact that the quality of both instrumentation and with very limited data, defined three areas of relative subsidence and one of relative uplift (fig. 5). The average annual elevation changes contoured in figure 5 were calculated with respect to bench mark 37—54-26 (S—32 equivalent—see prefatory note, appendix C), located at the old Los Angeles County Court House. However, the periods of time on which these calculations are based ranged from about 4 to about 12 years. Accordingly, comparisons from point to point within the map area are significant only to the extent that the average rates of vertical movement remained constant over the total period of observation. Although Grant and Sheppard were able to delineate broad areas of subsidence both surveying practices doubtlessly varied. This approach assumes that an unbiased selection of level surveys should produce neither positive nor negative measurement bias. This assumption of equal precision among the separate surveys does not necessarily extend to the applied adjustments or to particular elevation determinations. INTRODUCTION 9 118°30’ MONICA MOUNTAINS 34°00’ PACIFIC OCEAN EXPLANATION J_LI_|_LLLI_L+0.01J_L|_LLLLL Isobase line Showing average annual elevation change, in feet. Contour interval 0.01 foot per year. Dashed where ap- proximately located. Hachured on low side 2 MILES 1 0 1 2 KILOMETFIES 22’"30 118°15’ HOLLYWOOD BL VD .1 m A Center IMPERIAL FIGURE 6.—Average annual rates of elevation change of parts of the Los Angeles basin with respect to Los Angeles (City) Bureau of Engineering datum, between 1949 and 1955. Compiled by the writers from record elevations given in the precise bench mark index of the Los Angeles Bureau of Engineering. Box shows area of plates 2 and 4. north and east of the Baldwin Hills (fig. 5), the part of the basin just northeast of the hills did not appear to be subsiding. The only (relatively) positive movement noted by Grant and Sheppard was detected along the east-west Manchester Avenue line, immediately south of the Baldwin Hills (fig. 5). Because the axis of this positive movement was crossed by only one level line, its trend could not be specified; any extension north of Manchester Avenue, however, would have to be generally north-northeastward or northwestward. Stone (1961, p. 58) has evaluated the elevation changes deduced from repeated surveys “for more than 9,000 stations leveled over the past 25 years by the Los Angeles City Engineer”; however, neither the datum(s) to which these elevation changes were referred nor the time intervals over which they were observed has been specified. He concluded that in general the areas “within late Quaternary sedimentary basins are subsid- ing, while some foothill stations are rising” and that “even minor features oflocal geology affect the rates of movement.” We have calculated elevation changes along selected level lines of the Los Angeles Bureau of Engineering for the period 1949—55 (fig. 6) in order to: (1) examine the later history of movement along several of the lines employed by Grant and Sheppard, and (2) bracket the Baldwin Hills with level surveys that fix the geographic limits of the unusually rapid elevation changes de- veloped there in recent years. The elevation changes shown in Figure 6 and those calculated by Grant and Sheppard were both derived from adjusted record elevations; they differ, perhaps significantly, in that the 10 1949 and 1955 record elevations of the Los Angeles Bureau of Engineering have been adjusted with respect to two or more datum control points, whereas earlier elevations derived by the Los Angeles Bureau of Engineering in this area were adjusted with respect to a single control point (Los Angeles Bureau of Engineer- ing, Precise Bench Mark Index, p. 4, 20). Because the elevations of the control points themselves may have been changing with respect to each other (changes currently believed to be small—see prefatory note, appendix C), subtle differences can be expected in the apparent patterns of vertical movement shown in figures 5 and 6. Differences in adjustment procedure during the separate survey periods may explain in part, for example, the apparent occurrence of regionally developed subsidence along Manchester Avenue be- tween 1949 and 1955, as contrasted with the gentle uplift developed along this same reach prior to 1939 (compare figs. 5 and 6). Although detailed point-to-point comparisons of the results of these two comparative elevation studies (figs. 5 and 6) would be futile, a few general observations can be made: (1) the prominent subsidence along La Cienega Boulevard south of the Santa Monica Moun- tains seemingly has persisted through the two survey periods, even though the area of subsidence has certainly contracted and changed in its general config- uration. (2) Elevation changes along Venice Boulevard have remained small through both survey periods. (3) Although generally subsiding since 1949 with respect to the Los Angeles Bureau of Engineering datum, Man- chester Avenue has remained free of significant differential subsidence, yet no longer shows evidence of local uplift. (4) The nose or axis of relative uplift that extends southeast from Pico Boulevard toward the Baldwin Hills (fig. 6) may have developed since the first survey period or been unrecognized earlier owing to inadequate data. The causes of the apparent elevation changes represented in figures 5 and 6 are not understood in detail; these movements are characterized, however, by several revealing associations. (1) When taken to- gether, the positive movement along Manchester Avenue (fig. 5) and the nose of uplift extending southeast from Pico Boulevard (fig. 6) define a north- northwest-trending axis of relative uplift that roughly parallels the Newport-Inglewood zone (fig. 1). Along its southern extension, however, this axis of vertical movement is,displaced 1-2 miles west of the Newport- Inglewood zone. (2) The conspicuous subsidence along the coast, between Venice Boulevard and Manchester Avenue (fig. 5), centers on the main producing area'of the Playa del Rey oil field; this area probably is not associated with significant reductions in ground-water RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA levels or tectonic downwarping (Grant and Sheppard, 1939, p. 313—319; California Department of Water Resources, 1962, pls. 11A—1IC). Grant and Sheppard (1939, p. 319) conclude, accordingly, “that the subsid- ence in the Venice—Playa del Rey area is a local movement due to the development of the oil field.” (3) The area of extensive subsidence east of Western Avenue (fig. 5) lies toward the north end of the flat, featureless Los Angeles plain. Thus the axis of this subsiding area coincides, in a general way, with the structural axis of the basin and the area of most intensive recent alluviation. These considerations suggested to Grant and Sheppard (1939, p. 323—324) that this subsidence might be due to differential compaction of the recent sediments, coupled with some structural downwarp. (4) The subsidence field centering on La Cienega Boulevard, immediately south of the Santa Monica Mountains, is not clearly associated with any single phenomenon. The east-central salient of this subsiding area coincides in part with the old Salt Lake oil field (fig. 7), but the most pronounced subsidence (along La Cienega Boulevard) lies about 2,000 feet north of the nearest oil well in the northwest corner of the field (Grant and Sheppard, 1939, p. 307). Nearly the entire subsidence domaln, however, is one in which there may have been major changes in the ground- water regime during the period immediately preceding the levelings from which figure 5 was constructed (Grant and Sheppard, 1939, p. 310) and is one which has since been characterized by large reductions in meas- ured ground-water levels (California Department of Water Resources, 1962, pls. 11A—llC). However, there seems to be little correlation between the area of greatest subsidence and those of either maximum water-level declines—at least within the shallow aquifers (California Department of Water Resources, 1962, pl. 11A, llC)—or maximum aquifer thickness (California Department of Water Resources, 1961, pl. 3A, 6G). Thus, in spite of the suggestive associations, fluid extraction seems to be an incomplete explanation for the La Cienega subsidence. Grant and Sheppard (1939, p. 311—312) suggest that tectonic forces may have contributed to the origin of this feature, a suggestion strengthened by more recent information. The gener- ally south-sloping buried erosion surface that underlies the surficial deposits of this area, has been folded into an east-northeast-trending syncline that coincides roughly with the northern and most conspicuously developed part of the subsiding area (fig. 7). Hence this syncline, which is bounded on the north by the frontal fault of the Santa Monica Mountains and on the south by the structural high of the Salt Lake oil field, is apparently attributable to relatively recent downwarping between the structures underlying its fianks. INTRODUCTION 1 18°22'30” 11 \\\\\\\\\\\\\\T 34°05’ ' " I Ill/ill 1 0 1 l—“HT—H'r‘I—‘r—l—i——' 1 0 1 l EXPLANATION SANTA MONICA MOUNTAINS + err- ’: _l- — _ Anticline /’ (r / \ Showing crestline 2 MILES 2 KILOMETRES SANTA MONICA BLVD + ._ _ _ Anticlinal bend Showing trace and plunge of axis Syncline Showing troughline —- —1oo — Contour on base of fresh- water-bearing deposits Depths in feet below mean sea level I—L—l—l—L—OIOZALJ—LL Isobase line Showing. average annual elevation change, in feet. Contour interval 0.01 foot per year. Dashed where ap- proximately located. Hachured on low side WESTERN AVE Oil field FIGURE 7.—Contours on the base of freshwater-bearing deposits (California Department ofWater Resources, 1961, pl. 24A and 24B) and average annual rates of elevation change between 1925 and 1938 in the La Cienega Boulevard area of Los Angeles. (See fig. 5.) ELEVATION CHANGES ALONG CONTROL LINES THROUGH THE BALDWIN HILLS AND ENVIRONS During 1939 and 1943 a series of level lines were established or releveled in the Baldwin Hills area by the Los Angeles Department of Water and Power (Hayes, 1943, p. 1—2, 4, 7—8). The locations of the three longest of these lines are shown in figure 8; a detailed history of each of the three is given in appendix A. Elevation changes along lines A, B, and C (fig. 8) can be related to those elsewhere in the northwestern Los Angeles basin in several ways, but they are related most simply and directly through a US. Coast and Geodetic Survey monument located at the intersection of Crenshaw Boulevard with the Atchison, Topeka, and Santa Fe Railway. According to Hayes (1943, p. 5) the Los Angeles Bureau of Engineering "had not detected any appreciable elevation change [at the Crenshaw Axis of syncline adjacent to Santa Monica Mountains from Califor- nia Department of Water Resources (1962, pl. 3A). Locations of oil fields from California Division of Oil and Gas (1961, p. 652) and Crowder (1961, pl. 3). ‘ Boulevard—AT&SF intersection] between the years 1933 and 1936,” an observation that accords with the pre-1939 elevation changes shown in figure 5. Because the elevations derived by the Los Angeles Bureau of Engineering for the southern area between 1933 and 1949 were adjusted with respect to the single datum control point at the Civic Center (Los Angeles Bureau of Engineering, Precise Bench Mark Index, p. 20), and because the Crenshaw Boulevard—AT&SF bench mark has remained demonstrably stable with respect to the Civic Center datum control point—at least between the years 1933 and 1936—it follows that elevation changes derived through comparisons with the Crenshaw Boulevard—AT&SF bench mark may be compared directly with those derived from the Civic Center datum control point (that is, those shown in fig. 5). The 1949—55 elevation changes represented in figure 6 are less easily 12 RECENT SURFACE MOVEMENTS IN THE BALDWIN 1 18°22’30" HILLS, LOS ANGELES COUNTY, CALIFORNIA EXPLANATION Level route A Level route B Level route C \OH‘W'H, : "1 uumn, A u, . P . lemme“ deposits .u" "mum,” 9 Hollywood E—11 (PBM 40) 3/0 PBM 31 2 m m > . (Baldwnn Aux A 34°00 ’ — SLAUSON AVE SEPUL V50 A BL VD El 3 p (”gun/mm” 6/02; , 1] ‘ BM St Ma 555 W '- 63d ST ' ”New 0 PBM 3 J BM 2 E g 67th 840,98 ,. _ ‘ BRE IMARKET g $ 7 <4 AVE - é PB 1 9‘9 /v" “ CRENSHAW BLVD v\ < MANCHESTER AVE 100001 000 2000 FEET 250 0 250 500 METRES FIGURE 8.—Approximate routes of level lines A, B, and C. After Hayes (1943, fig. 1). compared with those along the Department of Water and Power control lines for two reasons: (1) the record elevations used in the construction of figure 6 were derived with respect to two or more control points (Los Angeles Bureau of Engineering, Precise Bench Mark Index, p. 20); and (2) they were determined for a period in time (1949—55) relatively remote from the 1933—36 interval of demonstrable stability at the Crenshaw Boulevard—AT&SF intersection. Level lines A and B (figs. 8, 9, and 10) are tied directly to the Crenshaw Boulevard—AT&SF bench mark; elevation changes along these lines can be compared diredtly with those derived from the Civic Center control point. Changes along line C (figs. 8 and 11), on INTRODUCTION 13 Railway and Manchester Ave. ' E End of circuit Atchlson, Topeka, and Santa Fe + _o m AT&SF and Inglewood Ave. AT&SF and Commercial St.(?) AT&SF and Centinela Ave. AT&SF and Crenshaw Blvd. I m Beginning of crrcufl 'u' 2 m x E «1 0. 3 >. I '0 i: m u. (D E < AT&SF and Florence Ave. AT&SF and West Blvd. + .0 DWP—October 1943 ‘ usc and 68—1935 \/ E . LI. 3 LII o _ z E o z o.o\/\/\ 9 :7: > I.“ _l I.“ l 9 _. 2000 O 2000 4000 FEET 500 0 500 1000 METRES APPROXIMATE SCALE FIGURE 9.—Changes in elevation along level line A between 1935 and 1943. Based on leveling of the US. Coast and Geodetic Survey and the Department of Water and Power (formerly the Bureau of Water Works and Supply), City of Los Angeles. After Hayes (1943, fig. 2). the other hand, can be compared with those determined PBM 58—see appendix C, PBM 40, II.). by the Los Angeles Bureau of Engineering elsewhere in Several generalizations can be made concerning the the Los Angeles basin only through the medium of PBM elevation changes recorded along level lines A, B, and C. 1 and level line B (or, alternatively, though less simply, Lines A and B (figs. 9 and 10) both show uplift with Centinela Ave. and Sepulveda Blvd. Centinela Ave. and Redondo Blvd. (Florence Ave.) 'E Centinela Ave. and Florence Ave. Centinela Ave and Short St Centinela Ave. and Market St. ,m Crenshaw Blvd. and 67th St. +0.2 +0.1 - — DWP—October 1943 Bureau Engineering—September 1933 .0 o l .0 _. ELEVATION CHANGE, IN FEET 2000 0 2000 4000 FEET 500 0 500 1000 METRES APPROXIMATE SCALE FIGURE 10.-Changes in elevation along level line B between 1933 and 1943. 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Line B shows a seemingly smoother pattern of elevation changes, but the more erratic pattern of elevation changes along line A may reflect either the greater number of stations recorded along this route or its location along the possibly less stable right-of-way of the railway. When taken together, the points of maximum relative uplift along level lines A and B define an essentially north-south line between a point approximately 3,000 feet east-northeast of the Man- chester Avenue—AT&SF intersection and a second point approximately 1,000 feet east of the La Tijera Boulevard—Centinela Avenue intersection. Level line C (fig. 11) has been characterized since 1939 by a general pattern of moderate uplift (with respect to PBM 1) over its northern half and by pronounced subsidence over most of the remainder. The north end of line C (at least since 1946—see appendix A, III.) is identified with down-to-the-south tilting about an axis lying roughly midway between Washington and Adams Boulevards. The southern boundary of this tilted block is marked by a sharp break in the profile of elevation changes, PBM 53 having subsided about 0.07 foot more than PBM 51, which lies several hundred feet to the south. This break coincides with a small differential subsidence trough between Adams Boulevard and Bangor Street. The other narrow subsidence troughs shown in profile C (fig. 11), particularly within the reach of major subsidence between PBM 10 and PBM 43, probably derive from local backward legs in the line of leveling (bench marks PBM 29, PBM 30, and PBM 31, for example, are geographically inverted from their positions as rep- resented in fig. ll—Walley, 1963, fig. 1). Since 1946 there has been an increasing loss of survey stations, such that later relevelings suggest a progressively, smoother pattern of elevation changes. The elevation changes represented in figures 9, 10, and 11, show several associations comparable with those shown in figures 5 and 6. (1) The essentially north-south line defined by the point of maximum uplift along level lines A and B (figs. 9 and 10) is subparallel to FIGURE 11,—Changes in elevation along level line C between 1939 and 1962. Line C was not releveled during the 1962 leveling owing to the destruction of many of the original bench marks; elevation changes at remaining points formerly included with level circuit C and now shown by the Department of Water and Power with level line E are indicated by the circled dots of the 1962 survey. PBM numbers refer to precise bench-mark numbers assigned by the Department of Water and Power. Modified after Hayes (1959, fig. 2) and Walley (1963, fig. 2—A). 15 and about 1 mile west of the physiographic and structural axis of the Newport-Inglewood zone. (2) The south endof line C (PBM 1), which has been uplifted moderately with respect to the Crenshaw Boulevard— AT&SF bench mark (fig. 8), lies almost directly over the center of the Newport-Inglewood zone. (3) The uplifted end of the apparently southward tilted block along line C lies somewhat above the general level of the nearby basin, along a roughly east-west trending ridge of dissected Pleistocene fan or terrace deposits. An aeromagnetic profile trending about N. 50° E across this ridge (Schoellhamer and Woodford, 1951) shows a sharp break about 1 mile southeast of PBM 58, coinciding roughly with the scarp along the southern margin of the dissected Pleistocene deposits and suggesting relatively elevated basement rock on the north. A simple Bouguer gravity map (McCulloh, 1957) tends to corroborate the aeromagnetic data; it shows a gradient steepening upward toward the north beyond a line that approxi- mates the southern margin of the dissected Pleistocene deposits. Furthermore, a well drilled in 1960 about one mile east of PBM 58, bottomed in “slate” at the surprisingly shallow depth of 5,506 feet (Popenoe, 1960, p. 913). (4) The zone of prominent subsidence along level line C coincides both with the east edge of the Inglewood oil field (fig. 3) and the most elevated part ofthe Baldwin Hllls' ELEVATION CHANGES Elevation measurements in the northern Baldwin Hills date from the end of the nineteenth century (US. Geological Survey 15-minute topographic maps of the Redondo, 1896, and Santa Monica, 1902, quadrangles). These early elevation determinations are of limited value, however, for they were derived through rela- tively inaccurate vertical-angle measurements. Although a number of level surveys have since been run through the Baldwin Hills, most of these have employed separate datums, thereby precluding direct comparisons among the individual surveys; that is, there is no prima facie basis for assuming that a particular datum control point will remain unchanged in elevation with respect to a second control point. Thus, much of our effort has been directed toward the reduction of pertinent level data to a common datum. Bench mark S—32 (located in the Los Angeles Civic Center area; see prefatory note, appendix C), together with its resets or nearby derivatives, has been adopted as a primary datum control point because it has proved to be the most convenient (and perhaps the only) control point permitting comparisons among many of the level surveys through the northern Baldwin Hills. However, 16 because the vertical movements recognized in the Baldwin Hills are, in any ultimate sense, relative movements, it is not only sufficient but highly desir— able that the measured movements be described with re— spect to a local control point bordering or immediately external to the described system—in this case, the differential subsidence centering in the northern Baldwin Hills. This control point, in turn, need only have been characterized by a history of relative stability with respect to the framework immediately adjoining the identified system. Attempts to relate the measured vertical movements to “absolute” datums (see, for example, Leps, 1972; Casagrande and others, 1972), such as distant bench marks referred to 1929 Mean Sea Level, are generally no more than exercises in futility. Such attempts compound the imperfections in the method (by increasing unnecessarily the level—line length and enhancing the likelihood of large time gaps at junction points) and obscure the existence of significant intrasystem relative movements (through the inclusion of movements properly assigned to the system of next highest order—in this case, either the Newport-Inglewood zone or the Los Angeles basin). The elevations of two secondary control points have been used as local datums; vertical movement at these control points with respect to S—32 is determinable through repeated levelings of the Los Angeles Bureau of Engineering and the Los Angeles Department of Water and Power. These secondary control points are: (1) PBM 58 (also designated as 10—W and 12—01050 by the Los Angeles Bureau of Engineering), located at the inter- section of Washington Boulevard and Vineyard Avenue in Los Angeles (fig. 8); and (2) Hollywood E—11 (also designated as PBM 40 by the Los Angeles Department of Water and Power), together with its several resets, located near the north edge of the Baldwin Hills (fig. 8). PBM 58 has served as the northern terminus for level line C, which has been used by the Department of Water and Power since 1939 as a basic elevation control line. It has remained relatively stable through time, having subsided at an average rate of only about 0.00841 ft/yr with respect to S—32 between 1933 and 1960 (see appendix C, Hollywood E—11, II.C.1.). Hollywood E—ll (or one of its resets) has, since 1939, been used as a reference bench mark within the northern Baldwin Hills by the Department of Water and Power (Walley, 1963, p. 2—3). Hollywood E-11 itself was destroyed in 1953; prior to its destruction, however, PBM 40—C was established nearby and “designated as a fixed elevation bench mark for relative studies in this area, as PBM N0. 40 likewise had earlier been so designated” (Walley, 1963, p. 3). Because Hollywood E—11(PBM 40) and PBM 40—C are separated by only about 33.5 feet (Hayes, 1955, p. 4), they are assumed to have remained unchanged in RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA elevation with respect to each other, and Hollywood E—11 has been retained here as a secondary control point even though it was abandoned as a reference bench mark by the Department of. Water and Power, beginning with their 1963 report (Hayes, 1959, fig. 1, and Walley, 1963, fig. 1). Accordingly, elevations derived with respect to PBM 40—C are considered identical with those derived with respect to Hollywood E—11. Although Hollywood E~11 occurs along the edge of an area of intense subsidence (fig. 11), it has sustained little elevation change with respect to reference bench marks outside this differentially subsiding system. Thus between 1939 and 1962 it subsided at an average rate of 0.01098 ft/yr with respect to PBM 58 (appendix C, Hollywood E—11, II.D.2.). Moreover, between 1946 and 1962 it subsided at an average rate of only 0.00794 ft/yr with respect to PBM 58 (appendix C, Hollywood E—11, II.D.2.); this lesser rate obtained, accordingly, during a period in which expanded elevation studies were undertaken in the northern Baldwin Hills and following a period during which adjustments of ob- served elevations may have produced incorrect deter- minations of elevation changes along line C (see appendix A, 111.). Furthermore, because PBM 58 has been subsiding at about 0.00841 ft/yr with respect to S—32 (appendix C, Hollywood E—l 1, II.C.1.), Hollywood E—11 has apparently been subsiding at about 0.00841 ft/yr + 0.01098 ft/yr = 0.01939 ft/yr with respect to S—32. The relative stability of Hollywood E—11 is even more significantly demonstrated, however, through comparisons with control points located immediately adjacent to, but clearly beyond the differentially subsiding area identified in figure 11. Between 1939 and 1962 Hollywood E—11 subsided at an average rate of 0.00260 ft/yr with respect to PBM 1 (fig. 11), about 2/3 mile south of the south edge of the differential subsidence bowl; between 1946 and 1962, moreover, Hollywood E—11 subsided at an average rate of only about 0.00169 ft/yr with respect to PBM 1 (fig. 11). Subsidence at Hollywood E—11 with respect to PBM 43, the nearest regularly observed bench mark clearly outside the identified differential subsidence system, averaged about 0.00763 ft/yr between 1939 and 1958 (fig. 11); between 1946 and 1958 subsidence at Hollywood E—11 with respect to PBM 43 averaged about 0.0043 ft/yr (fig. 11). These observations indicate, accordingly, that Hollywood E—11 is certainly an appropriate reference for the description of such vertical movements as have occurred within the limits of the differential subsidence system centering in the north- ern Baldwin Hills. SUBSIDENCE AT PBM 67 AND PBM 68 The earliest level surveys through the northern ELEVATION CHANGES Baldwin Hills apparently were run in 1910 by the Los Angeles Investment Company. These surveys estab- lished the elevations of a large group of Baldwin Hills bench marks, several of which were still in existence at the end of 1963. Derivations of the 1910 elevations of two of these recoverable bench marks, “DD” (or PBM 68) and “HH” (actually its nearby derivative, PBM 67), through the use of the Los Angeles Investment Company elevation control surveys, are given in appendix F; their locations are shown in figure 8. Although these early elevations are actually calculated here (appendix F) with respect to the City of Inglewood datum rather than any of the three control points described above, it can be shown that leveling emanat- ing from either 8—32 or the City of Inglewood datum should produce nearly equivalent elevations (see appendix F, prefatory note). Subsidence at PBM 67 with respect to Hollywood E—ll is calculated to have been 4.324 feet during the period 1910—63 (see appendix G). Subsidence at PBM 67 since 1946 is based on a direct comparison with Hollywood E—ll; subsidence between 1910 and 1946, on the other hand, is based on a presumption of stability between 8—32 and the City of Inglewood datum, a - calculated 1910 elevation of Hollywood E—l 1, and the acceptance of a 1910 stake elevation adjacent to HH as roughly 0.20 foot less than that of monument HH (see appendix F, PBM 67). In spite of the crude nature of this determination, it is likely that the calculation given in appendix G is a good approximation of subsidence at PBM 67 since 1910 (see appendix H, I.E.). In 1911 the Department of Water and Power ran an elevation control survey into the Baldwin Hills in connection with the proposed establishment of a reservoir in this area (Hayes, 1943, p. 15); this leveling included concrete monument DD, subsequently desig- nated as PBM 68 by the Department of Water and Power (see appendix B). PBM 68 (fig. 8) is particularly significant here, for it is the only bench mark in the northern Baldwin Hills whose elevation was measured (with respect to an external control point) before 1926 that has been remeasured from time to time since? The November 1911 elevation of PBM 68, as derived through use of the Department of Water and Power control surveys in this area and with respect to both “According to the California Department of Water Resources (1964, pl. 15), elevation changes since 1917 are also determinable at four additional bench marks in the Baldwin Hills area. This representation, however, is misleading. One of the four “bench marks” is simply the low point in a topographic saddle; a bench mark as such was never established in this saddle and the 1917 elevation ofthis point is ofdoubtful validity and utility (see appendix H, I.A.). Furthermore, no elevations were recorded for any of the three additional bench marks (or any nearby derivatives) before 1926; thus there exists no means ofdetermining elevation changes at the respective bench marks between 1917 and the dates of earliest elevation measurement on these points. This conclusion is actually supported by a statement in the text of the report (California Department of Water Resources, 1964, p. 40) where it is noted “that the subsidence at the center ofthe [subsidence] bowl [in the northern Baldwin Hills] may have started any time before 1926.” 17 8—32 and Hollywood E—ll as fixed in elevation since 1911, is determined to have been 319.568 feet (see appendix C). This figure accords reasonably well with the 1910 elevation of PBM 68 of 319.778 feet derived through the medium of the Los Angeles Investment Company leveling in the northern Baldwin Hills (see appendix F). Although PBM 68 was releveled in 1917 in connection with surveys that originated locally (see appendix C, PBM 68, I.), there were no elevation measurements made on this bench mark between 1911 and 1943 that could be tied to external control points. Since 1943, however, elevation measurements of PBM 68 with respect to Hollywood E—11 have been repeated more or less quadrennially by the Department of Water and Power (see appendix D). Differential subsidence at PBM 68 since 1917 and '1911, respectively, is calculated in appendices D and E and illustrated in figures 12 and 13. Figure 12A shows subsidence at PBM 68 since 1917 as determined by the Department of Water and Power (see appendix D, 1.). It was assumed in the construction of this graph: (1) that the 1917 elevation of PBM 68 derived through comparison with the elevation of a nearby topographic saddle is identical with that derivable through comparison with Hollywood E—11 as fixed in elevation in 1939 (see appendix D, I.); and (2) that this topographic saddle remained unchanged in elevation between 1911 and 1917 (see appendix C, PBM 68, I.). Figure 128 shows subsidence at PBM 68 since 1911 with respect to Hollywood E—11 as fixed in elevation since 1939 (see appendix D, II). This representation assumes that the 1939 elevation of Hollywood E—ll is the same as that that would have been derived from the control point that produced the 1911 elevation of PBM 68, and that this control point remained unchanged in elevation with respect to Hollywood E—l 1 between 1911 and 1939. The 1911 elevation of PBM 68 was in fact, however, derived from a control point far removed from and unrelated here to Hollywood E—ll, the bench mark from which subsequent elevations of PBM 68 have been derived. Figure 120 shows subsidence at PBM 68 since 1911 with respect to Hollywood E—ll as fixed in elevation in 1911 (see appendix D, III.) The November 1911 elevations of both PBM 68 and Hollywood E—l 1, with respect to 8—32, have been derived here (see appendix C) in order to compare directly the change in elevation between the two since 1911, rather than just since 1943, as is implicit in figures 12A and 123. The representation of subsidence at PBM 68 shown in figure 120 is clearly an improvement over that shown in either figure 12A or 123, for it is unnecessary to assume that leveling emanating from separate, unrelated 18 321 IlllllllllllIllllllllllllll A 320 - 319 — _ 318 - _ 317 — _ 316 - _ 315|l|l||||||llll|l||||||l|ll 321lllllllllll’llllllllllllIll 320 — B _ 319 — _ 31s — _ 317 — _ ELEVATION. IN FEET 316 - _ Illllllllllllllllllllllllll 315 321 lllllll|||||||||ll||ll|Ill C _ 320 — 2 319 - 318 — 317 — 316 — 5% l | | I l l 31 1960- éééé YEAR 1912 ~ 1916 — 1920 - 1924 — 1928 - 1932 — control points would produce identical elevations of PBM 68. This graph is also based on a more objective derivation of the 1911 elevation of PBM 68 than that employed in figure 123 (although the two differ by less than 0.14 foot) since: (1) the questionable adjustment procedures utilized in the original 1911 elevation determination of PBM 68 shown in figure 12B have been avoided; and (2) consideration has been given to possible vertical movement of the control point from which the 191 1 Department of Water and Power circuit originated (see appendix C, PBM 68). Calculation of the November 1911 elevation of Hollywood E—11 is based in part on the use of average rates of subsidence at Hollywood E—l 1, with respect to both 8—32 and PBM 58, between the years 1939 and 1962. Because the average change in elevation at Hollywood'E—ll with respect to 8—32 has RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA FIGURE 12.—-Alternative derivations of the subsidence of PBM 68 with respect to Hollywood E—11. A, Since 1917 (Walley, 1963); (see appendix D, 1.). B, Since 1911; assumes that elevation of Hollywood E—11 has remained invariant with respect to control point from which 1911 elevation of PBM 68 was derived (see appendix D, II.). C, Since 1911; based on 1911 elevations of PBM 68 and Hollywood E—11 derived from comparisons with 8—32 (see appendix D, III.). Dashed lines show calculated subsidence at PBM 68 between 1926 and 1943; dotted lines include period during which no externally controlled elevation measurements were made in the northern Baldwin Hills. 1. Probable subsidence between 1926 and 1943 calculated from subsidence at PBM 31 and LA. County BM 4 between 1926 and 1943 and a comparison of subsidence at PBM 68 with that at PBM 31 and the site of LA. County BM 4 between 1943 and 1958; this representation is clearly the best founded of the three paths shown (see appendix D for details). 2. Maximum probable subsidence between 1926 and 1943 calculated from subsidence at PBM 31 and LA. County BM 4 between 1926 and 1943 and a comparison of subsidence at PBM 68 with that at PBM 31 and the site of LA. County BM 4 between 1943 and 1962; based on probably aberrant values for subsidence of PBM 68 versus subsidence of PBM 31 and BM 4 (see appendix D for details). 3. Minimum probable subsidence between 1926 and 1943 calculated from subsidence at LA. County BM M4 and LA. County BM 4 between 1926 and 1943 and a comparison of subsidence at PBM 68 with that at the sites of LA. County BM M4 and LA. County BM 4 between 1950 and 1958; based on probably aberrant measurement of subsidence at BM M4 between 1931 and 1943 (see appendix D for details). been fairly uniform and probably no greater than about —0.02 foot/year (at least between 1939 and 1962), any error implicit in this procedure is considered small and probably in a direction that would maximize the difference between the calculated 1911 elevation and the measured 1939 elevation of Hollywood E—ll (see appendix C, PBM 40). Elevation changes at PBM 68 during the interval 1911—43 (fig. 120—dashed lines) may be calculated through comparisons with measured vertical move- ments at other bench marks within the Baldwin Hills subsidence field (see appendix D, IV-IX). The probable accuracy of these calculated changes may be judged only through comparisons among the rates of subsidence at these various points through time. Thus, as shown in appendix D, the ratios of subsidence at PBM 68 to subsidence at the several other bench marks employed in these calculations have held fairly constant, except during the interval 1958—62; hence, use of the average ratios derived from measurements recorded through 1958 should lead to approximately valid values of subsidence at PBM 68 between 1926 and 1943. Figure 13 shows a recalculation with respect to PBM 58 of the most probable subsidence path of PBM 68 shown in figure 120 (see appendix E). This graph is neither more nor less accurate than the one shown in figure 120; its chief purpose is to show the change in elevation at PBM 68 with respect to a regularly observed control point outside the Baldwin Hills. This representation (fig. 13), accordingly, eliminates the ELEVATION CHANGES 321 IllIlllllllllllllllllllllrl 320- _ 319 - 318 - 317 - ELEVATION, IN FEET 316 - I l I :3 315 "1‘ $5: ii: .3? YEAR FIGURE l3.—Subsidence of PBM 68 with respect to PBM 58 since 1911. Dashed line shows calculated subsidence between 1926 and 1943; dotted line includes period during which no externally controlled elevation measurements were made in the northern Baldwin Hills. Only the most probable calculated path of subsidence is shown here (see appendix E for details). effects of the maximum probable subsidence at Hol- lywood E—11 (with respect to points beyond the area of recognized differential subsidence) on the subsidence path of PBM 68 shown in figure 12C. Subsidence at PBM 68 has been calculated with respect tosecondary control points Hollywood E—l 1 and PBM 58 rather than S—32 for the following reasons: ( 1) Hollywood E—ll has been used since 1939 by the Department of Water and Power as a primary reference bench mark in its detailed studies of vertical move- ments in the northern Baldwin Hills (Walley, 1963, p. 3). (2) Since 1939 Hollywood E—ll and PBM 58 are known to have remained relatively stable with respect to PBM l, which lies well south of the northern Baldwin Hills subsidence field (fig. 11); hence we see no particular advantage in calculating elevation changes at PBM 68 with respect to yet another control point outside the northern Baldwin Hills. (3) The seven Department of Water and Power level surveys run since 1911 that have included PBM 68, have not been tied to S—32 or to any equivalent control point. The available evidence indicates that the elevation of PBM 68 was unaffected by the Inglewood earthquake of 1920. This is suggested especially by the approximate coincidence between the 1911 record elevation of PBM 68 and its 1926 calculated elevation (fig. 13). This apparent coincidence could, conceivably, have resulted from various combinations of uplift and subsidence. Nevertheless, significant uplift of this bench mark at the time of the earthquake seems most unlikely. Had PBM 68 been subsiding since 1911 at a rate equal to that which has obtained since 1926 or 1943, uplift of 1.8 or 2.2 feet should have been required to produce the elevations indicated for 1926 and 1943, respectively (fig. 13). Uplift of this amount seems unusually large to have 19 been associated with an earthquake of magnitude 5—51/2. The maximum measured uplift (with respect to a widely spaced array of bench marks) associated with the Long Beach earthquake of 1933, which was an order of magnitude greater than the Inglewood earthquake of 1920, has been given as 0.610 foot (Gilluly and Grant, 1949, p. 465, 469). (Had PBM 68 been subsiding at rates greater than those that obtained after 1926 or 1943, even greater uplift should have occurred in association with the 1920 earthquake; had it been subsiding at lesser rates, proportionately smaller amounts of uplift could have occurred in 1920, in accordance with the conclusion that little elevation change took place at the time of the earthquake.) Subsidence of PBM 68 at the time of the 1920 earthquake is even more unlikely, for this should require both that no credence be given the calculated 1926 elevation of PBM 68, and that the actual rate of subsidence between 1920 and 1943 was even less than the average rate between 1911 and 1943. The change in the average rate of subsidence after 1943 would then be even more pronounced, and explanations of its origin particularly contrived, for these explana- tions would seemingly demand a spectacular increase in the average rate of subsidence corresponding with the beginning in 1943 of the period of repeated observations on PBM 68. It seems likely, then, that little elevation change at PBM 68 can be associated with the 1920 earthquake. This probability is strongly supported by the apparent stability of the City of Inglewood datum with respect to S—32 between 1910 and 1956 (see appendix F, prefatory note). This relative stability suggests that any elevation changes within the epicentral area of the 1920 earthquake must have been slight. MAXIMUM SUBSIDENCE DURING THE PERIOD 1911—63 The maximum probable subsidence within the Baldwin Hills subsidence field is significant chiefly because it affords an additional basis of comparison with other known areas of differential subsidence. N0 elevation measurements were made at the approximate center of subsidence prior to 1950. However, maximum subsidence with respect to Hollywood E—ll may be calculated by assuming that the point of maximum subsidence is coincident with PBM 122 (fig. 8). Although the site of greatest subsidence, as determined for various intervals, is known to have shifted some- what prior to 1964, PBM 122 probably was always within about 600 feet of this spot. The differential subsidence at PBM 122 between October 1943 and January 1964 is computed to have been about 3.30 feet (see appendix H, II.—VI.). Subsid- ence at PBM 122 between 1911 and 1943 is less firmly founded; it can be calculated in two general ways. The 20 first is through comparison of the subsidence at PBM 122 with that at an identifiable topographic landmark known as “BM saddle,” whose elevation may have been measured in 1911 but is not known to have been tied to PBM 68 until 1917 (see appendix H, I.A.). This proce- dure was adopted by both the US. Geological Survey (1964, p. 12) and the California Department of Water Resources (1964, p. 39) in estimating maximum subsidence between 1917 and 1943. This method produces a calculated value for the subsidence at PBM 122 between 1911 and 1943 of about 4.04 feet (see appendix H, l.A.—I.D.). Adding to this the 3.30 feet of subsidence between 1943 and 1964 leads to a total of 7.34 feet for the entire period November 1911—January 1964. Alternatively, the subsidence at PBM 122 between 1911 and 1943 may be calculated through a direct comparison with that at PBM 68. This compari- son indicates subsidence of 2.37 feet at PBM 122 between 1911 and 1943 (see appendix H, I.E.). Thus, the subsidence at PBM 122 over the entire period November 1911-January 1964 is calculated to have been approxi- mately 5.67 feet. The smaller value (2.37 feet) for the differential subsidence at PBM 122 between 1911 and 1943 is considered the better estimate for several reasons. (1) The first approach requires an assumption of vertical stability between “BM saddle” and PBM 68 (or between some external control point and the bench mark from “which the elevation of “BM saddle” was derived) during the period 1911—17. (2) The second method is based on elevation measurements at an established bench mark rather than on estimated elevation changes at an imprecisely defined “low point” in a topographic saddle. (3) The smaller figure more closely accords with that derived through a comparison of the subsidence at PBM 122 with the subsidence at PBM 67 (see appendix H, I.E.4.). Our best estimate of the 1911—64 subsidence at PBM 122 (5.67 feet) is slightly more than half that (9.7 feet) deduced by the California Department of Water Resources (1964, p. 39—40) for the period 1917—64 and almost exactly half the maximum subsidence (11.6 feet) given by Leps (1972, p. 516—518) for the same period. The California Department of Water Resources esti- mate, however, is based in part on inaccurate data for the measurement interval 1954—58 (see appendix H, I.C.), a 1917—43 subsidence figure derived through the use of unrelated datums (see appendix H, I.), and elevations measured at “BM saddle.” Leps’ estimate, moreover, is based on a questionable comparison between the 1917 elevation of the top of an iron pipe (of unknown length) extending upward from the concrete base of bench mark LAI (fig. 8) and the 1943 elevation of the concrete monument itself (see appendix I, III; Castle RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA and Youd, 1973, p. 93—94). Furthermore, because bench mark LAI was destroyed sometime after 1943, we cannot be certain that it was not disturbed between 1917 and 1943. Leps (1973, p. 100—101), on the basis of “personal surveying experience dating back to 1933,” rejects even the possibility of an exaggerated estimate for the subsidence at LAI based on the record elevations for this bench mark and contends that determination of the subsidence at several nearby bench marks corrob- orates his 11.6-foot estimate. In fact, however, Leps’ (1972, p. 516—518) estimate ofthe subsidence at LAI: (1) is at variance with his own subsidence figures for bench marks DD and HH (Castle and Youd, 1973, p. 93); (2) draws upon an alleged similarity between the physical configuration of bench mark LAI (identified with a 3-inch iron pipe) and that of bench marks DD and HH (identified with 3Ai-inch iron pipes that are indeed characterized by “minimum stickup” of no more than a few inches—Leps, 1973, p. 100); and (3) cannot be confirmed by a procedure that makes use of the disputed 1917—43 LAI subsidence figure of 7.6 feet (or the 1917—64 figure of 11.6 feet) in calculating supposedly supportive cumulative subsidence figures for nearby bench marks (Leps, 1973, p. 101). GENERAL PATTERN OF ELEVATION CHANGES The Los Angeles Department of Water and Power began its systematic studies of vertical movements in the Baldwin Hills in 1939 (Hayes, 1943, p. 1—2); it was not until 1950, however, that the area of coverage had been expanded to an extent that the vertical movements could be described over more than a very small part of the northern Baldwin Hills. Since 1950 the approxi- mately quadrennial level surveys of the Department of Water and Power have been expanded to include progressively larger areas, and the station density has been increased to the point that even very local differences in vertical movement can now be detected in the northern Baldwin Hills. The approximate pattern of average annual elevation changes during the period 1950—54 was the first of the relatively detailed representations of vertical move- ments in the northern Baldwin Hills produced by the Department of Water and Power (pl. 4). The 1950 and 1954 bench mark elevations, from which these average annual elevation changes have been computed, proba- bly were derived through direct comparisons with contemporary elevations along level line C (figs. 8 and 11). Thus levels emanating from line'C presumably were adjusted, if at all, with respect to individual bench-mark field elevations along this line. The pattern of movement between 1950 and 1954 (pl. 4) was generally negative and concentrically disposed about a point roughly 1,000 feet south-southeast of the struc- ELEVATION CHANGES tural crest of the western block of the Inglewood oil field anticline (figs. 3 and 4). A subsidiary center of negative movement lay about 1,500 feet east-southeast of the structural crest of the east block of the Inglewood oil field anticline. The gross isobase pattern developed for the period 1950—54 (pl. 4) is elongated along a northwest trending line essentially coincident with the axis of the Inglewood anticline (figs. 3 and 4). Several sharp fiexures of the isobases occur immediately west of Hollywood E—ll; this area is one of relatively good bench-mark control, as well as one in which several north- to northeast-trending faults have been mapped (pl. 2). The approximate pattern of average annual elevation changes in the northern Baldwin Hills developed by the Department of Water and Power for the period 1954—58 (Hayes, 1959, fig. 1), has been modified here (pl. 4) in order to accommodate an arithmetical error in the calculation of the average annual elevation change at PBM 122. The 1958 bench-mark elevations, like those of 1950 and 1954, apparently were derived from, and probably adjusted with respect to, observed elevations along level line C (Hayes, 1959, p. 10—11); the closures, in any event, were ofa “minor nature” (Hayes, 1959, p. 10). The 1958 surveys, however, were run over a 5-month interval—August 1958 to January 1959 (Hayes, 1959, p. 2)—as contrasted with the 1950 and 1954 levelings which were completed within l-month periods (Hayes, 1955, letter of transmittal). Because any elevation changes that occurred along line C during the 1-m0nth periods in which the 1950 and 1954 surveys were run probably were barely measurable, they are ignored. On the other hand, measurable elevation changes of up to a maximum of about 0.035 foot probably occurred along parts of this elevation control line within the 5-month 1958 survey period (fig. 11). Nevertheless, because the resulting errors in the computed average annual elevation changes arising from the lengthened 1958 survey period almost cer- tainly did not exceed 0.01 foot/year, the annual elevation changes represented in the upper right figure of plate 4 are assumed arbitrarily here to match those that would have been derived if the 1958 circuits had been run entirely within the month of October. The gross pattern of movement indicated for the period 1954—58 is much the same as that for the period 1950—54; however, there seem to be three minor but possibly significant differences in the patterns of movement shown for these two periods. (1) The rate of subsidence near and for some distance away from the center of the subsiding area declined slightly but measurably (roughly 15 percent) during the 1954—58 interval. (2) East-west profiles in the vicinity of the Stocker Street—La Brea Avenue—Overhill Drive inter- 21 section show that the number of isobases per unit of horizontal distance (the isobase gradient) increased sharply in this area after 1954. The narrow trough described by the isobase configuration in this area, moreover, crudely mimics the small "graben” defined by a series of "earth cracks” or contemporary surficial fault displacements that began to develop no later than 1957. The absence of a more precise correlation between the isobase configuration and the earth cracks may be due in part to the timing of the surveys relative to the formation of the earth cracks. (3) A prominent reversal in the sense of movement (with respect to Hollywood E—l 1) within the area east of Stocker Street and Overhill Drive developed sometime between 1954 and 1958 (see southeast corners of upper figures, pl. 4). This area is depicted as subsiding between 1950 and 1954, whereas only that part immediately adjacent to the Stocker Street-Overhill Drive intersection is shown as subsiding during the period 1954—58 (pl. 4). The apparent change in the rate of vertical movement here, of up to +0.06 foot/year, may have accompanied the initial displacements along the earth cracks generated during the latter part of the 1954—58 interval. Hence the maximum positive average annual elevation change of up to 002+ foot/year computed for the entire 1954—58 period was almost certainly no more than one-quarter to one-half that which would have been derived through measurements made within the much narrower 1957— 58 time window. Two interpretations of the elevation changes meas- ured in the vicinity of the Stocker Street—La Brea Avenue—Overhill Drive intersection during the inter- val, 1958—60 (figs. 14 and 15) have been developed from a special series of level surveys run toward the end of 1960 by the Department of Water and Power. These interpretations differ only in the area extending north-northeast from the Stocker Street-La Brea Avenue—Overhill Drive intersection; one (fig. 15) shows a trough defined by more or less parallel contours of negative movement, whereas the other (fig. 14) suggests no such throughgoing trough. Both interpretations, however, differ significantly from that shown for the period 1954—58 (pl. 4). Between 1954 and 1958 the subsidence apparently decreased north-northeastward away from the intersection (pl. 4), whereas during the shorter 1958—60 period it is represented as nearly uniform or actually increasing to the north along a zone crudely defined by the northward projection of cracks I and IV (figs. 14 and 15). The latest of the representations of vertical move- ments in the northern Baldwin Hills prepared by the Department of Water and Power and included with this report, is that for the period 1958—62 (pl. 4). The 1962 benchmark elevations used in calculating the average RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA | _ 118022, A Hollywood E 11 — 34°00' SToCKER sr O EXPLANATION O — —0.05 -' Isobase line Showing average annual elevation change, in feet. Contour interval 0.01 foot per year —e—e—ge——e— Earth crack ' Dashed where approximately located. U, up— thrown side; D, downthrown side 0 Bench mark S $1 a \ I: § § 500 0 500 1000 FEET (wade/7 125 o 125 $50 METRES /_\ r FIGURE 14,—Distribution of earth Cracks in the north-central Baldwin Hills as of 1960, and approximate pattern of average annual elevation changes measured with respect to bench-mark HollywoodE-ll for the period 1958—60. Compiled by the Surveys Section of the Water Engineering Design Division of the Department of Water and Power, City of Los Angeles. ELEVATION CHANGES 118°22’ — 34°00’ SToCKER sr EXPLANATION . — —0.05 — Isobase line Showing average annual elevation change, in feet. Contour interval 0.01 foot per year 0 _ Earthucrack . Dashed where approximately located. U, up- thrown side; D, downthrown side 0 Bench mark § ‘11 h > fi 500 O 500 1000 FEET L—I—+—r.J—l__l 125 0 125 I250 METR ES A Hollywood E—11 sLAUSON AVE a r’f’fl / FIGURE 15.—Distribution of earth cracks in the north-central Baldwin Hills as of 1960, and approximate pattern of aver- age annual elevation changes measured with respect to bench-mark Hollywood E—ll for the period 1958—60. A reinter- pretation of the same data used in the construction of figure 14. 23 24 annual elevation changes that occurred during the interval 1958—62 are based on leveling emanating from an unadjusted Department of Water and Power control survey run in April 1962 (Walley, 1963, p. 14—15, fig. 2—A); this line (level line E) is very nearly coincident with level line C (see fig. 8 and Walley, 1963, fig. 1), such that elevations derived from control points along this line should accord almost precisely with those derivable through comparison with control points along line C. The 1962 leveling was carried out during the period April 1962—January 1963 (Walley, 1963, letter of transmittal). However, even though the 9-month 1962 survey period was almost twice that of the 1958 survey period, maximum comparable errors in the average annual elevation changes probably were of about the same magnitude as those associated with the 1958 leveling (0.01 foot/year), since elevation changes along the 1962 Department of Water and Power control line probably reached a maximum of about 0.038 foot during the 1962 survey interval (Walley, 1963, fig. 2—A). Again, for purposes of this report, the annual elevation changes represented for the period 1958—62 (pl. 4) are assumed arbitrarily to match those that would have been derived had the entire set of 1962 surveys been run within the month of August. The gross pattern of movement shown for the period 1958—62 is much the same as that indicated for the periods 1950—54 and 1954—58 (pl. 4). The approximately 17 percent-deceleration in subsidence near the center and over much of the rest of the subsidence bowl between the periods 1954—58 and 1958—62 was nearly the same as that which occurred between 1950—54 and 1954—58. Comparison of the pattern of movement shown for the period 1958—62 with the patterns shown for the several preceding intervals, however, reveals several significant changes in the character of the vertical movement during this latest period. (1) A reduction in the rate of positive movement, compared with that of the preceding period, took place sometime between 1958 and 1962 within the block east of Stocker Street and Overhill Drive. This seemingly diminished rate of upward movement, however, may be of only relative significance, for Hollywood E—11 remained essentially unchanged in elevation with respect to PBM 1 between 1958 and 1962, whereas it subsided about 0.04 foot between 1954 and 1958 (fig. 11). (2) During the period 1958—62 the rate of subsidence in the area east of the Inglewood fault decelerated to about 50 percent of that for the period 1954—58; this change in rate was nearly three times the comparable deceleration (17 percent) in the area west of the Inglewood fault. The sharp deceleration in the east block is equally well displayed by the profile of elevation changes along level line C (fig. 11), which is confined entirely to the area east of the RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Inglewood fault. (3) Comparison of the 1958—62 eleva- tion changes (pl. 4) with the patterns shown in figures 14 and 15 indicates that the pronounced differential subsidence within the narrow trough extending north- ward from the La Brea Avenue—Stocker Street—Overhill Drive intersection apparently abated and in part reversed sometime between the beginning of 1961 and the end of 1962. The presence during the full period 1958—62 of a broad area of positive isobases of up to +0.01 foot/year toward the north end of the narrow trough of differential subsidence (pl. 4) suggests that measurable subsidence never extended northward beyond the area contoured in figures 14 and 15. Concern over continuing surface movements in the Baldwin Hills by the Los Angeles County Engineer stimulated an independent subsidence study during the early 1960’s (Los Angeles County, Department of County Engineer, 1961a, b); the results of this study consist of a synoptic representation of the average annual elevation changes in the Baldwin Hills area as of June 1961 (lower right figure, pl. 4). The principal differences between the patterns of vertical movement developed for the several survey intervals by the Department of Water and Power (pl. 4) and that ‘produced by the Department of County Engineer (pl. 4) are due chiefly to questionable treatment of the elevation data in the preparation of the portrayal of subsidence by the Department of County Engineer. (1) In constructing the Department of County Engineer representation (lower right figure, pl. 4), long- and short-term elevation changes were mixed indis- criminately; that is, the calculated average annual elevation changes were based were based on elevations measured over intervals ranging from 3 to 30 years (Los Angeles County, Department of County Engineer, 1961b). Because rates of movement are known to have changed at certain stations, and even in some cases to have undergone slight reversals (Los Angeles County, Department of County Engineer, 1961a), arbitrary combination of long- and short-term averages tends to misrepresent the actual pattern of elevation changes. The magnitude of the misrepresentation implicit in this practice is proportional to the known changes in the rates of vertical movement at the observed bench marks. (2) A second and more serious criticism of this interpretation (lower right figure, pl. 4) stems from the calculation of elevation changes at many of the bench marks from elevations measured with respect to at least two and perhaps a number of unrelated datums (Los Angeles County, Department of County Engineer, 1961a). The type of error inherent in this procedure is illustrated by the calculation of the Department of County Engineer of the average annual elevation change at PBM 409 (Los Angeles County, Department ELEVATION CHANGES of County Engineer, 1961b), located about 1,200 feet west of La Cienega Boulevard (lower right figure, pl. 4). As shown by the 1961 tabulation of bench-mark elevations (Los Angeles County, Department of County Engineer, 1961a), the —0.25 foot/year isobase at PBM 409 is based on a comparison of a 1961 Department of County Engineer elevation (presumably with respect to Tidal 8) with a 1958 Department of Water and Power record elevation with respect to PBM 1 (Los Angeles Department of Water and Power file card for PBM 409). The possibility that PBM 1 may have subsided with respect to Tidal 8 since its 1939 elevation was fixed by the Department of Water and Power (Hayes, 1943, p. 9—10) apparently was not considered. By way of comparison, the average change in elevation at PBM 409 with respect to the single control point PBM 1 during the period 1958—62 is calculated to have been —0.119 foot/year; the corresponding change with re— spect to Hollywood E—ll is calculated to have been —0.118 foot/year (Los Angeles Department of Water and Power file card for PBM 409). (The average annual change in elevation at PBM 409 with respect to the Los Angeles County datum between 1958 and 1961 cannot be computed without first deriving the 1958 elevation of PBM 409 with respect to the county datum.) Thus, the utilization of separate datums in the calculation of the average annual elevation changes shown in the lower right figure of plate 4‘1ed to a conspicuous distortion in the configuration of the actual pattern of vertical movements surrounding PBM 409. INITIATION OF SUBSIDENCE The beginning of differential subsidence in the Baldwin Hills can be determined only indirectly, for systematic releveling was not begun until the late 1930’s, well after the subsidence had begun. Its initiation is most reliably determined by: the history of vertical movement at PBM 68; and the comparative elevations recorded in 1910 and 1917 at four topo- graphic landmarks within the now-recognized sub- sidence bowl. The history of subsidence in the northern Baldwin Hills is perhaps best represented by both the measured and calculated vertical movement at PBM 68 (figs. 12 and 13). This bench mark, moreover, has sustained about three-quarters of the maximum amount of subsidence measured within the subsidence bowl; hence its history is probably more representative than are the histories of those bench marks subject to the sometimes aberrant movements produced at the precise center or along the periphery of a subsiding area. In spite of their obvious differences, the four separate interpretations of vertical movement presented in figures 12 and 13 agree in one significant respect: the average and nearly 25 uniform rate of subsidence between‘ 1943 and 1962 was considerably greater than the average rate over the period 1917—43 or 1911—43. Extrapolation of the PBM 68 subsidence curves backward from 1943 at the post—1943 average rates indicates that cumulative subsidence could not have occurred at PBM 68 between the years (1) 1917 and 1921 (fig. 12A); (2) 1.911 and 1924 (fig. 12B); (3) 1911 and 1929 (fig. 12. C), (4) 1911 and 1928 (fig. 13). The calculated subsidence curves shown in figures 12 C and 13 indicate that subsidence of PBM 68 below its 191 1 elevation did not take place until 1927 or 1926, respectively. Taken together these observa- tions indicate that subsidence could not have begun until the 1920’s and probably did not begin until the middle 1920’s. Although the data are less reliable, owing chiefly to the imprecisely established 1910 elevation of monu- ment “HH” (appendix G),- a similar conclusion is suggested by the history of vertical movement at PBM 67 (pl. 4). The average rate of subsidence at PBM 67 between 1943 and 1963 is calculated to have been approximately 0.145 foot/year whereas the 1910—43 rate averaged about 0.046 foot/year (appendix G). Thus the rate of subsidence at PBM 67 changed conspicuously between 1910 and 1943. Backward extrapolation of the average post-1943 rate suggests that there could have been no cumulative subsidence at PBM 67 between 1910 and 1933. Hence this less rigorous determination argues, as above, that subsidence at PBM 67 probably began no earlier than the 1920’s. A series of comparative elevations recorded in 1910 and 1917 within the presently recognized subsidence bowl (appendix I) provide particularly compelling evidence that subsidence could not have begun until after 1917. Thus comparisons between the 1910 and 1917 field elevations of four topographic landmarks indicate 0.025 foot of subsidence with respect to PBM 68 (DD) at two ofthese, 0.125 foot at a third, and 0.325 foot at a fourth (appendix I.III.B.4). Because the elevation of each topographic feature was recorded to only the nearest tenth of a foot, these elevation changes are regarded as trivial. That is, differences of a tenth of a foot can be reasonably expected in comparing one sequence with the next, even in the absence of any vertical movement. Furthermore, the last-named ele- vation change stems from elevation measurements recorded at the approximate summit of a very subdued knoll; because it is doubtful that the precise position recorded by the 1910 leveling could have been recovered in the 1917 leveling, the resultant elevation difference is considered equally doubtful. In any case, the 1910—17 elevation changes indicated for the first three features were many times less than the 0.251-foot, 0.119-foot, and 0.340-f00t changes derived for these same three 26 points, respectively, over an average 7-year interval between 1950 and 1962 (appendix I, III.B.5). Hence it seems unlikely that there could have been any significant differential movement between PBM 68 and other points within the subsidence bowl during the 1910-17 interval. Thus the apparent absence of differential movement within the subsidence bowl between 1910 and 1917 supports the preceding conclu- sion: namely, that differential subsidence did not begin until the middle 1920’s. HORIZONTAL MOVEMENTS Measurements of horizontal surface movements in the Baldwin Hills area have been carried out chiefly by the Department of County Engineer (Los Angeles County, Department of County Engineer, 1961b; Alexander, 1962; California Department of Water Resources, 1964, p. 40, pl. 16) and the Los Angeles Department of Water and Power (Walley, F. J ., 1963, p. 9—10; F. J. Walley, written communs. 1964 and 1970). Horizontal movements deduced from triangulation surveys of the Department of County Engineer are shown in the two lower figures of plate 4; length checks assembled under the auspices of the Department of Water and Power are presented in figure 16.3 Horizontal movement at triangulation point Baldwin Aux (see pl. 4) during the period 1934-61 was derived by the Department of County Engineer through compari- son of its 1961 position with its 1934 position as “determined by the 1934 Cooperative Control Survey of the metropolitan Los Angeles area” (Alexander, 1962, p. 2469). Specifically, “the apparent displacement of 2.21 feet for the 1961 position of Baldwin Aux, compared with that determined in 1934, involves the basic triangle defined by the stations Baldwin Aux, North- western, and Southwestern”; the latter two stations define a line of apparent “fixity of length” trending roughly north-south, about 3 miles east of Baldwin Aux (Alexander, 1962, p. 2471, 2473). “From secondary triangulation emanating from the 1961 position of Baldwin Aux, the horizontal movement [over the period 1936—61] of [the] other previously positioned points [shown on pl. 4] was determined and resulting movement vectors were computed” (Alexander, 1962, 3The precision ofthe triangulation surveys carried out by the Los Angeles County Engineer has been discussed by Alexander (1962, p. 2473—2474). Comparative surveys revealed adjusted spherical angle changes of up to 27.60 seconds between 1934 and 1961; the maximum probable error in observed direction associated with the 1961 surveys has been given as 0.42 second. Considerations of this sort led Alexander (1962, p. 247$2474) to conclude “that the bulk of this angular change is due to actual movement of the [primary triangulation] point [Baldwin Aux—see pl. 4], and not to the small discrepancy that normally could be expected in the observation ofa triangulation net.” Thus, ifbased on 1961 results, the maximum error in the displacement vector at trianagulation point Baldwin Aux, as determined by observation on triangulation point Denker along a single 30,185-foot line (the longest line involved in the triangulation ofBaldwin Aux) nearly normal to the displacement vector, should have been no more than (2) (4.2 X 10—1)(3.0185 X 10“) (4.848 X 10—5) = 0.123 foot, where 4.848 X 10—6 is the number of radians in 1 second of arc. Length measurements by the Department ofCounty Engineer, the Los Angeles Investment Company, and the Department of Water and Power were apparently read to 0.01 foot. RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA p. 2469, 2473). The 1961—63 displacements shown on plate 4 presumably were derived through measure— ments with respect to the same basic control network as that utilized in the 1961 retriangulation; however, no specific statement to this effect is found in the source reference (California Department of Water Re- sources, 1964). Horizontal displacements of the six identified trian- gulation points have been generally toward the center of subsidence (pl. 4). However, there seem to have been slight to moderate deflections of the displacement vectors away from the centripetal direction at those triangulation points whose positions were initially determined prior to 1961. Thus deflection from the centripetal at Baldwin Aux has been counterclockwise; deflections of the after three vectors have been clockwise. We see no evident relation between these deflections of the other three vectors have been clockwise. We see no evident relation between these more specific and probably more significant geometric association is defined by the essentially orthogonal relation between the horizontal movement vectors and the isobases around the triangulation points, especially as shown in the lower left figure of plate 4. Survey check points were set in March 1958 along the Stocker Street roadway athwart earth crack III (pl. 4) by the Los Angeles Department of Water and Power; the points were spaced at 5- to 10-foot intervals and extended about 30 feet east and west of crack III (Walley, 1963, p. 9). These check points were resurveyed in March 1963 at which time “the maximum horizontal displacement was found to be 0.05 of a foot” (Walley, 1963, p. 10). The “displacement” alluded to by Walley apparently refers to the approximate sum of the maximum northerly and maximum southerly shifts from the original alinement, where the end points are assumed to have remained unchanged. Thus between 1958 and 1963 a check point 2—3 feet west of crack III moved 0.029 foot north and one about 12—13 feet east of the crack shifted 0.028 foot south; the total of the two is 0.057 foot. Length checks were also made along this traverse in 1963. These checks showed that this approximately 50-foot line lengthened by 0.071 foot and that 0.064 foot of this was confined to the 5-foot segment straddling crack III (Los Angeles Department of Water and Power, written commun. 1970). Following the failure of the Baldwin Hills Reservoir in 1963, length checks were made by the Department of Water and Power along alinement control lines around the four sides of the reservoir (F. J. Walley, written commun. 1964), the center of which lies about 1,600 feet southwest of Hollywood E- 1 1. These checks “showed the east side to have shortened 0.09 ft., the south side to have lengthened 0.23 ft., the west side to have shortened HORIZONTAL MOVEMENTS 0.02 ft. and the north side (across the dam) to have lengthened 0.18 ft.” since originally measured in 1950 (F. J. Walley, written commun. 1964). The California Department of Water Resources (1964, p. 55) conclude from what we presume to be the measurements described by Walley, that there had been “a progressive elongation of the northeast-southwest [approximately 1,200-foot reservoir] diagonal between 1950 and 1963 of about 0.4 foot”; this elongation corresponds to an average extensional strain of about 0.033 percent. Similar length checks around the Baldwin Hills Reservoir described by Casagrande, Wilson, and Schwantes (1972, p. 581—582) indicate elongation along the northeast-southwest diagonal between 1950 and 1964 of 0.84 foot, or roughly twice that reported by the California Department of Water Resources (1964, p. 55); this greater lengthening corresponds with an average extensional strain of 0.071 percent (Casagrande and others, 1972, p. 581—582). The 1950 surveys used in these two separate determinations of diagonal length change are apparently identical; the subsequent length determinations must have been based on different sets of survey data, for Casagrande, Wilson, and Schwantes (1972, p. 582) recognize no shortening around the reservoir perimeter during the 1950—64 interval. We have no clear basis for choosing between the two cited diagonal strain values; we note, however, that compara- tive surveys conducted in 1969 indicate post-1950 elongation of the northeast-southwest diagonal of 1.14 feet (Casagrande and others, 1972, p. 581), a figure fully consistent with the reported 0.84-foot lengthening between 1950 and 1964. One of the most illuminating demonstrations of contemporary horizontal movement in the northern Baldwin Hills is based on length checks along two traverses established initially in 1924 and 1943, respectively (upper right figure, pl. 4 and fig. 16). Taped measurements between survey stations along these traverses were subsequently repeated in whole or in part on six successive occasions. (The latest of these length checks was made in 1969, subsequent to the period of expressed interest—see “Introduction.” How- ever, because the 1969 check was the only one to include all the stations incorporated in the several surveys, the resulting measurements are given here.) Thus, between April—May of 1924 and the latest survey in 1969, line DD reset—A’ apparently shortened by 2.64 feet; similarly, between 1943 and 1969, line C—C’ shortened by 0.51 feet. However, the greatest change recorded along traverse DD reset—A’ during the 1924—69 interval occurred over the relatively short segment a—h, which was reduced in length by 4.26 feet (fig. 16). Hence, whether shortening or lengthening occurred was apparently a function of the location of the segment 27 considered. Segments located between a and h, near the center of the subsidence bowl, generally shortened; those located along the northern reaches of line DD reset—A’, and thus within the peripheral part of the subsidence bowl, tended to lengthen between surveys. An apparent exception to this generalization is suggested by the first two length checks between stations a and h (fig. 16). This line is represented as having lengthened between each check through 1925; it subsequently shortened by as much as 5.21 feet. The 5.21-foot shortening measured along line a—h between 1925 and 1969 was the maximum change recorded between any two stations along either traverse. Horizontal strain along lines DD reset—A’ and C—C’, as determined for selected intervals, has been calcu- lated from the successive length checks shown in figure 16. The reliability of these calculations is proportional to the lengths of the lines from which the strain has been calculated. That is, the small errors inherent in the recovery of precisely the same points during successive surveys have a proportionately greater percentage effect on the shorter segments. By way of illustration, all the conspicuously large strains (those greater than 0.3—0.4 percent) stem from measurements over dis- tances of no more than a few feet. Hence, in constructing the interpreted strain profiles, greater weight has been given to data derived from the longer lines. Thus, the maximum extension along line DD reset—A’ between 1924 and 1969 must have been about 0.05 percent; the maximum contraction during the same interval was apparently about 0.20 percent (fig. 16). Taken together, the described length checks and associated surveys show that at least the eastern margin of the subsidence bowl has been characterized by extensional horizontal strain along lines roughly perpendicular to the isobases. The strain profiles shown in figure 16 indicate equally clearly that the central part of the subsidence bowl has been identified with contractional horizontal strain. This strain pattern is fully consistent with the centripetally directed horizon- tal displacements revealed by successive triangulation surveys. The kinematics dictated by these displace- ments compel that they be associated with a zone of radically oriented extensional strain surrounding a central core characterized by radially oriented contrac- tional strain. Although the evidence is equivocal, a comparison of the average rates of horizontal movement, as deter- mined for two identified triangulation periods, with the average rates of subsidence at PBM 68 during the same periods (fig. 17) indicates that the centripetally directed horizontal movements (together with the symmetri— cally related extensional and contractional strain) probably began in the middle 1920’s. Backward 28 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA DD—reset; adjacent to PBM 68 1969 11' C 1969 C I z 9. as a E i g - <0 tom con 5 N N m o r ‘2? § 3 1’3 m, + 1’ + a E ‘3 s o v .N— :93 NNN ('3 3 8 to - ° ‘- l I I l I II | I I I I J I J a) [\NCD 8 no «you: 8. o s 859 1945 + 0 + +++ w + N Nxco O o v— NNN ._ | J II | J 5’3. 8 8 1944 1930 1943 «a + + “'2 O ‘1’ KO I_I C") 0 v- 9. a 8%.: g g g a. :3 g a 0 ID (0‘90 '- O ‘— § 1’ 9 22‘: if 1 9 jg g; L__J o s i: ass 9 8 s a. e I 1 I II | | | | I I O “I o 1925 g 0 + + to O N |_____._____l a. t 2 no as Ix O 1:) o m ‘3 a g, g 1924 (October) 0 ,_ v— N I—_.._I__I__—I . N 3. 1924 (AprII—May) j; o B ‘3 '3 83 g o N ,_ I I J I I I | I II I I T I I I If I a b c de fgh I J k I m h n A STATION STATION I DD—reset A’ C C 8 0.1 T I I I II I I I I I E '9 1924 (combined)—1930 1943— < a, 69 E 1; u.I m 00 ‘ ' a E g ' . | | u.I :3 . E g o E 8 0—0.1 I I I I II I I I I I a b 0 de fgh i j k | m h n STATION STATION B FIGURE 16.—A, Taped distances, in feet, measured along lines DD reset—A’ and C—C’ (see upper right figure pl. 4). April-May 1924 (Los Angeles County Surveyor’s map 8635). October 1924 (Los Angeles County Surveyor’s map 8635). 1925 (Los Angeles In- vestment Company tract map 7937). 1930 (Los Angeles County, Department of County Engineer field book 289, p. 118—123). 1943 (Department of Water and Power field book 2633, p. 60). 1944 (Los Angeles County, Department of County Engineer field book 89— 166). 1945 (Department of Water and Power, Power Division field book 771, p. 55—57). 1969 (Department of Water and Power Divi- sion field book 3745, p. 2—24, 26). Data courtesy of F.J. Walley and T. M. Leps (written commun., 1970). Station designations (a, b, c, etc.) assigned by writers. B and C , Calculated horizontal strain along lines DD reset—A’ and C—C’ for selected periods between 1924 and 1969. Dots show average strain between indicated sta— tions. Curves estimated by eye; points weighted according to dis— tance between stations. HORIZONTAL MOVEMENTS PERCENT STRAIN Extension Contraction Extension Contraction Extension Contraction Extension Contraction DD—reset A' 0'1 F I I II I I I I $0.44 0.0 III - \_._,.// 1930—45 —0.1 0.1 I o 0-0 H I o —O.1 ’— _ ' l 1945—69 '224 -0.2 0.2 I o 0.1 — - o l O I | ' | I I l 1930—69 0 _o_2 1.79 0.1 o °-° I I —0.1 — _ 1924—69 0 —0.2 I I I II I I I I I a b d e fgh i j k I m HORIZONTAL SCALE 1000 0 1000 2000 FEET 250 0 250 500 METRES FIGURE 16.—Continued. 29 3O RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 0.14 r I I I I I I I I I I I I I 0.13 ' / _ / 0.12 — _ g /’ // ,, , 0.11 — r A’ ’0’ ’49, _ 2 / ,,¢’ ,z” an _ I ,a—0 A fr’ “'1: 0.10 / ”,, #4,’)k’ _ Lu >- /” /’—” c2: I 0.08 — _._,_.7V // _ g E 0.07 — / // EXPLANATION _ 2 E 0.06 ~// // 0 Hollywood C—10 D m / Western block " co ”- _ / A Inglewood D—1 LL 2 0.05 / _ 0 0.04 — // 0 Hollywood 0-11 _ E / Eastern block E 0.03 — // X Baldwin Aux. - 0.02 L// _ 0.01 - ._ 0.00 I 1 I I I I I I I I I I I I 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 RATE OF HORIZONTAL MOVEMENT AT VARIOUS TRIANGULATION FIGURE 17 .—Average rate of subsidence at PBM 68 versus av- erage rate of horizontal movement at four triangulation points within the Baldwin Hills subsidence bowl, as deter- mined for two periods between: (1) 1934 or 1936 and 1961; extrapolation of the lines defined by the plotted pairs shown in figure 17 suggests that horizontal movement at several of the identified triangulation points has varied directly and perhaps linearly with subsidence at PBM 68. This relation is most clearly demonstrated by a comparison of the rates of subsidence at PBM 68 with the rates of horizontal movement at the triangulation point (Inglewood D—l) nearest PBM 68 (pl. 4). That the suggested relation is so much less evident in a comparison of horizontal movements in the east block with subsidence at PBM 68 probably derives from the disproportionately large deceleration in subsidence recognized in the east block during the 1958—62 leveling interval. That is, subsidence at PBM 68 during the 1961—63 period probably was representative of that for the west block only. In any case, because the differential subsidence apparently began in the middle 1920’s, the inferred dependence of the horizontal movement rate on the subsidence rate argues that the horizontal dis- placements began at the same time. Furthermore, although it might be imprudent to suggest that the length checks along DD reset—A’ indicate that what we now identify as the central part of the subsidence bowl was under extensional strain before 1925, these checks argue forcefully that contractional strain, and thus the radially oriented displacements, could not have begun until 1925 or later. POINTS, IN FEET PER YEAR and (2) May 1961 and August 1963. Data from figure 12 and plate 4, and C. E. Brunty, Los Angeles County, Department of County Engineer (oral commun, 1969). EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS A series of earth cracks, as long as one-half mile and generally associated with measurable dip slip dis- placements, were recognized along the eastern margin of the Baldwin Hills subsidence field at least as early as 1957. The “cracks” are identified as such here, rather than as faults (which most of them clearly are), in keeping with the terminology of the Los Angeles Department of Water and Power (Walley, 1963, p. 5—13), the US. Geological Survey (1964, p. 8—11), and the California Department of Water Resources (1964, p. 41, pls. 17a and 17b), and in order to distinguish them from faults of more conventional recognition that are not known to have been active during historic time. The earth cracks are generally expressed as simple, single or en echelon ruptures of the ground surface along fairly straight, northerly trends (figs. 18—21). Open “potholes” and irregularly shaped subsurface cavities have been generated along several of these cracks (California Department of Water Resources, 1964, photos 54, 83, and 84, and pls. 22d—22m); both the potholes and the cavities, however, are probably erosional in origin. Open fissures are relatively un— common along the cracks, but they have been discov- ered locally (California Department of Water Re- sources, 1964, photos 55, 57, and 58). Excavations EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS FIGURE 18.~Extensive, locally broken patching along earth crack I where it passes through school yard north of Overhill Drive. View north-northeast. Photograph taken January 1961. athwart several prominent earth cracks (California Department ofWater Resources, 1964, pls. 22e, 22f, 22g, and 22k) suggest, however, that many of these open fissures are very shallow and probably were caused by (1) the extension and rupture of natural and artificial surface layers in response to vertical displacements along the cracks and(or) (2) desiccation along the upper parts of the opposed blocks. Thus, surficial fissuring and the presence of small subsurface cavities do not in themselves constitute unambiguous evidence of tension FIGURE 19.—Earth crack II, 200 feet southwest ofthe center ofStocker StreepLa Brea Avenue—Overhill Drive intersection. Vertical separation along crack about equal to height of pocketknife. View northeast. Photograph taken January 1961. 31 FIGURE 20.—Damaged wall intersected by earth crack I, 235 feet south of Overhill Drive. Photograph taken January 1961. across the earth cracks. The earth cracks (pl. 2) are confined almost entirely to the region east of the Inglewood fault and are generally restricted to the eastern margin of the northern Baldwin Hills subsidence bowl. The only reported crack west of the Inglewood fault occurs along the northern margin of the bowl. The cracks are concentrated in two general areas, one centering on the Stocker Street—La Brea Avenue—Overhill Drive intersection and the other forming a narrow zone LOGO—2,000 feet west and southwest of Hollywood E—ll. The striking degree of parallelism between the cracks and the faults andjoints in their vicinity suggests that the cracks are related to the geologic structure. There is no apparent relation, however, between lithology and the location or charac- ter of the earth cracks. Crack 1, for example, can be traced through sediments representing the majority of the stratigraphic units exposed at the surface in the Baldwin Hills, including sands, silts, gravels, and artificial fill. Where the sense of movement along the earth cracks could be determined, it has been almost entirely dip slip. Several cracks, however, showed no differential dis- placements of any sort; the zone of cracking along what is identified here as crack XIII, for example, seems to have been a rupture of this sort (D. H. Hamilton, oral commun. 1970). The planes along which the movements have occurred are believed to be generally steep; dips on the faults associated with crack IX (figs. 22 and 23), for example, average about 70° W. (California Department 32 imp-mm...» wwm a)“: _ RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA FIGURE 21.—Displacement along earth crack IX. View north (toward ruptured embankment of Baldwin Hills Reservoir). Photograph taken December 1963. Courtesy of the Los Angeles Department of Water and Power. of Water Resources, 1964, pls. 22d, 22e, 22g, 22k). Cumulative dip-slip displacements along individual earth cracks have ranged from almost imperceptible to at least 7 inches (California Department of Water Resources, 1964, p. 47). The average displacement, however, has been between 1 and 2 inches. Maximum dip slips or vertical separations (which should be nearly the same owing to the generally steep dips of the planes of movement) along all but one of the earth cracks shown on plate 2 have been measured and tabulated by the California Department of Water Resources (1964, pls. 17a and 17b). Maximum displacement apparently occurred along crack IX where the displacement (or an approximately equivalent vertical separation) has been given as 6 and 7 inches (California Department of Water Resources, 1964, pls. 17a and 17b, p. 47). Displacement on crack IX, however, may have been equalled or exceeded by displacements along cracks I and II. According to one report (D. R. Brown, oral commun. 1962), up to 4 inches of “cracking” had been observed along crack I through the Windsor Hills School yard (east of the Stocker Street—Overhill Drive intersection) by November 1957. During the 1957—63 interval an additional 2 inches of movement occurred along crack I, bringing the total to 6 inches. Four inches of movement had occurred along crack II by the time the photograph in figure 19 was made, and by the end‘of 1963 total displacement along this crack exceeded 5 inches, nearly that observed along crack IX. There seems to be little relation between displacement and crack length. Cracks I and IX, with 6- or 7-inch displacements, are relatively long. Crack II, on the other hand, which shows a minimum of 5-inches of displacement, is one of the shortest cracks observed in the Baldwin Hills. Where the earth cracks intersect white lines painted on asphalt surfaces, little if any lateral displacement of EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS Top of slepe Inlet line tunnel Drainage inspection chamber \ i \‘ “ST/.1183 lCrack IX Crack X 3' /l \ l \\ \\ l l l a l l l l /, : Sta 2+ao \JSta o+4o/ £/ l l i i l l i \ Excavation 2 l‘ l I l a a \ / ‘ ~ ~ ‘ ~ / \‘ / N All 50 O 50 100 150‘ 200 FEET 10 0 10 2O 30 40 50 METRES FIGURE 22.—Map of Baldwin Hills Reservoir showing: (1) traces of earth cracks IX and X; (2) location of California Department of Water Resources excavation 2; (3) locations of inlet line tunnel, Earth crack IX could not be followed beyond northernmost extent shown on map owing to erosion that accompanied failure of the reservoir. Adapted from California Department of Water Re- circulator lines, and drainage inspection chamber of the reservoir. sources (1964, pl. 22a). See plate 2 for location of map area. 33 34 WEST Reservoir bottom Asphalt paving Compac’ted earth lining (blanket) RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA EAST EXPLANATION Bedded sand Chiefly transported blanket material 7 0 1 2 3 4 5 FEET 0 1 METRE Sand with no apparent bedding Bedded silt or clay Silt or clay» with no apparent bedding E Concretion, enerally com- posed a CaC’Oa and (or) FezOs Contact Dashed where indefinite Minor shear FIGURE 23.—Drawing of north face of California Department of Water Resources excavation 2 intersecting earth crack IX. See figure 22 for location. Modified after California Department of Water Resources (1964, pl. 22e). the lines can be seen. Curbs and other rigid structures located athwart some of these cracks show minor horizontal displacements that could be interpreted as lateral offsets. However, none of these offsets amounts to more than a very small fraction of the dip-slip component, and they are generally ambiguously ex- pressed. Broken and horizontally offset curbings and other rigid concrete structures occur along or adjacent to the traces of cracks II, IV, VI, VIII, and IX; these offsets, however, average no more than 1/8—14 inch and range up to a maximum of 1/2 inch. The sense of lateral movement adduced from offsets of various structures and surfaces is inconsistent from crack to crack and even from place to place along the same crack. Concrete curbings along cracks II, IV, VI, VIII, and IX showed right-lateral offsets, whereas the concrete inspection chamber athwart crack IX was offset left—laterally (California Department of Water Resources, 1964, photo 72). Very slight offsets of white lines on asphalt surface extending across cracks II and IV and the development of feather fractures within the asphalt floor of the Baldwin Hills Reservoir adjacent to crack IX were consistent with left-lateral displacement. The apparently contradictory indications of the sense of lateral movement along cracks II, IV, and IX may be attributable in part to the manner of failure of rigid structures lying across these cracks. An oblique orientation of the structures with respect to the cracks, or irregular rupturing of surface layers, might result in a rotation of the structures during pure dip-slip movement in such a way as to simulate lateral displacement along the cracks. Furthermore, rigid structures riding athwart a fault along which lateral displacement has occurred may be rotated so as to produce offsets of the structures in a sense opposite to that of the displacement along the fault itself; this passive type of offset is illustrated schematically in figure 24. J/Incipient break Concrete beam\ ,o - _ ____¥ Fault trace F— "o . . /lncipient break Fault trace FIGURE 24.—Plan view showing possible horizontal offset of rigid structure intersected by fault along ground surface in sense opposite to that of the supporting crustal blocks. The depths to which the displacements along the earth cracks may have extended have not been clearly determined, but they are at least tens and possibly hundreds of feet. The only direct evidence of the depth of displacement comes from excavations across cracks IX and X, as logged by the California Department of Water Resources (1964, pls. 22a—22m) (figs. 22 and 23). These excavations revealed measurable offsets within the 8—10 feet of artificial fill lining the bottom of the Baldwin Hills Reservoir (completed in 1951). Because these offsets were clearly evident at the base of the fill (fig. 23), they undoubtedly extended to at least the bottoms of the excavations (that is, 18—20 ft beneath the floor of the reservoir). Several distributional features of the earth cracks also suggest that the displacements continue to depths of more than a few feet or even a few tens of feet. These include: (1) the long linear extent of earth cracks I, IV, and IX; (2) the considerable relief traversed by crack I, which can be traced along the ground surface through elevation differences of about EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS 35 75 feet between Overhill Drive and Stocker Street; and (3) the apparent consistency in the sense of the vertical separations recorded along a given crack. Oil well damage associated with two small earthquakes that took place in 1963 may also bear on the depth of displacement along the cracks. Two wells (Standard Oil Co. Stocker 5 and 17; pl. 2) are reported to have been damaged Within the Vickers zone (pl. 1) during an earthquake on February 18, 1963, and a third well (Standard Oil Co. Baldwin Cienega 27; pl. 2) was damaged at a depth of 1,520 feet in association with an earthquake on March 10, 1963 (California Department of Water Resources, 1964, p. 42). Regardless of the specific mechanism responsible for the damage to the wells, it is significant that: (1) damage to all three wells was confined to the east block of the Inglewood oil field (although Stocker 5 and 17 were spudded in the west block, they pass through the west-dipping Inglewood fault well above the top of the Vickers zone; see California Department of Water Resources 1964, pls. 8, 10); and (2) the location ofthe well damage is consistent with rupturing or bending of the casings in response to displacements projected to depth along the surface cracks. Thus the described oil well damage affords permissive evidence of earth crack displacements to depths of over 1,000 feet. Little is known of the history of movement along the earth cracks. Movement along cracks I, II, III, and IV had been recognized by the end of 1958 (Hayes, 1959, fig. 1). Crack XIII was apparently discovered about 1960 (Hamilton and Meehan, 1971, p. 341). Movement along crack V was recognized in 1962 and that along cracks VI and VII was first detected in February 1963. The remaining cracks (that is, VIII, IX, X, XI, and XII) were discovered after the failure of the Baldwin Hills Reservoir in 1963 (California Department of Water Resources, 1964, pls. 17a and 17b). Displacement along many of the cracks has since continued at least intermittently; there has, however, been almost no increase in their length. The earliest examination of any of the cracks by a trained observer was in May of 1957 when crack I was studied by Professor F. C. Converse (oral commun. 1961), a consulting foundation engineer. Converse first observed crack I in a large compacted fill on the east side of Stocker Street, and within a week or so he discovered that it extended south through the Windsor Hills School yard (fig. 18). It soon became apparent, moreover, that the cracking extended both north and south, well beyond the area of fill and could be traced with local discontinuity through a distance of almost one-half mile. Displacement along crack I may have begun even before 1957, however, for a civil engineer employed by the Los Angeles Department of Water and Power 36 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA O I I | I | I I BHBM 128 Original elevation 396.499 0.100 0.200 0.300 0.400 - 0.500 SUBSIDENCE, IN FEET 0.600 - 0.700 - I l l I I | | | I I I | I | 0.800 I I | I 1949 1950 1951 1952 1953 1954 | 1 955 1 956 | | | 1957 1958 1961 1962 YEAR 1959 1960 1963 1964 FIGURE 25.—Subsidence of BHBM 128 with respect to Hollywood E—11 (see pl. 4 and fig. 22), 1949—1963 (California Department of Water Resources, 1964, pl. 25d). reportedly recognized cracks extending across Overhill Drive west of the Windsor Hills School in the summer of 1949 (S. R. Powers, written commun. 1970). Further- more, according to a memorandum in the files of the Los Angeles County Department of County Engineer (A. G. Keene, written commun., 1970) the janitor of the Windsor Hills School recognized crack I as early as 1955. Several lines of indirect evidence indicate that movement along crack IX probably began as early as 1950 or 1951. Subsidence ofthe Baldwin Hills Reservoir gate tower bench mark BHBM 128 (fig. 25), about 50 feet east of crack IX (fig. 22), proceeded at a uniform rate (with respect to Hollywood E—11) of about 0.1 foot/year between July 1949 and the end of 1950, at which time the rate dropped abruptly to about 0.01 foot/year. In July 1951 the subsidence rate increased sharply to about 0.7 foot/year. The initial rate of 0.1 foot/year was resumed in August 1951 and continued until February 1952. At that time the average rate again decreased abruptly to about 0.05 foot/year, but it was interrupted about every 6 months by successive, small reversals. The abrupt change in rate at the end of 1950, as well as the successive reversals after the reservoir was filled (in 1951), may be interpreted as reflections of displacement along crack IX. The second line of evidence suggesting that move- ment along crack IX probably began as early as 1951, derives from observations in the drainage inspection chamber beneath the Baldwin Hills Reservoir. In October 1951 a crack 3/32 inch wide was detected within the concrete gallery of the inspection chamber, about 15 feet east of the trace of one of the two faults (R. R. Wilson, written commun., 1964) with which the movement along crack IX seems to have been associated (California Department of Water Resources, 1964, pls. 22d, 22e, 22g, 22h, and 22k). This crack continued to enlarge following its discovery, and additional cracks were discovered within the inspection chamber in 1958 and 1960, west and east, respectively, of the initial break (R. R. Wilson, written commun.,1964). Enlarge- ment of the main crack proceeded somewhat irregularly over the next 12 years, but at an apparently increasing rate (fig. 26). Hudson and Scott (1965, p. 169—171) point out that this graph (fig. 26) shows both an “indication of a definite change in the rate of crack development some time in 1957 and [again in] 1961,” and “a pronounced yearly periodicity, with peaks occurring in the spring.” Evidence of early movement along crack IX was also seen in the connector conduit between the gate tower and circulator lines along the floor of the Baldwin Hills Reservoir (see fig. 22), following its failure in 1963. This conduit, which overlies crack IX, showed apparent extension or slippage around a steel bell ring which, EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS 1.750 I l I I I 1.725 1.700 — - 1.675 1.650 0.550 0.525 0.500 0.475 0.450 0.425 0.400 0.375 0.350 0.325 — 0.300 0.275 0.250 — 0.225 0.200 0.175 0.150 — 0.125 — 0.100 - 0.075 — 0.050 — 0.025 — 0.000 - —0.025 I I llll|l|||l ..L. INCREASE IN WIDTH 0F CRACK, IN INCHES | l 1 955 1956 l,_|l $.33 $3 957 IBI 92 1 959 1 962 YEAR FIGURE 26.—Growth of crack in concrete liner of drainage inspection chamber of Baldwin Hills Reservoir (see pl. 2 and fig. 22), October 1951—December 1963. Average of repeated strain-gage measure- ments at top of north and south sides of inspection chamber. Adapted from R. R. Wilson (written commun., 1964) and Hudson and Scott (1965, p. 170). from the character of the corrosion products, was inferred to have been going on for a number of years before the reservoir failed (California Department of Water Resources, 1964, p. 61—62). The significance of the inspection chamber cracking and the extension of the conduit is not entirely clear. The drainage inspection chamber, for example, "had only minimal temperature reinforcement in the lon- gitudinal direction” (California Department of Water Resources, 1964, p. 61), and the connector conduit probably was not structured to Withstand pronounced extension. Hence the cracking and extension cannot be certainly ascribed to displacement along crack IX, and may have been due simply to the general horizontal movement that had taken place across the diameter of the reservoir since its completion. (See preceding section on "Horizontal Movements”) Nevertheless, the localization of the cracks and conduit extension along crack IX, together with the occasional reversals in the gate tower settlement curve, strongly suggest that these phenomena are due to something other than simple horizontal extension across the reservoir: 37 namely, differential displacement along crack IX. Settlement records around the perimeter and along the circulator lines of the Baldwin Hills Reservoir (California Department of Water Resources, 1964, pls. 25a—25c) suggest that movement along crack X may date back to 1951. Repeated leveling along both the south parapet wall and the south circulator line (California Department of Water Resources, 1964, pls. 25a and 25c) shows a prominent steepening to the west of the vertical movement gradient across crack X (or its projected trace); this steepening is consistent with continuing displacement since 1951 along the fault associated with this earth crack.4 Rates of movement along many of the earth cracks varied considerably from the time that they were first observed until the end of 1963. According to reports supplied to the Los Angeles County Department of County Engineer (D. R. Brown, oral commun., 1962), measurements along crack I (within the Windsor Hills Schoo1 yard) between October and December of 1957 indicated that “movement” was proceeding at about 0.10 foot per month, whereas the vertical separation rate during the 34-month period between December 1957 and October 1960 apparently averaged less than 0.008 foot per month. Again, according to Walley (1963, p. 7), the cracked section of Overhill Drive was resurfaced early in 1959; subsequent displacement along crack I where it crosses this resurfaced area has been less than 0.10 foot. The rate of movement also has varied along crack IV where it crosses La Brea Avenue. La Brea Avenue was resurfaced across crack IV before the close of 1959 and this crack had not reappeared prior to the middle of 1962. By 1963, however, cracking had begun again where crack IV intersects La Brea Avenue. The occurrence of calcium carbonate incrusted fractures in clay-tile drain athwart crack IX (California Depart— ment of Water Resources, 1964, p. 58) indicates that displacement within the natural foundation materials locally preceded failure of the Baldwin Hills Reservoir (and, by implication, the relatively large and appar- ently sudden displacement that is thought to have ‘The California Department ofWater Resources (1964, p. 60! has observed that a "trough of maximum settlement has been defined which crosses the reservoir in a north-south direction and which is parallel to and just westerly ofthe trace ofFault V [approximately coincident with crack X ofthis report]”*““ The settlement trough suggests that foundation deterioration was in progress along Fault 1“ (approximately coincident with earth crack IX ofthis report), The trough ofdifferential settlement alluded to here, however, is well defined only along the north wall ofthe reservoir and the northern part of the reservoir floor: it disappears almost completely toward the south end ofthe reservoir (California Department of Water Resources. 1964, pls. 2521725“ The configuration of this settlement trough closely mimics the distribution and thickness of fill placed within the reservoir area (California Department of Water Resources, 1964. pls. 2 and 11). Furthermore, the differential settlement along the north wall of the reservoir with respect to that along the northwest corner la zone of comparable regional subsidence but relatively limited fill} was more pronounced during the early life ofthe reservoir (see California Department ofWater Resources, 1964, pl. 25a l. Thus. although it is not unlikely that part ofthe settlement along this trough is attributable to a general "foundation deterioration," the described settlement probably is due chiefly to the compaction of fill underlying the northern part of the reservoir. 38 occurred along crack IX at about the time of failure—see below) by some substantial period of time. Whether this prefailure movement occurred as creep or small, discrete displacements has not been clearly determined. In any case, displacements had not extended upward to the floor of the reservoir by 1957, for it was drained during 1957 and no evidence of displacement was reported at that time from along the traces of cracks IX or X (California Department of Water Resources, 1964, p. 36). “Evidence of increasing displacement [along crack IX prior to the failure of the reservoir] was the presence of ostracods clinging to part of the broken paving surface. The remainder exhibited the lustre of a fresh break, which undoubtedly occurred on the day of the reservoir failure. This lends credence to the conclusion that the paving broke in at least two stages” (California Department of Water Resources, 1964, p. 58). Evidence of continuous, relatively uniform move- ment is best shown by crack II where it passes through a paved parking lot. This parking lot was resurfaced shortly after January 1961 when the photograph in figure 19 was taken. Rupturing was observed along the trace of this crack several months after resurfacing, and measurable vertical separations exceeded 1 inch by the end of 1963. Although reversals in the sense of displacement have never been observed along any of these cracks, local reversals in the sense of vertical movement (relative to Hollywood E—11) have been detected within the blocks east of some of these cracks. The reversal east of crack I sometime between 1954 and 1958, for example, has been described already. (See discussion of the pattern of elevation changes in the northern Baldwin Hills.) Reversals in the sense of vertical movement in the block east of crack IX are particularly indicated by both the settlement record of the Baldwin Hills Reservoir gate tower (fig. 25) and the results of periodic elevation measurements along a level line athwart crack IX (see fig. 27). Similarly, repeated leveling around the reservoir perimeter has disclosed at least one episode of prefailure uplift within the block immediately east of crack X (Castle and Youd, 1973, p. 97—98). All these reversals are most reasonably interpreted as rebound accompanying displacement along cracks I and IX. Because the Baldwin Hills area is seismically active, and because faulting commonly is associated with earthquake activity in other areas, Hudson and Scott (1965, p. 171—173), in conjunction with members of the Seismological Laboratory of the California Institute of Technology, investigated the relation between seismic- ity and crack growth in the reservoir area. These writers (Hudson and Scott, 1965, p. 171—172) concluded that a “correlation of fault movement and earthquakes is *** dubious, a conclusion which is borne out by a RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA relatively long list of small earthquakes close to the [Baldwin Hills] reservoir which do not appear to be connected with any special features on the crack growth curve” derived from measurements in the drainage inspection chamber (fig. 26). Nevertheless, the associa- tion noted earlier between two small earthquakes and oil well damage in the east block of the Inglewood field (California Department of Water Resources, 1964, p. 42) suggests an indirect relation between displacements along subsurface projections of the cracks and earth- quake activity. The distances of these earthquakes from the Baldwin Hills Reservoir (6 and 17 miles) given by Hudson and Scott (1965, p. 172), together with their “B” quality epicentral locations (J. P. Nordquist, oral commun., 1969), indicate, however, that these subsur— face displacements(?) must have been triggered by seismic waves generated well away from the oil field, as seems to have occurred in the Dominguez and Rosecrans oil fields (Richter, 1958, p. 156, 499). Although the evidence is in part contradictory, earth crack VII may be no more than the breakaway scar of a small landslide that developed in February 1963 (earth crack 8 of the California Department of Water Resources, 1964, p. 41, pls. 17a and 17b). Thus this crack may be unique among those shown on plate 2, in that none of the remaining cracks (with the possible but unlikely exceptions of VIII and XII) seem to have been generated in response to simple gravity failure. Accordingly, further discussion of movement along the earth cracks excludes that associated with crack VII. CAUSES OF THE SURFACE MOVEMENTS Gilluly and Grant (1949, p. 487—488) considered four possible explanations for the prominent differential subsidence in the Long Beach Harbor area. These four possibilities seem to be equally appropriate and inclusive as possible explanations for the surface movements in the northern Baldwin Hills as well. They are: (1) oil-field operations; (2) changes in ground-water conditions; (3) compaction of sedimentary materials in response to artificial or natural surface loading; and (4) tectonic activity. Detailed consideration of each of these possible causes leads to the conclusion that all or most of the subsidence and centripetally-directed horizontal movements, and much or all of the earth cracking and associated surficial faulting, are due to oil-field opera- tions. Tectonic activity may have contributed, in some small measure, to the earth cracking, but it is unlikely that it has contributed significantly to either the differential subsidence or the horizontal movements. Changes in ground-water and loading conditions have been very limited and their effects are thought to have been trivial. CAUSES OF THE SURFACE MOVEMENTS 39 INLET TUNNEL INSPECTION CHAMBER S T o to o 0') co 0 l\ in Stationfi882$8$$§82338882om leocoooa: + + + + + + + + + + + $$$$i¢$$$$$$$$NNFFF 000000 —0.20 _O.30 — M12—17—63 - I-Lfi —0.40 — — Lu u. E LII (5 2 E 10—20—63 _ O -0.50— 2 Q E ”J .1 Lu —O.60— _ —0.70— _ —0.80 FIGURE 27.—Elevation changes along inlet tunnel and drainage in- spection chamber of the Baldwin Hills Reservoir since October 1953, measured with respect to PBM 40—C (Hollywood E—ll equi- valent) (adapted from California Department of Water Resources, 1964, pl. 25e). A, Approximate location of major crack in concrete MOVEMENTS ATTRIBUTABLE TO OIL-FIELD OPERATIONS Gilluly and Grant (1949, p. 501) have shown that a relation between subsidence and oil withdrawal “is especially suggested [in the Long Beach Harbor area] by the coincidence in both place and time of the rapid subsidence with the exploitation of the [Wilmington] oil field.” These writers (1949, p. 463) have also concluded that there exists “a very close agreement between the relative subsidence of the various parts of the field and the pressure decline [developed in response to the extraction of underground fluids], thickness of oil sand affected, and the mechanical properties of the oil sands. liner of drainage inspection chamber (California Department of Water Resources, 1964, photo 72, pl. 22h). B, Location of earth crack IX beneath drainage inspection chamber (California De- partment of Water Resources, 1964, pl. 22h). See figure 22 for location of level surveys. This correlation is so close as to constitute conclusive evidence of a cause and effect relation between pressure decline and subsidence.” Because great volumes of fluids have been withdrawn in the northern Baldwin Hills in connection with the exploitation of the Inglewood oil field, the relations between surface movements and oil-field operations are examined here first. DEVELOPMENT OF THE INGLEVVOOD OIL FIELD The discovery well of the Inglewood oil field was completed on September 28, 1924 in the southernmost part of the present field (California Division of Oil and 40 TABLE 1.——Petroleum production statistics for the Inglewood oil field by zone through December 31, 1963 [Conservation Committee ofCalifornia Oil Producers (1964, p. P).Arranged in approximate order of increasing depth] Cumulative production Oil Gas Zone Discovery date (bbls) (Mcf) Vickers ____________ Se . 1924 174,526,000 95,135,000 Rindge ______________ Ju. 1925 22,312,000 20,128,000 Rubel ______________ Aug. 1934 22,694,000 24,513,000 Moynier ____________ Feb. 1932 11,056,000 18,656,000 Bradna ______________ Aug. 1957 1,278,000 2,020,000 Sentous ____________ Sep. 1940 7,578,000 19,493,000 Marlow-Burns ______ Aug. 1960 1,320,000 3,844,000 Miocene undifferentiated __ Mar. 1961 3,000 33,000 Total ______________________ 240,767,000 183,822,000 Gas, 1961, p. 576—577; Huguenin, 1926, p. 7, p1. II). Reservoir conditions within the upper oil zones were found to be roughly similar in both east and west blocks (Huguenin, 1926, p. 13), and development of the field apparently proceeded rapidly on both sides of the RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Inglewood fault (Huguenin, 1926, p. 7, pl. II). Peak annual oil production (18,371,536 bbls) and peak annual gas production (13,344,284 Mcf) were attained in 1925, and by June 1926 over 74 percent ofthe acreage developed to the end of 1963 had been proved (Huguenin, 1926, p. 5; California Division of Oil and Gas, 1963, p. 69). As of January 1, 1964 only slightly more than 1 percent of the cumulative oil production had been drawn from zones discovered after 1940, and little more than 4 percent of the cumulative production had come from zones discovered after 1934 (see table 1). Large quantities of water have also been produced from the Inglewood field. Cumulative figures are unpublished, but tabulations compiled from summary reports of the State Oil and Gas Supervisor (table 2) indicate that by January 1, 1964 approximately 374,699,000 bbls of water had been produced. The proportion of water, moreover, has generally increased with time (table 2), such that total liquid production has been maintained at high levels, even in later years. TABLE 2.—Fluid production and waterflooding statistics for the Inglewood oil field by year [Compiled chiefly from summary reports of the State Oil and Gas Supervisor. Gas production statistics for 192429 from files of the California Division of Oil and Gas (R. G. Frame, unpub. data, 1962)] Gross liquid Net liquid Gas/gross Gas/net Oil production Net gas production Water production production Water injected production Gas/oil liquid liquid Year (in bbls) (in MCF) (in bbls) (in bbls) (in bbls) (in bbls) (Mcf/bbls) (Mcf/bbls) (Mcf/bbls) 1924 __________ 6,180 6,893 58 6,238 6,238 1.114 1.103 1.103 1925 __________ 18,371,536 13,344,284 603,668 18,975,204 18,975,204 .727 .704 .704 1926 __________ 17,644,021 13,325,558 1,753,571 19,397,592 19,397,592 .755 .688 .688 1927 __________ 12,919,987 9,632,789 1,970,758 14,890,745 14,890,745 .745 .647 .647 1928 __________ 10,727,764 7,908,434 2,870,339 13,598,103 13,598,103 .737 .582 .582 1929 __________ 8,790,813 6,048,376 3,431,781 12,222,594 12,222,594 .688 .494 .494 1930 __________ 6,449,092 4,002,130 3,068,741 9,517,833 9,517,833 .621 .421 .421 1031 __________ 5,322,259 2,691,280 3,347,060 8,669,319 8,669,319 .506 .310 .310 1932 __________ 4,877,601 2,281,913 3,181,460 8,059,061 8,059,061 .467 .283 .283 1933 __________ 4,068,377 1,688,096 3,357,067 7,425,444 7,425,444 .416 .228 .228 1934 __________ 3,383,366 1,304,442 2,978,245 6,361,611 6,361,611 .385 .205 .205 1935 __________ 4,478,092 1,632,999 3,124,245 7,602,337 7,602,337 .364 .215 .215 1936 __________ 4,552,133 1,988,610 2,598,178 7,150,311 7,150,331 .436 .278 .278 1937 __________ 5,549,294 3,082,130 2,944,621 8,493,915 8,493,915 .556 .363 .363 1938 __________ 5,335,719 3,278,667 3,525,062 8,860,781 8,860,781 .613 .370 .370 1939 __________ 4,602,512 2,905,900 3,718,486 8,320,998 8,320,998 .631 .349 .349 1940 __________ 4,365,020 2,705,495 3,705,140 8,070,160 8,070,160 .621 .336 .336 1941 __________ 4,886,519 3,724,999 3,997,079 8,883,598 8,883,598 .762 .419 .419 1942 __________ 6,745,267 5,324,296 7,222,919 13,968,186 13,968,186 .790 .381 .381 1943 __________ 6,910,762 6,995,509 7,541,229 14,451,991 14,451,991 1.011 .484 .484 1944 __________ 6,460,872 7,487,389 9,194,841 15,655,713 15,655,713 1.158 .478 .478 1945 __________ 5,622,703 6,391,438 10,227,989 15,850,692 15,850,692 1.137 .403 .403 1946 __________ 4,724,278 4,969,617 10,412,511 15,136,789 15,136,789 1.051 .328 .328 1947 __________ 4,332,327 4,039,377 10,850,646 15,182,973 15,182,973 .933 .266 .266 1948 __________ 4,376,332 3,917,175 11,278,227 15,654,559 15,654,559 .896 .250 .250 1949 __________ 5,061,249 3,800,477 12,085,172 17,146,421 17,146,421 .751 .222 .222 1950 __________ 4,853,962 3,679,024 11,889,221 16,743,183 16,743,183 .758 .219 .219 1951 __________ 4,929,122 3,770,976 12,165,770 17,094,892 17,094,892 .765 .221 .221 1952 __________ 4,932,003 3,763,466 12,352,053 17,284,056 17,284,056 .763 .218 .218 1953 __________ 4,892,954 3,954,966 13,506,543 18,399,497 18,399,497 .809 .215 .215 1954 __________ 4,658,033 4,007,772 14,154,951 18,812,984 819,242: 17,993,742: .859 .213 .222 1955 __________ 4,356,631 3,436,670 13,867,612 18,224,243 819,242: 17,405,00h .789 .189 .197 1956 __________ 4,435,969 3,342,072 14,544,620 18,980,589 2,237,768 16,742,821 .754 .176 .200 1957 __________ 4,632,242 3,518,823 15,293,955 19,926,197 4,475,680 15,450,517 .759 .176 .228 1958 __________ 4,413,763 3,441,993 15,939,575 20,353,338 7,019,555 13,333,783 .781 .169 .258 1959 __________ 4,242,183 3,323,430 17,538,996 21,781,179 7,272,256 14,508,923 .783 .153 .229 1960 __________ 4,557,332 3,527,141 18,384,667 22,941,999 8,565,397 14,376,602 .774 .154 .245 1961 .......... 5,769,427 4,583,953 20,282,618 26,052,045 14,373,109 11,678,936 .794 .176 .393 1962 __________ 6,729,685 6,957,636 27,240,575 33,970,260 17,795,155 15,995,105 1.032 .205 .435 1963 __________ 6,921,366 7,390,448 38,528,470 45,449,836 23,288,351 22,161,485 1.067 .163 .334 CAUSES OF THE SURFACE MOVEMENTS 41 30|IITTIIIT|IIII|I|II|I Net liquid 10— PRODUCTION, IN MILLIONS OF BARRELS I I Net liquid 1920 1925 1930 1935 1940 YEAR 1945 1950 1955 1960 1965 FIGURE 28.—Annual oil, net water, and net liquid production from the Inglewood oil field through 1963. (See table 2.) Waterflooding was begun in the east block in 1954; flooding in the west block began in 1962 (Oefelein and Walker, 1964; California Division of Oil and Gas, 1963, p. 102). The initial pilot flood was centered about 2,200 feet northwest of the Stocker Street—La Brea Avenue— Overhill Drive intersection (pl. 2); it covered about 3 acres and incorporated a 100-foot section of the Vickers East zone—that is, the Vickers zone east of the Inglewood fault (Oefelein and Walker, 1964, p. 510—511; Walling, 1953, p. 56; Munger Map Book, 1970, p. 165). A second pilot flood, involving a 400-foot section of the Vickers East and covering about 10 acres, was started in 1956 immediately west of the first flood (pl. 2) (Oefelein and Walker, 1964, p. 510—511). About 4.5 million bbls of water were injected during the 3-year pilot flood stage (California Division of Oil and Gas, 1957, p. 94; California Department of Water Resources, 1964, pl. 9). "Full-scale” flooding throughout the entire 1,200— 1,300-foot Vickers East interval began in 1957 (Oefe- lein and Walker, 1964, p. 510—511); it apparently expanded rapidly and by 1963 injection in the Vickers East was proceeding at a rate of over 13 million bbls per year (California Division of Oil and Gas, 1963, p. 102). Although flooding operations in the west block were not begun until 1962, by 1963 approximately 40 percent of the annual injection was going into the Vickers West. Of the total injected to the end of 1963, 79.5 percent went into the Vickers East zone and 84.2 percent went into the Vickers East plus Rubel East zones (California Division of Oil and Gas, 1963, p. 102). The volumes of water injected annually over the field as a whole are given in table 2. Annual net water, net liquid, and oil production from the Inglewood field are shown in figure 28. Cumulative net-liquid and cumulative gas production through 1963 are presented in figure 29. Major production from the Inglewood field has been from the Vickers (also known as Vickers-Machado) zone. The Vickers is defined here to include the overlying Investment zone (see pl. 1) as well, for production from this zone has been combined with that of the Vickers by the Conservation Committee of California Oil Producers (W. R. Wardner, written commun., 1967). Although production statistics have not been published for the entire history of this zone, earlier production figures can be deduced from the production history of the field as a whole, the Vickers gas:oil ratio curve (fig. 30), and the Vickers oil productionznet water production ratio curve (fig. 31). Thus, about three-quarters of the oil and about 0 I I I | l I I I r I I I I Ifl I I 0 .. ------------ Z 5 """"""""" G _ s '- 100 " as 100 Z Qx ______________ g; D”) ------ 0.1 ----- O :E2oo— 4’90,- -ZOOBE c: 90,- O”- lII< °' to 2m 0-5 UJZSOO- -300w8 2— < I—z on 59 Luz :I—400- 4002< 2% gs D D 0 Q8500— 500§E m D 0 600 Li I l l l l l l l l l l l l l I l l 600 1 924 1 932 1 940 1948 1956 1 964 YEAR FIGURE 29.—Cumulative net liquid and cumulative gas production from the Inglewood oil field through 1963. Computed chiefly from production statistics presented in the summary reports of the State Oil and Gas Supervisor. (See table 2.) 42 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA """'."""""" U C _ too—sec 85 §5 :03 DC) hm L: ass IS an» LIJ’.-_T 29-9 0c g": LL00.80— a 5.9 25 9V $5 I:~,= . m2 gs a Vickers 3m :9 gason o E 0.60 - E a. ratio - o 2% <>. 9 2 040- 9:9, ‘89...." '— 020- r——-v———4 - Vickers zone inferred gas: oil ratio 000 I | I l I | I | I | I | I | I l x | I 1924 1932 1940 1948 1956 1964 YEAR FIGURE 30.—-Gas:oil ratios for the Inglewood oil field and the Vickers zone of the Inglewood field. 1924—33 values for the Vickers zone assumed to be identical with those for the en- tire field; production statistics given in the annual reviews of the Conservation Committee of California Oil Producers indicate that pre-1934 production from zones other than the Vickers was trivial (probably less than 250,000 bbls of oil). 1934—43 values derived through proration of the cumulative gas production for this interval according to annual oil production and extrapolation from earlier and later periods. four-fifths of the net liquid production from the In- glewood field have been drawn from a zone at a median depth of 2,100—2,200 feet (pl. 1). Annual oil, water and gas production figures for the Vickers zone are given in table 3; curves showing the cumulative net liquid and cumulative gas production through 1963 are presented in figure 32. 512'0lllllllllllllllllllllll .: \ O \ D \ 010.0” _ 0 1:: n. EBD— ' é E60- " 2 54.0— - ,: O 320— — 0‘ .. I ...... a. ...... goollllIIIIIIWl O‘ vwwwo uocu figsessiéséééé YEAR FIGURE 31.—Oil:net water production ratio for the Vickers zone of the Inglewood oil field. 1924—33 values assumed to be identical with those for the entire field; production statistics given in the annual reviews of the Conservation Committee of California Oil Producers indicate that pre-1934 production from all other zones was trivial (probably less than 250,000 bbls of oil). 1934—39 values (dashed line) derived through extrapolation from earlier and later periods. TABLE 3.—Fluid production and waterflooding statistics for the Vickers zone of the Inglewood oil field by year [“Vickers zone” production shown here includes that from the Investment zone (see pl. 1) as well, since production from this zone has been carried with that of the Vickers by the Conservation Committee of California Oil Producers (W. R. Wardner, written commun. 1967), Compiled chiefly from the annual reviews of the Conservation Committee of California Oil Producers. 1924—1933 Vickers figures assumed to be identical with those for the entire field, since the tabulations ofthe Conservation Committee indicate that pre-1934 production from all other zones was trivial (probably less than 250,000 bbls ofoil); 1934—43 gas production figures calculated from the gaszoil ratio curve given in figure 34; 1934—39 water production figures calculated from the oil productionznet water production ratio curve given in figure 31 ] Oil Net gas Water Gross liquid production production production production Year (in bbls) (in Mcf) (in bbls) (in bbls) 1924 ,,,,,,,,,,,,,, 6,180 6,893 58 6,238 1925 1 18,371,536 13,344,284 603,668 18,975,204 1926 _ 17,644,021 13,325,558 1,753,571 19,397,592 1927 _ 12,919,987 9,632,789 1,970,758 14,890,745 1928 _ 10,727,764 7,908,434 2,870,339 13,598,103 1929 _ 8,790,813 6,048,376 3,431,781 12,222,594 1930 , 6449,092 4,002,130 3068,741 9,517,833 1931 _ 5,322,259 2,691,280 3,347,060 8,669,319 1932 _ 4877,601 2,281,913 3,181,460 8,059,061 1933 _ 4,068,377 1,688,096 3,357,067 7,425,444 1934 3,152,812 1,171,894 4,129,800 7,282,612 1935 2,887,442 805,546 2 887,442 5,774,884 1936 1,996,051 544,922 2,193,000 4,189,051 1937 __ 1851,278 503,548 2,127,000 3,978,278 1938 __ 2,064,361 571,828 2,580,000 4,644,361 1939 _ 2,216,313 616,135 2,805,000 5,021,313 1940 1 2297,320 657,034 2,936,000 5,233,320 1941 1. 2,383,535 700,759 3,282,000 5,665,535 1942 1 3,510,906 1,074,337 6,430,000 9,940,906 1943 ,, 3,264,546 1,054,448 6,960,000 10,224,546 1944 ,1 3,094,649 1,169,777 7,330,000 10,424,649 1945 , 2,966,788 1,224,870 8,710,000 11,676,788 1946 ,1 2,637,000 1,136,000 8,440,000 11,077,000 1947 __ 2,510,000 985,136 8,215,000 10,725,000 1948 .1 2,701,000 965,175 8,190,000 10,891,000 1949 _ 3,415,000 1,494,000 10,400,000 13,815,000 1950 , 3,253,708 1,493,452 10,120,000 13,373,708 1951 , 3,179,000 1,595,908 10,630,000 13,809,000 1952 , 3213,000 1,535,857 10,260,000 13,473,000 1953 _ 3,311,000 1,899,000 10,760,000 14,071,000 1954 _ 3,243,000 2,049,000 12,340,000 15,583,000 1955 __ 2,910,000 1,488,000 12,080,000 14,990,000 1956 __ 2,859,000 1,209,000 12,110,000 14,969,000 1957 , 2,977,000 1,184,000 13,120,000 16,097,000 1958 - 2,791,000 1,110,000 15,320,000 18,111,000 1959 2,704,000 964,615 14,993,000 17,697,000 1960 2,728,000 980,000 14,606,000 17,334,000 1961 2 951,000 969,000 17,331,000 20,282,000 1962 3,244,000 1,318,000 23,611,000 26,855,000 1963 3,724,000 1,734,000 33,873,000 37,597,000 Net liquid , Gas/gross Gas/net Water injected production Gas/oil liquid liquid Year (in bbls) (in bbls) (Md/bbls) (Mcf/bbls) (Mcf/bbls) 6,238 1.114 1.103 1.103 18,975,204 .727 .704 .704 19,397,592 .755 .688 .688 14,890,745 .745 .647 .647 13,598,103 .737 .582 .582 12,222,594 .688 .494 .494 9,517,833 .621 .421 .421 8,669,319 .506 .310 .310 8,059,061 .467 .283 .283 7,425,444 .416 .228 .228 7,282,612 .372 .161 .161 5,774,884 .279 .139 .139 4,189,051 .273 .130 .130 3,978,278 .272 .127 .127 4,644,361 .277 123 123 5,021,313 .278 123 123 5,233,320 .286 127 127 5,665,535 .294 .124 .124 9,940,906 .306 .108 .108 10,224,546 .323 .103 103 10,424,649 .378 .112 .112 11,676,788 .412 .105 .105 11,077,000 .431 .103 .103 10,725,000 .392 .092 .092 10,891,000 .357 .089 .089 13,815,000 .437 .108 .108 13,373,708 .459 .112 .112 13,809,000 .502 .115 .115 13,473,000 .478 .114 .114 14,071,000 .574 .135 .135 819,242: 14,763,758: .632 .131 .139 819,242: 14,170,758¢ .511 .099 .105 2,237,768 12,731,232 .425 .081 .095 4,475,680 11,621,320 .399 .074 .102 7,901,555 11,091,445 .398 .061 .100 7,272,256 10,424,744 .356 .055 .093 8,565,397 8,768,603 .359 .057 .112 13,022,320 7,259,680 .328 .048 .133 16,556,103 10,298,897 .407 .049 .128 22,661,873 14,935,127 .466 .046 .116 CAUSES OF THE SURFACE MOVEMENTS 0 0 - 2 § 9:. OX '— 5:0100 10081:] gfi om Am OLI— 113E200 zooEg Zen 0):) Luz <0 2". on 59 Z< 35 I-‘D E 53 38400 400:? 00 2|- E a; “-500 I | I | I I I I I 500 1 924 1 932 1 940 1 948 1 956 1 964 YEAR FIGURE 32.—Cumulative net liquid and cumulative gas production from the Vickers zone of the Inglewood oil field through 1963. Computed chiefly from production statistics given in the annual reviews of the Conservation Committee of California Oil Produc- ers. (See table 3.) Reservoir pressure data from the producing zones of the Inglewood field are not generally available. A single curve showing changing reservoir fluid pressure in the Vickers East zone has been published (California Department of Water Resources, 1964, pl. 9), however, and is reproduced here as figure 33. It should be equally representative of fluid pressure decline within the upper levels of the Vickers West zone as well (at least through 1954 when waterflooding was begun), because: (1) reservoir conditions were initially similar in the east and west blocks, even though these blocks are separated by the nearly impermeable barrier of the Inglewood fault; and (2) development proceeded both uniformly and rapidly in the two blocks. A derived reservoir pressure curve (fig. 34) showing the “average” pressure decline in the Vickers zone in the absence of waterflood- ing has been constructed from the data of figure 33. GOOIIIIIIIIIIIIIIIII 3% I Started full-scale flood 3 Started _ pilot waterflood l0 0 O I RESERVOIR PRESSURE, IN POUNDS PER SQUARE INCH - o 8 8 I I I I I I I I I I I I I I I I I I I I 1 932 1940 1 948 1956 YEAR 0 I 1924 1964 FIGURE 33.—Fluid pressure at —1,330 feet in the Vickers East zone of the Inglewood oil field during the period 1925—63. After California Department of Water Resources (1964, p. 16, pl. 9). 43 8001||||I|||IIIIIIIIIII 700— " 600 - " 500 - — RESERVOIR PRESSURE, IN POUNDS PER SQUARE INCH & 8 | l 300 — — 200 - — 100 - " 0 I I I I I I I I I I I I I I I I I I I I I 1924 1932 1940 1948 1956 1964 YEAR FIGURE 34.—Calculated fluid-pressure decline midway through the central Vickers zone of the Inglewood oil field during the period 1925—63. Derived from figure 33 by proportional ex- trapolation of data to a depth of —l,850 feet (the approximate midpoint of the Vickers zone) and contingent upon the follow- ing assumptions: (1) uniform elevations among correlative intrazone horizons throughout the Inglewood field (a simple, horizontally layered system); (2) a calculated initial reservoir fluid pressure of 790 psi; (3) uniform decline of the fluidapres- sure gradient throughout the reservoir column (an assumption supported by the interzone pressure-decline history in the Wilmington field); and (4) an absence of waterflooding effects. The geographic limits of the Inglewood oil field, the Vickers zone, and the Inglewood oil-field anticline are approximately coincident (fig. 3). The Vickers zone boundary of figure 3 differs from the full field production boundaries only along the south or southeast edge of the field. The southeastern extension of the field beyond the Vickers boundary is apparently due in part, and perhaps entirely, to: (1) production from the Bradna, Sentous, and Marlow-Burns zones, the producing parts of which are restricted to the southeast flank of the structure (California Division of Oil and Gas, 1961, p. 577); and(or) (2) production brought in at the extreme southeast edge of the field in 1957 from beneath the "Bradna Community” lease (Bailey, 1957, p. 87). SL‘BSIDENCE A spatial coincidence between the Inglewood oil field and the well—developed differential subsidence in the northern Baldwin Hills is clearly demonstrated in the frontispiece and through comparison of figures 3 and 4 with plate 4. The patterns of subsidence represented on plate 4 are symmetrically arranged with respect to both the oil-field production limits and the producing structure itself. There is, in addition, an equally 44 well-defined coincidence between the center of subsid- ence and the approximate center of the Inglewood oil-field anticline; the center of the anticline is inferred, in turn, to coincide with the area of maximum petroleum accumulation and maximum fluid extrac- tion. Spatial coincidence between the Inglewood oil field and the Baldwin Hills subsidence is also shown by the geographical association between the subsidiary and subsidence dish recognized during the 1950—54 interval and the underlying structural crest of the east block (figs. 3 and 4, and pl. 4). Thus the subsidence field and the producing area of the oil field are concentrically centered, identically oriented, and similarly shaped. Although the Baldwin Hills subsidence field extends well beyond the producing limits of the Inglewood oil field, this feature characterizes a number of other US. oil-field subsidence domains. Wherever oil—field—related subsidence fields have been mapped, they are generally at least twice as large as the associated producing areas (Yerkes and Castle, 1970, p. 57—58). Thus the absence of a more precise congruency between the Inglewood oil field and the associated subsidence bowl should not be viewed as detracting from the well-defined spatial coincidence between these features. The coincidence in time between the onset and development of the differential subsidence in the northern Baldwin Hills and the discovery and exploita- tion of the Inglewood oil field is less easily shown than the corresponding spatial coincidence. Although Kresse (1966, p. 98) states flatly “that subsidence [in the Inglewood field] is occurring and that it can be compared to oil field development, both in time and space, can be demonstrated,” he seems to have had available only that evidence developed by the California Department of Water Resources (1964, p. 44); the synchroneity between subsidence and production cannot be dem- onstrated with this evidence. The temporal coincidence between the beginning of exploitation and the initiation of the spatially as- sociated subsidence is shown most convincingly by the relation between the production history and the history of vertical movement at PBM 68. Movement at PBM 68 is an especially significant index of this relation since: (1) PBM 68 is the only bench mark within the subsidence bowl whose elevation was measured with respect to the same or an easily related external datum both before and after exploitation began; and (2) it is probably more representative of the subsidence history than is that at the precise center or along the periphery of the subsidence bowl. Thus the several analyses of movement at PBM 68 all indicate that the differential subsidence probably did not begin until the middle twenties—or at about the time significant production began in 1925. This conclusion is supported both by the RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA history of movement at PBM 67 and by an apparent absence of differential subsidence between 1910 and 1917 within the subsequently recognized subsidence bowl. The existence of a more general correspondence between production and subsidence can be dem- onstrated by comparing the calculated and measured paths of subsidence at PBM 68 shown in figures 12C and 13 with the cumulative production from the Inglewood field as a whole (fig. 29) and the Vickers zone in particular (fig. 32). The most valid of the subsidence curves (fig. 12C , curve 1; fig. 13) indicate that PBM 68 did not subside below its 1911 elevation until 1927 or 1926, respectively; thus, differential subsidence must have begun soon after the start of major production from both the field and its chief producing zone (figs. 29 and 32). The subsidence curves in figures 12C and 13 and the liquid production curves in figures 29 and 32 closely mimic each other and indicate, thereby, a close correspondence between rates of liquid production and rates of subsidence. The correspondence between fluid production and subsidence is emphasized, moreover, if the relatively large pre-1932 and, to a lesser extent, post-1942 gas production are also considered (figs. 29 and 32). Thus, it is certainly clear that differential subsidence began soon after production began, and that there has been a very close correspondence between the rates of subsidence and rates of production. Alternatively, the approximate coincidence between the beginning of subsidence and the beginning of production can be shown through a direct comparison between both the full-field and Vickers zone cumulative liquid production and the measured subsidence at PBM 68 since 1911 (fig. 35). A significant relation emerges from this comparison: both curves (particularly that for the Vickers zone) are very nearly linear, and backward extrapolations of the measured parts (1943—62) of the net liquid production curves pass nearly through the origins of the graphs. Thus subsidence of PBM 68 below its 1911 elevation must have been essentially coinci- dent with the beginning of production, 13 or 14 years later. That the calculated parts of the curves (1926—43) fail to pass precisely through the origins of the graphs probably is due to one or more of at least three possible reasons: (1) The subsidence recorded at PBM 68 stems from comparison with an objectively calculated 1911 elevation of bench mark Hollywood E—l 1; correction for the likelihood that Hollywood E—11 .sustained no differential subsidence (with respect to control points immediately beyond the area of differential subsidence) before production began, would lower all points shown in both figures 12C and 35 by a maximum of about 0.14 foot (see appendix C, Hollywood E—ll, II.D.). (2) Subsidence at PBM 68 between 1926 and 1943 (fig. 120) CAUSES OF THE SURFACE MOVEMENTS 45 I I I | | I I I I INGLEWOOD FIELD VICKERS ZONE 1926 0 _ R _ 0 Q 1926 _ \\ . \\ E ‘\ - - \\ Lu \\ OII productlon \\ LI. \\ A \\ z. 1931\‘Q1931 Gross liquid production 1931\‘Q393‘ CD _ O _ _ __ g 1 1934\\ 1934 Net liquid production 1 1934\ @1934 E 1939 \ ‘Q \1939 LL . o 1943 1943 Lu . 1946 _ 3 2 ' 2 E 1950 U) m a 3 _ 3 _ 1954 _ 1959 1962 1962 4 4 l | 1 1 o o 100 200 300 400 500 PRODUCTIONJN MILLIONS OF BARRELS FIGURE 35.—Cumulative oil, gross liquid, and net liquid production from both the entire field and the Vickers zone of the Inglewood oil field versus cumulative subsidence at PBM 68 with respect to Hollywood E—11 since 1911. See figure 12 for explanation of dashed lines. Data from figures 12C, 29, and 32, and tables 4 and 5. was, of necessity, calculated from comparisons with vertical movements at nearby bench marks; hence the 1926—43 subsidence values may contain cumulative errors of as much as several tenths of a foot. (3). Determinations of subsidence at PBM 68 derive from elevations measured in 1911 rather than 1924, when production began; because differential uplift has been recognized west of the Newport-Inglewood zone in this area (Grant and Sheppard, 1939, p. 302, 319—322), it is conceivable that PBM 68 rose slightly with respect to Hollywood E—ll sometime between 1911 and 1924. The rate of subsidence and the post—1934 rates of net liquid production from the Inglewood field and the Vickers zone, in particular, have also varied linearly with respect to each other (fig. 36). The calculated pre-1934 subsidence rate probably was greatly influ- enced by high gas production (which is not reflected in the liquid production), thereby accounting for the two points lying to the right of the points representing later intervals of time. With this qualification, the rate of subsidence clearly is directly proportional to the rate of production. The relation between subsidence and liquid produc- tion from both the Inglewood field as a whole and the Vickers zone in particular may also be shown by comparing various aspects of liquid production with the maximum subsidence or with the volume of subsidence measured over selected time intervals. The data used and the results of these comparisons are tabulated in tables 4 and 5, several features of which require explanation. (1) In calculating fractional parts of the annual production, the total annual production has been treated as if it consisted of 12 equal monthly increments. (2) All production determinations have been made to the first day of the given month. (3) The volumes of subsidence have been calculated on the assumption that the depressed volumes approximate inverted elliptical cones. Measurements of the basal dimensions (a and b) of the cones are somewhat subjective; they are based in part on the projected positions of the zero isobases in both space and time. (4) The figure of 2.37 feet for maximum subsidence during the period 1911—43 has been used in preparing the tables because we consider it the best available estimate. Examination of the various groups of subsidence-to- production ratios given in tables 4 and 5 shows that the intragroup values have remained fairly uniform over a wide range of time intervals. The most significant ratios, namely those of maximum subsidence and volume of subsidence to net liquid production, extend over ranges of less than 1.3-fold for thefull field and about 1.2-fold for the Vickers zone. This range of values may be explained in part by the imprecise measure- ments of the apparent volumes of subsidence (and, thereby, the ratios based on these volumes) over the successive time intervals. Thus, in the absence of better information, the calculated volume of subsidence over the interval 1911—43 has been based on the assumption that the areal dimensions of the subsidence dish remained unchanged from their inception until 1954. It is likely, however, that the subsiding area over the 46 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Y Y 18 I | I 18 I I I INGLEWOOD FIELD VICKERS ZONE 0 1954—58 1950'“ 0 1943—46 0 1946—50 a 14 _ .1958_62 - 14 _ .1950_54 X 1954-58 (D O J Lu E _ _ _ 1946—50 _ < ' ‘ m 1926_31 1926—31.] Z If 1943—46 g 10 — — 10 — 0 — >. .1958—62 0: Lu D. Z 9 — 1931—34 — — 1931—34 ~ I— ' 0 8 1934-39 1939—43 a o n: n. e _ _ e _ _ Q 8 3 1934—39 In _ _ _ _ z 2 — — 2 — — (X=0.0088Y—0.0214) (X=0.0093Y+0.0023) 0 I I I 0 I I I X 0.00 0.05 0.10 0.15 0.20 0.00 0.05 0.10 0.15 0.20 RATE OF SUBSIDENCE, IN FEET PER YEAR RATE OF SUBSIDENCE, IN FEET PER YEAR FIGURE 36.—Rate of subsidence at PBM 68 versus rates of net liquid production from the Inglewood oil field and the Vickers zone of the Inglewood field, 1926—62. The points 1926-31 and 1931—34 were not included in least-squares solutions shown in illustration (see text). Data from figures 12C 29, and 32. Inglewood oil field expanded between 1943 and 1954. This probability is supported by the 14.7 percent increase in proved acreage in the Inglewood field from 850 acres at the end of 1943 (Bush, 1943, p. 20) to 975 acres by the end of 1954 (Musser, 1954, p. 62). Nonetheless, and in spite of the probable changes in the configuration of the subsidence cone and limitations on the measurement of successive subsidence volumes, the generally constant ratios between both measures of subsidence (that is, maximum subsidence and volume of subsidence) and net liquid production (fig. 87) again indicate a nearly linear relation between subsidence and net liquid production, whereby the curves relating subsidence volume to net liquid production project backward to, or close to the origin. The coincidence in time between subsidence and various aspects of oil—field operations can also be tested by comparing the differences in subsidence and produc- tion histories in the east and west blocks of the Inglewood field. Thus, during the 1958—62 interval, the average rate of subsidence in the east block fell to about 50 percent of that which prevailed during the preceding quadrennial period (pl. 4); this pronounced deceleration was about three times that in the west block during the same interval. It was, coincidentally, during this interval that. full-scale waterflooding was begun in earnest (table 2). Because approximately 80 percent of the water injected to the end of 19613 was confined to the east block, the preferential reduction in subsidence in this block provides an independent index of the temporal relation between liquid production and subsi- dence. The preceding comparisons between subsidence and production demonstrate a temporal coincidence, both generally and in detail, between subsidence and oil-field operations. This coincidence, combined with the clearly defined spatial association, constitutes persuasive evi- dence of a cause-and-effect relation between fluid CAUSES OF THE SURFACE MOVEMENTS extraction and surface subsidence over the Inglewood oil field. A direct comparison between subsidence at PBM 68 and reservoir pressure decline in the central part of the Vickers zone (fig. 38) shows that these parameters varied directly but nonlinearly during the period 1926—62. Similarly, the average rates of subsidence over successive measurement intervals generally have TABLE 4.—Subsidence and production data for the Inglewood oil field [The data that have been deduced, extrapolated, interpolated, grouped or otherwise modified by the writers are indicated by reference to "this report.” See appendix H for details ofthe calculation of maximum subsidence] California Division of Oil Discovery date September 28, 1924 and Gas (1961, p. 577) Maximum subsidence (d) relative to Hollywood E—ll Nov. 1911—Oct. 19431 ________ 2.37 ft Hayes, 1943, fig. 6; Hayes 1955, fig. 1; Walley, 1963, fig. 1; this report. Oct. 1943—Mar. 1950 ,,,,,,,, .99 ft Walley, 1963, subsidence chart for PBM 68; DWP file card for PBM 122; this report. Mar. 1950—Aug. 1954 ________ .89 ft DWP file card for PBM 122; this report. Aug. 1954—Oct. 1958 _______ .67 ft Do. Oct. 1958—Aug. 1962 H , .55 ft Walley, 1963, p. 5; this report Nov. 1911—Aug. 1962HH H 5.47 ft This report. Approximate dimensions (a and b) of semimajor and semiminor axes of subsiding area simplified to elliptical shape Oct. 1943 _________________ a=7,000 ft; b=5,500 ft Hayes, 1955, fig. 1; this report. Mar. 1950 . _ 327,000 ft; b:5,500 ft Do. Aug. 1954 . _ 8:7,000 ft; b=5,500 ft Do. Oct. 1958 . _ a=7,000 ft; b=5,500 ft Hayes, 1959, fig. 1; this report. Aug. 1962 ,,,,,,,,,,,,,,,,, a=6,600 ft; b=5,200 ft Walley 1963, p. 5. Volume of subsidence (wabd/B) Nov. 1911‘Oct. 1943 ________ Oct. 1943—Mar. 1950 H Mar. 1950—Aug. 1954H __ 35,860,000 ft“ Aug. 195L0ct. 1958 H H 27,020,000 ft3 Oct. 195&Aug. 1962 H H 19,760,000 f‘ta Nov. 19117Aug. 1962 ,,,,,,,, 218,092,000 ft3 95,552,000 fta __ 39,900,000 ft“ Volume of oil produced2 Nov. 191170ct. 1943 ,,,,,,,, 138,256,000 bbls 776,500,000 ft” 33,115,000 bbls 185,900,000 ft3 21,540,000 bbls 120,700,000 fta Bush 1942, p. 36; this report. Oct. 1943—Mar. 1950 ,,,,,,,, Bush, 1949, p. 23; this report. Mar. 1950—Aug. 1954 ,,,,,,,, California Division of Oil and Gas, 1950, p. 26; Musser, 1954, p. 62; this report. Aug. 1954—Oct. 1958 ,,,,,,,, 18,675,000 bbls Musser 1958 p. 79; this report. 104,800,000 ft“ 19,685,000 bbls 110,500,000 ft3 231.152,000 bbls 1,298,000,000 “3 Oct. 1958—Aug. 1962 ,,,,,,,, California Division of Oil and Gas, 1962, p. 107; this report. Nov. 1911»Aug. 1962 ,,,,,,,, Musser, 1961, p. 84; this report. TABLE 4,—Subsidence and production data for-the Inglewood oil field —Continued California Division of Oil Discovery date September 28, 1924 and Gas‘ (1961, p. 577) Gross liquid production2 Nov. 1911—0ct. 1943 ________ 201,205,000 bbls This report. 1,130,000,000 fta Oct. 1943—Mar. 1950 ,,,,,,,, 101,033,000 bbls Do. 567,600,000 ft3 Mar. 1950—Aug. 1954 ________ 77,730,000 bbls Do. 436,500,000 {‘5’ Aug. 1954—Oct. 1958 ________ 80,233,000 bbls Do. 450,600,000 fta Oct. 1958—Aug. 1962 ________ 95,757,000 bbls Do. 537,700,000 ft3 Nov. 1911—Aug. 1962 ........ 555,952,000 bbls Do. 3,120,000,000 fta Net liquid production2 Nov. 1911—Oct. 1943 ________ 201,205,000 bbls This report. 1,130,000,000 it3 Oct. 1943—Mar. 1950 ________ 101,033,000 bbls Do. 567,600,000 ft3 Mar. 1950«Aug. 1954 ________ 77,250,000 bbls Do. 433,000,000 ft3 Aug. 1954‘Oct. 1958 ________ 67,093,000 bbls Do. 376,600,000 fta Do. Oct. 1958—Aug. 1962 ________ 53,307,000 bbls Do. 299,800,000 ft3 Nov. 1911—Aug. 1962 ________ 499,882,000 bbls Do. 2,803,000,000 fl:a Maximum subsidence/gross liquid production Nov. 1911A0ct. 1943 _______ Oct. 194&Mar. 1950 - Mar. 1950—Aug. 1954- Aug. 1954—Oct. 1958 _ Oct. 1958—Aug. 1962 _ H Nov. 1911—Aug. 1962 ,,,,,,,, 0.210 X IO'E/ft2 .175 X 10'5/0;2 .204 X IO'H/ft2 .149 X IO'B/ft2 .102 x 10‘3/ft2 .175 X 104/652 Maximum subsidence/net liquid production Nov. 1911—Oct. 1943 ________ Oct. 1943—Mar. 1950 H. Mar. 1950—Aug. 1954H, Aug. 1954—Oct. 1958 H- Oct. 1958—Aug. 1962 H- Nov. 1911—Aug. 1962 ,,,,,,,, 0.210 x 10‘3/ft2 .175 x 10'5/ft2 .205 x 10“3/ft2 .178 x 10“‘/ft2 .184 X 10‘5/ft2 .195 X 10“’/ft2 Maximum subsidence/oil production Nov. 191170ct. 1943 ________ Oct. 1943rMar. 1950 - Mar. 1950—Aug. 1954, Aug. 1954—Oct. 1958 , Oct. 1958—Aug. 1962 i _H Nov. 19117Aug. 1962 ,,,,,,,, 0.305 X 10"‘/ft2 .532 X 10“5/l"t2 .737 x 10'8/ft2 .639 X 10'5/ft2 .497 X 10"*/ft2 .421 X 10'“/ft2 Volume of subsidence/gross liquid production Nov. 1911v0ct. 1943 ,,,,,,,, 0.085 Oct. 1943~Mar. 1950 H , .070 Mar. 1950~Aug. 1954H , .082 Aug. 1954—Oct. 1958 H , .060 Oct. 1958—Aug. 1962 H , .037 Nov. 1911~Aug. 1962 _______ .070 Volume of water produced Nov. 1911~Oct. 1943 ,,,,,,, 62,949,000 bbls California Division of Oil and Gas production statistics; this re- port. Oct. 1943-Mar. 1950 . H HH 67,918,000 bbls Do. Mar. 195&Aug. 1954. H . 56,190,000 bbls D0. Aug. 195+Oct. 1958 _ A . 61,558,000 bbls Do. Oct. 195ELAug. 1962 . , , 76,072,000 bbls Do. Nov. 19117Aug. 1962 ,,,,,,, 324,800,000 bbls Do. Volume of water injected Nov. 1911—Oct. 1943 ........ 0 bbls California Division of Oil and Gas production statistics. Oct. 1943—Mar. 1950 ,,,,,,,,, 0 bbls Do. Mar. 1950—Aug. 1954 ........ 477,500 bbls California Division of Oil and Gas production statistics; this report. .H 13,140,000 bbls D0. 42,450,000 bbls Do. 56,070,000 bbls Do. Aug. 1954—Oct. 1958 , Oct. 1958—Aug. 1962 , .H Nov. 1911—Aug. 1962 ,,,,,,,, Volume of subsidence/net liquid production Nov. 1911—Oct. 1943 ________ 0.085 Oct. 194&Mar. 1950 H , .070 Mar. 195(LAug. 1954.. . .083 Aug. 1954—Oct. 1958 H , .072 Oct. 195&Aug. 1962 H , .066 Nov. 19117Aug. 1962 ,,,,,,,, .078 Volume of subsidence/oil production Nov. 1911—Oct. 1943 ,,,,,,,, 0.123 Oct. 1943—Mar. 1950 H .214 Mar. 1950—Aug. 1954H .297 Aug. 195L0ct. 1958 H .258 Oct. 195&Aug. 1962 H H .179 Nov. 1911—Aug. 1962 ........ .168 xFigure based on the acceptance of 1911 elevations ofpoints “DD" (PBM 68! and Hollywood 13—11 as true elevations with respect to S—32. 42 X 231 2Volume in cubic feet based on conversion factor of: 1 bbl = 1 x 1 X 12 2 5.615 ft“. 48 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA TABLE 5.—Subsidence and production data for the Vickers zone of the TABLE 5.——Subsidence and production data f0?” the Vickers 20719 0f the Inglewood oil field Inglewood oil field —Continued [The data that have been deduced, extrapolated, interpolated, grouped, or otherwise modified by the writers are indicated by reference to "this report.” See appendix H for details ofthe _ Caligornia DiViSiOD 01" 011 calculation of maximum subsidence.) Discovery date September 28, 1924 an Gas (1961, p. 577) California Division of Oil Net liquid production2 Discovery date September 28, 1924 and Gas (1961, p. 577) Maximum subsidence ((1) relative to Hollywood E—ll NOV‘ 1911-00% 1943 ———————— ééé’égg’ggg $15 This rePm- Oct. 1943—Mar. 1950 ,,,,,,,, 7313951000 bbls Do. Nov. 1911—Oct. 19431 ________ 2.37 ft Hayes, 1943, fig, 6; Hayes, 1955, 412,115,000 ft” fig. 1; Walley, 1963, fig. 1; this Mari 1950—Aug, 1954 ........ 61,118,000 bbls Do. report. 343,200,000 it3 Oct. 1943—Mar. 1950 ,,,,,,,, .99 ft Walley, 1963, subsidence chart for Aug. 1954—Oct. 1958 ________ 53,932,000 bbls Do. PBM 68; DWP file card for PBM 299,500,000 ft3 122; this report. Oct. 1958—Aug. 1962 ,,,,,,,, 35,269,000 bbls Do. Mar. 1950—Aug, 1954 ,,,,,,,, .89 ft DWP file card for PBM 122; this 198338900 053 report. Nov. 1911—Aug. 1962 ,,,,,,,, 394,896,000 bbls D0. Aug. 1954—Oct. 1958 ________ .67 it Do. 2,217,342,000 ft“ Oct. 1958—Aug. 1962 ___ , .55 ft Walley, 1963, p. 5; this report, Nov. 1911—Aug. 1962 ,,,,,,,, 5.47 it This report. Maximum subsidence/gross liquid production Approximate dimensions (a and b) of semimajor and semiminor axes of subsiding area simplified to elliptical shape >< 10-8Ift2 X 10 ' E/ft2 Oct. 1943 ,,,,,,,,,,,,,,,,, 3:7,000 ft; b=5.500 ft Hayes, 1955, fig, 1; this report. X 10“ E/ft2 Mar. 1950 fl ., a:7,000 ft; b=5,500 ft D0. X 10‘3/1‘1;2 Aug. 1954 _- V a:7,000 ft; b=5,500 ft Do. , , . X 10'5/ft2 Oct. 1958 ,, 27,000 ft' b=5,500 ft Hayes, 1959, fig. 1; this report. Nov. 1911—Aug. 1962 ________ .217 X 10‘3/ft2 b=5,200 ft Walley, 1963, p. 5. Volume of subsidence (7rabd/3) Maximum subsidence/net liquid productlon Nov. 1911—Oct. 1943 ,,,,,,,, 95,552,000 ft3 Oct. 1943—Mar. 1950 , __ 39,900,000 fta Nov. 1911—Oct. 1943 _______ 0.245 X 10‘8/ft2 Mar. 195&Aug. 1954, __ 35,860,000 it3 Oct. 1943—Mar. 1950 W , .240 X 10"3/ft2 Aug. 195470ct. 1958 1. 27,020,000 fta Mar. 1950—Aug. 1954,, , .259 X IO'E/ft2 Oct. 195&Aug. 1962 ,,,,,,,, 19,760,000 fta Aug. 1954—Oct. 1958 W . .224 X 10 'E/ftz Nov. 1911—Aug. 1962 ________ 218,092,000 fta Oct. 1958—Aug. 1962 _, , .276 X 10 "Wt” Nov. 1911—Aug. 1962 ,,,,,,,, .247 X 10 's/ft2 Volume of oil produced2 Maximum subsidence/oil production Nov. 1911—Oct. 1943 ,,,,,,,, 113,988,000 bbls This report. 640,041,000 ft3 Oct. 1943—Mar. 1950 "- ______ 18,680,000 bbls Do. 104,891,000 ft3 Nov. 1911r0ct. 1943 ,,,,,,,, 0,370 X 10 ‘B/ft2 Mar. 1950—Aug. 1954 ,,,,,,,, 14,307,000 bbls Do. Oct. 1943—Mar. 1950 _ .945 X 10 "‘lft2 80,335,000 ft” Mar, 195(kAug. 1954. 1.110 X 10 "Wt2 Aug. 195t0ct. 1958 ________ 12,325,000 bbls Do. Aug, 195L0ct. 1958 _ V, .969 X 10 "Wt2 69.205.000 ft” Oct. 1958—Aug. 1962 _ .889 X 101m2 Oct. 1958—Aug. 1962 ,,,,,,,, 11,019,000 bbls Do. Nov, 19117Aug. 1962 ________ .573 X 10'3/ft2 61,872,000 ft3 Nov. 1911—Aug. 1962 ,,,,,,,, 170,139,000 bbls Do. 955,332,000 ft3 Volume of subsidence/gross liquid production Volume of water produced Nov. 1911—Oct. 1943 , , , 0.099 Nov. 1911—Oct. 1943 ________ 58,175,000 bbls This report. Oct. 1943—Mar. 1950 V" , .097 Oct. 1943—Mar. 1950 -_ , 54,715,000 bbls Do. Mar. 1950—Aug. 1954, W .104 Mar 1950—Aug 1954-. 1 47,292,500 bbls Do. Aug. 195L0ct. 1958 , q .072 Aug 1954—Oct 1958 _, . 44,747,000 bbls Do. Oct. 195&Aug. 1962 _ _- .047 Oct 1958—Aug 1962 _- _ 64,535,000 bbls Do. Nov. 1911—Aug. 1962 ,,,,,,,, .087 Nov. 1911«Aug. 1962 ,,,,,,,, 278,643,000 bbls , Do. Volume of water injected Volume of subSIdence/net liquid production Nov. 1911~Oct. 1943 ________ O bbls California Division of Oil and Gas production statistics. Nov. 1911—Oct. 1943 ,,,,,,,, 0.099 Oct. 1943—Mar. 1950 ________ 0 bbls Do. Oct. 1943—Mar. 1950 , , .097 _ 477,500 bbls Do. Mar. 1950—Aug. 1954, , .105 _ 13,140,000 bbls Do. Aug. 1954—Oct. 1958 , , .090 _ 40,285,000 bbls DC. Oct. 195&Aug. 1962 , .100 Nov. 1911—Aug. 1962 _______ 53,886,000 bbls Do. Nov. 1911—Aug. 1962 ,,,,,,,, .098 GYOSS liquid production2 Volume of subsidence/oil production Nov. 1911—Oct. 1943 ,,,,,,,, 172,163,000 bbls This report. 966,692,000 ft3 Nov. 1911—Oct. 1943 ,,,,,,,, 0149 Oct. 1943—Mar. 1950 ,,,,,,,, 73,395,000 bbls D0. Oct. 194&Mar. 1950 A .381 412,116,000 fta Mar. 1950~Aug. 1954. .447 Mar, 1950—Aug. 1954 ________ 61,599,000 bbls D0. Aug. 195+Oct. 1958 , .391 345,822,000 ft" Oct. 195&Aug. 1962 _ __ .320 Aug. 1954—Oct. 1958 ,,,,,,,, 67,072,000 bbls D0. Nov. 1911AAug. 1962 ,,,,,,,, .228 376,608,000 ft3 Oct. 1958—Aug. 1962 ,,,,,,,, 75,554,000 bbls D0. Nov. 1911—Aug. 1962 77777777 123:7231888 {$15 Do. ‘Figure based on the acceptance of 1911 elevations ofpoints "DD" (PBM 68) and Hollywood E—11 as true elevations with respect to 8—32. 2 2'519'914’000 ft” 2Volume in cubic feet based on conversion factor of: 1 bbl =_E%‘ =5.615 ft”. CAUSES OF THE SURFACE MOVEMENTS 49 E 0 I I I I I I 0 I I I I E § INGLEWOOD FIELD \\ VICKERS ZONE 9 \\ . \\ :3: 50 _ Oil production _ 50 _ \\\ _ u_ . A . \ \ 0 Gross IIqUId productIon g \ \ g 100 — Net liquid production — 100 - 1943 _ =I z z. 1950 1950 E 150 - — 150 — — g 1954 > LLI g 200 - — 200 — 1958 — III 1962 a 1962 196? 1962 “a“ I I I I | I 250 I l I I I w 250o 0.5 1.0 1.5 2.0 2.5 9.0 3.5 0 0.5 1.0 1.5 2.0 2.5 3.0 , 7 7 ,, PRODUCTION, IN BILLIONS OF CUBIC FEET _ _ FIGURE 37.—Cumulative oil, gross liquid, and net liquid production from both the entire field and the Vickers zone of the Inglewood oil field versus cumulative volume of subsidence over the field since 1911. Calculation of successive volumes of subsidence based on the assumption that their shapes have closely approximated inverted elliptical cones. (See tables 4 and 5.) varied directly but also nonlinearly with (both accelera- tions and decelerations in) the average rates of reservoir pressure decline over the same intervals (fig. 39). Although this relation seemingly broke down temporar- ily around 1950, reservoir pressure had by this time declined to about 10 percent of its original value (that is, from about 790 psi to 80 psi at —1,850 feet). Thus, small 400 I I I 1962 1958 1 954 8 O I .1 I (D 01 O | 200 "‘ ‘ CUMULATIVE FLUID PRESSURE DECLINE IN POUNDS PER SQUARE INCH 3 o I I 1926 I . I I O 1 2 3 4 CUMULATIVE SUBSIDENCE, IN FEET 0 FIGURE 38.—Cumulative subsidence at PBM 68 versus cumulative- pressure decline in the Vickers zone of the Inglewood oil field for the period 1926—62. Data from figures 120 and 34. errors in measured fluid pressure after the middle 1930’s could have imparted relatively large percentage changes in the pressure-decline rate, such that appar- ent departures from the normally direct relation between pressure-decline rate and subsidence rate may be of little significance during the later production years. The first of the observed correlations (between subsidence and reservoir pressure decline) is consistent with a a cause-and-effect relation between reservoir pressure decline in the Vickers zone and subsidence over the Inglewood oil field; the second (between subsidence rate and pressure-decline rate) is both consistent with and supports such a relation. Both relations, however, particularly the first, are less convincing evidence of the connection between oil-field .0 0! III III III III III III IIIIIII III 50 .0 A I 9 w I Fluid-pressure decline .0 N I O L. I SUBSIDENCE, IN FEET PER YEAR LIIIIIIIIIIIIII I 1942 1946 1950 1954 1958 YEAR O‘OIIIIIIIIIII 1926 1990 1934 1935 I FLUID-PRESSURE DECLINE, IN POUNDS PER SQUARE INCH PER YEAR 0 1 962 FIGURE 39.—Annual average subsidence at PBM 68 and annual average pressure decline in the Vickers zone plotted against time. ‘ Data from figures 120 and 34. 50 operations and subsidence than the previously cited comparisons between production and subsidence. SUBSIDENCE IN OTHER OIL FIELDS A~number of examples have been reported to date of differential subsidence associated with producing oil fields. Poland and Davis (1969, p. 199), moreover, have observed in their recent review of this subject that “doubtless many oil fields away from the ocean or other large water bodies have subsided as much as several feet, but without repeated precise leveling such subsid- ence may pass unnoticed.” The geologic similarities between many of the oil and gas fields in which there has been major surface subsidence are especially significant. Among the nine subsiding, or formerly subsiding, oil and gas fields cited by Poland and Davis (1969), production has been chiefly or entirely from rocks of Cenozoic (mainly late Cenozoic) age and generally from relatively shallow (3,000—4,000 feet or less) horizons (see in addition Pratt and Johnson, 1926, p. 584, and California Division of Oil and Gas, 1961). Most of the domestic examples of differential surface subsidence identified with oil fields occur in California; examples outside California include the Goose Creek (see fig. 48), Mykawa, South Houston (Weaver and Sheets, 1962, figs. 1 and 2), and Saxet fields in Texas. Well-defined subsidence has now been reported in seven other California oil fields in addition to the Inglewood field: Playa del Rey (Grant and Shep- pard, 1939, p. 313—319); Long Beach (Grant, 1944, p. 148—149); Huntington Beach (Gilluly and Grant, 1949, p. 526; Estabrook, 1962, p. 8—9, fig. 2); Santa Fe Springs (Gilluly and Grant, 1949, p. 527); Wilmington (Gilluly and Grant, 1949; Grant, 1954); Torrance (Golzé, 1965, p. 100); and Buena Vista (Whitten, 1961, p. 319; 1966, p. 74; this report, fig. 49). Recent investi- gations have also disclosed at least localized differen- tial subsidence over 10 other California fields: Domin- guez, Edison, Fruitvale, Greeley, Kern Front, Midway-Sunset, Paloma, San Emidio Nose, Tejon North, and an unnamed field in Orange County (Yerkes and Castle, 1970, p. 57—58). Nearly half of the California examples lie within the Los Angeles basin and three of these (Long Beach, Huntington Beach, and Dominguez) occur along the Newport—Inglewood zone. Thus, if it is accepted that the fields listed above have subsided in response to oil-field operations, the Inglewood field, simply on the basis of its location and reservoir characteristics, should be regarded as one with a high potential for exploitation-induced subsid- ence. The number of oil fields in which a temporal relation can be established between subsidence and production is considerably fewer than the number in which a spatial association is evident, for the repeated levelings RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA required to establish this relation have not generally been carried out. Thus, 0f the five oil and gas fields cited by Poland and Davis (1969) in which there is at least a suggestion of a coincidence in time between exploitation and subsidence, all occur in low-lying coastal environ- ments where potential inundation by the sea consti— tutes an evident and sensitive indicator of subsidence and repeated levelings are less necessary. These few examples suggest, nevertheless, that the close correla- tion in time between subsidence and production in the Inglewood field is not simply fortuitous. There are, exclusive of the Inglewood field, only two domestic oil or gas fields in which a coincidence in time between subsidence and exploitation has been demonstrated—Goose Creek, Texas, and Wilmington, California. The Goose Creek oil field was discovered in 1917. By 1918 the Gaillard Peninsula near the center of the field had begun to submerge, and by no later than 1926 the entire peninsula had disappeared beneath the waters of San J acinto Bay (Pratt and Johnson, 1926, p. 577—57 9). Because the Gaillard Peninsula had persisted essentially unchanged in outline and had shown no direct evidence indicative of subsidence for nearly a century prior to 1917 (Pratt and Johnson, 1926, p. 589), it is certainly clear that oil-field operations and subsidence began at about the same time. The relation through time, however, between the rates of subsidence and the rates of oil, gas, water, and sand production, to which the subsidence has been attributed (Pratt and Johnson, 1926, p. 577), is unknown. Repeated level surveys in the Los Angeles and Long Beach harbor areas show that differential subsidence centering on the Wilmington field was absent or inconspicuous before development began in 1936 (Gilluly and Grant, 1949, p. 465—469, 482), yet was well advanced by 1941 (Gilluly and Grant, 1949, p. 469—471). Marigrams taken from the harbor area, moreover, indicate clearly that measurable subsidence of the oil field had begun by 1937 (Gilluly and Grant, 1949, p. 47 8—481). Finally, a fair correlation between rates of subsidence and rates of oil production, and a much better correlation between rates of subsidence and rates of net-liquid production, have also been shown for the Wilmington field (see Poland and Davis, 1969, p. 205; Hudson, 1957, fig. 23). COMPARISON WITH THE WILMINGTON OIL FIELD The subsidence over the Wilmington oil field is probably the best and most carefully studied example of this phenomenon in the world. To the extent that the Wilmington and Inglewood examples are similar, this similarity supports the conclusion that the generally accepted explanation for the subsidence over the Wilmington field (see Harris and Harlow, 1947; Gilluly and Grant, 1949; Miller and Somerton, 1955, p. 68, 70; CAUSES OF THE SURFACE MOVEMENTS Poland and Davis, 1969, p. 201) applies equally to that over the Inglewood field. The Wilmington and Inglewood oil fields are grossly similar in the following ways: (1) Both oil fields lie within the western part of the Los Angeles basin (fig. 1). (2) In each case petroleum occurs chiefly within relatively unconsolidated clastic rocks ranging in age from middle Miocene through Pliocene (California Division of Oil and Gas, 1961, p. 576—577, 686—687).- (3) Major productive horizons occur at relatively shallow depths of from about 2,000 to 4,000 feet in the Wilmington field (California Division of Oil and Gas, 1961, p. 576—577; Poland and Davis, 1969, p. 207) and about 1,000 to 3,500 feet in the Inglewood field. (4) Both fields occur within large, open anticlines broken into two or more major blocks by faults that have acted as barriers to fluid migration (Gilluly and Grant, 1949, p. 483; California Department of Water Resources, 1964, p. 14—15). The Wilmington and Inglewood fields are dissimilar in the following ways: (1) The Wilmington field lies entirely within a large, relatively stable crustal block bounded by the Newport-Inglewood zone on the north- east and the Palos Verdes Hills fault zone on the southwest (Yerkes and others, 1965, p. A5), whereas the Inglewood field lies athwart the active Newport- Inglewood zone (fig. 1). (2) Structural arching in the Wilmington field, in which limbs at depths between —2,300 and —-3,300 feet dip at angles of up to about 20° (California Division of Oil and Gas, 1961, p. 684), is somewhat gentler than that in the Inglewood field, in which limbs at depths between —800 and —1,200 feet dip at angles of up to about 25° (fig. 3). (3) The Wilmington field, much larger than the Inglewood field in both area and production, produced 884,534,330 barrels of oil over a 24-year period, whereas the Inglewood field produced only 221,463,251 barrels of oil during a 36-year period (California Division of Oil and Gas, 1961, p. 577, 687). Annual fluid production, water flooding, and various gas/liquid ratios for the Inglewood and Wilmington fields can be compared in tables 2 and 6. The annual liquid production from the two fields can be compared in figures 28 and 40. A comparison between cumulative production and cumulative maximum subsidence in the Wilmington field shows: (1) that differential subsidence did not begin before production began in 1936; and (2) that periods of major subsidence have generally coincided with periods of heavy production (fig. 41). The relatively low subsidence rate during the early years of exploita- tion, moreover, correlates with a period of generally low gas production. This correspondence between produc- tion and subsidence broke down, however, during the later production years. Thus, by the end of 1958 the 51 TABLE 6.—Fluid production and waterflooding statistics for the Wilmington oil field by year. [Compiled from summary reports of the State Oil and Gas Supervisor] Oil Net gas Water Gross liquid production production production production Year (in bbls) (in Met) (in bbls) (in bbls) 91,089 unknown 6,609 97,698 14,047,340 3,480,000 159,137 14,206,477 34,021,599 17,700,000 379,036 34,400,635 31,091,297 25,360,000 419,526 31,510,823 30,237,750 25,750,000 759,856 30,997,606 30,683,188 25,650,000 1,734,025 32,417,213 33,378,681 31,108,935 2,648,562 36,027,243 34,298,354 32,951,165 3,933,020 38,231,374 36,892,094 38,497,054 5,658,850 42,550,944 36,173,033 38,153,281 6,801,978 42,975,011 40,175,993 40,491,653 7,850,817 48,026,810 47,686,643 51,714,619 9,251,923 56,938,566 48,320,459 55,920,765 11,510,109 59,830,568 43,495,989 49,261,566 13,390,295 56,886,284 46,227,417 49,597,076 14,631,504 60,858,921 50,786,902 53,550,889 17,571,264 68,358,166 48,105,364 42,566,775 20,695,450 68,800,814 44,341,298 36,889,300 22,446,183 66,787,481 41,561,100 34,018,746 24,330,956 65,892,056 38,879,018 31,210,293 25,960,920 64,839,938 36,799,908 29,704,516 28,929.099 65,729,007 32,427,190 26,215,132 30,634,598 63,061,788 29,676,471 25,033,097 31,881,762 61,558,233 26,944,459 20,462,403 34,615,165 61,559,624 27,550,499 17,522,921 48,740,374 76,290,873 27,971,235 12,997,816 58,403,025 86,374,260 Water Net liquid Gas/gross Gas/net injected production Gas/oil liquid liquid Year (in bbls) (in bbls) (Mcf/bbls) (Mcf/bbls) (Mcf/bbls) 1936 97,698 .... _... ._.. 14,206,477 0.248 0.245 0.245 34,400,635 .520 .514 .514 31,510,823 .815 .805 .805 30,997,606 .852 .832 .832 32,417,213 .836 .792 .792 36,027,243 .923 .863 .863 38,231,374 .961 ,862 .862 42,550,944 1.043 .905 .905 42,975,011 1.054 .889 .889 48,026,810 1.008 .843 .843 56,938,566 1.084 .908 .908 59,830,568 1.157 .935 .935 56,886,284 1.132 .866 .866 60,858,921 1.072 .815 815 68,358,166 1.054 .783 .783 68,800,814 .885 .618 618 651,700(?) 66,135,781(?) .832 .552 .558 1,414,971 64,477,085 .819 .493 .528 4,378,704 60,461,234 .803 .482 .517 9,368,272 56,360,735 .807 .452 .527 13,862,295 49,199,493 .807 .416 .533 30,813,528 30,744,705 .843 .407 .813 87,185,762 —25,626,138 .759 .332 -___ 133,555,117 —57,264,244 .636 .230 -_._ 154,282,971 —67,908,711 .465 .150 -... slope of the production curve had actually reversed, whereas the subsidence continued (although at a slower rate). The slope reversal in the production curve derives from the onset of massive waterflooding in 1957 and 1958 (see table 6 and fig. 40); because the initial repressuring was concentrated chiefly in the southern part ofthe field (Poland and Davis, 1969, p. 21 1), and up through 1960, at least, was nonuniform with respect to both producing area and producing zone (Musser, 1960, p. 133—134), the cumulative production and cumulative maximum subsidence curves should not be compared for the years after 1957. In any case, and regardless of the fidelity of the correspondence, it is evident that the maximum subsidence over the Wilmington field has varied directly with net-liquid production. Comparisons between various aspects of liquid production and maximum subsidence in the Wil— mington field show that between 1945 and the initiation PRODUCTION, IN MILLIONS OF BARRELS 52 70 IIIIIIIIIIIIIIIIIIIIIIIIIIIIW 60— _ 5o _ Net liquid I 30— 10- ZINeI vllaltei'}..‘1~ -'. _30 — Net liquid /////A —50 — _ /J I _60 _ _80 _ _90 _ r777J//// A IIIlIllIIllIIlLIIIIJIIIIIIII 0 1935 1940 1945 1950 1955 1960 YEAR FIGURE 40.—Annual oil, net water, and net liquid production from the Wilmington oil field through 1961. (See table 6.) 1965 of full-scale waterflooding in 1957, there existed a near-linear relation between net liquid production and maximum subsidence (fig. 42). Because cumulative net liquid production during the 12-year period 1945—57 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA E: o o " m X 0 I— ; w 200— —2oou. a 9 a: 9 9E4oo~ -4000 ID 0 E. E <12 3Figures in parentheses based on subsidence volumes modeled on inverted elliptical cones. = 5.615 ft‘3 directly and almost linearly with net liquid production; (3) the volume of subsidence has varied directly and almost linearly with net liquid production; (4) the rates of subsidence have varied directly with the rates of net liquid production; (5) changes in subsidence rate have been associated with corresponding changes in gas production rate; and (6) subsidence has varied directly but nonlinearly with changes in measured reservoir pressure. Thus, despite prominent dissimilarities in physical size and magnitude of production and subsidence, the many other physical similarities, and the strong similarities between the several measures of subsidence versus fluid production are sufficiently striking that the subsidence over each field can be attributed to the same cause or causes. Published investigations of the Wilmington subsidence attribute it unanimously to compaction following withdrawal of fluids during oil-field operations (Harris and Hawlow, 1947; Gilluly and Grant, 1949; Miller and Somerton, 1955, p. 68, 70; Poland and Davis, 1969, p. 201). Hence, the various cited similarities between the Inglewood and Wil- mington examples support the conclusion that the subsidence over the Inglewood field is also due to withdrawal of fluids associated with oil-field operations. PHYSICAL RELATIONS THEORETICAL AND EXPERIMENTAL BASES Poland and Davis (1969) have summarized briefly the application of consolidation theory to the analysis of surface subsidence. The general principles outlined by 1200 I 1 1 1 1100 7 I _. <0 01 .1 | 1 000 900 — 800 - 1947 70° ‘ 1947 ' 1946 . 600 _ 1945 1946 A 1945 500 — o _ UpperTerminal zone 1941 A 400 - Ranger zone r 1 941 300 — r 200 - — 100 — CUMULATIVE FLUID-PRESSURE DECLINE, IN POUNDS PER SQUARE INCH 1936 I I I I 0 5 10 15 20 25 CUMULATIVE SUBSIDENCE, IN FEET 0 FIGURE 43.—Cumulative maximum subsidence versus cumulative measured pressure decline in the Ranger and Upper Terminal zones of the Wilmington oil field. Data from figure 41 and DeGolyer and MacNaughton Core Laboratories (1957, charts 3 and 4). these writers provide the framework for the following discussion. Central to the arguments of Poland and Davis (1969, p. 193—197) is the acceptance of Terzaghi’s principle of effective stress, which states that within a porous, fluid—filled medium p = p’ + u, where p = total stress or pressure, p’ = effective (grain-to-grain, intergranular, “solid”) stress or pressure, and u = fluid (porewater, reservoir, neutral, internal) stress or pressure.5 In a confined water system in which the compressibility of water is disregarded, unit head decline (which may be equated with reduction in fluid pressure) will produce an equal increase in effective pressure; in an unconfined water system any reduction in liquid level will produce an increase in effective pressure through loss of buoyancy, and the total pressure will decrease slightly owing to the loss of fluid mass from the system (Poland and Davis, 1969, p. 193—196). Because the overburden is supported by both fluid and effective pressure, decrease in fluid pressure to a point approaching zero will increase the effective pressure to a value approaching 5Fatt (1958. p. 1926, 1930) has found experimentally that for actual in situ conditions in porous rock, the relation may be closer top = p' + nu, where n is a function ofp and the compressibility of the solid materials, being close to unity in the 1,000 psi range. 56 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 0.6 | 1 I | VOID RATIO(e) 0.6 I I I I I I I I I I I Reoompressional 0.2— ft" - N _ A B .“lTransitionglme lo— Virginal E s a s a s §§§§§§§§§§§§ PRESSUREJN POUNDS PER SQUARE INCH FIGURE 44.—-Void ratio as a function of applied pressure for adjacent sand and clay samples from a post-Eocene Bolivar Coast formation at a depth of 3.100 feet; dashed lines show hypothetical relations in the absence of any transitional zone. A, Natural scale. B, Semi- logarithmic e-log p plot. After van der Knaap and van der Vlis (1967, p. 89). that of the lithostatic pressure; the resulting compres- sion will be proportional to the magnitude of the increase in effective pressure (Poland and Davis, 1969, p. 193—196). The principles outlined above indicate that reduc- tions in reservoir (fluid) pressure accompanying with- drawal of fluids will increase effective pressure on the skeletal materials of the reservoir. This increase may be treated as an externally applied load; the resulting compression (compaction) is a function of both the mag- nitude of the load and the compressibility of the skeletal materials (Poland and Davis, 1969, p. 196—197). One-dimensional consolidation tests on a variety of natural and artificially reconstituted sedimentary materials show that compaction (commonly expressed as changes in void ratio) or strain varies directly With applied load (Terzaghi and Peck, 1967, p. 65—68; Johnson and others, 1968, p. A17-A19; van der Knaap and van der Vlis, 1967, p. 88—89; Allen and Mayuga, 1970, p. 415). Compaction per unit load, moreover, generally decreases with increasing load, much as shown in figure 44A. (See also Terzaghi and Peck, 1967, p. 65—68.) Test data ordinarily are plotted, however, in a semilogarithmic manner, whereby void ratio (e) is graphed against the log of the applied pressure (p); such graphs generally have the form shown in figure 44B. The resulting curves, depending on the consolidation history of the sample, commonly are divisible into three parts (see fig. 44): (1) a steeply sloping “virginal” part representing a range of applied pressures to which the sample had not been subjected previously; (2) a gently sloping recompressional or preconsolidated part repre- senting a range of applied pressures to which the sample had been subjected previously; and (3) a zone transi- tional between these two (Terzaghi and Peck, 1967, p. 73—78; Johnson and others, 1968, p. A19; van der Knaap and van der Vlis, 1967, p. 89). At elevated pressures and over limited pressure ranges, particularly Within those parts of the e-log p plots represented by the transitional zone, compaction commonly varies nearly linearly with applied pressure, as plotted at natural scale (Taylor, 1948, p. 216; Gilluly and Grant, 1949, p. 512; Terzaghi and Peck, 1967, p. 65—67; fig. 44, this report). Thus, in the general case compaction increases linearly or at progressively decreasing rates with respect to increasing load. The inverse relation (that is, one in which compaction increases at progressively increasing rates with increasing load) is much less likely and probably occurs only Within the transition zone between preconsolidated and virginal pressures. The likelihood of the occurrence and the prominence of the effect of this inverse relation is a function of the contrast between the slopes of the recompressional and virginal parts of the e-log p curve, the initial slope of the recompressional portion, and the radius of curvature of the transitional zone. Because the curves for dense sands generally show less contrast in slope between recompressional and virginal parts, the effect is more apt to be expressed in surficial deposits than in such materials as oil sands (Terzaghi and Peck, 1967, p. 67). In order to examine the extent to which the compressibilities of oil-field reservoir materials may increase with increasing load, we have prepared natural-scale e—p plots for two Bolivar Coast (Lake CAUSES OF THE SURFACE MOVEMENTS Maracaibo) samples (fig. 44A), seven arbitrarily selected Wilmington samples from depths of between 2,500—4,500 feet (Witucki, 1959, unnumbered figures), and an “average” (2,000 to 4,000-foot) Wilmington sand (Allen and Mayuga, 1970, p. 415). The plots for the two Bolivar Coast samples shown in figure 44A indicate that any reversal in the generally decreasing rate of change in void ratio with respect to increasing stress is so slight as to be undetectable. Of the seven Wilmington samples (three sands and four clays or shales), two showed no inflection in the e-p curves, four showed very slight, almost undetectable inflections, and the seventh (the shallowest clay) showed a marked inflection; the "average” Wilmington sand showed no inflection. The “transitional zones” between the experimentally re- loaded and Virginal parts of the e-log p curves were, in all of the examined cases, very sharp. This sharp transition may more nearly approximate the in situ condition than does the generally smooth transition between recompressional and Virginal parts of the curve developed from laboratory studies. However, barring the nearly complete absence of a smooth transitional zone, increases in the compaction rate (with respect to pressure) within the transitional zone generally do not even begin to compare with the average compaction rate over the curve as a whole. Hence we conclude as a close approximation, that compaction of the clastic sedimen- tary materials that make up these reservoirs varies directly and at constant or progressively decreasing rates with respect to increasing pressure. RELATIONS BETWEEN RESERVOIR‘PRESSURE DECLINE AND SUBSIDENCE The preceding discussion indicates that compaction in idealized or hypothetical reservoir systems (where the effects of time may be disregarded on the assump- tion that drainage is rapid) varies directly and generally at constant or progressively decreasing rates with increasing effective pressure (declining fluid pressure). That is, %1% either remains constant or 2 decreases with increasing effective pressure (372$ 0), where C is compaction and E is effective pressure. The observational evidence (figs. 38 and 43), however, indicates that subsidence over (or compaction in) the Inglewood and Wilmington fields has increased at 6Pressure decline in the Vickers zone (fig. 34) is considered representative of that for the field because: (1) through 1963 about 72.5 percent of the oil and about 78 percent of the net liquid production (but only about 50 percent ofthe gas) had come from the Vickers zone; (2) about two-sevenths of both the measured subsidence in the northern Baldwin Hills and the liquid production from the Inglewood field between 1911 and 1963 had been generated by 1934, up to which time there had been almost no production from zones other than the Vickers; (3) variations in production from the remaining zones ofthe Inglewood field are very doubtfully related to changes in subsidence rate, whereas there is an excellent correspondence between liquid production from the Vickers zone and subsidence (See Conservation Committee of California Oil Producers, 1964, p. P; this report, figs. 126', 13, and 32). 57 progressively increasing rates with respect to declining fluid pressure (increasing effective pressure).6 That is, fihas increased with declining fluid pressure (L28 >0) dAP dAP2 ’ where S is subsidence and AP is pressure decline. A similar, direct but nonlinear relation between subsi— dence and reservoir pressure decline has also been recognized in an unnamed Bolivar Coast oil field (van der Knaap and van der Vlis, 1967, p. 93—94). This seeming inconsistency between the pressure decline- subsidence relations associated with actual examples and those predicted for an idealized system may be explained by one or more of the following: 1. Terzaghi’s principle of effective stress may be inapplicable in multifluid reservoirs; 2. The relation between decreasing reservoir pres— sure and surface subsidence may have been obscured by creep effects; 3. Compaction generated after the first 5 or 10 years of production may be due chiefly to dewatering of fine-grained interbeds, to which the mea- sured fluid pressures do not apply; 4. The compressibility of certain oil-field reservoir materials may increase with increasing stress; 5. Small declines of liquid level in each of many layers of a multilayered reservoir, such as the Vickers zone, lead to small losses in fluid pressure and equivalent small increases in effective pressure. The resulting, individually small increments of compaction may lead, however, to large cumulative values of compac— tion for the entire zone; 6. Measured and calculated reservoir-pressure— decline curves, such as those in figures 33 and 34, may not be representative of the average or true reservoir fluid pressure decline. Terzaghi’s effective stress equation has been investi- gated chiefly in connection with laboratory studies of foundation problems; its applicability remains untested over the wide range of fluid pressures within the multifluid environments that characterize producing petroleum reservoirs. Hence, the possible inapplicabil- ity ofTerzaghi’s equation to this system could explain in part why the observed relation between pressure decline and subsidence (fig. 38) is inconsistent with that predicted by our hypothetical model. Bishop (1961, p. 38—46) and Skempton (1961) have verified experimentally a general two—phase form of the effective stress equation, first proposed by Bishop in 1955, and considered applicable to volume changes (compaction) in oil-plus—water systems (Bishop, in British National Society, International Society of Soil Mechanics and Foundation Engineering, 1961, p. 63); thus, plzp—ua+x(ua—uw), 58 where ua and uw are the pore pressures of air and water, and x varies directly with the degree of saturation. For dry soils x = 0 and for completely saturated soils it equals 1. In both limiting cases the general expression reduces to Terzaghi’s equation, p’ = p—u. The term “(ua—uw)” is an expression of “capillary pressure” and varies directly with effective pressure; thus, in an air-water system changes in the moisture content (and therefore changes in the “capillary pressure”) will necessarily lead to changes in effective pressure. However, because measurable fluid pressures in pe- troleum reservoirs may be indistinguishable from one or the other of the partial fluid pressures, and because we are unable to assign values to x and the partial fluid pressures in such systems, we are unable to apply this modified equation to petroleum systems. (It should be noted, however, that the invalidation of the unmodified form of Terzaghi’s equation of effective stress, as applied to petroleum systems, would not in itself contribute to an explanation of the roughly linear relation between subsidence (compaction) and liquid production.) Creep phenomena provide a second possible explana- tion for the observed relation between pressure decline and subsidence in the Inglewood oil field (fig. 38). Van der Knaap and van der Vlis (1967, p. 91), for example, have observed that the full effects of compaction in the producing layers need not be instantaneously propa- gated to the surface. Thus an exact correspondence between pressure decline and subsidence need not be expected. Subsidence over the Inglewood field, moreover, tended to lag behind pressure decline during the first decade of production (figs. 12C, 13, 33 and 34). Creep effects, accordingly, may provide a partial explanation for the absence of a correspondence between pressure decline and subsidence more in keeping with that predicted for an idealized system. It is unlikely, however, that the progressively increasing subsidence with respect to the very limited pressure decline after 1933—34 can be more than incidentally attributed to creep. (Again, moreover, this explanation for the observed relation between subsidence and pressure decline contributes in no way toward an explanation of the essentially linear relation between fluid production and subsidence; creep effects may, in fact, account for the absence of an even more precisely linear relation between these two parameters.) Compaction generated in response to dewatering of shaly interbeds suggests a third possible explanation for the observed relation between subsidence and reservoir pressure decline in the Inglewood oil field (fig. 38). Thus in a system such as the Vickers zone, where the reservoir sands are interlayered with fine-grained and relatively impermeable shales, and a stable hydraulic gradient is presumed to have existed between sands and shales prior to exploitation, any rapid drop in RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA reservoir pressure will produce fluid-pressure gradients across the sand-interbed boundaries. If reduced fluid pressures are maintained within the reservoir sands over long periods of time, pressure equilibration between the sands and shale interbeds will lead to dewatering and resultant compaction of the shales. Dewatering of the shales will be inhibited by the low permeability of these materials; hence, most of the subsidence generated after the initially large and seemingly nearly total loss of reservoir fluid pre8sure could have developed as a result of slow compaction of the shaly interbeds. Although a part of the total Vickers zone compaction is almost certainly due to interbed compaction, it is unlikely that this mechanism has accounted for nearly all of the post-1932 subsidence. Laboratory studies by van der Knaap and van der Vlis (1967, p. 92), for example, have shown that Bolivar Coast clay beds 5 feet or less in thickness will, in response to an instantaneous (unspecified) drop in fluid pressure, consolidate to 80 percent of their ultimate consolidation in about 2 years or less. Thus over short intervals of time (generally less than those that have obtained between repeated level or casing collar surveys in the Inglewood and Wilmington oil fields), the compaction of clay layers 5 feet or less in thickness should be nearly indistinguishable from that of the reservoir sands; that is, for any given reservoir pressure drop, both sands and clay layers no more than 5 feet thick can be expected to have attained nearly their maximum compaction within 2 or 3 years. Therefore, because only. about 28 percent of the Vickers zone consists of shale beds more than 5 feet thick, assignment of the post-1932 compaction to interbed compaction suggests that nearly all the post-1932 subsidence is due to the compaction of only about 28 percent of the section. Hence if this subsidence (about 75 percent of that which occurred through 1963—see figs. 120 and 13) is due to interbed compaction, it implies that the compressibility of the shales is aboutsix or eight times that of the reservoir sands. Inasmuch as van der Knaap and van der Vlis (1967, p. 85, 90) have shown that both sands and clays from Bolivar Coast fields compact ultimately to almost the same extent, the occurrence of such relatively high shale compressibilities is considered unlikely. This conclusion is supported in part by the studies of Allen and Mayuga (1970) who report’ that 67.6 percent of the compaction within the upper four producing zones of the Wilmington field (where the compactible sands comprise 242 m out of a total section more than 470 m thick) has occurred within the reservoir sands, whereas only 32.4 percent has occurred within the shales or siltstones. V A second consideration that argues against the attribution of the post-1932 compaction to interbed compaction, derives from the roughly exponential CAUSES OF THE SURFACE MOVEMENTS ._ relation that obtains between thickness and compaction of clay layers in at least some oil fields. For example, whereas ten 4-foot Bolivar Coast clay layers will compact to about 80 percent of their ultimate compac- tion in about 1 year, two 20-foot layers and one 40-foot layer will compact to the same degree in about 25—30 and 110—120 years, respectively (van der Knaap and van der Vlis, 1967, p. 92). Thus, because about 74 percent of the Vickers zone shale beds over 5 feet thick consist of beds over 20 feet thick, it is likely that any interbed compaction due to a nearly total loss of reservoir pressure before 1932 was confined largely to the small percentage of shale beds between 10 and 20 feet thick (roughly 170 feet out of a total section of 2,300 feet). Changing consolidation characteristics provide a fourth possible explanation for the increasing rate of subsidence with respect to declining reservoir fluid pressure in the Inglewood field (fig. 38). Grant (1954, p. 23) has, in effect, argued that accelerated subsidence may begin at some critical, threshold value of reduced reservoir pressure, which reflects in turn the maximum effective pressure to which the reservoir skeleton had been previously subjected. Accordingly, should the effective pressure increase above this threshold value in response to a substantial reduction in reservoir pres- sure, compaction per unit pressure increase might be considerably greater than that within the preconsoli- dated range. Several considerations indicate that changes in compressibility probably cannot explain the subsidence—reservoir pressure decline relations in the Inglewood field nor can they explain the similar relation recognized in the Wilmington oil field. The development of a prominent angular unconfor- mity between the so-called Pico Formation and the overlying Pleistocene sands and gravels, as shown in figure 2, suggests the removal of a substantial thickness of the pre—Pleistocene section (Robertson and Jensen, 1926, p. 35—39). The amount removed cannot be precisely determined; however, a crude estimate of the section eroded from the structural crest of the east block may be obtained by projecting westward (in vertical section) the so-called Pico-Pleistocene sand contact from a point immediately west of the Crenshaw Boulevard— Stocker Street intersection, where the two units seem to be nearly conformable (see Castle, 1960). This projec- tion suggests that about 1,600 feet of section was removed from the crest before the Pleistocene materials were deposited. This implies in turn that the pre- Pleistocene section centering on the structural crest of the east block has been overconsolidated by an amount approximating the lithostatic equivalent of 1,600 feet of brine saturated, hydraulically continuous section, min- us that attributable to the roughly 50 feet of overlying 59 and seemingly unsaturated Pleistocene sands (whose load effect may be taken here as approximating that of 100 feet of saturated, hydraulically continuous sec- tion).7 Thus, it is concluded that the Vickers zone prob- ably has been overconsolidated by at least (1600—100) (62.5) (0.70) (1.7) 144 = 775 psi, where 1600—100 = equivalent thickness in feet of hy- draulically continuous materials removed from the post-Vickers section, weight of 1 cubic foot of water in pounds, volume ratio of grains to the total volume of sediments (T. H. McCul- loh, written commun. 1966), density of grains minus buoying ef- fect of water, and number of square inches per square foot, (see Gilluly and Grant, 1949, p. 502). Therefore, if the average reservoir pressure at the beginning of produc— tion may be taken as 790 psi (see fig. 38), it is unlikely that the change in effective pressure has ever exceeded the preconsolidation pressure, for the average reservoir fluid pressure probably has declined by no more than about 750 psi over the entire productive history of the Vickers zone (see fig. 34). The average reservoir pressure in the Vickers zone is calculated to have declined about 600 psi between 1925 and 1930; it declined over the next 30 years by no more than about 150 psi (fig. 34). If it is accepted that the relatively limited subsidence that accrued during the initial period of rapid pressure decline was due to compaction within the preconsolidated range, then it follows that the diminished, but substantial subsidence (about 1 foot at PBM 68 between 1931 and 1943; see fig. 120) that occurred after this period of rapid pressure decline derived from compaction within the “virginal” range, for it was seemingly associated with an almost negligible reduction in pressure decline (about 40 psi between 1931 and 1943; see fig. 34). This explanation, however, suggests that the achievement of the precon- solidation limit was coincident with the sharp break in II 62.5 0.70 — I 1.7 144 = 7It is assumed that the land surface and the position in space of the fluid-pressure gradient bore the same relation to each other when erosion began as they do now, since the post-"Pica” surface must have been moderately elevated above sea level in order that erosion might ensue and fluid pressureswithm the Cenozoic formations 11‘} this area probably have remained closely adjusted to normal hydraulic gradients established with respect to prevailing sea levels. However, the critical erosion surface may have stood at an even higher elevation and the degree of preconsolidation may have been correspondingly greater (owing to a corresponding drop in fluid-pressure levels); this possibility is supported by the recognized sea—level lowerings associated with Pleistocene glaciation, maximum values (with respect to present sea level) ofwhich have been given as 525 feet (Donn and others,1962, p. 2127214) and 418 feet (Curray, 1965, p. 725). 60 TABLE 8.——Measured reservoir-pressure decline in selected zones of the Wilmington oil field [Data from DeGolyer and MacNaughton Core Laboratories (1957, p. 11, charts 2, 3, and 4). Psig = pounds per square inch gage] Tar zone Ranger zone Upper Terminal zone Unweighted average Reservoir pressure Reservoir pressure Reservmr pressure percentage Inte rval decline decline decline decline of initial . Per— ‘ Per- _ PerA pressure pslg cent p51g cent p51g cent 1936—1/1/45 1,120—940 16 1,850—755 44 1,455—925 36.5 31.8 1/1/45~1 1/56 ‘940—390 49 I755—290 34.5 1925—280 44.5 42.6 9/26/45—11/15/49 905—730 155 720—535 135 880-575 21 16.7 11/15/49—4/11/57 1730—365 32.5 1535—280 19 ‘575—265 21.5 24.4 ‘ Estimated reservoir pressure decline (fig. 34). Had it been achieved much earlier, the amount of subsidence between 1926 and 1931 should have been proportionately larger; had it been reached much later, the subsidence should have nearly ceased during the decade of negligible pressure decline after 1930, whereas, in fact, it apparently proceeded at a reasonably rapid rate. Moreover, if the post-1930 subsidence was due chiefly to compaction within the virginal compression range, it is difficult to ‘ account for the accelerated subsidence that began about 1942 or 1943 and continued at an approximately uniform rate through 1962. The rate of pressure decline seems to have accelerated slightly around 1944 or 1945 (to no more than one—tenth that which prevailed during the 1925-31 period), but it must have quickly dropped to a rate that should have promoted a subsidence rate no greater and probably much less than that which obtained during the 1932—42 period (roughly half that of subsequent years). Accelerated subsidence over the Wilmington field apparently began during the early or middle 1940’s (fig. 41). It could be argued, accordingly, that this accelera- tion was simply coincident with the achievement of effective pressures within the virginal compressional range and, hence, accelerations in the rates of compac- tion (even in the absence of comparable accelerations in the decline of reservoir pressure within the compacting zones). This argument is refuted, however, by a comparison of measured reservoir pressure decline with compaction over two intervals beginning in 1945 (9/26/45—11/15/49 and 11/15/49—4/11/57; see tables 8 and 9). Measured reservoir pressure declines in the Ranger and Upper Terminal zones during the first interval very nearly equalled those that occurred during the second interval, whereas reservoir pressure in the Tar zone declined by a factor of two during the second interval. Compaction, on the other hand, more than doubled during the second interval in both the Ranger and Upper Terminal zones and increased by an infinite factor in the Tar zone. This apparent increase in the rate of compaction with respect to reservoir pressure decline (or increased effective pressure) within the RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA TABLE 9,—Casing collar surveys of compaction in upper three producing zones of the Wilmington oil field over two selected time intervals [After Poland and Davis, 1969, p. 207—208] Interval Tar zone Ranger zone Upper Terminal zone (compaction in ft) (compaction in ft) (compaction in ft) 9/26/45—1 1/ 15/49 11/15/49—4/11/57 1-0.02 1.49 1.77 3.79 2.78 6.46 ‘Tension. virginal compressional range is, however, inconsistent with the results of modern laboratory investigations which show that compaction entirely within the virginal range increases at linear or progressively decreasing rates with respect to increasing effective pressure. Thus, the observed relation between subsid- ence and reservoir pressure decline in the Wilmington, as well as the Inglewood field, is seemingly unexplained by the suggestion that increasing compressibilities of the reservoir materials should or could be associated with increasing effective pressures. The preceding considerations indicate that the relation between reservoir pressure decline and sub- sidence over the Inglewood field (and, by extension, compaction of the Vickers‘zone) cannot be attributed to major differences in the preconsolidated and “virginal” compaction characteristics in the Vickers zone. Buoyancy losses within the multilayered reservoir system respresented by the Vickers zone, following an initially large decompression, provide a fifth possible explanation for the increasing rate of subsidence with respect to reservoir pressure decline in the Inglewood field (fig. 38). Poland and Davis (1969, p. 193—196) have shown in connection with simple water systems, that the increase in effective pressure (Ap’) developed during reservoir depletion may be separated conceptually into two stages: that due to artesian head decline in a confined System and that due to buoyancy loss as- sociated with liquid-level decline (once the desaturation point is reached) in an unconfined system. Artesian head decline in a confined system may be likened to decompression through the production of dissolved gas in the liquid-saturated petroleum system, whereas water-level decline in an unconfined system may be compared to liquid production from a petroleum reservoir once a free gas phase has developed. Although neither primary nor secondary gas caps have been reported from the Vickers zone (Oefelein and Walker, 1964, p. 510), the initial solution GOR (gaszoil ratio) of 90 ft3/bbl at 570 psi and 100°F given by Oefelein and Walker (1964, p. 511) indicates that a widely dissemi- nated free gas phase probably was generated very early in the production history of this zone (Standing, 1947, p. 97). CAUSES OF THE SURFACE MOVEMENTS The coexistence of a relatively incompressible liquid (water), a relatively compressible liquid (oil), and gas, under conditions in which these fluid proportions have been constantly changing, seemingly invalidates direct comparisons with water systems. If, however, the reservoir pressure decline curve presented in figure 34 is representative of fluid pressure decline in the Vickers zone, then the maximum increase in effective pressure (Ap’) due to decompression of the liquid-saturated system should be approximately equal to the specified reservoir pressure decline (that is, since p changes only slightly with loss of fluid mass, it should amount to perhaps 95 percent of the pressure decline), and thus analogous to that developed in response to a specified artesian head decline in a simple water system. In any case, by the time that a free (albeit disseminated) gas phase had developed, the reservoir could no longer be viewed as liquid saturated. Because the Vickers zone had not been uniformly depleted during its primary recovery stage (Oefelein and Walker, 1964, p. 511), a direct analogy with the liquid—level decline stage in a simple water system may seem inappropriate. How- ever, the magnitude of the increased effective pressure arising from a comparable effect may be estimated by treating the entire Vickers zone as a single unit divisible into a finite number of mechanically indepen- dent subunits of equal thickness. The decompressed Vickers system may be visualized as a series of superposed or stacked reservoir units of small thickness, within which fluid pressures had by 1930 declined to small fractions of their preexploitation values, but which remained just liquid-saturated up to the beginning of liquid-level decline and buoyancy loss. That is, fluid pressure within each layer was charac- terized by a normal hydrostatic gradient increasing downward from zero at the top. Changes in effective pressure resulting from liquid-level decline through a single-unit equivalent of the Vickers zone may be calculated through use of an expression modified from one derived by Poland and Davis (1969, p. 195). Thus, as shown in appendix J: (1) the cumulative increase in effective pressure due to liquid-level decline or loss of buoyancy in this simplified, single-unit system could have been no greater than about one-half that due to decompression, even if it is falsely assumed that the entire increment attributable to decompression oc— curred before 1930; and (2) the effects of liquid-level decline or loss of buoyancy on the increase in effective pressure were inordinately greater during the early production years than they were after about 1940—45. Hence the acceptance of this scheme suggests that about 70 percent of the increase in effective pressure should have occurred during the first 10 years of production, and buoyancy losses during later years could have 61 accounted for no more than about one—fourth of the cumulative change in effective pressure. In order to simplify the treatment, the calculations of average increase in effective pressure attributable to liquid-level decline (appendix J) have been based on the assumption that an unlayered, hydraulically continu- ous system is mechanically equivalent to the described system—that is, one divisible into an unspecified number of equithick layers separated by rigid, im- permeable membranes of zero thickness and charac- terized by normal hydrostatic gradients increasing downward from zero at the top. In fact, however, the average increase in effective pressure generated in response to liquid-level decline through such a system is inversely proportional to the number of layers in the system.8 Therefore, the actual average increases in effective pressure due to buoyancy losses are only 1/ Q times those tabulated in appendix J, where Q equals the number of layers in the system. Because the Vickers zone is divisible into at least 10 seemingly hydraulically independent layers (see pl. 1 and Oefelein and Walker, 1964, p. 510), buoyancy losses probably have accounted for no more than 2 or 3 percent of the increased effective pressure due to fluid production from the Vickers zone. Accordingly, the seeming aberration in the subsidence-reservoir pressure decline relation de- veloped in the Inglewood field (fig. 38) can be no more than incidentally attributed to buoyancy losses during the post-1930 production years. sThe average change in effective pressure in an unconfined system, in which liquid level has declined from the top to the base of the reservoir, may be given as Ap’ = yp(1—n+nfl)(T/2), where Ap’ = average change in effective pressure, unit weight of liquid, reservoir porosity 0 liquid retained above the saturation level expressed in percent of total volume, and, 3 ll || ll T = reservoir thickness. This expression is modified from one given by Poland and Davis (1969, p. 195); their equation is divided by 2 because it permits calculation of the change in effective pressure at the base of the drained column only, whereas the average change in effective pressure is sought here. Hence, for the two specified systems, let Apl' = the average increase in effective pressure developed in response to liquid-level decline through an unlayered reservoir of thickness T, characterized by a normal hydrostatic gradient increasing downward from zero at the top, and Ap2’ = the average increase in effective pressure developed in response to liquid level decline through each of f layers of equal thickness t, characterized by normal hydrostatic gradients increasing downward from zero at the top and comprising a total thickness T; Apz’ is a function ofthe thickness t and, in this idealized system, independent of the total thickness T. Then Apl’ = (yr)(l—n+npi(T/2) Apz’ = (yrHl'nHic) (1/2) and since T = 9,! API' ”—7 2 p_ Apz The effects of mass loss are disregarded here, for it can be shown that liquid-level decline through the full 1,650-foot, single-unit Vickers zone equivalent would decrease the average geostatic pressure by only about 23 psi. 62 The possibility finally remains that the pressure. decline curves presented in figures 33. and 34 are not representative of the true or average reservoir fluid pressure decline for the Vickers zone as a whole. Thus, in the-general case, curves of this sort may, at best, be representative only of fluid pressure decline in the immediate area of the well (or wells) from which the data derive. Pressure sinks, analogous to cones of depression developed in simple water systems, are generally formed around producing oil wells (Glenn, 1950; van der Knaap and van- der Vlis, 1967). These sinks usually become “deeper. and wider as time goes on” (van der Knaap and van der Vlis, 1967, p. 91). Gilluly and Grant (1949, p. 518) have indicated that “both common sense and hydrodynamic theory show that the pressure drop is greatest at these points [of well penetration] or the oil would not continue to flow to them and that the pressure drop diminishes away from the wells. Accordingly, the pressure decline curves are maximal curves and by no, means represent the average pressure decline through- out the oil sand. On the average the pressure decline over the area of the producing part of the field must be considerably less.” Thus in considering this problem in the Wilmington field, Miller and Somerton (1955, p. 68,} 70) observed that “reductions in average [or true] pressures in the reservoir are virtually impossible to determine with a satisfactory degree of accuracy” and there is, accordingly, some “question as to whether average static reservoir pressures should be used in the analysis [of subsidence].” Permissive evidence from the Inglewood field strengthens the conclusion that the curves shown in figures 33 and 34 are not representative of the actual or average fluid pressure decline in the Vickers zone. Oefelein and Walker (1964, p. 511) have described an infill drilling program in the Vickers east pool which was begun in 1947, and during which “several of the infill wells drilled on 2-acre spacing, produced 100 to 200 BOPD initially despite large cumulative with- drawals from nearby older wells which were averaging 25 B/D [BOPD]. This initial rate can be attributed to incomplete drainage of all sands in the complexly faulted, long vertical section.” Thus production from the separate fault blocks may have proceeded without having significantly affected reservoir pressures in the adjacent blocks. Although the pressure decline curve shown in figure 33 was based on observations at more than one well ( R. C. Erickson, oral commun. 1967) and might thus be expected to incorporate the effects shown by the infill wells, it is possible that these effects were not incorporated and that the initial (1947—54) reservoir pressures characteristic of these younger wells ap- proached those that obtained within the Vickers in 1925. RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Because pressure sinks centering on producing wells are an expected consequence of production, and because the Vickers zone may havebeen characterized by the preservation of areas of relatively high fluid pressures, it is likely that the pressure decline curves presented in figures 33 and 34 are not representative. of the true or average fluid pressure decline in the Vickers zone. We have considered six possible explanations for the seeming inconsistency between the reservoir pressure decline-subsidence relations in the Inglewood field (fig. 38) and those predicted for an idealized system. There exist unresolved questions concerning the applicability of the unmodified form of Terzaghi’s effective stress equation to petroleum systems and the influence of creep with respect to the effects of reservoir compaction at the surface. However, neither the invalidation of Terzaghi’s equation nor the possible operation of creep contribute to an understanding of the approximately linear relations between liquid production and various measures of subsidence (figs. 35, 36, and 37). On the other hand, the likelihood that net fluid withdrawals more accurately reflect true or average reservoir fluid pressure reductions than do actual reservoir pressure measurements (see Miller and Somerton, 1955, p. 70), leads directly to an explanation of this relation. Thus it is the sixth explanation that seems the likeliest: namely, that the curves presented in figures 33 and 34 are representative of fluid pressure decline developed only at certain producing wells and are not representa- tive of the average fluid pressure decline within the compacting zones of the Inglewood oil field. RELATIONS BETWEEN LIQUID PRODUCTION AND SL‘BSIDENCE The identification of a linear relation between various aspects of liquid production and subsidence in the Inglewood oil field (figs. 35, 36, and 37) was unexpected, for Gilluly and Grant (1949, p. 501—502) rejected the occurrence of a similar relation in the Wilmington field. Subsidence in the Wilmington oil field generally has been considered directly proportional to measured reservoir pressure decline or to various logarithmic expressions of liquid production (Gilluly and Grant, 1949, p. 463, 502—518; Miller and Somerton, 1955; Hudson, 1957, p. 43—59). However, although there are very few examples of oil fields in which both production and subsidence are well enough known to be compared over extended periods, linear relations between liquid production and subsidence may be more characteristic of subsiding oil fields than heretofore suspected (Castle and others, 1970). Castle, Yerkes, and Riley (1970) have compared production and subsidence in the Inglewood, Wilming- ton, Huntington Beach, and three unidentified Bolivar CAUSES OF THE SURFACE MOVEMENTS -' Coast oil fields. These comparisons demonstrate recog— nizable linear relations between cumulative net liquid production and one 'or more measures of subsidence in all six fields. This relation, moreover, is far less linear if subsidence is compared only with oil or gross liquid production. Departures from linearity seem to have characterized the early production'stages in at least five of the six fields. Subsidence rates in the Bolivar Coast and Wilmington fields were, in proportion to their production rates, relatively low during the early years of development; subsidence rates over the Inglewood field (and perhaps the Huntington Beach field as well) are believed to have been relatively high during the early production years. - Although the approximately linear relation between net liquid production and subsidence is still not fully understood, a general explanation is suggested by simple analogy with a tightly confined artesian system of infinite areal extent (Castle and others, 1970). Thus the artesian coefficient of storage may be defined as the volume of water released from storage within a column of aquifer underlying a unit surface area during a decline in head of unity; in an artesian system that is hydraulically isolated from any free—water surface, the volume of water represented by the storage coefficient will be derived entirely from the expansion of the confined water and compaction of the reservoir skele— ton. Therefore, the total volume of reservoir compaction must be linearly related to cumulative production, provided only that the bulk modulus of elasticity of the water and the modulus of compression of the reservoir skeleton remain invariant over the relevant stress interval. In the case of a well field in which the liquid-extraction flux is very high (that is, one characterized by closely spaced wells and high produc- tion rates) and hydraulic diffusivity9 is (for whatever reason) very low, fluid-pressure decline will be ex- pressed chiefly as mutually interfering cones of depres- sion-surrounding individual wells and will be largely confined to the main body of the well field. Thus production will be obtained chiefly from liquid expan- sion and reservoir compaction within the areal limits of the well field itself rather than by extraction and consequent but almost unmeasurable, subsidence from an extensive peripheral region. Under these circum- stances, then, the average fluid pressure decline anywhere within the field (and the consequent increase in effective pressure and resultant compaction) will tend to become linearly related to cumulative produc- tion. 9Hydraulic diffusivity, a term analogous to thermal diffusivity, is defined as the transmissivity of an aquifer (hydraulic conductivity times thickness) divided by its storage coefficient. This ratio describes the rate at which a head change propagates through the aquifer. ‘ 63 The system described above becomes directly analo- gous to an oil field if two restrictions are imposed .on the oil-field model: (1) the proportion of gas in the produced fluid must remain constant (it is assumed that the expansive effect of the gas is a function of its concentration in the fluid system); and (2) the compress- ibilities of both brine and oil in the reservoir state must be virtually identical (alternatively, the oilznet water ratio must remain constant, in which case the relation between oil production and subsidence, as well as between net liquid production and subsidence would tend to be linear). The second restriction is the most vulnerable feature of this model. Although departures from linearity during the early production years may be associated with changes in liquid or skeletal compressibilities, it is likely that they ‘ are due chiefly to changes in the produced gasznet liquid ratio. Thus relatively low gas production from the Wilmington and Bolivar Coast fields during their initial development was associated with relatively low subsid- ence rates. The early development of the Inglewood field, on the other hand, was characterized by both high gas production and relatively rapid subsidence (figs. 120, 29 and 32). ' COMPACTION Estimates of expectable compaction of the Vickers zone provide reasonable ' limits on the amount of subsidence that might occur over the Inglewood oilfield. However, because we have been unable to determine average or real drops in reservoir pressure over given production intervals, we may calculate no more than the ultimate compaction that might develop in response to a total loss of reservoir fluid pressure. Furthermore, the absence of consolidation test data from the Inglewood field, plus a general insufficiencyof consoli- dation test data over relevant pressure ranges, severely restrict approaches to this problem. Accordingly, estimates of compaction must be based on the following assumptions: (1) compaction has been confined to the reservoir sands and to shale layers less than 5 feet thick; (2) both sands and shale have experienced comparable compaction in response . to comparable increases in , effective pressure; (3) compaction within the compact- ing materials is independent of time; and (4) consolida— tion test data developed in other oil-field studies (specifically those of the Wilmington field and one Bolivar Coast field) are applicable to the Vickers zone of the Inglewood oil field. The last of these assumptions is considered especially questionable. Nevertheless, the measured compression indices from both the Wil- mington and the Bolivar Coast fields are in close agreement (appendix K), suggesting that compacting Cenozoic petroleum reservoirs may possess similar 64 consolidation characteristics. Furthermore, because the Wilmington and Inglewood sediments were derived from and deposited within similar geologic environ- ments, it is likely that they are at least petrographically similar. The calculated estimates of compaction of the Vickers zone (appendix K) range over an order of magnitude. This range derives chiefly from major differences in the inferred compaction history, as indicated by differences between recompressional and Virginal parts of the e-log p curves. The Vickers zone parameters, coupled with the test data presented in appendix K, lead to several estimates of compaction, all of which exceed the subsidence measured through 1963. However, because the Vickers zone is believed to have been largely or entirely preconsolidated (see section on “Relations Between Reservoir Pressure Decline and Subsidence”), the values of 60—80 feet given in appendix K, which assume no preconsolidation, probably grossly exceed the ulti- mate compaction of this zone. Accordingly, the figures of 8.71 feet and 9.80 feet (appendix K, II.B.1.) or 7.26 feet and 10.9 feet (appendix K, II.C.1.), which assume preconsolidation and recompressional compaction, are believed to more accurately define the ultimate compac- tion range and resultant subsidence over the Inglewood field. Because the compression indices used in calculat- ing the recompressional compaction are drawn from test results on experimentally unloaded and reloaded samples in which the testing was begun at relatively high pressures, the resulting estimates probably consti- tute maximal values of ultimate compaction (Leonards, 1962, p. 152). The fortuitous agreement between these figures and the 8.93 feet of compaction calculated through use of the Tar-Ranger compression modulus (appendix K, I.) probably stems from the testing of these materials at relatively high stress levels (and corre— spondingly reduced strain rates) or to a degree of preconsolidation within the tested materials prior to sampling. The tabulated estimates of compaction (appendix K) provide reasonable limits on the ultimate compaction of the Vickers zone and, hence, the ultimate subsidence over the Inglewood oil field. Thus, provided only that use of the Wilmington-Bolivar Coast test data leads to errors no greater than 100 percent in either direction, the estimates presented in appendix K, coupled with our skeletal knowledge of the late Cenozoic history of the Baldwin Hills, suggest that the ultimate compaction of the Vickers zone should be not much less than 5—10 feet nor much more than 10—20 feet. CONCLUSION The differential subsidence in the northern Baldwin RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Hills can be reasonably attributed entirely to exploita— tion of the Inglewood oil field, as indicated by the following points: the well-defined spatial association between the pattern of subsidence and the outlines of the oil field; the centering of the subsidence bowl over the centers of both the oil field and the producing structure; the approximate coincidence between the beginning of production and the beginning of sub— sidence; the nearly linear relations between liquid production and subsidence; the sharp deceleration of subsidence in the east block associated with the establishment of a waterflooding program there; the numerous oil fields in which both a spatial and, to a lesser degree, a temporal association between produc- tion and differential subsidence can be recognized; the many similarities between the Inglewood subsidence and the exploitation-related subsidence in the Wil— mington oil field; and the mechanical compatibility of subsidence with liquid production and attendant reser- voir pressure decline. HORIZONTAL MOVEMENTS The spatial associations between the centripetally directed horizontal movements, the Inglewod oil field, its producing structure, and the prominent subsidence in the northern Baldwin Hills, are clearly established by their coincident centering and generally symmetri- cal relations to each other (pl. 4 and figs. 3 and 4). Moreover, although a temporal relation between the horizontal displacements and oil-field production can- not be established directly, its existence is strongly suggested by the apparent coincidence between the onset of the horizontal displacements and the beginning of subsidence at PBM 68 (see section on "Horizontal Movements” and fig. 17). Thus, since both production and subsidence began in the middle 1920’s, it seems likely that the onset of the horizontal movements closely coincided with the beginning of exploitation. This conclusion is forcefully supported by the fact that the genetically associated contractional strain iden- tified in the central part of the subsidence bowl could not have begun before 1925 (fig. 16). In any case, the clearly defined and geometrically restricted spatial relations between the horizontal movements and the patterns of differential subsidence shown in the northern Baldwin Hills, together with the indicated temporal association between the subsidence and the horizontal displace- ments, suggest either that one was derived from the other or, more likely, that both have developed in response to a common cause. Accordingly, if a cause- and-effect relation between oil-field exploitation and subsidence is accepted, a cause-and—effect relation between exploitation and the horizontal movements must be accepted as equally valid. CAUSES OF THE SURFACE MOVEMENTS HORIZONTAL MOVEMENTS IN THE WILMINGTON AND BUENA VISTA OIL FIELDS There are, in addition to the Baldwin Hills, two well-documented examples in which centripetally or axially directed horizontal surface movements have coincided with oil-field exploitation: the Wilmington and Buena Vista oil fields. Many other examples may exist, but in the absence of appropriate triangulation or trilateration surveys they remain unrecognized. Be- cause the horizontal surface movements at Wilmington and Buena Vista are also associated with differential subsidence centering on these fields, they too are reasonably attributed to oil-field exploitation. Measured horizontal displacements developed in and around the subsiding Wilmington field have been described by Grant (1954). The movements are symmet- rically disposed about both the subsidence bowl and the oil field (Grant, 1954, p. 20; California Division of Oil and Gas, 1961, p. 684). Horizontal displacements of more than 6 feet by 1951 (Grant, 1954, p. 20) and of more than 11 feet by 1966 (Yerkes and Castle, 1970) have been measured over the Wilmington subsidence bowl. These horizontal movements, moreover, have been directed toward the center of the subsidence bowl, and accompanied by contraction in the central part and by extension around the periphery of the bowl (Grant, 1954, p. 20, 23). The horizontal movements described for the Wilmington field suggest, accordingly, a horizontal strain pattern virtually identical with that recognized in the Baldwin Hills. Horizontal displacements in the Buena Vista oil field (fig. 48) have been discussed by Whitten (1961, p. 318—319; 1966, p. 74—75) and Howard (1968).10 These centrally directed movements, moreover, again have been accompanied by contraction (and negative dilata- tion) over the central part of the field and extension (and dilatation) along its flanks (Howard, 1968, p. 750—752). The displacement vectors observed within the Buena Vista oil field are directed less toward a unique “center” than toward the axis of this conspicuously elongate oil field. They are in addition, assymetrically developed across the field. This asymmetry, however, accords with both the apparent pattern of subsidence and the oil field itself (fig. 48)—as shown, for example, by the fact that through 1959 there had been about four times as much oil withdrawn from the “Hills” area as there had been from the “Front” area (California Division of Oil and Gas, 1960, p. 41—43). Thus, although contemporary displacements along the active thrust fault shown in mBecause three of the four apparently stable triangulation points shown in figure 48 are located within active oil fields, significant errors may exist in the pattern of horizontal displacements if their positions were assumed to be stable rather than actually measured with respect to an independent network; the data source (Whitten, 1961) did not permit an evaluation of this possibility. 65 figure 48 may have obscured the relation, the general correspondence between the patterns of production and subsidence and the pattern of horizontal movements indicates that the horizontal movements have indeed been “caused by collapse from the withdrawal of oil” (Whitten, 1966, p. 74). MECHANICAL BASIS Several models have been proposed to explain the axially or centripetally directed horizontal movements known to accompany differential subsidence. The earliest of the models suggested to explain the radially oriented horizontal movements over the Wil- mington field has been designated the “tension center” model (Stanford Research Institute, 1949, p. 67—69). It presupposes: (1) the existence of a spherical compacting volume at depth; (2) a homogeneous isotropic earth; (3) elastic behavior of the involved materials; and (4) negligible weight of the removed material. This model has been expressed as an equation which relates horizontal displacement (u) at a specified radius (r) from the center of subsidence, to the differential subsidence (w) at that radius, and the depth (h) to the tension center: u = rw/h. By this expression, horizontal displacement varies from zero at the center of subsid- ence (where r = 0), through a maximum, and back to zero at the periphery (where w = 0). Thus, according to the model, both horizontal and vertical movements may be considered complementary expressions of the same strain system. A second model, which was also developed to explain the horizontal movements over the Wilmington field, has been termed the “vertical pincers” model by McCann and Wilts (1951, p. 1) and is attributed to Grant (1954). This model is based on an analogy with a plate or prism which is clamped at both ends and deforms under its own weight (Grant, 1954, p. 19). The bending of such a plate or beam will produce a concave downward configuration toward the distal ends of the plate, and a concave upward configuration toward the central part of the plate; where the two surface configurations merge at the inflection points, rotation of initially vertical elements of the beam and concomitant horizontal displacement should be greatest. McCann and Wilts (1951, p. 1—3, 12—16) conclude from an analysis of the surface movements in the Wil- mington field that the “tension center” model adequately explains the observed horizontal move- ments, whereas the “vertical pincers” model cannot. Lee and Shen (1969) have analyzed horizontal surface movements associated with differential subsidence by means of physical model studies and finite element methods. The only source of deformation permitted in these analyses is the subsidence introduced beneath a 66 a c A’ g 0.02- - _, . o z - o.o1 — — EQuE-Hfi M A .. omo . o o A A. NZEE 0 ' U T‘ Ewme o ggzg —0.01 — 0 — E -o.02 - o #5 LL! 5515 80$ E2; 903 5 Lu. _ _ 0 a: fig? —o.1o — - 52$ — . l - g —g_ DD—reset (adjacent to PBM 68) (I) a —0.20 C .3 B B’ E 0.02— 1 EEEE 0.01 — A - _ O 0 egg? 0 M A EEEQ ' ' ‘ p ' gng —o.01 — . - E —o.02 B! I; _ m 225 5% E52 0. 0w IE m“ (z) I: _ _ mlifi ow> —o.1o — — 2‘2“: 3‘3 - ' —o.2o 1000 0 1000 2000 FEET Lf—i—fiJfiJ 250 0 250 SOOMETRES FIGURE 45.—Calculated horizontal displacement and horizontal strain along lines A—A’ and B—B’ during the period 1954—58 (see pl. 4). Based on empirical relation developed by Lee and Shen (1969, p. 143—144, 147—148) in which m = 2/3 Ha, where m = horizontal movement, H = thickness of the “stiff layer” overlying compacting zone, and a = subsidence slope angle. In this constructionH = 875 feet or roughly the average depth to the top of what is defined here as the Vickers zone. Curves fitted by eye. beam or “stiff” layer designed to represent the overbur- den above a compacting volume at depth (Lee and Shen, 1969, p. 145—149). Under these circumstances the horizontal displacement, m, is related to the subsidence slope angle, a, by the expression m = kHa, where k is a constant derived for the effects of shear and variable modulus andH = the thickness of the overlying “stiff” layer; the physical model and finite element investiga- tions indicate a good fit with the equation where k = 2/s RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA (Lee and Shen, 1969, p. 143-144, 147—149). Results of the application of this relation to Baldwin Hills subsidence profiles generated between 1954 and 1958 (and hence generally prior to full-scale waterflooding) (fig. 45) are in general agreement with the observa- tional evidence and support the conclusion that axially or centripetally directed horizontal movements are necessarily associated with differential subsidence. Thus the distribution of the calculated horizontal dis- placements shown in figure 45 seems to approximate that observed in actual examples of this phenomenon. Moreover, although the calculated strain profiles less faithfully mimic these examples, the form of the calcu- lated profile along line DD reset— ’ roughly matches that actually measured along this same line (fig. 16). That is, the central part of the bowl is in both cases characterized by contractional (or negative exten- sional) horizontal strain, whereas the periphery is under extension. CONCLUSION The horizontal surface movements in the northern Baldwin Hills can be reasonably attributed entirely to exploitation of the Inglewood oil field, as indicated by the following points: the clearly defined spatial and symmetrical relations between the horizontal surface movements and both the oil field and the essentially coincident differential subsidence bowl; the approxi- mate coincidence between the onset of exploitation and the onset of the horizontal movements; the similarities between these relations and those developed in and around other oil fields; and the mechanical compatibil- ity of this type of horizontal movement with subsidence due to oil-field operations. EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS The earth cracks and associated fault displacements centered on the Stocker Street—Overhill Drive—La Brea Avenue intersection and the Baldwin Hills Reservoir form a third category of contemporary surface move- ments reasonably attributed to exploitation of the Inglewood oil field. The relation between exploitation and cracking, however, is more obscure than that between exploitation and either the subsidence or the horizontal movements. A spatial association between the earth cracks and the Inglewood oil field can be seen by comparing plate 2 and figure 3. All the cracks are confined to the oil field or the immediately adjacent, peripheral area; none are known elsewhere in the Baldwin Hills. Many or most of the earth cracks are roughly orthogonal to radii emanating from the approximate center of the field (as CAUSES OF THE SURFACE MOVEMENTS 67 well as that of the subsidence bowl); only two (XII and XIII) trend more or less toward the center of the oil field. Although the general restriction of the cracks to the east block seemingly invalidates such conclusions as , could be drawn from the spatial or geometrical associations between the earth cracks and the oil field, both the oil field and the history of its exploitation are characterized by asymmetries of various types. For . example, until the end of 1963 at least, waterflooding ‘ was essentially confined to the east block, thereby f destroying any preexisting symmetry of exploitation and the resultant requirement that the cracks be symmetrically distributed with respect to the field. Thus quite the opposite conclusion could be drawn: the apparent asymmetry of exploitation is consistent with the asymmetrical distribution of the cracksz direct temporal association between exploitation and the generation of the cracks is suggested only by the fact that cracking of this sort was not recognized until the Inglewood field had been in operation for some time. Earthquake-associated oil well damage (see section on “Earth Cracks and Contemporary Fault Displace- ments”), which is not known to have occurred before 1963, is consistent with faulting along the subsurface projection(s) of one or more of the earth cracks. Because production from the Inglewood oil field has been overwhelmingly from the Vickers zone, the apparent restriction of damage or inferred rupturing to producing zones no deeper than the Vickers suggests that the subsurface faulting, and hence the surface cracking, are thus related to the exploitation of the field. FAULTING IN OTHER OIL FIELDS A number of other examples of faulting associated with oil-field operations have been reported in the literature. These additional examples, located in the Texas Gulf Coast region and the southern San Joaquin Valley, as well as in the Los Angeles basin, support the likelihood of a cause-and-effect relation between the exploitation of the Inglewood oil field and earth cracking in the northern Baldwin Hills. Faulting along the edge of the Goose Creek oil field east of Houston, Texas (fig. 46), apparently began sometime after 1917, the year development began (Pratt and Johnson, 1926, p. 577—581; Sellards, 1930, p. 29—30). The surficial ruptures at Goose Creek are “compound” or discontinuous in plan (Sellards, 1930, p. 30); the faulting has been characterized by vertical displacements as great as 16 inches and by downdrip- ping of the blocks toward both the nearly coincident center of subsidence and the center of the oil field (fig. 47) (Pratt and Johnson, 1926, p. 578—581; Sellards, 1930, p. 29—30). All the faulting, moreover, has occurred FIGURE 46.—View east along “fracture” on Hog Island near the south edge of the Goose Creek oil field, Texas. After Pratt and Johnson (1926, p. 581). at or beyond the edge of the oil field, along the periphery of the subsidence bowl, and nearly parallel to the subsidence isobases. Movement along the Goose Creek faults probably proceeded unevenly and, in part, as discrete jumps. Direct evidence in support of this inference is lacking, but slight earthquakes were felt locally during a period when movement is known to have been taking place along these faults (Pratt and Johnson, 1926, p. 581), and Sellards (1930,_p. 29—30) has V2 0 v2 1 MILE 1/2 o 1/2 1 KILOMETRE /\ /'—U- / \ » aaoo» /‘D\\\ . / \ OII-field boundary / $3 F‘0.10_’/—\ MINIMUM/Ill \ : / \ ’1,” EXPLANATION D —-2.50— — —0.10- . 1917-25 1924—25 Surficnal fault Contours of equal subsidence, U, upthrown side; D, downthrown in feet side FIGURE 47 .——Contours of equal subsidence (in feet) around the Goose Creek oil field. After Pratt and Johnson (1926, p. 582, 584). 68 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA indicated that “the drop [or displacement] accompany- ing the break [along the north edge of the oil field] was necessarily a sudden drop.” Most of the surficial faulting associated with other Texas Gulf Coast oil fields has also occurred in the Houston area. Weaver and Sheets (1962, fig. 1, p. 260, 263) have described contemporary surface faulting within or peripheral to the following metropolitan Houston fields: the Eureka Heights, the Clinton, the Webster, the South Houston, and the Mykawa. Al- though the nature and history of this faulting have not been described in detail, a well-defined spatial associa- tion between much of the faulting and operations in the oil fields listed above is clearly evident. Judging from their map (Weaver and Sheets, 1962, fig. 1), a large part of this faulting is similar to that around the Goose Creek field, and in at least one field (the Mykawa) it is spatially associated with an area of differential subsid- ence centering on the field (Weaver and Sheets, 1962, figs. 1 and 2). The only other Texas field in which historic surface faulting has been recognized is the Saxet field near Corpus Christi (Yerkes and Castle, 1970, p. 58). This faulting occurred along a 1.5-mile break and was characterized by dip-slip displacements of over 2 feet, in which the downdropped block lay toward the center of the oil field. The Saxet faulting has also been associated with more than 3 feet of differential subsidence (Yerkes and Castle, 1970, p. 58). Direct associations between oil-field operations and surface faulting have not been firmly established in all these examples, and other phenomena may have contributed to the faulting. The metropolitan Houston area, for example, has been characterized by the with- drawal of large volumes of ground water, and Weaver and Sheets (1962, p. 254) indirectly attribute “the most extensive movement of the surface* * * to the extraction of water.” Furthermore, many Gulf Coast oil fields occur over salt domes subject to solution collapse, probably unrelated to the production of petroleum, and various types of surface rupturing have apparently developed in response to such collapse (Sellards, 1930, p. 9—16, 23—28).11 1|Although unrelated to oil-field operations, a relevant example of surface faulting associated both spatially and temporally with Frasch-process extraction of sulfur from the caprock of a salt dome is also known from the Texas Gulf Coast (Deere, 1961). Initial field measurements of both vertical and horizontal surface movements above the salt dome were begun 3 months after mining started (Deere, 1961, p. 59—60). A well-defined subsidence bowl was recognized 9 months after extraction began. Within 31 months it had grown to a diameter of 4,0004%000 feet and a depth of nearly 5 feet over a central producing area no more than 400 feet wide (Deere, 1961, p. 60—63). After 31 months of operation, centripetally directed horizontal displacements ranging up to 1.3 feet were observed at five triangulation monuments around the subsidence bowl, and horizontal strain (as measured along two lines athwart the subsidence bowl) reached a maximum of 0.65 percent compression at the center of the bowl and 0.20 percent in tension along the flanks (Deere, 1961, p. 62—63). “A surface crack 2,000 feet long" * * formed suddenly [about 1,000 feet west of the producing zone] during the fifth month of operation in which the ground on the mining side of the crack? * * dropped down from 1 to 4 in.” (Deere, 1961, p. 61—62). Displacement apparently continued following initial recognition of the crack, but cumulative figures have not been The only other reported domestic examples of surficial faulting associated with oil-field operations occur within or around the Buena Vista, McKittrick, and Kern Front fields in the south San Joaquin Valley, and an unnamed field in the Los Angeles basin, all in California. Faulting in the Buena Vista Hills (fig. 48) is similar to that in the Baldwin Hills chiefly in the sense that it has been unassociated with recognized seismic activity and has been proceeding more or less continually over a period ofmany years (Koch, 1933, p. 701; Wilt, 1958, p. 169, 171; Nason and others, 1968, p. 101). However, the Buena Vista displacements have been confined to a single surface, and there is no clear evidence indicating that this movement has occurred along a preexisting fault, although a structure section prepared by Koch (1933, p. 707) seems to support such an interpretation. It is not known when historic movement began on the Buena Vista fault. According to Wilt (1958, p. 169), it was not until 1932, about 22 years after exploitation began (California Division of Oil and Gas, 1960, p. 39), that “it became evident to the oil companies operating in the Buena Vista Hills Field that many wells were being sheared off by an active thrust fault.” Koch (1933, p. 701, 709) has indicated that “casing failures referable to the Buena Vista thrust occur at depths ranging from 76 to 794 feet,” but these “well failures have occurred only in a narrow shallow zone near the trace, indicating either greatest movement, or most concentrated move- ment, that is, narrowest fault zone, near the outcrop of the fault.” A contour map of the gently north-dipping fault surface (Koch, 1933, p. 702) shows that the active subsurface segment extended no more than 2,000 feet north of the surface trace (fig. 48). Minimum rates of movement along the fault for various periods, as computed by Koch (1933, p. 703-704) from shortening of surface pipelines and deformation of well casings range from 0.139 to 0.266 foot/year and 0.076 to 0.224 foot/year, respectively. The maximum average rate of movement parallel to the dip (as derived from repeated observations of established control points on the surface) is computed to have been only 0.068 foot/year given. One of Deere‘s (1961, p. 62) illustrations indicates that the total displacement after 31 months probably was more than 6 inches; furthermore, according to Deere (1961, p. 64), "vertical displacement of the fault [whose trace at the surface is represented by the crack] ranges up to 1 ft. or so.” Of particular interest in connection with the northern Baldwin Hills surface ruptures is the fact that the displaced block away from the producing zone showed uplift with respect to a zero datum line established 9 months after production began (Deere, 1961, p. 62—63). This differential uplift, of up to about 0.1 foot, may be analogous in part to that which has occurred east of cracks I and IX in the Baldwin Hills. The preceding observations show, then, that the extraction of sulfur from a depth of 1,300—1,600 feet below the surface has led to the development ofboth surficial faulting and a measured surface strain pattern very similar to that which evolved during exploitation of the Inglewood oil field. Examples of historic surface rupturing have also been reported from within and around several water fields (Robinson and Peterson, 1962; Weaver and Sheets, 1962, Fett and others, 1967; Schumann and Poland, 1970). Most of these examples, moreoever, have been associated with measured differential subsidence. Fault displacements have occurred along a few of the water-field ruptures, but most are expressed simply as open fissures. CAUSES OF THE SURFACE MOVEMENTS 69 119°30’ l A Elk \ \A“ *N‘\ 6 35° _ \\ (Ir 1s \ ”/L y EXPLANATION \ ‘8 y” \ )’ A_A_A \ y x; 2 Surface trace of low-angle A— reverse or thrust fault ( ,r. -r-’fi— \P \1~ Sawteeth on upper plate XX \ 5‘ ‘5 -r-—r'-r" / *S‘S‘W- Oil-field boundary / \ T‘x Hachures on oil-field side (1 X—t— -1— -1~ * \\ **\ \ .K-ssa \ 8054’ \ (—o.m) t X 4 \ Bench mark k\ l \\\ P49 \ Number in parentheses shows ele- \ \ 7:4 o W's“ . . ~1\ 0 (4.02;) when change, m feet, between \A (I \ \ 1957 and 1964 \\ €151 (X3739) 4 _ O A \ '9 o _ x4132 O \r~ 831:2?) \ , \Qiiénm .0 Av» **\x Bench mark \ \ k4?) H 397) \ {3133,024132 4954 \\ Number in parentheses shows ele- \ \ 4 Kiss. 0(- --10 02) vation change, in feebbetween \ \ (”0' ) 5865* é—_132( -o.142) 1961 and 1964 \‘K 6' /“ (_ -033, x \ ‘l‘x («SW-1W 0.29M U-o1132) *‘l-+a——+-—P"‘" ‘K J - (‘0 / \ \N'fi’./HT’JSE( 2“ b @1275”? Triangulation point showing \ \\ ( 52% L 1' (-0-187) honzontal—movement vector \ H-saa * a. 13; fik *\ H.145). *\ (‘—o.21a)‘\om§e) VECTOR SCALE x 004,3, AEast 1.0 o 10 FOOT 41 \x 1, ‘§?’\\ (-0.141) 49% H—H—F—r‘ - 3‘ 0.25 o 0.25 METRE. ’Ong, “Erma (551.133) \\ 1 o 1 MILE K62, Hm" \ \‘x \ 449$ \\ \\ 1 o 1 KILOMETRE \x \ ‘Kagg 4,1.» \ X \ X a 3L \ X — w \\ \\ \ k) ASpellacy \\ ATemblor \ FIGURE 48.—Map of part of the Buena Vista Hills area showing: (1) - approximate boundaries of parts of the Buena Vista (divisible into the Buena VistaPront—or flank—and Buena Vista Hills areas), Midway-Sunset, and Elk Hills oil fields (California Division of Oil and Gas, 1960, p. 38, 40, 112, 164); (2) surface trace of historically active fault along south flank of the Buena Vista Hills (Wilt, 1958, (Wilt, 1958, p. 169, 171); continuation of movement at about this rate is supported by observations between 1956 and 1967, which show that the average slippage rate during this interval was approximately 0.083 foot/year (Nason and others, 1968, p. 100). p. 170, 172); (3) record elevation changes at selected bench marks in the Buena Vista Hills area (US. Coast and Geodetic Survey, 1966, p. 5—6, 18); (4) horizontal movements between 1932 and 1959 relative to undefined network that includes the seemingly stable triangulation points Temblor, Spellacy, East, and Elk (Whitten, 1961, p. 318—319). The location of the fault trace (fig. 48 near the axis of maximum subsidence and the zero-horizontal dis- placement line (that is, the discontinuity between northerly and southerly directed horizontal displace- ment vectors) suggests that it lies within the zone of 7O horizontal compression; thus thrust faulting, rather than normal or gravity faulting or simple fissuring, is reasonably expected here. Neither Koch (1933) nor Wilt (1958) has suggested that the Buena Vista Hills faulting might be other than tectonic in origin. However, because both the subsid- ence and the horizontal movements have been attrib- uted to oil-field exploitation by Whitten (1961, p. 319; 1966, p. 74), and because the sense of displacement on the fault is consistent with these measured movements, it is likely that the faulting is equally attributable to oil-field operations. This interpretation is supported by Koch’s (1933, p. 709) observation with respect to the relatively surficial expression of the faulting: “it seems impossible that the shift in the center of the north flank of the [Buena Vista Hills] anticline could be less than the shift at or near the fault trace.” Howard (1968, p. 750—752), moreover, has shown that the area within the southern (footwall) block immediately south of the fault trace has been characterized by extensional and dilatational strain; strain patterns of this type are completely inconsistent with regional tectonic com- pression. Historic faulting in the McKittrick oil field has been described by Koch (1933, p. 711) and Yerkes and Castle (1970, p. 57). Koch (1933, p. 711) reported that buckling movements in a concrete highway 1 mile south of the town of McKittrick were proceeding “at the rate of about .8 inch per year.” Movement apparently has persisted on this fault for many years, for it showed evidence of recent displacement when visited in 1969. Surficial faulting associated with the development of the Kern Front oil field (Brooks, 1952; Hill, 1954, p. 11) is more akin to that in the Baldwin Hills than is that in the Buena Vista field. This faulting has been expressed chiefly as dip—slip ' movements along the probable surface trace of the Kern Front fault which, in turn, marks the east edge of the Kern Front oil field (Brooks, 1952, p. 159). The Kern Front field, moreover, has been identified with differential subsidence of more than 1 foot (Yerkes and Castle, 1970, p. 57). Movement on the fault apparently began no later than 1949 and has been characterized by cumulative displacements of up to 1.2 feet along a 3-mile trace, with downdropping toward the center ofthe oil field (Hill, 1954, p. 11; Brooks, 1952, p. 159; Yerkes and Castle, 1970, p. 57, 61). Although limits could be placed on the time of the initial major movement in 1949, the seismological stations at Berkeley and Pasadena recorded no seismic activity in the Kern Front area during this limited interval (Hill, 1954, p. 11). Surficial fault displacements along the north edge of an Orange County oil field Within the Los Angeles basin were first recognized in 1968 (Yerkes and Castle, 1970, RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA p. 58). These displacements, which were apparently confined to a single, steeply dipping reverse fault trending at a high angle to the field boundary, ranged up to about 0.2 foot along a surface trace of about 0.22 mile (Yerkes and Castle, 1970, p. 58). No shocks were recorded by the Seismological Laboratory at Pasadena within 20 miles of this location during the month preceding and month following the earliest probable recognition of this faulting on or about October 1, 1968 (J. M. Nordquist, oral commun., 1968). Several examples of subsurface faulting associated with oil-field operations have been described from the Los Angeles basin. The most unequivocal case of subsurface faulting attributable to exploitation has been recognized in the Wilmington field. According to Frame (1952, p. 5) “nearly horizontal earth movement on two main slippage planes” has taken place within the Wilmington field; “these planes consist of thin shale beds about seven or eight feet thick*** at average depths of 1,550 and 1,700 feet.” Resulting oil well damage has been confined to the central part of the subsidence bowl (Frame, 1952, pl. I), but, as shown by Grant (1954, p. 20), it seemingly lay athwart the inflection line—that is, damage occurred within parts of both the extensional and compressional horizontal strain zones measured at the surface (Frame, 1952, pl. I; Grant, 1954, p. 20). The Wilmington displacements apparently occurred chiefly as sharply defined movements in December 1947, November 1949, August 1951, September (‘2) 1951, and April 1961 (Frame, 1952, p. 7; Bailey, 1961, p. 118). These movements were accompanied by local earthquakes recorded at Pasadena, 28 miles away, as distinctive seismograms characterized by a relatively large development of long-period motion of a sort attributed to shocks of shallow focus (Richter, 1958, p. 155—156). The maximum horizontal displacements associated with the 1947 and 1949 movements were both about 9 inches (Frame, 1952, p. 7, 9); the maximum 1951 and 1961 displacements are unknown. We have been unable to determine the sense of movement along the slip planes; the upper plate probably moved outward from the center of subsidence (with respect to the underlying block), thereby reducing the accumulated contractional strain observed at the surface (Yerkes and Castle, 1970, p. 60—61) and inferred to extend to depth. This conclusion seems to accord with the views of Grant (1954, p. 22—23). Richter (1958, p. 155), on the other hand, has attributed the movements to “slumping on an enormous scale, incidental to subsidence.” In any case, the clearly defined spatial association and less specifi- cally defined temporal association between this faulting and the exploitation-induced subsidence and horizontal movements, leave little doubt that the faulting is CAUSES OF THE SURFACE MOVEMENTS 118°15’ \ \ \ EL SEGUNDO BLVD \ \ _) (—o.005) ‘ EXPLANATION Approximate location of oil-field boundary _T__._ Approximate subsurface loca- \ (—o.03\7) \ \ \ VERMONT AVE / \ FIGUEROA ST (—0.016) ‘ \ \ \ \ . . ROSECRANS AVE (+0-002) (_0'004) (*0'009) feet, In the Dominguez A VALON BL VD tion of fault, showing direc- tion of dip Only those faults along which his- toric movement has been re- corded are shown here 0 (—0.187) Relative elevation change, in (-0.003) N (—0.oo1)i \ (—0.028) \ WESTERN AVE Od—O FIGURE 49.—Map of part of the western Los Angeles basin showing (1) Approximate boundaries of the Dominguez and Rosecrans oil fields (California Division of Oil and Gas, 1961, p. 552, 664, 648); (2) location at depth (between 5,000 and 7,000 feet below sea level) of faults along which subsurface displacements are reported \ (0.000) ' —‘ 1 KILOMETRE 7/} r \ oil-field area between 1953 d: l \ l / aAv Norsmwm 0 ____ _ _. 0404/30 oil-field area between 194546 and 1960 . (—o.oa7) Relative elevation change, in feet, in the Rosecrans and 1960 \ \\, / / 6‘2 (—O.187) VICTORIA sr (—o.220) 1 MILE I Martner, 1948, p. 112); (3) elevation changes calculated through a comparison of record elevations given for the Dominguez oil field area by the US. Coast and Geodetic Survey for 1945—46 and the Los Angeles County Road Department for 1960 and the Rosecrans oil field area by the City of Los Angeles Bureau of Engineering for to have occurred during historic time (Bravinder, 1942, p. 392; 1953 and 1960. equally attributable to the exploitation of the Wil- mington oil field. The only other reported examples of subsurface faulting associated with oil-field operations occurred ) within the Dominguez (Bravinder, 1942) and Rosecrans ) (Martner, 1948) oil fields (fig. 49), about midway along the onshore section of the Newport-Inglewood zone. Surface subsidence has been slight over the Dominguez field and almost unmeasurable over the Rosecrans field (fig. 49); it is likely that any centripetally directed 71 72 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA horizontal surface displacements have been correspond- ingly small. Subsurface fault displacements in the Dominguez oil field occurred on October 21, 1941 (after 18 years of production) and ranged up to at least 7 inches (Bravinder, 1942, p. 388, 391); the displacement or ”deflected movement” in the Rosecrans oil field took place on June 18, 1944 (after about 20 years of production) and amounted to “a few inches maximum” (Martner, 1948, p. 105, 116). In neither example is the sense of movement known. Well damage in both fields seems to have occurred chiefly at depths of 5,000—6,000 feet, well above the lowest producing zones (Bravinder, 1942, p. 391, 393—395; Martner, 1948, p. 110—111; California Division of Oil and Gas, 1961, p. 553, 645). The subsurface displacements in both oil fields, more- over, were also associated with earthquakes. However, unlike those that occurred in the Wilmington field, these ”earthquakes appear to have originated at the usual depth of about 16 kilometers” such that “the damaging displacements must have been triggered, either by the direct shaking of the earthquake or by the readjustment of the local strain pattern” (Richter, 1958, p. 156). If the strain system relieved by faulting can be attributed to compaction of the producing zones, it should be best developed above the lowest of these zones. Because major well damage and, by inference, maximum displacements, seem to have occurred well above the deepest producing zones, it is likely that the postulated preearthquake strain pattern derived in part from exploitation of the two fields. The limited surface deformation may stem from the resistance to collapse imparted to the entire geologic section by the strong arching shown in both the Dominguez and Rosecrans anticlines (California Division of Oil and Gas, 1961, p. 552, 644). MECHANICAL BASIS The generation of the earth cracks may be explained by two separate but conceptually complementary schemes, identified here as the horizontal-tension and elastic-rebound compaction models. Both models are consistent with the existence of a marginal zone of extensional horizontal strain around a recognized subsidence bowl; both are consistent, therefore, with the existence of the vertical and horizontal movement pattern identified in the Baldwin Hills (see section on "Movements Attributable to Oil-field Operations” and Yerkes and Castle, 1970, p. 60—65). It is only the second or elastic-rebound model, however, that seems to explain fully the nature of the observed fault displace- ments. Because both models require the existence of a surface strain pattern attributable to oil-field opera- tions, their construction is ultimately dependent on the exploitation of the Inglewood oil field. T STABLE \ / '\ oi F FIGURE 50.—Mohr diagram showing hypothetical states of stress at depth, where: o = normal effective stress; 1' = shear stress; 01= greatest principal effective stress; 0'3 = least principal effective stress; To: cohesive shear stress; rem = shear stress at failure; and d) = angle of internal friction. Solid circle shows initial stress conditions. Dashed circle shows stress conditions at failure resulting from increased deviator stress—specifically, an in- crease in 01 and a simultaneous decrease in 03. Dotted circle shows stress conditions at failure resulting from fluid pressure increase (Ap) with no change in the deviator stress. The horizontal-tension compaction model predicts the occurrence of ruptures along steeply dipping surfaces oriented normal to the maximum strain axes (and, hence, to the horizontal displacement vectors, as well) within the zone of extensional horizontal strain; it depends ultimately on stress relations at depth as deduced from the evolving surface strain pattern. We can only speculate on the stress conditions that existed as exploitation began, and can be certain only that they must have been changing as it progressed. However, the contemporary faulting has been generally normal; thus we infer that during some undefined period preceding failure, the greatest principal effective stress, crl, was oriented approximately vertically, and the least princi- pal effective stress, (73, was approximately horizontal and normal to the strike of the specified fault (Hubbert, 1951). Reductions in 0-3 compel corresponding decreases in normal stress and increases in tangential stress; because increasing extensional horizontal strain must be accompanied by reductions in similarly directed stress, continuing extension ultimately will result in the reduction of 0-3 to some threshold value at which failure will occur (fig. 50). If, as in this example, 01 is vertical, faulting will occur ideally on surfaces dipping at 45° + d)/2 (Hubbert, 1951, p. 362—364). The chronology of cracking seems to fit the hor- izontal-tension model, for none of the earth cracks had been certainly recognized as surficial fault displace- ments before 1957, some time after the horizontal strain pattern had become well established. Furthermore, because the identified faults dip generally toward the center of the subsidence bowl, the fact that most of the downdropped blocks lie toward the center of the bowl is consistent with continuing extension and resultant reductions in 03. However, the vertical rebound CAUSES OF THE SURFACE MOVEMENTS 73 associated with the exterior blocks (that is, those away from the center of the bowl—see below) remains unexplained and must result from the operation of some complementary, unspecified mechanism. D. R. Brown (oral commun. 1961) has suggested that the cracking and associated fault displacements may have originated as a rebound phenomenon related to the release of elastic strain energy accumulated in associa- tion with subsurface compaction. Essentially the same model has been more recently proposed by the Califor- nia Department of Water Resources (1964, p. 60) to explain displacement along the rupture designated here as crack IX. The elastic-rebound compaction model requires that compactive or compressive elastic strain energy be accumulated in the marginal blocks around the subsiding oilfield as a result of downdrag by the more or less inelastically compacting interior blocks; its princi- pal features are illustrated in figures 50 and 51. Because all, or nearly all, of the reservoir compaction has been confined to the Vickers zone, the effects of any exploitation-induced strain beneath the Vickers zone may be disregarded. We infer again, moreover, that during some finite period preceding failure, 01 was approximately vertical and 0-3 was contained within the horizontal and oriented normal to the strike of the identified fault. According to this model, then, as subsidence proceeded within the central part of the compacting oil field, and as extensional horizontal strain continued to increase around the periphery of the field, vertically directed elastic strain tended to increase within the marginal blocks. Thus with continuing fluid extraction and resultant compaction, 03 continued to diminish (in association with increasing extensional horizontal strain) while 0'1 increased simultaneously (in association with increasing vertically directed elastic strain) within the marginal parts of the oil field. Both effects tended to enlarge and displace Mohr’s stress circle to a position of tangency with Mohr’s failure en- velope (fig. 50), whereby faulting should occur along steeply dipping surfaces containing the intermediate principal effective stress (Hubbert, 1951, p. 359—364). Thus at some unknown time, but probably at least as early as 1951 and certainly no later than 1957, radially oriented extensional horizontal strain is inferred to have increased to the point that frictional resistance to movement along certain favorably oriented potential failure surfaces was locally overcome by increased tangential stress, due both to reduction of the least principal effective stress and increased vertically di- rected elastic strain within the marginal blocks, and rupture and displacement of the exterior blocks ensued. The sense, magnitude, and chronology of the dis- placements observed along the earth cracks are ——- Producing area———- ‘— Contractional zone Extensional zone ————> A A I Generally elastic C . compaction Generally inelastic / compaction Base of compacting layer A—A ’.-r Preexploitation datum C—B—A '.- Subsidence profile immediately preceding faulting C—B—B’—A’: Subsidence profile immediately following faulting Plan view of idealized subsidence bowl showing location of profile and fault FIGURE 51.—Idealized dimensionless profile showing rebound of elastically compressed block located largely or completely beyond the oil-field producing area but within the zone of extensional horizontal strain around the periphery of the subsidence bowl. generally consistent with those predicted by the elastic-rebound model. According to this model, com- pactive strain (including surface strain) may be viewed as having accumulated within an array of vertical surfaces radiating outward from the approximate center of subsidence, curving only so as to remain parallel to the isobase gradient, and thereby parallel to the horizontal-displacement vectors. Hence any elastic strain release should occur largely within these vertical surfaces with little or no movement at right angles; the generally dip-slip nature of the reported displacements clearly meets this expectation. In those very few cases in 74 which measurable lateral movements have occurred, the sense of lateral motion has been mechanically compatible with the postulated model. Thus where the strike of an established displacement surface and the trend of the immediately adjacent isobases depart significantly, any fault-block motion should parallel the maximum horizontal strain axis and thus lead to a component of lateral slip toward the center of subsid- ence. Left-lateral movement on crack IX is an example of this type of slip. The elastic-rebound model predicts that the down- dropped fault blocks should lie toward the center of subsidence and that the peripheral blocks should be uplifted (with respect to control points adjacent to the area of recognized differential subsidence) following rupture. Movements developed along the Baldwin Hills earth cracks generally meet these predictions. The only cracks along which the displacements seem to have been the reverse of that predicted by the model are cracks III and IV near the Stocker Street—La Brea Avenue—Overhill Drive intersection (pl. 2). However, cumulative displacement along both these cracks has been no more than about 11/2 inches (California Department of Water Resources, 1964, pls. 17a and 17b), as contrasted with combined displacements of about 10 inches or more along cracks I and II or cracks IX Or X. Furthermore, cracks III and IV occur within the western periphery of the subsidiary subsidence bowl developed in the southern part of the eastern block; thus downdropping to the east is construed as consistent with the elastic-rebound model. The minimum cumulative rebound at the reservoir gate tower bench mark during the period June 1949—January 1964 may be calculated by summing the positive increments shown by the upward jogs in the settlement curve (fig. 25) (which we infer to be expres- sions of rebound); this summation leads to a figure of 0.318 foot. The additional rebound that probably oc- curred and would have been measured had elevation measurements been recorded continuously, is esti- mated to have been at least 0.13 foot. Thus the mini- mal total rebound of 0.45 foot immediately east of crack IX very nearly matches the vertical separation, 0.50—0.58 foot, along crack IX that must have occurred during this same interval (roughly the life of the Baldwin Hills Reservoir). This very close correspon- dence between measured displacement and vertical re- bound measured immediately east of the fault supports the conclusion that the displacement is nearly exclu- sively the product of vertical movement of the eastern block only, and hence is clearly consistent with elastic rebound of the peripheral block. The available data indicate that the magnitudes of the displacements measured along the earth cracks are RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA compatible with those predicted by the elastic-rebound model. The validity of the comparisons between subsidence and rebound outlined below rests on the assumption that the elevations of the interior blocks, immediately adjacent to the earth cracks, remained unchanged during episodes of actual fault movement. This assumption is supported by: (1) the fact that the west end of the level circuit athwart crack IX remained unchanged in elevation between November 1963 and January 1964 (see fig. 27); (2) the excellent correspon- dence between measured displacement (vertical separa- tion) on crack IX and estimated vertical rebound of the east block adjacent to this crack (see above); and (3) the general occurrence of the cracks beyond the oil-field production limits, such that there should be little tendency toward further compaction and resultant drop of the interior blocks during episodes of displacement. The patterns of average annual elevation change shown on plate 4 suggest that between 1950 and 1958, a period of relatively uniform although slowly decelerat- ing subsidence, cumulative subsidence immediately east of crack IX (pl. 2) was about 22 percent of that at the center of subsidence. This figure, however, is uncor— rected for the likelihood that the block east of crack IX experienced small increments of rebound during this interval (fig. 25). A more realistic figure may be obtained by adding together: (1) the measured positive increments at the gate tower bench mark between March 1950 and October 1958 (0.088 foot); (2) an amount (0.071 foot) based on the probability that rebound occurred instantaneously rather than over the full intervals between levelings, and that subsidence continued over these intervals at rates approximating those of the smoothed subsidence curve; and (3) the total measured elevation change (0.425 foot) between March 1950 and October 1958. This sum is then compared with the subsidence at the center of the bowl over the same interval (see appendix H). The result indicates that between 1950 and 1958 subsidence at the reservoir gate tower bench mark was actually about 37 percent of that at the center of the bowl. Thus, if the cumulative subsidence at the center of the subsidence bowl between 1911 and 1964 was about 5.67 feet, there should have been about (0.22) (5.67 feet) = 1.25 feet or, more likely, (0.37) (5.67 feet) = 2.10 feet of subsidence immediately east of crack IX during this period. A similar calculation based on the single measurement interval 1950—54 shows that the maximum probable subsidence im- mediately east of crack I between 1911 and 1964 was about 1.8 feet. Therefore, according to the elastic- rebound model, the maximum? expectable vertical separations along cracks IX and I between 1911 and 1964 should have been about 1.25 or 2.10 feet and 1.8 feet, respectively. The cumulative vertical separations CAUSES OF THE SURFACE MOVEMENTS actually measured along both cracks IX and I through 1963 were about 0.50—0.58 foot, or approximately one-half to one-quarter the predicted maximums; this fractional figure is necessarily based on the implicit assumption that any displacements generated prior to 1950 (and thus preceding construction of the Baldwin Hills Reservoir) were trivial. Displacements or vertical separations well below the maximum expectable values are almost certainly due either to incomplete recovery by the end of 1963 or the only partly elastic compression of the exterior blocks. Thus the fractional amounts of the maximum expecta- ble recovery (or displacement) actually recorded by the end of 1963 are consistent with those to be expected in a highly compressed, water-saturated, and probably poorly drained sedimentary column. Displacements matching or in excess of the predicted maximum values would seriously dispute the elastic-rebound model. Castle, Yerkes, and Youd (1973, p. 39—43) have calculated stress changes beneath the Baldwin Hills Reservoir associated with the first 30 years of produc- tion and resultant compaction in the Inglewood oil field. The calculated changes are based on measured surface strains within the reservoir area and conservative but realistic values for the modulus of elasticity; these stress changes are thus believed to approximate those that occurred during this same 30-year period along the subsurface projection of crack IX (pl. 2). Necessary assumptions involved in the calculations are: (1) that fluid pressures remained unchanged outside the produc- ing area of the oil field; (2) that no compaction occurred below a depth of 2,500 feet, the approximate base of the Vickers zone; and (3) that the preexploitation horizontal to vertical effective stress ratio (o-h/o-v) was 0.5. The results of this simple analysis show that stress conditions consistent with failure, where ah/av<1/3, were achieved after 30 years of production down to depths of at least 1,000 feet and probably down to 1,600 feet or more. These calculations thus support indirectly the probable operation of either compaction model, particularly the elastic-rebound model, during the primary recovery phase of exploitation—that is, through the period prior to any waterflooding. Several possible objections to exploitation-based explanations for the earth cracks are almost self- evident. The most valid of these objections arises from the general restriction of the earth cracks to the east block. This restriction may be no more than apparent, however, and the cracks may not be virtually confined to the east block but may be simply more'conspicuous there owing to the relative abundance of paved surfaces, curbings, and other cultural features. They are, nevertheless, certainly concentrated in the area east of the Inglewood fault. 75 The areal restriction of the earth cracks probably can be attributed chiefly to both the density and the apparent concentration within this same area of steeply dipping faults and joints (pl. 2) oriented more or less normally to the inferred axes of radially oriented strain. Preexisting fractures of this disposition are especially susceptible to compaction-induced failure. Fractures similarly situated with respect to the subsidence bowl also occur in the extreme northwest part of the area (west-southwest of the La Cienega Boulevard—Jefferson Boulevard intersection—pl. 2). However, because there has been relatively little construction there, surflcial faulting or cracking might go undetected. Limitations on fluid migration in the east block provide a second possible explanation for the areal restriction of the earth cracks. Compression of a fluid-saturated reservoir will lead to compaction of the fluid column as well as that of the reservoir skeleton, provided only that no path exists for escape of the fluids, such as laterally along the reservoir beds or out through a producing well. Thus, the vertical recovery potential of the compressed but undrained reservoir should, owing to the increased expansive capacity of the compressed fluid, exceed that of the drained reservoir. Because the east block is much more highly faulted and hence less easily drained than the west block (pl. 2 and figs. 3 and 4), particularly with respect to areas beyond the productive limits of the oil field, elastic rebound is much more apt to occur east of the Inglewood fault. The initial restriction of waterflooding to the east block has almost certainly accounted in part for either the localization or chronology of movement on the spatially associated earth cracks. Flooding operations, moreover, may have contributed to the cracking and faulting in two conceptually distinct but effectively similar ways. The disproportionately large deceleration in subsid- ence and compaction rates in the east block only during the 1958—62 interval is attributed to the injection of disproportionately large volumes of water during this same interval (see p.39 ff, on “Movements Attributable to Oil-field Operations”). Thus the increas- ing contrast during this interval in subsidence and compaction rates between the major blocks must have generated disproportionately steepened isobase and compaction gradients over a limited reach of the east limb of the subsidence bowl; we infer that these steepened gradients compelled an increase in the radially oriented extensional horizontal strain de- veloped in the east block to levels generally above those that prevailed elsewhere around the subsidence bowl. Because the probability of rupturing predicted by both the horizontal tension and elastic-rebound compaction models increases with increasing extensional strain 76 and decreasing a3, preferential development of the earth cracks in the east block through at least 1963 was certainly a reasonable expectation (Castle and others, 1973, p. 34—35). The second way in which waterflooding probably has contributed to surface rupturing is through the eleva- tion of pore-water pressures at depth (Hamilton and Meehan, 1971). We have disregarded the effects of changing reservoir fluid pressures on stress conditions in the preceding analyses of faulting, chiefly because such changes have been generally negative and, hence, have decreased the likelihood of faulting (see below). Increasing fluid pressures, however, tend to promote instability and an increased likelihood of faulting. Because fluid pressure is a scalar, and thus directionally independent quantity, application of the principle of effective stress (see section on “Movements attributable to oil-field operations”) indicates that increased fluid pressure should result in uniform reductions in the principal effective stresses. It is easily shown through use of a Mohr’s diagram in which the coordinate system is defined in terms of effective compressive stress, that uniform reductions in the principal effective stresses compel displacement of the stress circle toward tangency with the failure envelope (fig. 50). Since the deviator stress remains unchanged, this displacement occurs without any concomitant increase in the diame- ter of the stress circle. Thus decreased stability must derive from the diminished normal stresses that tend to promote frictional resistance to movement (shearing resistance) and, unlike the effect of simply reducing the least principal stress, can in no way be attributed to increased shear stress. Hamilton and Meehan (1971) have examined the relation between waterflooding and contemporary faulting in the Inglewood oil field and conclude that the faulting is causally related to increased reservoir fluid pressures due to flooding operations. Thus, according to Hamilton and Meehan (1971, p. 339—340), at least two episodes of fault movement along crack IX (deduced from leveling records and the monitored growth of cracks along the trace of this rupture) closely correlate with flooding operations in both space and time. Furthermore, “all recorded episodes of fault movement since 1957 have occurred after one or more of the following: initiation of injection in nearby wells, increases of injection pressure, or problems such as dropping fluid pressure concomitant with increases of fluid take, loss of fluid in narrow zones, and so on” (Hamilton and Meehan, 1971, p. 340). The likelihood that artificial elevation of reservoir fluid pressures may have provoked faulting is enhanced by the generation of injection pressure gradients well above the minimal 0.64 psi/foot cited by Hubbert and Willis (1957, p. 162) RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA as necessary for hydraulic fracturing in areas of incipient normal faulting. Hamilton and Meehan (1971, p. 338) show, in this connection, that injection gradients of 0.8 psi/foot or more commonly have been generated in Vickers East flooding operations; this observation is supported by the 0.95 psi/foot maximum operational gradient reported by Oefelein and Walker (1964, p. 512). In any case, massive increases in reservoir fluid pressure may have been unnecessary; any increase in fluid pressure would act to decrease shearing resistance and to increase the probability of faulting. In spite of the several suggestive associations between waterflooding and cracking, it is unlikely that the localization of the faulting can be attributed solely or even largely to the effects of injection (Castle and others, 1973). Although fully documented evidence of surface cracking dates only from 1957, reports of rupturing along crack I date from 1949 and 1955, and permissive, yet virtually compelling evidence of fault- ing along crack IX dates from 1951 (see section on “Earth cracks and contemporary fault displacements” and figs. 25 and 26). Moreover, direct evidence of dip-slip movement along crack X also dates from as early as 1951 (see section on “Earth cracks and contemporary fault displacements” and California Department of Water Resources, 1964, pls. 25a and 25c). Waterflooding operations, however, were not begun on even a pilot scale until 1954. Furthermore, although we have no specific data on injection pressures developed during the pilot floods, of the nine injectors known to have been operative at the end of 1957, only two were injecting at gradients above 0.5—0.6 psi/foot (Hamilton and Meehan, 1971, p. 338). Hence it is unlikely that the relatively high gradients of 0.8 psi/foot or more that became commonplace in later years were widely employed before 1958. Moreover, because the nearest pilot injector was separated from crack I by 2,000 feet and several steeply dipping faults (pl. 2), it is very unlikely that the limited injection through 1955 (1,638,484 bbls—see tables 2 and 3) could have provoked the reported rupturing along crack I in 1955. Thus waterflooding is inferred to have accelerated or aggravated a process already in operation and cannot be identified as a major factor in either the activation of the “earth crack” faults or their localization in the east block. Several additional lines of inquiry support this conclusion: ' Hamilton and Meehan (1971, p. 338) cite the seemingly striking correlation between the first explic- itly documented movement on crack I in May 1957 and the start of flooding in a nearby injector in the same month as evidence that faulting has depended largely on fluid injection at elevated pressures. Close examina- tion of this and similar correlations, however, chal- CAUSES OF THE SURFACE MOVEMENTS lenges their implied significance. According to F. J. Converse, clearly defined cracking along the trace of crack I appeared “early in May, 1957” (S R. Powers, written commun., 1970). Because the indicated injector (Baldwin Cienega—Stocker—LW 281—pl. 2) was placed in operation on May 12, 1957 (Castle and others, 1973, p. 30), this rupturing may have actually preceded the initiation of flooding here. In any case, even if injection had been under way for 3 or 4 months, the lifetime average injection rate for this well of 1,150 bbls/day (Castle and others, 1973, p. 30) suggests that no more than about 100,000 bbls could have been injected before clearly recognized movement began on crack I. This postulated 100,000-bbl volume is certainly insignificant as compared with: (1) the 4.5 million bbls introduced into the Vickers East during the pilot floods; (2) the nearly maximum annual Vickers East injection of 13 million bbls reached in 1961 (Musser, 1961, p. 111); or (3) the approximately 85 million bbls of oil and water and 22 million Mcf of gas extracted from the Vickers East alone before flooding began (as deduced from fig. 32 and Oefelein and Walker, 1964, p. 509). This conclusion takes on even greater significance when it is perceived that: (1) initial injection pressure gradients averaged 0.5—0.6 psi/foot; and (2) injection was conducted under “full-scale” conditions through a section many hundreds of feet thick in which reservoir fluid pressures at 1,300 feet below sea level had declined from an estimated initial value of 570 psi to measured values of 20—100 psi at the start of flooding (see fig. 33 and Oefelein and Walker, 1964, p. 510). Reservoir pressures in simple, finite systems vary directly with increasing volumes of introduced water; hence threshold fluid pressures necessary for failure (faulting) are less readily achieved with the introduction of a fixed volume of water where the initial reservoir pressures are, as in this case, very low. Thus to admit that the injection of 100,000 bbls of water into the pressure-depleted Vickers zone could have provoked movement over a surface on the order of 105—407 ft2 simply supports the conclusion that compaction-induced failure had been so closely ap- proached by May 1957 that even very local and otherwise trivial reductions in shearing resistance could trigger faulting. We note in passing, moreover, that the only other injector operating south or east of the pilot floods in May 1957 was BC—LAI—LW 240 (pl. 2); injection began in this well on April 22, 1957 (California Division of Oil and Gas, unpub. data). Because BC-LAI—LW 240 is more than 2,000 feet west of crack I and is separated from it by several steeply dipping faults, it is unlikely that injection through this well could have influenced fluid pressures along the subsur- face projection of crack I. 77 (2) Although flooding was not begun in the west block until 1962, it increased rapidly thereafter. By the end of 1969, flooding in the combined Vickers West-Rindge zones was proceeding at an annual rate of 32,360,506 bbls and cumulative injection had reached 147,468,809 bbls (California Division of Oil and Gas, 1969, p. 101). Flooding operations by the end of 1969, moreover, covered nearly the entire producing area of the west block (Munger Map Book, 1970, p. 165). We have no data on injection pressures utilized in the west block; we assume that they matched approximately those gener- ated in the Vickers East flooding operations. In spite of the large and apparently expanding waterflooding program (and other secondary recovery operations), the only example of surface rupturing reported from the west block is crack XIII (pl. 2). This crack, which apparently developed around 1960 (Hamilton and Meehan, 1971, p. 341), is atypical, however, in that it trends toward the center of the subsidence bowl and has not been associated with any differential movement. Hamilton and Meehan (1971, p. 341) argue that rupturing along crack XIII is due to increased fluid pressures generated in response to injection through two nearby disposal wells; however, the maximum volume of water that could have been introduced through these wells by the end of 1961 was 202,149 bbls (Musser, 1961, p. 115). Thus if we infer that waterfiooding was a major factor in the surficial faulting around the Inglewood field, the injection of 147 million bbls by the end of 1969 (which contrasts significantly with the 8 million bbls injected in the Vickers East through 1957, or even the 73 million bbls injected through 1963—Musser, 1957, p. 83; California Division of Oil and Gas, 1963, p. 102) should have induced at least some additional rupturing in the west block. (3) Among the 15 domestic oil fields for which we have evidence of historic faulting (see preceding discussion), waterflooding accompanied or preceded faulting in only one other field. Thus the general absence of contempor- ary flooding or other secondary recovery operations in most of these fields indicates that waterflooding cannot be invoked as a general explanation for faulting associated with oil-field operations. Parenthetically, experience in the Wilmington field suggests that waterfiooding may actually inhibit faulting, either by preventing the accumulation of additional elastic strain or by permitting an alternative form of relief for that already accumulated (Castle and others, 1973, p. 39). A possible objection to models that attribute the rupturing and displacements entirely to the effects of oil—field operations derives from the recognition of relative uplift southeast of the area of previously recognized differential subsidence. If these positive 78 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA movements are indeed unrelated to exploitation, and if it can be assumed that their magnitude remains unchanged as projected northward into the southeast- ern part of the Inglewood field, these movements suggest that comparable increments of differential uplift adjacent to crack I (pl. 4 and figs. 14 and 15) may be equally unrelated to exploitation. Thus the prerup— ture' isobase gradient may not be due entirely to exploitation-induced differential subsidence. Because both the horizontal-tension and elastic-rebound models require the achievement of some critical, threshold isobase gradient in order for rupture of occur, there exists some possibility that the rupturing may be due in part to phenomena other than exploitation of the Inglewood oil field. (If these postulated, relatively positive movements were of regional rather than local scope and projected undiminished northward through the entire Baldwin Hills area, they would be of no significance in this context, for this would result simply in uniform elevation of the entire system.) Direct evidence of relatively positive vertical move- ments southeast of the area of previously recognized differential subsidence is very limited. Positive vertical movements in excess of 0.01 foot/year, with respect to both Hollywood E—11 and PBM 1, were recognized during the 1958—62 interval in the area extending southeast from Slauson Avenue near Overhill Drive (pl. 4 and fig. 11). Although this area lies beyond the clearly recognized differential subsidence bowl defined by the 1950—54 surveys (pl. 4 and fig. 11), it has not yet been determined whether comparable movements occurred here before 1958. Permissive evidence of such move- ment derives from the history of vertical movement at PBM 10 (fig. 11), located about 1,200 feet west- northwest of the Slauson Avenue—Overhill Drive intersection (Walley, 1963, fig. 1), and thus about 1,000 feet inside the oil field (fig. 3). During the period 1939—54, PBM 10 subsided at an average rate of about 0.004 foot/year with respect to PBM 1 (fig. 3), a rate 0.01—0.03 foot/year less than that shown by other similarly situated bench marks around the Inglewood oil field. That PBM 10 was subsiding no more rapidly than 0.004 foot/year prior to the recognition of any earth cracks, suggests the occurrence of otherwise un- explained relative uplift in this area. Although the rebound east of crack I can be fully explained by compaction at depth (see also Deere, 1961, p. 62—63; Lee and Strauss, 1970), the possible occur- rence of positive vertical movements of as much as 0.02 foot/year (with respect to PBM 1) within the differential subsidence domain and unrelated to oil-field operations, suggests that a small fraction of the prerupture isobase gradient and associated strain may be unrelated to exploitation. It is unlikely, however, that this fraction could have exceeded the fractional contribution of the postulated positive movements to the average prerup- ture isobase gradient within the differential subsidence bowl. That is, it is unlikely that it could have been greater than<0.02 foot per year/>019 foot per year (compare pl. 4 and fig. 11). This fraction, accordingly, should have been insignificant in the absence of the exploitation-induced differential subsidence. CONCLUSION The earth cracks and associated displacements can be reasonably attributed largely or entirely to the exploi- tation of the Inglewood oil field, as indicated by the following points: the spatial and temporal associations between the earth cracks and both oil-field operations and exploitation-induced subsidence; the similarities in occurrence between these ruptures and displacements and those developed in and around other oil fields; and theoretical considerations which argue that these ruptures and displacements are consistent in form and magnitude with those expectable around the margins of artificially generated subsidence bowls. MOVEMENTS ATTRIBUTABLE TO CHANGES IN GROUND-WATER REGIMEN Land subsidence and associated surface deformation due to the extraction of ground water have been recognized in a number of areas around the world, including many in California (Poland and Davis, 1969). Several of these areas, moreover, occur within the Los Angeles basin (Estabrook, 1962, p. 7—8, fig. 1; Miller, 1966, p. 274—275; Gilluly and Grant, 1949, p. 494—497). GROUND—WATER DEVELOPMENT IN THE BALDWIN HILLS AREA Systematic exploitation of the ground-water re- sources of the Los Angeles coastal plain probably began about 1870 (Poland and others, 1959, p_. 99); it apparently proceeded rapidly, for Mendenhall (1905, p. 14—15) has indicated that by 1905 formerly flowing wells located near the north end of the Newport- Inglewood zone had ceased to flow and “cheaper” artesian water could no longer be obtained. Poland, Garrett, and Sinnott (1959, p. 99) conclude that a significant increase in ground-water draft in the northwestern Los Angeles basin began sometime after 1919, but detailed data on withdrawals between 1904 and 1930 are unavailable. Ground-water withdrawals between 1931 and 1945 in the Torrance-Inglewood area, south of the Baldwin Hills, and in the Culver City area, north and west of the Baldwin Hills, reached annual maximums of 78,400 acre-feet in 1945 and 12,933 acre-feet in 1940, respectively (Poland and others, 1959, p. 6, 12, 106—107). Between 1934 and 1957 withdrawals CAUSES OF THE SURFACE MOVEMENTS 79 from the West Coast basin, which equates roughly with the Torrance-Inglewood area of Poland, Garrett, and Sinnott (1959), reached an annual maximum of 94,100 acre-feet for the season 1952—53, and withdrawals from the Santa Monica basin, which equates roughly with the Culver City area of Poland, Garrett, and Sinnott (1959), reached maximums of 12,000 and 12,400 acre-feet during the 1939—40 and 1950—51 seasons, respectively (California Department of Water Re- sources, 1962, p. 38-39, 71). Declines in water table or pressure head probably accompanied withdrawals of ground water from many or most of the aquifers in the northwest Los Angeles basin. Poland, Garrett, and Sinnott (1959, pl. 15) show, for example, that water levels along the Newport- Inglewood zone southward from the Baldwin Hills declined 100—150 feet between the initiation of ground-water development and 1945. They also indi- cate for the area south of the Baldwin Hills that water levels in the "Silverado zone” declined a maximum of about 30 feet, and those in the shallower “ZOO-foot sand” declined about 8 feet during the period 1933—41 (Poland and others, 1959, pl. 10); water-level declines in the "Silverado zone” immediately north of the Baldwin Hills apparently reached a maximum of about 30 or 40 feet during the somewhat longer interval 1933—45 (Poland and others, 1959, pls. 9 and 12). The California Department of Water Resources (1962, pl. 110) has shown that over the period 1934—57, water levels in the shallow aquifers only declined a maximum of 30—40 feet in the area immediately west of the Baldwin Hills and about 80 feet both north and southeast of the hills. In short, the development of ground-water resources and resultant changes in ground-water regimen in the northwest Los Angeles basin locally have been both substantial and rapid—and possibly accelerated—- during the period in which surface movements have been recognized in the northern Baldwin Hills. Several considerations, however, indicate that water withdrawals and any attendant changes in ground- water levels have been both relatively insignificant and uniformly distributed within the Baldwin Hills area itself (see frontispiece). (1) Mendenhall’s (1905, pls. V and VI) maps reveal concentrations of water wells north, west, and south of the Baldwin Hills; a map compiled some 40 years later (Poland‘and others, 1959, p. 6—9, pl. 2), shows a generally similar distribution of wells. Only four or five of the scores of water wells shown on these maps could be characterized as “lying Within the Baldwin Hills,” and even these few occur along the outermost periphery, rather than toward the interior of the hills. Thus there appears to have been relatively little withdrawal of ground water within the Baldwin Hills proper through at least 1943 and virtually no change in the distribution of development activity between 1904 and 1943. These generalizations are strengthened through consideration of progressively smaller areas centering in the hills. (2) Hydrographic contours on maps showing water levels and water-level changes have not generally been extended into the Baldwin Hills (Mendenhall, 1905, pl. 1; Poland and others, 1959, pls. 9, 10, and 12; California Department of Water Resources, 1962, pls. 11A, 11B, 11C, and 12). The absence of these contours, which probably reflects an absence of ground-water development, is consistent with the conclusion of Poland, Garrett, and Sinnott (1959, pls. 9 and 12) that the northern two-thirds of the Baldwin Hills is “largely non-water bearing.” (3) The locally thick veneer of Pleistocene sands and gravels overlying much of the Baldwin Hills probably falls chiefly within the vadose zone; changes in the ground- water regimen within these materials are thought to have been minor. The preceding generalizations may not apply to the “central graben,” the structural block bounded by the Inglewood fault on the east and the roughly parallel series of faults 2,000—2,500 feet to the west-southwest (pl. 2). Several water wells, one of which (the Moynier well) was sited about l/2.—1/2 mile south of the north edge of the hills (Robertson and Jensen, 1926, p. 41, 43), have been drilled within the relatively low central graben area (see frontispiece). The Moynier well, located as far toward the interior of the hills as any known to us, passed “through the lowest Pleistocene conglomerate [and presumably into the clay-silt unit included here with the "Pico”] at 80 feet or 120 feet above sea level” (Robertson and Jensen, 1926, p. 41, 43). Horizontal projection of this “Pico”-Pleistocene contact southward toward the center of the hills suggests that the undifferentiated Pleistocene sands and gravels there may be as thich as 200 feet. These deposits probably are no thicker than 200 feet, however, for the lower Pleistocene so-called San Pedro Formation within the central part of the Inglewood field is represented as ranging from O to 200 feet in thickness (pl. 1). Moreover, even if the undifferentiated Pleistocene sands and gravels in the central part of the "graben” are as much as 300 feet thick, they occur largely within a long, dissected ridge about 1,000 feet wide and crop out at elevations of up to 330—340 feet, and thus about 100—150 feet above the surrounding drainageways. Hence, assuming the system to be unconfined, the ground- water table probably could not be naturally maintained at more than 200—250 feet above sea level anywhere within the central graben area, and maximum water- level decline could have been no greater than about 100~120 feet, even with complete evacuation of water. Within the area immediately north of the Baldwin Hills 80 and west of the Inglewood fault, water levels declined about 30 feet in the shallow aquifers between 1934 and 1957, and about 20 feet in the “Silverado zone” between 1933 and 1945 (California Department of Water Resources, 1962, p1. 11C; Poland and others, 1959, pls. 9 and 12). These declines suggest that water-level declines within the central graben have been much less than 100 feet—provided only, as seems likely, that hydraulic continuity between these two areas is unbroken by faults or pinchouts (Castle, 1960) and, as also seems likely, that hydraulic gradients have been no greater than 50 feet/mile (Poland and others, 1959, pls. 9 and 12). This conclusion is supported by the California Department of Water Resources (1964, p. 43), whose studies indicate that the Pleistocene formations within “an area bounded on the west by La Cienega Boulevard, on the northeast by the toe of Baldwin Hills, and on the south by Stocker Street * * * have never been saturated, nor has there been any extraction of ground water from them.” Little is known regarding infiltration of ground water in the Baldwin Hills, but variations in the rates of infiltration may have induced local changes in ground-water levels. Seepage from the Baldwin Hills Reservoir, for example, decreased from about 23 gpm in 1951 to about 9 gpm in early 1963 and then increased again to about 13 gpm by December 1963 (California Department of Water Resources, 1964, p. 56). This seepage may have locally saturated or thoroughly wetted the immediately underlying materials, mate- rials that probably were unsaturated before the reservoir was filled (California Department of Water Resources, 1964, p. 25). Infiltration from other sources, such as tract development, swimming pool leakage, and broken sewerlines may have equalled or exceeded that from the reservoir. However, because both climatic and cultural changes of the sort that might promote variations in infiltration have been felt more or less uniformly over the entire west basin, these variations should have been expressed equally uniformly over the entire area. - The preceding evidence indicates that there has been very little change in ground-water levels in the Baldwin Hills since 1900. Thus changes in ground-water level cannot be cited as likely explanations for the surface movements observed in the northern Baldwin Hills. This is not to suggest that there have been no changes whatever in local ground-water conditions..Whether the greatest conceivable changes in ground-water levels could have induced the observed movements is con- sidered below. SUBSIDENCE Substantial declines in water table or pressure head have been recognized over the past several decades RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA within the major aquifers underlying the lowland areas surrounding the Baldwin Hills. These aquifers, moreover, are correlative in part with the undifferen- tiated Pleistocene sands and gravels within the hills (fig. 2) that have been identified chiefly with the San Pedro Formation and, to a much lesser extent, undivided upper Pleistocene deposits (Poland and others, 1959, pls. 2 and 3). Thus, water-level declines of as much as 60 feet or more occurred within the shallow aquifers between 1934 and 1957, both northeast and southeast of the Baldwin Hills (California Department of Water Resources, 1962, pl. 1 IC), and declines of about 40 feet were measured within the underlying “Silverado zone” between 1933 and 1945, both southeast of the hills and immediately north of the northern scarp (Poland and others, 1959, pls. 9 and 12). Differential subsid- ence over these same areas, however, has been slight or nonexistent. Annual elevation changes along that section of Manchester Boulevard overlying the areas of greatest water-level decline, at about the longitude of Crenshaw Boulevard, ranged from about 0.00 foot/year to +0.01 foot/year during the 1930’s (fig. 5) and from less than —0.01 foot/year to about —0.02 foot/year between 1949 and 1955 (fig. 6). If these elevation changes are compared with those over nearly the entire length of Manchester Boulevard, it is clear that differential subsidence over the areas of greatest water-level decline during the 1930’s was generally no greater than that elsewhere along Manchester Boulevard (except in the area 2 miles and more east of the Newport- Inglewood axis), and that between 1949 and 1955 it was about the same as that detected over the entire 6- or 7-mile reach examined here. Similarly limited subsidence seems to have occurred east of Fairfax and north of Jefferson Boulevard, the area of greatest water-table or pressure-head decline north of the Baldwin Hills; reported subsidence there during the 1930’s (fig. 5) averaged less than 0.01 foot/year, and that between 1949 and 1955 (fig. 6) was apparently less than 0.03 foot/year. The profiles of elevation change shown in figure 11 indicate that the average rates of subsidence in this area may have been even less than 0.01—0.03 foot/year; subsidence with respect to PBM 1 along La Brea Avenue between the north edge of the hills and Washington Boulevard during the period 1939—62 probably was nowhere more than 0.005 foot/year. Thus, although there seems to be some correlation between subsidence during the period 1949—55 with the area of greatest known pressure-head decline within the “Silverado zone” north of the hills, differential subsidence, as shown by a comparison of elevation changes along Washington Boulevard, proba- bly was nowhere much greater than 0.01 foot/year. In CAUSES OF THE SURFACE MOVEMENTS any case, because differential subsidence over the areas of greatest drawdown within the aquifers surrounding the hills has been but a small fraction of that observed within the hills themselves, it is unlikely that the major subsidence in the northern Baldwin Hills can be attributed in any significant degree to reductions in ground-water levels within the local formational equivalents of the aquifers surrounding the hills. It is very unlikely that water-level or artesian-head decline in the sands and gravels of the “central graben” has been as great as that in the area surrounding the Baldwin Hills. However, even if it is conceded that water-table reductions of as much as 120 feet may have occurred within the central graben area (see preceding section), it is nearly certain that this decline could not have generated surface subsidence of the magnitude measured in the northern Baldwin Hills. Thus, during the period 1933—45 artesian head within the BOO-foot “Silverado zone” underlying Dominguez Gap north of Wilmington, declined about 30 feet; this head reduction was associated with 0.354 foot of subsidence over approximately the same interval (Poland and others, 1959, p. 144—145, pls. 9 and 12). Ifit is assumed: (1) that the materials underlying the aquifers in the Dominguez Gap and central graben areas are similar; (2) that the saturated thickness of the central graben “aquifer” was no greater than 120 feet; (3) that the water table in the central graben area was reduced through its entire 120-foot thickness; and (4) that decrease in geostatic load attributable to water loss was negligible, use of the subsidence-head-decline parameters associated with the extraction of water from the confined aquifers in the Dominguez Gap area permits the following calculation of the maximum conceivable subsidence in the uncon- fined “aquifer” of the central graben area: [(0.354ft/300 ft)/30ft] [120s] [120m] = 0.284 ft.12 Hence subsidence due to water-table decline probably could account for no more than about 1/2o of that actually measured over the central graben. To conclude, it is very unlikely that changes in ground-water conditions have contributed significantly to the differential subsidence recognized in the northern Baldwin Hills, as shown by: the absence of any history of ground-water extraction; the probability that major changes in the ground-water regimen could not have occurred within the Baldwin Hills during historic time; the almost complete absence of measurable surface subsidence over areas of substantial water-table or pressure-head decline in aquifers correlative with the Pleistocene sands and gravels exposed in the Baldwin 12The first term represents the compaction due to a 1-foot drop in pressure head per foot of reservoir section; the second term represents the saturated thickness of the central graben reservoir; the third term represents the average pressure-head decline generated by a 120-foot drop in water level through the unconfined central graben reservoir. 81 Hills; the probability that even the maximum conceiv- able water-table decline would have produced only a small fraction of the observed subsidence in the central graben area; and the absence of any spatial or temporal correlation between the observed subsidence and ground-water development within and around the hills. This conclusion, accordingly, supports that of the California Department of Water Resources (1964, p. 52, 57), who observe that “the formations underlying the Baldwin Hills are devoid of significant quantities of potable ground water, and hence pumpage from water wells has never posed a threat of land subsidence in this area.” There is almost no possibility that the Baldwin Hills subsidence is an example of hydrocompaction or “shallow subsidence” developed in response to infiltra- tion of water into loosely compacted sediments, chiefly because there is no known source for broadly developed, selective infiltration centering on the northwestern section of the hills. Hydrocompaction, moreover, is unknown locally, and the sediments cropping out in the Baldwin Hills are in their mode of origin unlike those subject to this effect (Bull, 1964, p. A1; Lucas, 1965, p. 111—112). HORIZONTAL MOVEMENTS The symmetrical and orthogonal relations between the center of subsidence and associated isobases on the one hand, and the centripetally directed horizontal movements on the other hand (pl. 4), indicate that the subsidence and horizontal movements are causally related. Because the differential subsidence cannot be explained by changes in ground-water conditions, the centripetally directed horizontal movements are equally unexplained by such changes. EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS The earth cracks developed in the northern Baldwin Hills occur not only within an area of generally “non-water-bearing” sediments, but also Within what is probably the least “water-bearing” part of this area, for it is in the northern half of the east block that the potential water-bearing materials are thinnest. Thus the probability of any substantial changes in ground- water conditions in this very restricted area is even lower than that for the hills in general. Furthermore, because displacements along the earth cracks locally extend well into the underlying rocks, movements along these cracks probably are unrelated to changes in ground-water conditions in the overlying sands and gravels. The occurrence of the earth cracks within a section of the northwestern Los Angeles basin in which there has been no significant extraction of potable groundwater, 82 together with the inferred extension to depth of displacements on the earth cracks, indicate that the earth cracks and associated fault displacements cannot be attributed to changes in ground-water conditions. MOVEMENTS ATTRIBUTABLE TO SURFACE LOADING Sediments commonly undergo consolidation in re- sponse to surface loading. They may also expand following unloading, as suggested, for example, by the 0.03 foot rebound of the Baldwin Hills Reservoir following its drainage in 1957 (California Department of Water Resources, 1964, p. 60). Loading or unloading may be classified as natural or artificial. It is inferred from both the measured uplift along the Newport-Inglewood zone in this area and the physiographically youthful aspect of the hills, that the Baldwin Hills have been undergoing uplift and denuda- tion during most of late Quaternary time. Thus, because most of the erosion products have been carried out beyond the hills, it is likely that unloading rather than loading has dominated local geologic history through- out the 1ast few thousand years. Artificial earthmoving activities in the Baldwin Hills over the past three or four decades have been characterized by both loading and unloading. Both have been relatively uniformly distributed over the hills and both have been limited chiefly to cuts and fills measured in tens or hundreds rather than thousands of cubic yards. We recognize, however, three examples of major earthmoving operations within the Baldwin Hills: (1) construction of the Baldwin Hills Reservoir during the late 1940’s and early 1950’s—which was accompanied by extensive excavation and the placement of about 2 million yards of various locally derived materials (California Department of Water Resources, 1964, p. 24, 26—28); (2) construction of La Cienega Boulevard through the western half of the hills during the early 1950’s—which required extensive grading from the area north of Centinela to the north edge of the hills; (3) subdivision development in the southwestern quarter of the hills, chiefly during the 1950’s—during which entire drainageways were filled to depths of 25—35 feet over distances of up to about 1 mile. SUBSIDENCE Because natural changes in mass distribution in the Baldwin Hills have been dominated by unloading, the pronounced subsidence developed here cannot be explained as a result of natural loading. Similarly, because artificial fill has been distributed fairly uniformly over most of the Baldwin Hills during historic time, and because the three major construc- tional efforts listed above lie near the edge of the RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA subsidence bowl, it is unlikely that this subsidence can be attributed to artificial loading. This conclusion is supported by the likelihood that the surficial sediments in the Baldwin Hills are relatively insusceptible to compaction. Eagen and Brown (1959, p. 7) report that the “greatest settlement [under load within the Los Angeles basin] usually occurs in lowland areas of lagoon or flood-plain environment in which fine-grained cohesive sediments and organic material have been deposited to a considerable depth.” Thus even the filling of the Baldwin Hills Reservoir, the center of which lies about 1,600 feet southwest of Hollywood E—11 had only a slight effect on the subsidence pattern. The settlement record of the reservoir gate tower (fig. 25), which was founded within an excavated section of the reservoir (California Department of Water Resources, 1964, pls. 2 and 11), extends from August 1949—about 1% years prior to filling (California Department of Water Resources, 1964, p. 23, 31; Casagrande and others, 1972, p. 565—567)—through February 1964. This record shows that the average settlement rate (relative to Hollywood E—ll) preceding filling was no less and perhaps somewhat greater than that which obtained after the reservoir was filled. We conclude that the differential subsidence center- ing in the northern Baldwin Hills probably is unrelated to natural or artificial loading, as indicated by: the geologically recent (and probably continuing) uplift and denudation of the hills; the absence of any apparent spatial or temporal relation between the general pattern of subsidence in the northern Baldwin Hills and the placement of the larger fills; and the relatively unsusceptible nature of the near-surface sediments to continuing compaction. HORIZONTAL MOVEMENTS Because the geometric relations between the cen- tripetally directed horizontal movements and the dif- ferential subsidence developed in the northern Baldwin Hills indicate that these movements are causally related, the horizontal movements can be no more attributed to loading phenomena than can the subsidence. EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS Although natural unloading in the Baldwin Hills probably has exceeded natural loading during Holocene time, differences between the two during the past several decades probably have been nearly unmeasura- ble. Moreover, such natural unloading or loading as may have occurred during historic time must have operated relatively uniformly throughout the northern Baldwin Hills. Hence, it is very unlikely that the locally CAUSES OF THE SURFACE MOVEMENTS developed earth cracks can be attributed to natural loading effects. Similarly, because artificial cut-and-fill activity has also been more or less uniformly distributed throughout the hills, it is equally unlikely that the cracks and associated displacements are due to artificial loading or unloading. The preceding arguments retain their validity, moreover, even if consideration of loading effects is restricted to areas of high fault or joint density. A dubious circumstantial argument may be made in support of an association between artificial loading and rupture and displacement along the earth cracks; it cannot apply, however, to the southern group of earth cracks and thus be considered as evidence of a general association between loading and cracking.‘ The chief points of this argument are as follows: (1) the northern group of earth cracks is located in the Baldwin Hills Reservoir area (pl. 2 and fig. 22); (2) cracking of the drainage inspection chamber, which lies athwart crack IX, was first recognized in October 1951 (fig. 26), shortly after the reservoir was filled; and (3) artificial fill and stored water were concentrated in the area west of the earth cracks (California Department of Water Re- sources, 1964, pls. 2, 11, and 22a). The preceding points suggest that loading in the reservoir area, particularly that associated with the filling of the reservoir, may have compressed the foundation materials differen- tially with respect to the location of the major earth cracks. Therefore, following this line of argument, drag-induced compression of the materials east of the earth cracks ultimately may have reached some threshold value above which frictional resistance to movement was overcome and rupture and elastic rebound of the east block ensued (figs. 25 and 27). Several considerations, however, dispute this hypothesis. In the first place, because settlement began even before construction of the reservoir (fig. 11) and was no more than slightly accelerated by its filling (fig. 25), the settlement and presumably associated rebound must stem from some other cause. Secondly, there seems to have been little response to unloading west of crack IX subsequent to the reservoir failure and loss of stored water in December 1963 (fig. 27); if the compression of the underlying materials was measura- bly elastic and due largely to reservoir loading, recovery should not have been so preferentially and exclusively confined to the east block. There exists a slight possibility that the timing of the displacements in the reservoir area may have been influenced by surface loading. If leakage through the reservoir lining saturated the natural foundation materials, the water load contained within the over- lying reservoir may have induced significant increases in pore-water pressure and corresponding decreases in 83 the normal stresses acting across any actual or poten- tial rupture surface. It is unlikely, however, that any displacements could have occurred had there been no accumulation of elastic strain in the underlying mate- rials, which, as shown above, cannot be attributed to surface loading. Casagrande, Wilson, and Schwantes (1972, p. 573— 576) have suggested a complex variation of the preceding argument to explain the faulting in the area of the Baldwin Hills Reservoir. According to these writers, the faulting along cracks IX and X (faults I and V of their description) that preceded failure of the reservoir was the result of "differential settlements*** produced by (1) water and embankment loads applied to the foundation soils which were loosened on the west [downthrown] side of the faults during original faulting, and (2) by wetting and erosion in these loosened masses.” The differential movement along crack IX that closely accompanied or followed reservoir failure is attributed to rebound of the east block resulting from release of stress accumulated during a previous tectonic episode; the rebound is considered to have been triggered by the introduction during failure of nearly full reservoir hydrostatic head and resultant loss of shearing resistance along the fault (Casagrande and others, 1972, p. 579—580). The reservoir failure, in other words, is viewed not as an effect of rebound, but rather as its cause. The Casagrande, Wilson, and Schwantes (1972) model, although conceptually appealing, is deficient in several significant respects. It certainly cannot, for example, be invoked as a general explanation of ground rupturing, for it provides no insight into the fully analogous rupturing in the area of the Stocker Street—La Brea Avenue—Overhill Drive intersection. This hypothesis also requires that the faulting that preceded reservoir failure be explained by active consolidation or compaction of the westerly blocks against passive east blocks (Casagrande and others, 1972, p. 573—576). Our studies, on the other hand, show that displacement along crack IX (and probably along crack X as well) was the product of rebound of the east block against a passive west block throughout the entire operational history of the Baldwin Hills Reservoir. Furthermore, although very localized differential sub- sidence concentrated west of crack X, in particular, probably is due to differential settlement or consolida- tion (Casagrande and others, 1972, p. 574), much of this settlement is almost certainly the result of collapse of the natural foundations eroded through piping and continuing consolidation of relatively thick fill west of the earth cracks (California Department of Water Resources, 1964, p. 58, pls. 2, 11, 22f, and 22g); thus the occurrence of such settlement by no means precludes 84 the operation of completely unrelated faulting, which may, in fact, have contributed to its development (California Department of Water Resources, 1964, p. 63). Moreover, the flat determination that “this type of differential settlement could not be explained by displacements of blocks along faults” (Casagrande and others, 1972, p. 574—57 5) is particularly unwarranted, for it implies that faulting of a conventional nature could not have bounded these narrow zones of differen- tial settlement. In fact, however, vertical movement of this sort is fully consistent with high-angle faulting developed in association with extensional horizontal strain (Cloos, 1968)—such as that recognized in the area of cracks IX and X (Casagrande and others, 1972, p. 581—582). Furthermore, the large survey time windows of 6.4 and 13.1 years that led to the Casagrande, Wilson, and Schwantes (1972, p. 57 4—57 5) determination, would both include such movements as may have been associated with reservoir failure and tend to obscure the existence of slight but significant episodes of rebound in the easterly blocks. Finally, the tacit exclusion of any likely mechanical relation between the broadly defined strain system centering on the northern Baldwin Hills and faulting in the Reservoir area (Casagrande and others, 1972) is inconsistent with the very restricted spatial and temporal relations among these features. To conclude, it is very unlikely that the earth cracks and associated displacements are due to surface loading or unloading, as shown by: the generally random distribution of surface loading or unloading as con- trasted with the very restricted development of the earth cracks; and the probability that the observed subsidence and preferential rebound of the east blocks cannot be reasonably explained as a response to surface loading. MOVEMENTS ATTRIBUTABLE TO TECTONIC ACTIVITY Southern California is clearly recognized as tectoni- cally active (see sections on “Geology,” “Seismicity,” and “Regional Elevation Changes”); hence there exists a reasonable basis for assuming that the surface movements in the northern Baldwin Hills are simply manifestations of this apparently continuing activity. Gilluly and Grant (1949, p. 488), however, have focused sharply on the problem of attributing particular movements to specific tectonic forces, for “causes of tectonic movements are so obscure that it is always possible to assert their effectiveness without the possibility of direct disproof; in the nature of the case, the demonstrated adequacy of another mechanism known to be operative and competent to produce the observed effects can only make it unnecessary to appeal to the unknown tectonic forces.” In other words, there is RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA a tendency to dismiss as “tectonic” those surface or crustal movements insusceptible to direct analysis. The effects of continuing tectonic activity in the Baldwin Hills may be expressed in a variety of ways. Rather than examining the full spectrum of tectonic phenomena that may have been operative here, the following discussion considers only those phenomena relevant to the observed surface movements. SUBSIDENCE Several partly incompatible lines of evidence could be interpreted as suggesting a tectonic involvement in the northern Baldwin Hills subsidence: (1) the growth of the subsidence bowl within a zone of recognized folding; (2) the apparent northward migration during Quaternary time of the crest of the major anticlinal fold in the Baldwin Hills; (3) the locally developed, ephemeral uplift along parts of the Newport-Inglewood zone west and north of the center of the hills; and (4) the approximate coincidence in space between the “central graben” and the subsidence bowl. Detailed considera- tion, however, shows that none of these associations is especially significant, either individually or collective- ly, and none explains the initiation of differential subsidence in the middle 1920’s. There is no doubt that the differential subsidence is spatially associated with a major fold, for it roughly mirrors the underlying Inglewood oil-field anticline (pl. 4 and figs. 3 and 4). Thus, it might be argued that the subsidence simply reflects downfolding along the same axis. Several observations, however, indicate that it is extremely unlikely that the natural sense of folding has been reversed. In the first place, uplift rather than subsidence has dominated the general pattern of vertical movement in this area during late Quaternary time. The relatively elevated nature of the hills, coupled with their mantle of upper(?) Pleistocene debris, suggests that this uplift is continuing. Secondly, the nearby, structurally elevated Cheviot Hills, Where until recently any tectonic effects could not have been masked by petroleum exploitation, have been as- sociated with contemporary uplift rather than subsi- dence. These hills, about 4 miles north-northwest of the Baldwin Hills and about 12/3 miles east-northeast of the Pico-Sepulveda intersection (figs. 5 and 6), remained unexploited for petroleum until 1958 (Conservation Committee of California Oil Producers, 1964, p. N). Before 1958, moreover, this area had been charac— terized by at least ephemeral uplift. Thus, as shown in figure 6, the Cheviot Hills structure lies both within a small nose or reentrant of surface uplift in the 1949—55 pattern of isobases and along the boundary of a positive area that seemingly persisted during the late 1920’s and through most of the 1930’s (fig. 5). This coincidence CAUSES OF THE SURFACE MOVEMENTS suggests that in the absence of underground fluid extraction, locally developed and seemingly youthful structural highs have continued to rise through historic time.13 In any case, the elevation of the very young sediments exposed in the Baldwin Hills, coupled with the recognition of preexploitation positive movement in the Cheviot Hills oil-field area, indicates that tectoni- cally induced reversals in the sense of folding along the Inglewood oil-field anticline should have been very unlikely. Even were it conceded that there had been no tectonic reversal in the sense of folding of the Inglewood oil-field anticline, it might still be argued that the differential subsidence represents downwarping developed in as- sociation with either the postulated northward migra- tion of the major fold axis during Quaternary time, or very recent westward displacement of the axis of the Newport-Inglewood zone. This argument, however, requires not only uplift along the shifted axis, but complementary downwarping along opposite sides of the shifted axis. Because differential subsidence of an order approaching that identified in the northern Baldwin Hills has not been recognized north or west of the hills, this hypothesis is considered invalid. Finally, it might be suggested that even though the Baldwin Hills as a whole have been undergoing tectonic uplift during Holocene time, this need not preclude an accompanying downdrop of the poorly defined “central graben” (fig. 2 and California Department of Water Resources 1964, pl. 10). The differential subsidence could thus be interpreted as a contemporary expression of the development of the graben. Several arguments, however, refute this postulate. (1) The configuration of the differential subsidence bowl (pl. 4) fails to conform in detail to that of the graben (frontispiece, pl. 2 and figs. 3 and 4). The central graben is a roughly linear feature about 2,000 feet wide and is best developed at the extreme north end of the hills, whereas the subsidence bowl is elliptical, centered about 3,000 feet south of the north edge of the hills, and extends without interrup- tion almost one-half mile northeast and nearly 1 mile southwest of the boundaries of the central graben. The major axis of the subsidence bowl, moreover, intersects that of the graben at an angle of 25—30°. (2) If the 200-foot scarp along the Inglewood fault, which forms the east boundary of the central graben (frontispiece and pl. 2) was generated in response to continuing subsidence of the graben, contemporary subsidence of up to 0.125 foot/year at the fault and up to 0.20 foot/year at the center of the subsidence bowl suggests that the scarp itself may have evolved over a period of about 13A comparison of elevation measurements made along Pico Boulevard between 1955 and 1963 by the Los Angeles Bureau of Engineering suggests that uplift over the Cheviot Hills (with respect to bench marks east of the hills) ceased sometime between 1955 and 1960. 85 1,000—1,600 years—an inordinately short interval for the creation of a physiographic feature of this size (California Department of Water Resources, 1964, p. 45). Moreover, if the subsidence resulted from differen- tial vertical movement of the central graben, there should be evidence of contemporary displacement on the Inglewood fault, whereas, in fact, there is none. (3) The presence of contractional horizontal strain (through a 90° range) in the central part of the subsidence bowl (see section on “Horizontal Movements”) is completely inconsistent with any tectonic model of graben forma- tion. Tectonically activated normal faulting and as- sociated depression of the blocks that comprise this “graben” (fig. 2 and California Department of Water Resources, 1964, pl. 10) should have been accompanied by extensional horizontal strain, particularly if dis- persed and attenuated in propagating to the surface in order to explain the absence of actual surface ruptures along the graben bounding faults (see, for example, Hubbert, 1951); tectonically induced contractional strain is, under these circumstances, mechanically impossible. Thus there appears to be no consistency between the presumably tectonic evolution of the graben and the continuing differential subsidence in the northern Baldwin Hills. In summary, it is unlikely that the differential subsidence centering in the northern Baldwin Hills can be attributed to tectonic downwarping, as indicated by: the inverse structural relation between the differential subsidence and the underlying Inglewood oil-field anticline; a late Quaternary history of continuing uplift rather than subsidence over the Baldwin Hills as a whole; evidence that the nearby Cheviot Hills had been undergoing uplift rather than subsidence prior to their exploitation for petroleum; the probability that migra- tion of the Inglewood oil-field fold or the Newport- Inglewood axis could not have been accompanied by the asymmetrical development of subsidence athwart either of these axes; and the incompatibility of the subsidence and associated contractional strain with the tectonic evolution of the central graben. This judgment is further supported by the absence of any recognized tectonic event with which the onset of subsidence can be associated. HORIZONTAL MOVEMENTS The geometric relations between the pattern of differential subsidence and the centripetally directed horizontal movements indicate that these movements must be genetically related; because the subsidence is probably unrelated to tectonic activity, it is equally unlikely that the horizontal movements are related to tectonic activity. 86 EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS The earth cracking and associated fault displace- ments are much more readily attributed to tectonic activity than are the differential subsidence and radially oriented horizontal movements. Tectonic gen- eration of the earth cracks is suggested especially by the following: (1) the cracks are coincident with or nearly parallel to faults known to have been active during Quaternary time; and (2) they occur within the seismically active Newport-Inglewood zone. In spite of these suggestive considerations, it is unlikely that the contemporary separations and displacements along the earth cracks are more than incidentally tectonic. In the first place, although the earth cracks occur along or parallel to preexisting faults and joints, their relatively specific definition with respect to the sub- sidence bowl (that is, confined to the periphery of the bowl and roughly perpendicular to radii emanating from its center) suggests that the cracking and dis- placements are mechanically associated with the sub- sidence, which is almost certainly of nontectonic origin. Secondly, most of the domestic examples of clearly tectonic historic surface faulting have been precisely identified with perceptible and generally large earth- quakes. Branch and secondary faulting commonly have accompanied these shocks, but always in conjunction with rupturing along the main trace of the primary fault (Bonilla, 1967, table 1). Parenthetically, the two moderate to large earthquakes (the 1920 Inglewood and 1933 Long Beach shocks) that are known to have occurred along the Newport-Inglewood zone are not known to have been accompanied by surface faulting (Taber, 1920, p. 137; Wood, 1933, p. 53). Moreover, all but possibly one of the recognized examples of aseismic tectonic surface faulting have occurred along the main traces of major faults, such as the San Andreas and Hayward (see Bonilla, 1967, p. 17—18, and table 1). Historic precedent suggests, accordingly, that tectoni- cally induced separations and displacements along the earth cracks should have been accompanied by percep- tible earthquakes or identifiable displacements on the Inglewood fault, neither of which has been recognized. Thirdly, the sense of prehistoric movement on those faults paralleling or coincident with the earth cracks apparently ranged through 90°. “At one place on the fault plane [about midway along the length of the fault identified with crack IX]* * * horizontal striae were found showing that the last movement at this location was entirely horizontal with no vertical displacement. At another place on the fault plane, at the toe of the north bank of the reservoir, the striae were along the direction of maximum dip of the fault plane which was RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS AN GELES COUNTY, CALIFORNIA S.85°W, dipping 80°” (California Department of Water Resources, 1964, p. 13; Wilson, 1949, p. 25). We have, in addition, measured crudely defined slickensides pitch- ing 50°—70° south along a north-northeast striking fault about one-half mile northwest of the Stocker Street— LaBrea Avenue—Overhill Drive intersection. Thus, because prehistoric movements along these faults have ranged from dip-slip through oblique-slip to lateral-slip, and because the style of faulting along the Newport- Inglewood zone has been characteristically right- lateral, the nearly exclusively dip-slip nature of the contemporary displacements. along the earth cracks represents the least expected sense of tectonic dis- placement on these cracks. Fourthly, subsurface movements, as indicated by oil-well damage, have not been reported from below the highly productive but relatively shallow Vickers zone. Although this restriction has been attributed by A. J. Horn (as paraphrased by the California Department of Water Resources, 1964, p. 42, 44) to the fact that relatively few wells penetrate deeper zones, 216, or a significant one-third of the 1963 field total of 651 active wells, penetrated zones beneath the Vickers (Conserva- tion Committee of California Oil Producers, 1964, p. P). We suggest, alternatively, that the damaging move- ments may, in fact, have been confined to the Vickers zone or above (California Department of Water Re- sources, 1964, p. 44); acceptance of this alternative explanation is incompatible with assertions that fault- ing or fault-inducing strain have propagated from depth in response to tectonic activity. Finally, the observed faulting is mechanically incon- sistent with tectonic failure generated in a surface strain environment of the sort recognized in the northern Baldwin Hills. If the faulting were purely tectonic it would have to have been: (1) conjugate or shear faulting complementary to that generated along the Inglewood fault; (2) branch faulting; or (3) exten- sional faulting. If the faulting was either conjugate or branch it should have been chiefly transcurrent in order that it accord with the predominantly right-lateral movement on the Inglewood fault. Conjugate shearing, moreover, probably would have been accompanied by at least minor displacement on the Inglewood Fault. Branch faulting should have been not only predomi- nantly transcurrent, but uniformly right-lateral. Be- cause the historic faulting recognized through at least 1963 was chiefly dip-slip, because there appears to have been no discernible historic displacement on the In- glewood fault, and because at least small components of left-lateral movement were recognized along several of the ruptures (particularly crack IX), it is doubtful that the faulting was either conjugate or branch in nature. The generally dip-slip and seemingly normal character SUMMARY AND CONCLUSIONS of the faulting, coupled with its high-angle orientation with respect to the axis of the Inglewood oil-field . anti— cline indicates that any tectonic faulting is more likely the product of extension along or parallel to the anti- clinal axis. However, the contractional strain meas- ured in the central part of the subsidence bowl effec- tively destroys this hypothesis. The coincidence in space between the earth cracks and earthquakes in and around the Baldwin Hills (see pl. 3) is of little apparent significance, for as shown by Hudson and Scott (1965, p. 171—173), there is no evident temporal relation between fault movements at the Baldwin Hills Reservoir site and local earthquake activity. Hudson and Scott have also observed that no significant local seismic events, as indicated by a continually recording seismograph set up at the reservoir site, were recorded during the several weeks following the faulting associated with the reservoir failure. Accordingly, assertions that the earth cracks can be associated With seismotectonic activity would have to be supported by a rigorous statistical study demonstrating not only their spatial coincidence, but a temporal association as well. Very small increments of relative uplift in the area east of crack I are perhaps the best suggestion of an at least limited tectonic involvement in the earth cracking and associated displacements. As shown in the discus- sion of earth cracks and contemporary fault displace- ments attributable to oil-field operations, a probable maximum of 0.02 foot/year of positive movement (with respect to control points outside of the area of previously recognized differential subsidence) in the block east of crack I may be unrelated to oil-field operations, and may have thus accounted for up to about 10 percent of the prerupture isobase gradient there. Accordingly, this postulated tectonic contribution may apply in equal measure to the critical isobase and compaction gra- dients at which rupturing and displacement could occur. Alternatively, local tectonic effects may have controlled the timing of the rupturing, in that the threshold gradients may have been attained somewhat earlier than in the absence of any such effects. There is, however, no reason to suppose that these suggested increases in the compaction and subsidence isobase gradients could have induced rupturing had not the apparently nontectonic subsidence been proceeding concurrently. Thus, in the absence of oil-field opera- tions, elevation changes within the presently recog- nized area of differential subsidence probably would have matched very closely those elsewhere in the Baldwin Hills, thereby inhibiting the evolution of abnormally steepened isobase gradients and an as- sociated potential for rupturing. To conclude, the earth cracks and associated dis- 87 placements are doubtfully of tectonic origin, as indi- cated by: their probable mechanical association with the apparently nontectonic subsidence; the absence of displacements on the Inglewood fault in conjunction with displacements along the earth cracks; the absence of surface faulting associated with relatively large earthquakes along the Newport-Inglewood zone; the likelihood that purely tectonic displacements would have been other than essentially dip-slip; the confine- ment of damaging subsurface movements to relatively shallow parts of the oil field; the mechanical incompati- bility between recognized contractional horizontal strain along the axis of the Inglewood oil-field anticline and tectonically-induced extensional faulting; and the absence of a well-defined temporal correlation between the local seismicity and the development of the cracks. Up to about 10 percent of the prerupture isobase and compaction gradients east of crack I and, hence, perhaps 10 percent of the forces responsible for the generation of the earth cracks and displacements there, may be of tectonic origin; this postulated fraction, however, should have been of little significance in the absence of the concurrently evolving nontectonic differential sub- sidence. SUMMARY AND CONCLUSIONS Various expressions of contemporary surface defor- mation have now been recognized within a wide range of geologic environments. Such deformation, which we define here to include both measured vertical and hori- zontal movements and surficial rupturing and faulting exclusive of that associated with slope failures, has been attributed to a broad spectrum of artificial and natural phenomena. Surface movements identified in the Baldwin Hills of southern California comprise a particularly well- documented example of surface deformation associated with oil-field operations. Movements recognized here include well-defined differential subsidence centering on the Inglewood oil field; horizontal movements di- rected more or less toward the center of subsidence; and earth cracking and associated surficial faulting con- fined largely to the eastern margin of the subsidence bowl. Although these movements are clearly associated in space with oil-field operations, their temporal asso- ciations are less well defined and the possible effects of ground-water extraction, surface loading, and tec- tonic active have greatly complicated their analysis. GEOLOGIC FRAMEWORK The Baldwin Hills are located toward the north end of the Newport-Inglewood zone of folds and faults, where they occur as an isolated physiographic feature elevated about 350—400 feet above the terrace and alluvial de- posits of the surrounding Los Angeles basin lowland. 88 The hills are underlain by a sequence of gently to mod- erately arched and conspicuously faulted Cenozoic sedimentary and volcanic rocks; this sequence in turn overlies crystalline basement rocks at a depth of over 10,000 feet. Conspicuous displacements have occurred on both the north-northwest trending Inglewood fault, which transects the hills diagonally, and similarly oriented faults elsewhere along the Newport-Inglewood zone. Right-lateral displacements along the Inglewood fault of 3,000—4,000 feet since middle or late Pliocene time and 1,500—2,000 feet during Quaternary time are indicated by offset structures and physiographic fea- tures; vertical separations of at least 200 feet during late Quaternary time are clearly indicated in the north-central part of the hills. Displacements along generally north to north-northeast trending branch or cross faults have been only a small fraction of those along the Inglewood fault. Deformation of the older rocks underlying the Bald- win Hills probably began no later than middle Miocene time. Conspicuous fault scarps developed across upper Pleistocene deposits and the extremely youthful phys- iographic dissection indicate that this deformation has continued through much of Quaternary time. Evidence of continuing deformation in and around the Baldwin Hills derives chiefly from the historic seis- micity and measured elevation changes. Epicentral lo- cations of earthquakes, as recorded by the Seismologi- cal Laboratory at Pasadena since 1934, correlate fairly well with the axis of the Newport-Inglewood zone. Furthermore, the M 5 to 51/2 Inglewood earthquake of 1920, the largest earthquake of record in the Baldwin Hills area, is believed to have originated along the Po- trero fault, immediately southeast of the hills and en echelon with the Inglewood fault. However, neither this nor any other historic shock along the Newport- Inglewood zone is known to have been associated with surficial fault displacements. Leveling in and around the west and central Los Angeles basin has shown that nearly all stations within the Quaternary sedimentary basin have been subsiding, whereas foothill stations commonly have been rising. The northwestern part of the basin has, in addition, been characterized by several broad and seemingly persistent differential subsidence bowls and a zone of positive movement roughly coin- cident with the Newport-Inglewood zone. ELEVATION CHANGES Repeated levelings through the Baldwin Hills have clearly defined a broad bowl of differential subsidence centering on the northwestern part of the hills. This elliptical subsidence bowl is identified with a north- west-trending long axis of about 2.7 miles and a north- east-trending short axis of about 2.0 miles. RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA Elevation changes in the northern Baldwin Hills generally have been calculated with respect to control point Hollywood E—11 (PBM 40 of the Los Angeles De- partment of Water and Power) along the northeast edge of the subsidence bowl. More or less quadrennial level- ings along a control line extending northward through and beyond the eastern half of the hills show that Hol- lywood E—ll has subsided since 1939 at a rate of less than 0.003 foot/year with respect to a bench mark (PBM 1) about 2/3 mile south of the well-defined area of differ- ential subsidence. It has also subsided at about 0.01 foot/year with respect to a control point (PBM 58) about 2 miles north of the hills, and at less than 0.02 foot/year with respect to 3-32, about 6 miles east-northeast of the hills and the primary control point for the City of Los Angeles. Thus Hollywood E—11 is identified with a his- tory of relative stability with respect to bench marks well outside the area of differential subsidence. Reconstruction of successive level surveys with re- spect to Hollywood E—ll has permitted an evaluation of subsidence since 1910 and 1911 at two points well within the presently recognized subsidence bowl. Bench mark PBM 67 is estimated to have subsided approximately 4.324 feet between June 1910 and Feb- ruary 1963, and bench mark PBM 68 is calculated to have subsided 3.846 feet between November 1911 and June 1962. Maximum subsidence has closely matched the subsidence at bench mark PBM 122; between 1911 and 1963 PBM 122 is estimated to have subsided about 5.67 feet, or only about one-half that of previous estimates of maximum subsidence in the northern Baldwin Hills between 1917 and 1964. The history of vertical movement at bench mark PBM 68 is particularly significant, for this is the only bench mark in the northern Baldwin Hills leveled before 1926 that has been repeatedly revealed since. Analysis of the leveling data suggests little elevation change at PBM 68 (or elsewhere throughout the Baldwin Hills- Inglewood area) associated with the Inglewood earth- quake of 1920. Several independent evaluations show that differential subsidence at PBM 68 probably began in the middle 1920’s; the calculated paths of subsidence at PBM 68 indicate little if any subsidence of this bench mark between 1911 and 1926. A comparison of the ele- vations recorded at four identifiable topographic fea- tures within the now recognized area of differential subsidence suggests that there was no subsidence in this area between 1910 and 1917 and, hence, supports the preceding conclusion. HORIZONTAL MOVEMENTS Horizontal displacements of six triangulation monu- ments within the northern Baldwin Hills subsidence bowl have been determined for various times between SUMMARY AND CONCLUSIONS 89 1934 and 1963, through comparisons of their positions with respect to a north-south base line about 3 miles east of the hills. These displacements have been di- rected generally toward the center of subsidence and almost precisely perpendicular to the immediately ad- jacent isobases of equal elevation change. Maximum movement, has been recorded at triangulation point Baldwin Aux, on the northeast limb of the subsidence bowl; this monument was displaced 2.21 feet between 1934 and 1961. Horizontal displacements between 1936 and 1961 at three additional points ranged from 0.95 foot to 1.85 feet. Displacements of 0.10 to 0.29 foot were recorded at all six triangulation monuments during the period 1961—63. Measurement of interstation distances along several traverses through the area of now recognized subsid- ence was begun at least as early as 1924. Subsequent length checks along these lines have shown that the eastern margin of the subsidence bowl has been characterized by extensional strain along lines at generally high angles to the isobases of vertical move- ment. The central part of the subsidence bowl has been similarly identified as a zone of contractional strain. Reliable measurements of horizontal strain range up to maximums of about 0.2 percent in the central contrac- tional zone and more than 0.07 percent in the periph- eral, extensional zone. EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS Fully documented contemporary “earth cracking” and surficial faulting in the northern Baldwin Hills dates from at least as early as 1957 . This rupturing has been confined largely, if not entirely, to the structural block east of the Inglewood fault and concentrated in two areas centering on the Baldwin Hills Reservoir and the Stocker Street-LaBrea Avenue—Overhill Drive intersection. The earth cracks are relatively straight, generally continuous features. They commonly trend north to north-northeast and more or less normally to radii emanating from the center of subsidence. The cracks are also oriented subparallel or moderately obliquely to the Inglewood fault and parallel to or coincident with otherwise identifiable faults or joints. Displacements along the earth cracks have been almost entirely dip- slip along steep to nearly vertical surfaces. Cumulative displacements have ranged up to 6 or 7 inches; their magnitudes, moreover, seem to have been independent of the length of cracking. Where lateral movements have been recognized none have been more than small fractions of the corresponding dip-slip components; these horizontal components have averaged about 1A944 inch and have reached a maximum of about 1/2 inch. Moreover, the apparent sense of lateral movement is ambiguous and actually reverses as traced along sev- eral ruptures. Individual fault blocks defined by the earth cracks generally have been downdropped rela- tively toward the center of subsidence. The contempo- rary displacements are known to have occurred to depths of at least tens of feet,and indirect evidence indicates that they probably extend several hundred feet beneath the surface. Ruptured or bent oil-well casings on trend with several of the earth cracks comprise permissive evidence of displacements at depths of over 1,000 feet. Displacements along the earth cracks seem to have been characterized by more or less episodic but continu- ous creep or small, discrete jumps. A probable exception to this generalization was the several inches of differ- ential movement that took place along a crack through the floor of the Baldwin Hills Reservoir on December 14, 1963. The chronology of movement along the cracks remains poorly known. Thus, even though rupturing was not generally recognized until 1957, the cracking of a concrete structure athwart one of the cracks, the occa— sional rebound of certain frequently monitored bench marks, and other geodetic evidence of differential movement around the Baldwin Hills Reservoir, suggests that rupturing and displacement probably began at least as early as 1951. CAUSES OF THE SURFACE MOVEMENTS The contemporary surface deformation observed in the Baldwin Hills is almost certainly attributable to one or more of the following phenomena: (1) exploitation of the Inglewood oil field; (2) changes in ground-water conditions; (3) compaction of sedimentary materials in response to surface loading; (4) tectonic activity. De- tailed consideration of each of these possible causes indicates that all the recent surface movements recog- nized in the Baldwin Hills are due largely or entirely to operations in the Inglewood oil field. MOVEMENTS ATTRIBUTABLE TO OIL—FIELD OPERATIONS Much of the northern Baldwin Hills is occupied by the Inglewood oil field. From the beginning of production in 1924 until the end of 1963, this field produced 224,974,000 bbls of oil, 374, 699,000 bbls of water, and 182,676,000 Mcf of gas. Most of this production has been drawn from the upper Pliocene Vickers zone, which occurs at a median depth of about 2,100—2,200 feet. Waterflooding in the Inglewood oil field, on other than a pilot scale, began in 1957. It was initially con- fined to the Vickers zone in the east block; flooding operations in the west block began in 1962. SUBSIDENCE A number of considerations indicate that the differ- 90 ential subsidence recognized in the northern Baldwin Hills can be attributed entirely to the exploitation of the Inglewood oil field: (1) the coincidence among the ap- proximate centers of the oil field, the producing struc- ture, and the subsidence bowl; (2) the similar outlines of both the oil field and the differential subsidence domain; (3) the approximate coincidence between the initiation of significant production in 1925 and the onset of differential subsidence around 1926; (4) the generally linear relations between various meas— ures of subsidence and production from both the field as a whole and the exceptionally prolific Vickers zone in particular; (5) the sharp deceleration in the rate of sub- sidence within the east block of the oil field coincident with the start of full-scale waterflooding there; (6) the many other oil fields in which both spatial and temporal associations between production and subsidence have been recognized; (7) the many similarities between the subsidence-production relations of the Inglewood oil field and those of the Wilmington oil field, where the rela— tion between oil-field operations and subsidence is un- equivocal; and (8) the theoretical relations between subsidence, or a tendency toward subsidence, and in- creased effective pressure associated with the extrac- tion of underground fluids. In the idealized underground reservoir system, effec- tive (grain-to-grain) pressure increases directly and equally with decreasing fluid pressure. It can also be shown that compaction varies directly and at generally constant or progressively decreasing rates with de- creasing fluid pressure or increasing effective pressure. Compaction in both the Inglewood and Wilmington oil fields, however, seemingly has increased at pro- gressively increasing rates with respect to measured down-hole fluid—pressure decline. Of the various possi— ble explanations for the inconsistency between the pressure decline-subsidence relations indicated for these actual examples and those predicted for an idealized system, the most likely is that measured or calculated down-hole fluid-pressure decline is not representative of the average or real reservoir fluid— pressure decline away from producing wells. Hence the fact that the relation between subsidence and meas- ured reservoir pressure decline is the inverse of that predicted from theoretical considerations does not in itself invalidate the conclusion that compaction has proceeded in response to fluid-pressure decline asso- ciated with exploitation of the Inglewood oil field. The nearly linear relations between various meas- ures of net liquid production and subsidence may be explained through analogy with a tightly confined artesian system of infinite areal extent, where produc‘ tion must derive from liquid expansion and(or) reser- voir compaction. In a system such as this, the total RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA volume of reservoir compaction must be linearly re- lated to the cumulative production, provided only that the bulk modulus of the liquid and the compression modulus of the reservoir skeleton remain invariant over the relevant stress interval. Use of test data from studies of compaction in two other oil fields yield esti- mates of the ultimate compaction of the Vickers zone resulting from a total loss of reservoir fluid pressure. Although these estimates range over an order of mag- nitude, our best estimate, based on these data and con- siderations of late Cenozoic history in this area, is about 10 feet, or roughly 12/3 that measured through 1963. HORIZONTA L MOVEMENTS The centripetally directed horizontal displacements and the post-1925 horizontal strain recognized in the northern Baldwin Hills may be attributed entirely to the exploitation of the Inglewood oil field. This conclu- sion stems from: (1) the well-defined symmetrical rela- tions between the horizontal displacements and both the oil field and the associated differential subsidence bowl; (2) the approximate coincidence between the start of production in 1925 and the onset of both the centripetally directed horizontal displacements and centrally located contractional strain in the middle or late 1920’s; (3) the similarities between the horizontal movements recognized here and those developed in and around other subsiding oil fields; and (4) the mechani- cal compatibility of these movements with subsidence induced by the extraction of subsurface materials. Experimental studies, finite element analyses, and various theoretical models all require that surface sub- sidence generated through compaction at depth be ac- companied by horizontal surface displacements di- rected toward the center of subsidence. Furthermore, both common sense and strain analyses based on the described horizontal displacements indicate that con- tractional or compressional strain should be set up in the central or axial region of the subsidence field, and that extensional strain should be generated more or less normally to the isobases of equal elevation change (and thereby parallel to the radially oriented horizon- tal displacements) within the peripheral part of the subsidence field. Thus, to the extent that the differen- tial subsidence is due to oil-field operations, the as- sociated horizontal movements must be equally due to the exploitation of the Inglewood oil field. EARTH CRACKS AND CONTEMPORARY FAULT DISPLACEMENTS The contemporary earth cracks and surficial fault displacements developed around the eastern margin of SUMMARY AND CONCLUSIONS the subsidence bowl can be attributed largely or en- tirely to the exploitation of the Inglewood oil field. This conclusion is based on: (1) the well-defined spatial and temporal relations between the surface rupturing and both oil-field operations and the differential subsidence identified with these operations; (2) the similarities be- tween these cracks and displacements and those de- veloped in and around other oil fields or areas of un- derground materials extraction; and (3) the occurrence of strain patterns, as deduced from the meas- ured vertical and horizontal surface movements, that tend to promote rupturing and fault displacements. The cracks and displacements may be fully explained by an exploitation-based, elastic-rebound compaction model. This model requires the generation of elastic compression in response to compaction- induced downdrag of the sedimentary sections com- prising the upper parts of the structural blocks around the periphery of the subsidence bowl. The sense of faulting is entirely consistent with this model, and the magnitudes of the displacements have been about one-quarter to one-half those predicted for a purely elastic system. As much as about 10 percent of the measured isobase and compaction gradients critical to the construction of this model is conceivably un- explained by exploitation of the Inglewood oil field; it is very unlikely, however, that this fraction could have led to rupturing and displacement in the absence of exploitation. The almost total restriction of cracking and surficial faulting to the east block probably stems chiefly from the density and generally favorable orientations of preexisting fractures in this area. The elastic-rebound compaction model favors the occurrence of ruptures and displacements along steep surfaces, more or less parallel to the isobases within the extensional horizon- tal strain zone; preexisting fractures of this orientation are conspicuous in the east block and generally absent in the west block. It is also likely that the initial re- striction of waterflooding to the east block aggravated, and conceivably provoked, the faulting there. This flooding, which was carried out at pressures generally above hydrostatic, probably promoted failure in two ways: (1) by increasing the isobase and compaction gradients and, hence, the extensional strain, over a limited reach of the east limb of the subsidence bowl; and (2) by elevating the pore-water pressures along potential failure surfaces. MOVEMENTS ATTRIBL‘TABLE TO OTHER (TAL‘SES CHANGES IN GROUND-“HATER REGIMEN Exploitation of the ground-water resources of the west Los Angeles basin began about 1870 and was cer- 91 tainly in full swing by the turn of the century. How- ever, although great volumes of potable water have been produced from within this area, little has been drawn from the generally nonwater-bearing sediments underlying the Baldwin Hills. The only measurable production has, in fact, come from along the south edge of the hills and from within the northernmost part of the “central graben,” an obscurely defined structural feature along the eastern margin of the west block. We conclude that the differential subsidence and symmetrically related horizontal displacements iden- tified in the Baldwin Hills are no more than inciden- tally due to changes in ground-water conditions. This conclusion derives from: (1) the absence of any record of significant ground-water extraction from within the hills; (2) the likelihood that no more than minor amounts of ground water could have been drawn from the deposits underlying the hills; (3) the nearly com- plete absence of measured surface subsidence as- sociated with major head declines in aquifers corre- lated with the sands and gravels that crop out in the hills; (4) the probability that even the greatest credible drawdowns of water levels could have produced only a small fraction of the recognized subsidence; and (5) the lack of any spatial or temporal correlation between the observed movements and ground-water exploitation within and around the hills. Several of the points listed above also argue that the earth cracks and surficial fault displacements cannot be due to changes in ground-water conditions. This conclusion is reinforced by the probability that the fault displacements extend well below any potable ground-water horizons. CHANGES IN SURFACE LOADING The Baldwin Hills have been undergoing more or less continuous uplift and denudation throughout Quaternary time. Thus because erosion rather than alluviation must have dominated the late Quaternary history, unloading rather than loading has charac- terized the geologic history of the hills during prehis- toric Holocene time. Furthermore, although locally large volumes of materials have been involved, artifi- cial cutting and filling have been distributed more or less equally over most of the Baldwin Hills. It is very unlikely that the differential subsidence and symmetrically associated horizontal movements are in any way due to either natural or artificial changes in surface load. This conclusion is supported by: ( 1) the continuing natural denudation of the hills; (2) the absence of any apparent spatial or temporal association between the evolving differential subsid- ence bowl and the placement of the largest fills recog- nized in this area; and (3) the fact that the near-surface 92 sediments are relatively insusceptible to load-induced compaction. The earth cracks and surficial fault dis- placements are equally unrelated to loading, as shown by: (1) the generally random distribution of both cuts and fills as contrasted with the very restricted occur- rence of the earth cracks; (2) the apparent absence of any temporal relation between local cut-and-fill opera- tions and the growth of spatially associated earth cracks; and (3) the impossibility of explaining both the settlement and subsequent rebound of the easterly blocks adjacent to the earth cracks as the products of surface loading. TECTONIC ACTIVITY The identification of the Newport-Inglewood zone as an active tectonic lineament suggests that the surface movements observed in the Baldwin Hills may be no more than surficial expressions of this continuing ac- tivity; consideration of the total evidence, however, in- dicates that the described movements can be no more than incidentally attributed to tectonic effects. Although the occurrence of the subsidence bowl within an area of recognized and more or less continu- ous folding and uplift, together with its approximate coincidence with the “central graben,” suggests that it may have evolved in response to tectonic forces gener- ated at depth, it is very unlikely that either the differ- ential subsidence or the symmetrically related hori— zontal displacements formed through tectonic downwarping. This is indicated especially by: (1) the inverse relation between the subsidence bowl and the underlying Inglewood oil-field anticline; (2) late Qua- ternary uplift of the hills as a whole; (3) the occurrence of relative uplift over a nearby structurally elevated area, prior, at least, to its exploitation for petroleum; (4) a mechanical incompatibility between the described subsidence pattern and associated horizontal strain on the one hand and the tectonic evolution of the “central graben” on the other hand; and (5) the absence of any recognized tectonic event with which the onset of the subsidence can be associated. The coincidence or parallelism between many of the contemporary earth cracks and faults known to have been active during Quaternary time and the occurrence of the cracks within a well-defined zone of seismicity are seemingly compelling evidence of a tectonic basis for the contemporary surface rupturing; again, however, it seems very unlikely that the earth cracks and contem- porary fault displacements are the result of tectonic activity. This is shown by: (1) the probable mechanical association between the cracks and the apparently nontectonic subsidence; (2) the absence of faulting along the Inglewood fault in conjunction with faulting along the earth cracks; (3) the likelihood, as suggested by local RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA historic precedent, that purely tectonic displacements would have been other than dip-slip; (4) a seeming inconsistency between postulated branch or conjugate faulting and the observed essentially dip-slip move- ments along the earth cracks; (5) a mechanical incompatibility between postulated extensional fault- ing developed athwart the axis of the Inglewood oil-field anticline and the contractional horizontal strain recog- nized in the center of the subsidence bowl; (6) the confinement of damaging subsurface movements to relatively shallow producing horizons; and (7) the absence of any clearly defined temporal relation between crack growth and local seismicity. Up to about 10 percent of the prerupture isobase gradient is conceivably of tectonic origin. Because the elastic- rebound compaction model demands that some threshold isobase or compaction gradient be exceeded in order for displacement to occur, up to perhaps 10 percent of the forces necessary for crack growth may have been of tectonic derivation; this fraction, however, could have been of little significance in the absence of the concurrently evolving and apparently nontectonic subsidence. CONCLUSION The various clearly defined spatial and temporal relations between subsidence and oil-field operations that have been demonstrated both for this and other oil fields indicate that the differential subsidence and associated horizontal movements generated in the Baldwin Hills are due to exploitation of the Inglewood oil field. This conclusion is strengthened by various theoretical considerations and a host of experimental studies. 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Mines Bull. 170, chap. 2, p. 65-81. Yerkes, R. F., and Castle, R. 0., 1970, Surface deformation associated with oil and gas field operations in the United States, in Land subsidence: Internat. Assoc. Sci. Hydrology-UNSECO, v. 1, no. 88, p. 55—66. Yerkes, R. F., McCulloh, T. H., Schoellhamer, J. E., and Vedder, J. G., 1965, Geology of the Los Angeles basin, California—An in- troduction: U.S. Geol. Survey Prof. Paper 420eA, p. A1—A57. APPENDIXES A—K 98 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA APPENDIX A Survey history and adjustments of level lines A, B, and C I. Line A. Level line A (figs. 8 and 9) was established in 1935 by the US. Coast and Geodetic Survey; it was releveled in 1943 by the Los Angeles Department ofWater and Power (Hayes, 1943, p. 4—5). The 1935 record elevations along line A given by the Coast and Geodetic Survey, and with which the 1943 elevations of the Depart- ment of Water and Power were later compared, presumably were adjusted with respect to the Coast and Geodetic Survey primary net, but this was not specified by Hayes. The first part of the 1943 releveling ofline A between its east end and Centinela Avenue, a segment over which lines A and B are mutually inclusive, was adjusted to conform with the corresponding retracement of line B; that part westward from Centinela Avenue was left unadjusted (Hayes, 1943, p. 6). Because the closure over the full 22,000-f00t length of the 1943 releveling of line B was only +0.007 foot (Hayes, 1943, p. 5), all ofline A may be treated as if it had been left unadjusted over its entire length. 11. Line B. Level line B (figs. 8 and 10) was established in 1933 by the Los Angeles Bureau of Engineering; it was releveled in 1943 by the Department of Water and Power (Hayes, 1943, p. 7—8, fig. 3). The 1933 record elevations utilized by the Department of Water and Power probably were adjusted with respect to the Bureau of Engineering’s Civic Center datum control point, but this was not specified by Hayes. Because, as noted above, the 1943 re- leveling ofline B closed only 0.007 foot high, it too may be treated as unadjusted with respect to the starting bench mark. III. Line C. Level line C (figs. 8 and 11) was established in 1939 by the Department of Water and Power; it was releveled by the Department of Water and Power in 1943, 1946, 1950, 1954, and 1958 (Hayes, 1959, fig. 2). Although this line was not releveled in 1962, bench marks common to line C were incorpo- rated in a more recently established control line (Walley, 1963, p. 15—16, fig. 2—A); eleva- tion changes along line C between 1958 and 1962, accordingly, may be calculated directly from changes along this later survey line. According to Hayes (1943, p. 9—10), both the 1939 and 1943 levelings along line C were adjusted with respect to a common starting elevation for PBM 1 that was determined through the 1943 leveling of line B (that is, an elevation equal to the 1933 Bureau of En- gineering record elevation of PBM 1 plus 0.050 foot). The 1939 and 1943 surveys were adjusted “because it was not believed at the time the levels were of sufficient accuracy to be depen- dent on the initial bench mark at Centinela Avenue and Market Street, due to the ordinary types of instruments and rods used for leveling. The levels of 1946, 1950, 1954, and 1958, using more refined equipment, were plotted based on the starting bench mark PBM No. 1 at Centinela Avenue and Market Street and allowed to fall where they would without the overall adjustment into the closing bench mark at Washington Boulevard and Vineyard Av- enue” (Hayes, 1959, p. 12). Real changes in elevation with respect to PBM 1 along level line C since 1946 (assuming no instrumental bias) can be determined directly from the profile given in figure 11. Elevation changes since 1939, on the other hand, can be deter- mined only through an evaluation of the adjustments applied to the 1939 and 1943 surveys. A. According to Hayes (1943, p. 10), the 1939 leveling "closed 0.049 ofa foot high, while the 1943 circuit closure was 0.038 ofa foot high.” It could not be determined from an examina- tion of the original field notes, whether these closures were based on the record or “cor— rected” starting elevation for PBM 1. 1. If the 1939 closure was based on a “corrected” starting elevation (the Bureau of Engineer- ing 1933 record elevation +0.050 foot) and an “uncorrected” 1933 record elevation for PBM 58 (DWP fieldbook 2604, p. 17; LABE-CE fieldbook 16980, p. 1, 6), instru— mentally perfect leveling over a line in which PBM 1 and PBM 58 had remained absolutely stable with respect to each other (and where the 1933 record elevations are accepted as valid) should have led to a closure of +0050 foot; that is, the actual closure may have been only —0.001 foot, and the change in elevation at PBM 58 between 1939 and 1946 should be 0.050 foot less than that represented in figure 11. 2. Alternatively, if the 1939 closure is based on “uncorrected” record elevations for both PBM 1 and PBM 58, and ifthe leveling were instrumentally perfect, then PBM 58 rose by 0.049 foot with respect to PBM 1, the leveling should not have been adjusted APPENDIX B 99 downward, and the change in elevation of PBM 58 between 1939 and 1946 should be 0.049 foot less than shown in figure 11. 3. In either case, it seems likely that the change in elevation at PBM 58 between 1939 and 1946 probably is exaggerated in figure 11 by perhaps 0.05 foot; a similar exaggera- tion, diminishing progressively toward PBM 1, may be distributed throughout the profile. However, because the 1939 and 1943 closures on level line C were nearly identical, it is likely that the same adjust- ments were applied to both levelings such that they may be compared directly with each other. However, neither should be compared directly with subsequent relevel- ings along line C. B. Even though elevation changes along line C (as portrayed in fig. 11) may be misrepresented somewhat, no attempt has been made to reconstruct figure 11 on the basis of an uncorrected starting elevation and unad- justed intermediate elevations for the 1939 and 1943 surveys because: (1) changes in the profiles would be slight; (2) a precise recon- struction would require not only a reevalua- tion of the 1939 and 1943 surveys from the original field data, but replotting of the 1946 and subsequent levelings as well; and (3) elevation changes at critical bench marks may be calculated independently without reconstructing the entire profile. APPENDIX B Location of PBM 68 (identified alternatively as DD) I. Two separate survey points within the northern Baldwin Hills have been identified as “DD.” One is a concrete bench mark that is believed to have been set in 1910 by the Los Angeles Investment Company; the second, a triangulation point about 30 feet distant, seemingly was set by the Los Angeles Investment Company sometime between 1910 and 1913. It is necessary that we show: (1) that the existent concrete bench mark occupied and identified in 1943 as PBM 68 by the Department of Water and Power (and not the triangulation point 30 feet distant) is the one occupied and identified in 1911 as DD by the Department of Water and Power; (2) that the same concrete bench mark identified as PBM 68 by the Department of Water and Power is identical with DD as established by the Los Angeles Investment Company in 1910; and (3) that this concrete bench mark has not been moved since it was originally established. Evi- dence of the existence of two separate survey points named “DD” is as follows: A. A Los Angeles Investment Company Z—ft con- tour map dated 1910 shows DD at an estimated elevation of about 313.4: ft. 1. A penciled notation on this same map describes DD as having been moved "30’:” eastward to a point that would place it at an elevation of 316.0+ ft. B. A Los Angeles Investment Company 5-ft con- tour map dated April 1913 shows DD at an elevation of about 315.8: ft. II. Considerations listed below indicate that the concrete bench mark inscribed “DD”, which has been utilized by the Department of Water and Power since 1943 as PBM 68 (DWP filecard for PBM 68), is in the same position as originally set by the Los Angeles Investment Company and is identical with bench mark DD occupied by the Department of Water and Power in 1911 (DWP fieldbook 1458, p. 10). A. According to Mr. William Ball (oral commun., 1965) of the Los Angeles Investment Com- pany, the concrete bench mark inscribed "DD” was never removed from its original position. B. The ground elevation of a point identified as "DD” on the 1910 Los Angeles Investment Company 2-ft contour map has been esti- mated at about 313.4: ft; the 1910 elevation of a concrete monument identified as "DD,” derived from an adjacent stake elevation established by the Los Angeles Investment Company, is computed here to have been approximately 314.015 ft (LAIC fieldbook 7, p. 3; DWP fieldbook 1458, p. 29). The 1911 elevation of DD given by the Department of Water and Power was 313.930 ft (DWP fieldbook 1458, p. 10); a reevaluation of the leveling data that led to this elevation has shown that it is slightly in error, but almost certainly by no more than about +0.10 ft. The datums employed in these two independent elevation determinations are believed to be nearly identical (see appendix F). 1. Because the elevation of DD measured by the Department of Water and Power in 1911 probably differed by no more than 0.5 ft from that determined in 1910 by the Los Angeles Investment Company, yet was almost certainly more than 1.9 ft below the ground elevation at the apparently relo- cated position of DD (LA. and LB), it is 100 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA FIGURE 52.—Part of original triangulation net of the Los Angeles Investment Company in the northern Baldwin Hills showing relations between DD (PBM 68) and nearby control points together with the calculated coordinates for points DD and HH (LAIC calculation book, p. 9). probable that concrete bench mark DD occupied by the Department of Water and Power in 1911 is the same concrete monu- ment set in 1910 ‘by 'the Los Angeles Investment Company at the original site of DD. C. The distance between monuments HH and DD (fig. 52) measures about 1,842 ft on a photostat copy of a 1917 topographic map of the old Centinela Reservoir site (Hayes, 1943, fig. 6). The distance HH—DD calculated from coordinates computed from the original sur- vey measurements (fig. 52) of the Los Angeles Investment Company (LAIC calculation book, p. 9) is 1851.4450 ft (F. J. Walley, written commun, 1965), whereas the cor- rected distance HH—DD calculated from the revised coordinates for HH and DD has been given as 1882.02 ft (LAIC, hill tract calcula- tion worksheet). 1. Because the distance HH—DD as shown on the 1917 Centinela Reservoir map is probably no greater than and certainly much closer to HH—DD as originally surveyed than it is to the corrected distance HH—DD, it is almost certain that concrete bench mark DD occupied by the Department of Water and Power in 1917 is identical with DD as originally set by the Los Angeles Invest- ment Company in 1910. Because, in addi- tion, the 1917 elevation of DD as derived by the Department of Water and Power through a comparison with the elevation of a nearby topographic saddle that was presumed to have remained unchanged between 1911 and 1917, is given as 314.24 ft (DWP fieldbook 1579, p. 4—5), it is probable that concrete bench mark DD occupied in 1917 is the same as that occupied by the Department of Water and Power in 1911. D. The distance HH-PBM 68 (identified alterna- tively as DD by the Department of Water and Power) was taped in 1964 at 1851.44 ft (F. J. Walley, written commun, 1964). 1. Because the taped distance HH—PBM 68 al- most perfectly matches distance HH—DD calculated from the original survey mea- surements of the Los Angeles Investment Company, concrete bench mark PBM68 is certainly identical with DD as set at the original site of DD by the Los Angeles In- vestment Company. Furthermore, unless: (1) two virtually identical monuments in- scribed "DD" existed within a few tens of feet of each other in 1911; or (2) concrete monument DD was moved eastward 30 feet to the site of triangulation point DD by 1911, and thence back to its 1910 location sometime before 1943,’ PBM 68 must be identical with concrete monument DD oc- cupied by the Department of Water and Power in 1911. APPENDIX C Derivation of the November 1911 elevations of PBM 68 and Hollywood E—ll. The November 1911 elevations of PBM 68 (identified alternatively as DD—see fig. 8) and Hollywood E—11 (identified alternatively as PBM 40—see fig. 8) are based here on a comparison with the elevation of 8—32 (Civic Center basic control point) established by the US. Coast and Geodetic Survey supplemental adjustment of 1933—34 (generally re- ferred to simply as the "1934 adjustment”). NOTE—Bench marks S—32 reset (located at the Hall of Justice) and 37-54-26 (located on North Broadway 235 ft south of Temple Street) have been used as basic control points by the LABE (Los Angeles (City) Bureau of Engineering) since 1934 (LABE Precise Bench Mark Index, p. 19—20). Primary elevations of the basic control points APPENDIX C employed by the LABE since 1934, however, have been determined by the US. Coast and Geodetic Survey (LABE Precise Bench Mark Index, p. 17—18, 20). The 1936 elevation of S—32 reset was derived directly from the elevation of S—32 as fixed in the 1934 adjustment (LA. County level book 719, p. 145—150), so that S—32 and S—32 reset may be treated as precisely equivalent points. Because S—32 reset has been held fixed by the US. Coast and Geodetic Survey since 1936 at an elevation subsequently accepted by the LABE (LABE Precise Bench Mark Index, p. 25), it follows that the 1934 elevation of S—32 established by the US. Coast and Geodetic Survey has been accepted as unchanged since that time by the LABE; S—32, accordingly, is considered the primary Civic Center basic control point. Because S—32 and 37-54-26 are separated by only about 300 ft, they are assumed to have remained unchanged in elevation with respect to each other. This assumption is supported by observations at the two bench marks between 1953 and 1960 (LABE Precise Bench Mark Index, p. 25); both plus and minus movements of 0.000 to about 0.004 ft/yr of 37-54-26 with respect to S—32 reset have been recorded. Accordingly, S—32, S—32 reset, and 37-54-26 may be treated as coincident points; that is, elevations derived simultaneously from the 1934 adjustment eleva- tions of any of these three points would be virtually identical, equally valid, “true” elevations with respect to S—32. The LABE 1933—34 general leveling survey (referred to as the “1934 general leveling”) for the southern area—defined by the LABE to include nearly all of metropolitan Los Angeles south of the Santa Monica Mountains (LABE Precise Bench Mark Index, p. 4)—had as its basis a single US. Coast and Geodetic Survey elevation in the Civic Center of Los Angeles. The 1949 and subsequent general leveling surveys have omitted as a basis the US. Coast and Geodetic Survey elevation in the western San Fernando Valley—previously employed as one of two bases for the northern area—and have included instead one in the harbor area (tidal 10, H—768 1946, or tidal 8) as well as one in the Civic Center (LABE Precise Bench Mark Index, p. 19—20). Where more than one control point has been used to establish an adjusted elevation—as has been the case since 1949 for those elevations established by the LABE along its primary network—the difference between the adjusted elevation and the “true” or observed elevation with respect to a single control point is a function of its distance from this single control point; in other words, the closer a point to the Civic Center basic control point S—32, the closer its adjusted elevation will be to its observed elevation with respect to S—32. Precise bench marks in the Baldwin Hills area are much closer to S—32 than they are to the basic control points in the harbor area (PBM 58, for example, is approximately 5.5 miles from S—32 and approximately 20 miles from tidal 8). Moreover, S—32 reset and tidal 8 have had a history of relative stability with respect to each other; closures over the 25-mile course between these two points have been both plus and minus, ranging from a minimum of 0.013 ft to a maximum of 0.18 ft over time intervals of up to three years (Ralph Algranti, LABE, oral commun., 1965). Thus, it is concluded here that those elevations in the Baldwin Hills area given by the LABE as adjusted with respect to both S—32 (or its equivalents) and tidal 8, tidal 10, or H—768 1946, may be treated as the approximate equivalents of those derived through a direct comparison with S—32. PBM 68 (identified alternatively as DD) I. The November 1911 elevation of DD has been given as 313.930 ft by the Department of Water and Power (DWP fieldbook 1458, p. 10). Its 1917 elevation has been given as 314.240 ft (DWP fieldbook 1579, p. 5); this figure, however, apparently was derived through a comparison 101 with the elevation of a topographic saddle at the north end of the old Centinela Reservoir site that assumed that this saddle had remained un- changed in elevation between 1911 and 1917 (DWP fieldbook 1579, p. 4-5). There is, accord- ingly, no firm basis for assuming that the 1917 elevation of DD given above is anything more than a crude approximation, nor is there any basis for concluding that DD actually rose between 1911 and 1917. A. Elevations of points derived from LABE bench mark elevations established prior to 1925—— as was the 1911 elevation of DD—ordinarily are corrected to the datum employed by the LABE since 1925 through the addition of 5.775 ft (LABE Precise Bench Mark Index, p. 17). 1. The November 1911 elevation of DD with respect to the datum adopted by the LABE in 1925 accordingly would be given as: 313.930 ft + 5.775 ft = 319.705 ft. II. In order to establish the 1911 elevation of DD with respect to the elevation of S—32 as fixed in the 1934 adjustment, the figure of 319.705 ft computed under I.A.1. should be amended as follows: A. Datum correction: 1. The November 1911 elevation of DD may be treated provisionally as having been de- rived through a comparison with the eleva- tion of a LABE precise bench mark located at Santa Barbara Avenue and Western Avenue (DWP fieldbook 1458, p. 1). The starting elevation of 136.912 ft at the Santa Barbara-Western precise bench mark utilized in the 1911 derivation of the elevation of DD was adjusted upward from an observed elevation of 136.899 ft, which was derived in March 1908 from the elevation of a LABE precise bench mark located at Wilshire Boulevard and Hoover Street (LABE-CE fieldbook 2726, p. 1); the basis for the adjustment was a closure of —-0.015 ft on a precise bench mark whose elevation had been derived in turn from that given for the LABE precise bench mark at Wilshire and Hoover (LABE-CE fieldbook 2726, p. 24). The corrected eleva- tion of the LABE precise bench mark located at Wilshire Boulevard and Hoover Street (LABE-CE fieldbook 2676, p. 30) was derived in turn in March 1908 from the corrected elevation for a US. Geological Survey bench mark located on a step at a 102 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA courthouse entrance (LABE-CE fieldbook 2676, p. 2). This US. Geological Survey bench mark must have been S—32 since its description and elevation (corrected to the post-1925 LABE datum) correspond almost precisely to that given for 8—32 by the Geological Survey (Birdseye, 1925, p. 110). a. 332.822 ft—elevation of 8—32 as given by the LABE in March 1908 (LABE-CE fieldbook 2676, p. 2). 338.63 1 ft—elevation ofS—32 as given in the 1933—34 adjustment by the US. Coast and Geodetic Survey (1947, p. 28). b. 338.631 ft —332.822 ft = 5.809 ft—datum correction to be added to elevations derived from 8—32 (as fixed at 332.822 ft by the LABE) in order to bring them into conformity with the 1934 elevation of S—32 since employed by the LABE. c. Accordingly, the following correction should be made to the 319.705-ft 1911 elevation of DD computed under I.A.1.: 5.809 ft — 5.775 ft = +0.034 ft. B. Movement correction for the LABE precise bench mark at Santa Barbara Avenue and Western Avenue: 1. The elevation of the LABE precise bench mark at Santa Barbara and Western was established in March 1908 (LABE-CE fieldbook 2726, p. 19). 2. The following adjusted elevations with re- spect to 8-32 (or its approximate equiva- lents; that is, the USGS datum adopted in 1925, 37—54-26, 8—32 and tidal 8, and so forth) have been recorded by the LABE for a precise bench mark (18—15330) located at the intersection of Santa Barbara and Western Avenues: 1985—140791 ft (LABE-CE fieldbook 16901, p. 26) 1953—140508 ft (LABE Precise Bench Mark Index) 1960—140.240 ft (LABE Precise Bench Mark Index) a. It is concluded on the basis of the longest period of observation at 18—15330, which best records the general history of verti- cal movement in this area, that the Santa Barbara-Western intersection has been subsiding with respect to 8—32 at an average annual rate of about: 140.791 ft — 140.240 ft = 0.022 ft/yr. 25 yrs (Although this computed rate of sub- sidence probably is the most objective figure obtainable, it is thought to consti- tute a maximum with respect to earlier periods, for Grant and Sheppard (1939, p. 302) have shown, in a rough way at least, that this same area was subsiding prior to 1939 at a rate of about 0.007 ft/yr.) b. Accordingly, between March 1908 and November 1911 the LABE precise bench mark at Santa Barbara and Western is calculated to have subsided approxi- mately (3.6 yrs) (0.022 ft/yr) = 0.079 it below the elevation recorded in March 1908, so that its November 191 1 elevation should have been 136.912 ft — 0.079 ft = 136.833 ft. 3. Since the 1911 elevation of DD has been derived in turn from the LABE precise bench mark at Santa Barbara and Western, the following correction should be made to the 319.705-ft 1911 elevation of DD com- puted under I.A.1.: 136.833 ft — 136.912 = —0.079 ft. C. Adjustment correction. 1. Hayes (1943, p. 16) has noted that parts ofthe level circuit fixing the 1911 elevation of DD “were rerun because of errors; questionable adjustments have been applied in the field notes; and unsound surveying methods were practiced to some extent.” This in- dictment has precipitated a reevaluation of the original level data aimed at (1) a determination of the reliability of the surveying that produced the November 1911 elevation of DD; and (2) a more accurate, objective determination of the 1911 elevation of DD. The level circuit establishing the 1911 elevation of DD actually consisted of two separate loops: The first loop began with the LABE bench mark at Santa Barbara and Western, ran to a bench mark located at St. Mary’s Academy (referred to herein as “B.M. St. Mary’s”) near the Crenshaw Boulevard— Slauson Avenue intersection, and closed on a LABE bench mark at Arlington and Slauson Avenues (DWP fieldbook 1458, p. 1—3, 30); the second loop began with B.M. St. Mary’s, ran to DD (as a side shot) and closed on B.M. St. Mary’s (DWP fieldbook 1458, p. 3—18, 26—29). 2. a. An elevation of 161.418 ft was derived for B.M. St. Mary’s in 1911 through a comparison with the record elevation of APPENDIX C ' 103 number of turns between B.M. St. Mary’s and the Santa Barbara- Western bench mark and BM. St. Mary’s and the Arlington-Slauson 136.912 ft for the LABE precise bench . mark located at Santa Barbara and Western (DWP fieldbook 1458, p. 1,3). (1.) Employment of the above elevation as a starting elevation for B.M. St. Mary’s led to a closure of —0.122 ft on a LABE bench mark located at Arlington and Slauson (DWP fieldbook 1458, p. 30). The 1908 record elevation for the bench mark (DWP fieldbook 1458, p. 1—3, 30) leads to an adjusted November 1911 elevation for B.M. St. Mary’s of 161.418 ft + (16/22) (0.074 ft) = 161.472 ft. b. Mr. L. M. Charles (written commun, 1965) of the Department of Water and Power, has carefully reconstructed the circuit B.M. St. Mary’s (arbitrarily assigned a starting elevation of 161.540 ft)—DD— B.M. St. Mary’s through a coupling of the second run, corrected rod readings for the first part of the circuit (DWP fieldbook 1458, p. 26—30) with the original (and apparently acceptable) rod readings for the second part of the circuit (DWP fieldbook 1458, p. 10—18), as shown below: Arlington-Slauson bench mark utilized in the determination of this closure (DWP fieldbook 1458, p. 30; LABE-CE fieldbook 2577, p. 16), however, was 0.032 ft below that obtained through a virtually contemporaneous, direct tie with the LABE precise bench mark located at Santa Barbara and Western (LABE-CE fieldbook 2458, p. 17, 39; LABE-CE fieldbook 2577, p. 16). Be- cause both elevations are corrected profile elevations, there is no basis for choosing between them; acceptance of an averaged record elevation for the — m. 7 Arlington-Slauson bench mark leads to Adjusted elevation (in ft» Elevation (in it.) a closure of about —0.138 ft. B.M.1§t(.)lé\/(I)ary’s Pg1'7226:570 161540 (2.)Since bench mark 18—14630, located at l , ' 1.060 171.510 Van Ness and Slauson Avenues (one 11'580 183090 0720 182370 block east of Arlington and Slauson), 9.425 191.795 ' ' subsided between 1935 and 1956 at an 11.540 202.500 0835 190960 average rate of about 0.359 ft/21 yrs = 0.605 201.895 0.0171 ft/yr with respect to bench mark 10470 212865] 0 880 211 485 18—15330 located at Santa Barbara and 11.330 222.815 . i Western (see LABE-CE fieldbook 9790 231925 0680 222135 16901, p. 26 and LABE Precise Bench 3.195 228.730 Mark Index), the Arlington-Slauson 11‘810 240540 0 610 239 930 intersection is calculated to have sub- 4.920 244.850 ' ‘ I _ sided about (0.0171 ft/yr) (3.75 yrs) = 9.830 243.580 11'100 233700 0.064 ft with respect to the Santa 0.620 242.960 Barbara-Western intersection between 4035 246995 1 370 245 625 the February 15, 1908, date of plotting 11.590 257.215 ‘ ‘ of the old LABE bench mark at Ar- 11.760 268.465 0510 256705 lington and Slauson (LABE-CE 0.545 267.920 fieldbook 2577, p. 1, 16) and November 11'162 279082 0 600 278 482 1911. Therefore, acceptance of the 1908 11.115 289.597 . . record elevations for the Santa Pg. 27—Contour-point-check: 3.318 333.622] 285.193 Barbara-Western and Arlington- 11.395 300.482 I ' Slauson bench marks should have led 10.710 310.627 0565 299'917 to an instrumentally perfect closure of 0.585 310.042 about —0.064 ft for a level survey run “090 321132 1 770 319 362 between these points in November 1.820 321.182 ' ‘ 1911; the “corrected” closure, accord- 4.620 324.827 0975 320207 ingly, is computed to have been 5.420 319.407 —(0.138 ft —0.064 ft) = —0.074 ft. A ”-595 331-002 2660 [3128342 prorated adjustment based on the 10885 [3139.227 I ' 104 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA + 11.1. — Elevat' “11'5th + . , _ .. m AdJUSEE‘d ... “5‘?" “£19.22" “‘ E13: 2:.“ “.2727“ 5.935 [3133.292 10.305 431.107 11.120 344.412 0.640 430.467 11.290 333.122 10.850 441.317 0.750 333.872 0.240 441.077 7.600 326.272 11.990 453.067 6.590 332.862 0.685 452.382 11.280 321.582 11.745 464.127 2.800 324.382 0.400 463.727 B.M. Pg.29: 8.190 316.192 316.211 11.770 475.497 5.730 321.922 0.510 474.987 7.610 314.312 11.410 486.397 0.920 315.232 0.790 485.607 1.900 313.332 10.915 496.522 11.000 324.332 B.M. Pg. 14: 2.965 493.557 493.602 0.780 323.552 0.630 494.187 11.890 335.442 9.370 484.817 1.130 334.312 2.235 487.052 0.530 334.842 8.135 478.917 11.430 323.412 0.680 479.597 0.470 323.882 g 5.800 473.797 "D.D." Pg. 29: 10.000 313.882 313.906 5.150 478.947 B.M.-2X2 Stk. marked 8.340 315.542 315.566 11.295 467.652 “315.675” Pg. 29: 11.660 312.222 0.730 468.382 0.170 312.392 10.775 457.607 B.M. #1 Pg. 30: 10.855 301.537 301.562 0.450 458.057 ————————— B _M-_#1— EBag————————- 2 3 9 63 10.780 447.277 . . . . 60 44 . 7 B.M. #3 299.925 1 Page 10 RB" 1458 2.210 447.427 .780 Difference in elevation “-065 458.492 B.M. #1 301.537 1.330 457.162 .780 2.580 459.742 B‘M' #3 300-757 Elevation relative to 2 370 450 172 11.940 447.802 B.M. #1 in above circuit . I 11.060 439.112 ——————————————————————— 1.370 440.482 11.720 428.762 B.M. #3 Pg. 10: 300.757 300.782 0.390 429.152 3.930 304.687 11.870 417.282 3.355 301.332 0.430 417.712 0.815 302.147 B.M. Pg. 15: 11.790 405.922 405.976 1.805 300.342 1.095 407.017 1.170 301.512 11.790 395.227 1.770 299.742 0.135 395.362 5.035 304.777 11.330 384.032 9.170 295.607 0.915 384.947 10.720 306.327 11.490 373.457 B.M. Pg. 11: 3.040 303.287 303.315 0.790 374.247 9.080 297.247 10.855 363.392 10.355 307.602 0.650 364.042 0.555 307.047 11.245 352.797 9.775 316.822 0.865 353.662 0.520 316.302 11.895 341.767 10.530 326.832 0.905 342.672 1.370 325.462 11.740 330.932 9.760 335.222 0.820 331.752 1.870 333.352 11.405 320.347 5.345 338.697 0.870 321.217 6.730 331.967 11.385 309.832 4.500 336.467 0.380 310.212 9.630 326.837 B.M. Pg. 16: 11.765 298.447 298.509 11.145 337.982 0.410 298.857 B.M. Pg. 12: 3.450 334.532 334.566 10.950 287.907 \ 0.790 337.192 1.025 288.932 11.950 349.142 10.475 278.457 1.160 347.982 6.420 284.877 11.790 359.772 11.330 273.547 0.630 359.142 0.630 274.177 11.080 370.222 10.450 263.727 0.720 369.502 0.310 264.037 10.660 380.162 11.670 252.367 0.620 379.542 0.320 252.687 11.530 391.072 10.080 242.607 1.590 389.482 0.530 243.137 10.550 400.032 10.060 233.077 0.690 399.342 0.565 233.642 11.790 411.132 11.705 221.937 0.470 410.662 0.170 222.107 10.930 421.592 11.590 210.517 0.790 420.802 1.400 211.917 APPENDIX C 105 Adj usted + H]. — v ‘ . E33173?“ “rm" 10.760 201.157 1.290 202.447 9.455 192.992 1.030 194.022 9.175 184.847 1.060 185.907 10.640 175.267 0.650 175.917 9.725 166.192 2.005 168.197 B.M. St. Mary’s Pg. 18: 6.730 161.467 161.540 161.540 161.467 0073: error of closure for 98 T.P.’s .000745 = plus correction to be applied per T.P. This procedure, as shown above, leads to a closure of —0.073 ft, thereby providing a measure of the surveying accuracy, and an adjusted elevation for DD of313.906 ft. Employment of the corrected starting elevation of 161.472 ft deduced above for B.M. St. Mary’s would lead to the follow- ing corrected elevation for DD: 313.906 ft — (161.540 ft — 161.472 ft) = 313.838 ft. 3. Because the November 1911 elevation of DD derived from the 1908 record elevation for the LABE Santa Barbara-Western precise bench mark has been given previously as 313.930 ft, whereas the November 1911 elevation of DD derived from this same basis is recomputed above to have been 313.838 ft, the following correction should be made to the 319.705-ft 1911 elevation of DD computed under I.A.1.: 313.838 ft —313.930 ft = —0.092 ft. D. The total correction to be applied to the 1911 elevation of DD of 319.705 ft computed under I.A.1., accordingly, is given as: +0034 ft — 0.079 ft — 0.092 ft = — 0.137 ft. III. The November 1911 elevation of PBM 68 (DD) with respect to 8—32 as fixed in the 1934 adjustment, accordingly, is calculated to have been: 319.705 ft — 0.137 ft = 319.568 ft. Hollywood E—11 (PBM 40) I. Hollywood E—ll was chosen as a datum control point and its elevation fixed at 470.304 ft as of December 1, 1939 (DWP filecard for PBM 40) A. The elevation of 470.304 ft for Hollywood E—ll has been employed as the datum elevation (or has in turn fixed the elevation of adjacent bench mark PBM 40—C as the datum eleva- tion) in the calculation of elevations of bench marks subsequently occupied in connection with studies of subsidence in the Baldwin Hills by the Los Angeles Department of Water and Power (Hayes, 1947, p. 8; Walley, 1963, p. 3). II. In order to establish the 1911 elevation of Hollywood E—l 1 with respect to the elevation of 8—32 as fixed in the 1934 adjustment, the figure of 470.304 ft given under I. should be amended as follows: A. Adjustment correction: 1. The elevation of Hollywood E—l l of 470.304 ft is an adjusted elevation based on an assumption of stability between PBM 1 (located at Centinela Avenue and Market Street-see fig. 8) and PBM 58 (located at Washington Boulevard and Vineyard Avenue—fig. 8) (Hayes, 1959, p. 12). However, PBM 1 has been generally subsiding with respect to PBM 58 (10—W; 12—01050) (see profile of elevation changes along level circuit C—fig. 11). 2. An unadjusted 1939 elevation of Hollywood E—11 with respect to PBM 58 may be computed by adding the observed elevation difference between PBM 58 and Hollywood E—ll to the LABE elevation of PBM 58 accepted by the Department of Water and Power in 1939: a. 470.740 ft — 162.320 ft = 308.420 ft— elevation difference between PBM 58 and Hollywood E—ll (DWP fieldbook 2604, p. 9, 17). 161.860 ft—LABE elevation of PBM 58 accepted by the Department of Water and Power in 1939 (DWP fieldbook 2604, p. 17). b. 308.420 ft + 161.860 ft = 470.280 ft—1939 elevation of Hollywood E—11 with respect to PBM 58 as fixed at 161.860 ft. 3. The elevation of Hollywood E—l 1 of 470.280 ft (with respect to PBM 58) is a more objectively determined elevation than 470.304 ft, since it does not assume stability between PBM 1 and PBM 58. 4. Therefore, the following correction should be made to the 470.304-ft 1939 elevation of Hollywood E—11 given under 1.: 470.280 ft — 470.304 ft = — 0.024 ft. B. Datum correction: 1. The record elevation of the Civic Center basic control point 37—54—26 (8—32 equivalent) employed by the LABE in its 1934 general leveling of Los Angeles has been given as 327.306 ft (Grant and Sheppard, 1939, p. 106 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 300; LABE Precise Bench Mark Index, p. 20). The elevation of 37—54—26 determined in the 1934 adjustment of the US. Coast and Geodetic Survey (1947, p. 28) has been given as 327.309 ft. a. Accordingly, in order to bring into confor- mity the elevations established by the LABE in its 1934 general leveling survey with those simultaneously derivable through a comparison with S—32 (37—54— 26 equivalent) as fixed in the 1934 adjustment, 327.309 ft — 327.306 ft = 0.003 ft should be added to those eleva- tions derived from 37—54—26 in the LABE general leveling of 1934. 2. The 161.860-ft elevation of PBM 58 (10—W; 12—01050), accepted by the Department of Water and Power in 1939 (DWP fieldbook 2604, p. 17), was established in May 1933 in connection with the LABE 1934 general leveling survey (LABE—CE fieldbook 16980, P- 1, 6). a. Accordingly, the May 1933 elevation of PBM 58 with respect to 8—32 as fixed in the 1934 adjustment is calculated to have been: 161.860 ft + 0.003 ft = 161.863 ft. 3. Because the 1939 elevation of Hollywood E—l 1 has been derived in turn from PBM 58 as fixed at 161.860 ft (II.A.2.a.), the follow- ing correction should be made to the 470.304—ft 1939 elevation of Hollywood E—11 given under 1.: 161.863 ft — 161.860 =+0.003 ft. C. Movement correction for PBM 58: 1. Elevations of PBM 58 (10—W; 12—01050) with respect to 8—32 (or its equivalents) have been recorded as: Duty E/cz‘ulum Sol/rte l/H [Ii 1933 ____________ 161.863 II.B.2.a. (above) 1949 11-161.784 LABE Precise Bench Mark Index 1953 —"161.743 D0. 1955 ___161.694 Do. 1956 _____________ 161.684 Do. 1960 ,,,,,,,,,,,, 161.636 D0. a. The average annual rate of subsidence of PBM 58 with respect to 8—32 for the period 1933—60, accordingly, is calculated to have been: 161.863 ft — 161.636 ft 27 yrs 2. Extrapolation backwards of the 1933—60 average rate of subsidence of PBM 58 = 0.00841 ft/yr. permits the following calculation of sub- sidence of PBM 58 with respect to 8-32 be- tween November 1911 and May 1933: (0.00841 ft/yr) (21.5 yrs) = 0.181 it. a. This calculation of subsidence at PBM 58 may be slightly high. Since, as shown under II.C.1., the apparent rate of subsi- dence of PBM 58 during the period 1933—49 was roughly half that which obtained during the interval 1949—60, the rate of subsidence over the period 1911— 33 may be better reflected by the sub- sidence that accrued during the im- mediately following period, 1933—49, than it is by subsidence measured over the entire period 1933—60. (It is not known for certain, of course, whether the apparent increase in the rate of subsid- ence of PBM 58 between 1933—49 and 1949—60 reflects an actual acceleration of movement or resulted instead from the two-point adjustment procedure used in 1949 and subsequent years; it is assumed to reflect a real increase in rate of movement for reasons brought out in the prefatory note.) Other things being equal, the most objective calculation of the average annual rate of subsidence of PBM 58 should employ the longest period of observation possible; thus the average figure of0.00841 ft/yr is accepted here as a basis for computation of the subsidence of PBM 58 between 1911 and 1933. 3. Inasmuch as PBM 58 is calculated to have subsided 0.181 ft. with respect to 8—32 between November 1911 and May 1933, its November 1911 elevation must have been 0.181 ft greater than that given for May 1933 under II.A.2. a. Thus, the November 1911 elevation ofPBM 58 with respect to the 1933 datum employed by the LABE is calculated to have been: 161.860 ft + 0.181 ft = 162.041 ft. 4. Because the 1939 elevation of Hollywood E—11 has been derived in turn from the elevation of PBM 58 as fixed in May 1933 (II.A.2.), an evaluation ofits 1939 elevation with respect to PBM 58 as fixed in November 1911 requires that the following correction be made to the 1939 elevation of Hollywood E—11 of 470.304 ft given under 1.: 162.041 ft — 161.860 ft = +0.181 ft. APPENDIX D 107 D. Movement correction for PBM 40 (Hollywood E—11): 1. The profile of elevation changes along level = 0.01098 ft/yr. Were the shorter period of observation, line C shows that Hollywood E—ll has been undergoing measurable changes in eleva- tion with respect to PBM 58 since 1939; it is assumed that comparable changes in eleva- tion took place between 1911 and 1939. 2. The average annual rate of change in eleva- tion of Hollywood E—l 1 with respect to PBM 58 may be calculated through a comparison of elevation differences between these two points through time. . Elevation differences between Hollywood E—11 and PBM 58 for three separate points in time between 1939 and 1962 are computed as follows: December 1939: 470.740 ft; observed elevation of H01- lywood E—ll (DWP fieldbook 2604, p. 9) 162.320 ft; observed elevation of PBM 58 (DWP fieldbook 2604, p. 17) 308.420 ft; elevation difference between Hollywood E—ll and PBM 58 October 1946: 470.273 ft; observed elevation of H01- lywood E—ll (DWP filecard for PBM 40) 161.976 ft; observed elevation of PBM 58 (DWP filecard for PBM 58) 308.297 ft; elevation difference between Hollywood E—11 and PBM 58 April 1962: 456.743 ft; observed elevation of PBM 40—C (DWP filecard for PBM 40—C) 162.065 ft; observed elevation of PBM 58 (DWP filecard for PBM 58) 294.678 ft; elevation difference between PBM 40—0 and PBM 58 13.496 ft; elevation difference between Hollywood E—11 and PBM 40—C (DWP filecards for PBM 40 and PBM 40—C) 308.174 ft; elevation difference between Hollywood E—11 and PBM 58 b. Use of the longest period over which elevation differences between Hollywood E—ll and PBM 58 have been measured indicates that Hollywood E—ll has been subsiding with respect to PBM 58 at an average annual rate of about: 1946—62, utilized in the above computa- tion, it would lead to a lower rate of subsidence; accordingly, since elevation measurements between Hollywood E11 and PBM 58 over the period 1946—62 were of a higher order of precision than those obtained prior to 1946 (Hayes, 1959, p. 12), the calculated rate of 0.01098 ft/yr probably represents a maximum average figure for the subsidence of Hollywood E—ll with respect to PBM 58. 3. Extrapolation backwards of the 1939—60 average annual rate of subsidence of H01- lywood E—11 permits the following calcula- tion of subsidence of Hollywood E—ll with respect to PBM 58 between November 1911 and December 1939: (0.01098 ft/yr) (28.09 yrs) = 0308 ft. 4. Because Hollywood E—1 1 is calculated to have subsided 0.308 ft with respect to PBM 58 between November 1911 and December 1939, its November 1911 elevation with respect to PBM 58 must have been 0.308 ft greater than that given for December 1939; thus the following correction should be made to the 470.304-ft elevation of H01- lywood E—ll given under 1.: 470.612 ft — 470.304 ft = +0.308 ft. E. The total correction to be applied to the 1939 elevation of Hollywood E—11 of 470.304 ft listed under I, accordingly, is given as: —0.024 ft +0.003 ft +0.181 ft +0.308 ft = +0.468 ft. 111. The November 191 1 elevation of Hollywood E—l 1 (PBM 40) with respect to S—32 as fixed in the 1934 adjustment, accordingly, is calculated to have been: 470.304 ft + 0.468 ft = 470.772 ft. APPENDIX D Determinations of subsidence of PBM 68 with respect to Hollywood E—ll (fig. 8). I. Since 1917, as given by the Department of Water and Power (DWP filecard for PBM 68). A. The 1917 elevation of PBM 68 was derived from the elevation of a topographic saddle within the area of the old Centinela Reser- voir survey (DWP fieldbook 1579, p. 4—5) and can only be assumed to match the 1917 ele- vation of this point derivable through a com- parison with Hollywood E—ll; subsequent 108 elevations have been measured with respect to Hollywood E—ll as fixed at 470.304 ft (DWP filecard for PBM 68). Date Elevation of PBM 68 Cumulative subsidence (in ft! ofPBM 68(in f‘tl 12/1917 ______________ 320.015 10/25/1943 ____________ 317.428 2.587 10/31/1946 ____________ 317.141 2.874 4/11/1950 ____________ 316.753 3.262 6/5/1950 ______________ 316.745 3.270 9/28/1954 ____________ 316.120 3.895 10/7/1958 ____________ 315.651 4.364 6/15/1962 ____________ 315.254 4.761 11. Since 1911. A. It is assumed here that the 1939 elevation of Hollywood E—ll is the equivalent of one which has been derived from and has re— mained fixed with respect to the datum con- trol point from which the 1911 elevation of PBM 68 was derived. The 1911 elevation of PBM 68 was derived by the Department of Water and Power through a comparison with a LABE precise benchmark at Santa Bar- bara and Western Avenues (DWP fieldbook 1458, p. 10) and corrected to the post-1925 Los Angeles city datum (see appendix C, PBM 68 1.); subsequent elevations are with respect to Hollywood E—11 as fixed at 470.304 ft (DWP filecard for PBM 68). Date Elevation of PBM 68 Cumulative subsidence (m it! of PBM 68 (in ft) 11/1911 ______________ 319.705 10/25/1943 ____________ 317.428 2.277 10/31/1946 ____________ 317.141 2.564 4/11/1950 ____________ 316.753 2.952 6/5/1950 ,,,,,,,,,,,,,, 316.745 2.960 9/28/1954 ,,,,,,,,,,,, 316.120 3.585 10/7/1958 ____________ 315.651 4.054 6/15/1962 ____________ 315.254 4.451 111. Since 1911. A. Calculated with respect to Hollywood E—ll as fixed in elevation since November 1911. 1. The 1911 elevation of Hollywood E—ll has been derived through a comparison with 8—32 as fixed in the 1934 adjustment and is calculated to have been 470.772 ft (see ap- pendix C, PBM 40). Accordingly, 470.772 ft _ 470.304 ft = 0.468 ft have been added to 1 all elevations derived from Hollywood E—11 as fixed at 470.304 ft in order to obtain their elevations with respect to Hollywood E—11 as fixed in elevation since November 1911. RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 2. The 1911 elevation of PBM 68 has been de- rived through a comparison with 8—32 as fixed in the 1934 adjustment and is calcu- lated to have been 319.568 ft (see appendix C, PBM 68). Elevation of PBM 68 Cumulative subsidence Date (in ft) of PBM 68 (in ft) 11/1911 ______________ 319.568 10/25/1943 ____________ 317.896 1.672 10/31/1946 ____________ 317.609 1.959 4/11/1950 ____________ 317.221 2.347 6/5/1950 ______ 317.213 2.355 9/28/1954 ____ 316.588 2.980 10/7/1958 ____ 316.119 3.449 6/15/1962 ____________ 315.722 3.846 IV. January 4-12, 1934—October 13—25, 1943. A. PBM 68 and PBM 31 (Baldwin Aux—fig. 8) subsided with respect to Hollywood E—ll be- tween 1943 and 1962 as shown below (DWP filecards for PBM 68 and PBM 31). PBM 68 Ratio of PBM 31 Time interval Subsidence subsidence Time interval Subsidence (in ft! (in ft) PBM 31 10'25/41L10131/46 10/13/43—10/9/46 (3 yr ‘2 wk! "H". ., 0.287 1.550 (2yi‘11 m03'2Wk1111 0.185 lO’31’46-4/11/50 10/9/4Py3/15/5O (3 yr5mo 1!: wk) _ e, .388 2.155 (3 yr5m01wk) ,,,,,, .180 41150—92854 3/15/5‘1L8/19/54 (4 yr 5 mo 2%: wk) ,,,, .633 1.906 (4 yr 5 mo V.) wk) eeeeee .332 9/28/54—10/‘7/58 8/19/548/18/58 I4 yr 1 wk! ,,,,,,,,,, .469 1.892 (4 yr) ,,,,,,,,,,,,,,,, .248 10768—61562 8/18/5&4/25/62 (3 yr 8 mo 1 wk! ,,,,,, .397 3.545 (3 yr 8 mo 1 wk! ,,,,,, .112 10'25.’43—10/7’58 10/13/4378/18/58 (14 yr 11 mo 2 wk) ,,,, 1.777 1.880 (14 yr 10 mo 1 wk! ,,,, .945 10r25/43—6/15/62 10/13/4374/25/62 (18 yr7m03wk) ,,,, 2.174 2.058 (18 yr6mo2wk) ,,,, 1.057 1. As shown in the center column above, the ratios of subsidence of PBM 68 to subsid- ence of PBM 31 held roughly constant dur- ing the period 1943—58; the maximum di— vergence in these ratios (from 1.550 to 2.155) was approximately 39 percent. 2. A sharp change in the relative rates of subsidence of PBM 68 and PBM 31 is indi- cated for the period 1958—62. The maximum divergence in the ratio of the subsidence of one to that of the other (from 1.550 to 3.545) for the period 1943—62 was approximately 129 percent, about three times as great as that for the period 1943— 58. 3. In order to obtain the most representative estimate of the subsidence of PBM 68/ subsidence of PBM 31 with respect to Hol- lywood E-11 for the period 1934—43 through extrapolation backward from the APPENDIX D post—1943 period, the period 1958—62 should be regarded as probably aberrant and excluded from consideration in the calcula- tion of this ratio. (The validity of this ap- proach is reinforced by the fact that the 1958—62 interval is relatively remote from the 1934—43 period of interest). 4. Nevertheless, two sets of figures for the sub- sidence of PBM 68 between 1934 and 1943 are derived: (A) those calculated from a comparison of the subsidence at PBM 68 with that at PBM 31 between 1943 and 1958; (B) those calculated from a compari- son of the subsidence at PBM 68 with that at PBM 31 between 1943 and 1962. a. Since the figures associated with set B in- volve a probable aberration in movement between PBM 68 and PBM 31, the figures associated with set A are considered far more reliable. 5. Therefore, the subsidence of PBM 68 with re— spect to Hollywood E—11/the subsidence of PBM 31 with respect to Hollywood E—11 (including a correction for the minor differ- ences in the increments of time over which subsidence at the two bench marks was measured) has averaged: (A) (1943—58) 1.777 ft 0945 ft + 0.006 ft = 1'870‘ (B) (1943—62) 2.174 ft = 2.050. 1.057 ft + 0.003 ft B. PBM 31 subsided approximately 0.404 ft with respect to PBM 71 (W—169—fig. 8) between January 1934 and October 1943 (Hayes, 1943, fig. 5). This is precisely the figure ob- tained, moreover, through a direct compari— son of the elevation differences between PBM 31 and PBM 71 that existed in January 1934 and October 1943 respectively: January 4—12, 1934; (US. Coast and Geodetic 189.593 ft Survey, 1947, p. 1, 25—26) October 13—25, 1943; (DWP filecards for —189.189 ft PBM 31 and PBM 71; DWP fieldbook 2769, p. 26, 51) 0.404 ft. 1. Elevations of PBM 71 with respect to Hol- lywood E—11 for the period October 25, 1943, to October 22, 1962, ranged as follows (DWP filecard for PBM 71): 109 Date Elevation in feet 10/25/43 ________________________________________________ 322.469 11/5/46 ________________________________________________ 322.578 4/14/50 ________________________________________________ 322.587 11/18/54 ________________________________________________ 322.594 11/14/58 ________________________________________________ 322.630 10/22/62 ________________________________________________ 322.612 a. It is concluded, therefore, that for the period 1943-62, PBM 71 changed in elevation with respect to Hollywood E—ll at the av- erage rate: 322.612 ft —322.469 ft = . +0.0075 ft/yr. 19 yrs b. Extrapolation of this rate backward in time to the period 1934—43 indicates that PBM 71 rose approximately (9.75 yrs) (0.0075 ft/yr) = 0.073 ft with respect to Hollywood E—ll between January 1934 and October 1943. 2. Therefore, between January 4—12, 1934, and October 13—25, 1943, subsidence of PBM 31 with respect to Hollywood E—ll is com- puted to have been: 0.404 ft — 0.073 ft = 0.331 ft. C. Adoption of the post-1943 ratios of the subsid- ence of PBM 68 to the subsidence of PBM 31 (IV.A.5.) for the period 1934—43 permits the following calculations of subsidence of PBM 68 with respect to Hollywood E—ll for the period January 4—12, 1934 to October 13—25, 1943: (A) (0.331 ft) (1.870) = 0.619 ft, (B) (0.331 ft) (2.050) = 0.679 ft. V. October 29, 1926—April 7, 1931. A. PBM 68 and the site of LA. County BM 4 (not recovered after 1931) (fig. 8), located 185: feet south of Standard Oil Co. well Stocker 8 (LA. County level book 302, p. 6), which is in turn located about 100 feet south-southwest of the Overhill Drive—LaBrea Avenue inter- section, subsided with respect to Hollywood E—ll between 1950 and 1962 as shown below (DWP filecard for PBM 68; Hayes, 1955, fig. 1; Hayes, 1959, fig. 1; Walley, 1963, fig. 1): Subsidence of Calculated subsidence Time interval PBM 68 at the site of LA. PBM GS/BM 4 tin ft) County BM 4 (in ft) 4/11/50—9/28/54 (4 yr 5 mo 21/2 wk) ____ 0.633 0.380 1.666 9/28/54—10/7/58 (4 yr 1 wk) ___________ .469 .286 1.640 10/7/58—6/15/62 (3 yr 8 mo 1 wk) _______ .397 .148 2.682 4/11/50—10/7/58 ________ 1.102 .666 1.654 4/11/50—6/15/62 ________ 1.499 .814 1.841 110 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 1. As shown in the right-hand column above, PBM 68 and BM 4 subsided at roughly proportionately constant rates during the period 1950—58. 2. A sharp change in the relative rates of subsid- ence of PBM 68 and BM 4 is indicated for the period 1958—62. 3. In order to obtain the most representative estimate of the subsidence of PBM 68/ subsidence of BM 4 for the period 1926—31 through extrapolation backward from the post-1950 period, the period 1958—62 should be regarded as probably aberrant (just as it appeared to be for the subsidence of PBM 68/subsidence of PBM 31) and excluded from consideration in the calculation of this ratio. 4. Nevertheless, two sets of figures for the sub- sidence of PBM 68 between 1926 and 1931 are derived: (A) those calculated from a comparison of the subsidence of PBM 68 with that at the site of BM 4 between 1950 and 1958; (B) those calculated from a com- parison of the subsidence of PBM 68 with that at the site of BM 4 between 1950 and 1962. a. Since the figures associated with set B in- volve a probable aberration in movement between PBM 68 and BM 4, those figures associated with set A are again consid- ered far more reliable. 5. Therefore, the subsidence of PBM 68 with respect to Hollywood E—ll/subsidence of BM 4 with respect to Hollywood E—11 has averaged: (A) (1950—58); 1.654, (B) (1950—62); 1.841. B. 1. LA. County BM 2 is located at the intersec- tion of Overhill Drive and Fairview Avenue (LA. County level book 302, p. 5), about 1,000 feet east of PBM 3. The profile of elevation changes along level line C shows that PBM 3 has remained almost precisely stable with respect to PBM 1. a. Since BM 2 lies within this relatively stable zone, its stability is assumed to have matched that of PBM 3, and it isi concluded as a corollary that BM 2 has remained unchanged in elevation with respect to PBM 1. The probable stability of BM 2 with respect to PBM 1 may be corroborated in the following manner: Between 1922—26 and 1943 BM 2 is thought to have subsided about 0.003 ft with respect to USGS BM 16 located approximately 3,800 feet south- southwest of PBM 1 (Hayes, 1943, p. 10—11). Between 1933—35 and 1943 BM 16 subsided about 0.026 ft with respect to PBM 1 (Hayes, 1943, figs. 2, 3). It seems unlikely, accordingly, that the elevation of BM 2 has changed with respect to PBM 1 at a rate in excess of about 0.003 ft/yr. 2. The profile of elevation changes along level line C shows that Hollywood E—ll subsided about 0.028 ft with respect to PBM 1 between October 1946 and April 1962. a. It is concluded, accordingly, that during the period 1946—62, Hollywood E—11 changed in elevation with respect to PBM 1 at the following average rate: —0.028 ft ”15.5 yr) — —0.0018 ft/yr. b. Extrapolation of this rate backward to the period 1926—31 indicates that Hollywood E—ll subsided approximately (4.5 yr) (0.0018 ft/yr) = 0.008 ft with respect to PBM 1 between October 29, 1926, and April 7, 1931. 3. Therefore, between October 29, 1926 and April 7, 1931, Hollywood E—11 is computed to have subsided only 0.008 ft with respect to BM 2. C. Observed elevations of BM 4 with respect to a fixed elevation of 186.785 ft at BM 2 have . been recorded as follows (LA. County level book 302, p. 4, 6, 196, 198): 10/29/26 450.085 ft, 4/7/31 449.530 ft. 1. Accordingly, BM 4 subsided 0.555 ft with respect to BM 2 between October 29, 1926, and April 7, 1931. Hayes’ (1943, p. 12) figure of 0.635 ft apparently was based on a comparison between the 1926 observed elevation and a 1931 adjusted elevation that involved a substantial adjustment in BM 2 as well as BM 4. 2. Since Hollywood E—11 is computed to have subsided 0.008 ft with respect to BM 2 during the period 1926—31, BM 4 appa- rently subsided about 0.555 ft —0.008 ft = 0.547 ft with respect to Hollywood E—11 between October 29, 1926, and April 7, 1931. D. Adoption of the post-1950 ratios of subsidence of PBM 68 to subsidence of BM 4 (V.A.4.) for the period 1926—31 permits the following calcula- tions of subsidence of PBM 68 with respect to APPENDIX D 1 1 1 Hollywood E—ll for the period October 29, 1926, to April 7, 1931: (A) (0.547) (1.654) = 0.905 ft, (B) (0.547) (1.841) = 1.007 ft. VI. November 29, 1939—October 13, 1943. A. PBM 31 (Baldwin Aux) subsided 0.171 ft with respect to Hollywood E—ll between November 29, 1939, and October 13, 1943 (DWP filecard for PBM 31). 1. Adoption of the post-1943 ratios of subsidence of PBM 68 to subsidence of PBM 31 (IV.A.5.) permits the following calculations of subsidence of PBM 68 with respect to Hollywood E—ll for the period November 29, 1939, to October 13, 1943: (A) (0.171 ft) (1.870) = 0.320 ft, (B) (0.171 ft) (2.050) = 0.351 ft. VII. January 4—12, 1934—November 29, 1939. A. Subsidence of PBM 68 with respect to Hol- lywood E—ll between January 4—12, 1934, and October 13—25, 1943, has been calculated at (A) 0.619 ft and (B) 0.679 ft (IV.C.). B. The subsidence of PBM 68 with respect to Hollywood E—11 between November 29, 1939, and October 13, 1943, has been calculated at (A) 0.320 ft and (B) 0.351 ft (VI.A.1.). C. Assuming that the average elevation of PBM 68 for the period October 13—25, 1943 matched that which obtained on October 13, 1943, subsidence of PBM 68 with respect to Hol- lywood E—ll between January 4—12, 1934 and November 29, 1939, may be calculated by difference: (A) 0.619 ft -— 0.320 ft = 0.299 ft, (B) 0.679 ft —- 0.351 ft = 0.328 ft. VIII. April 7, 1931—January 4—12, 1934. A. There are no known elevation measurements that can be used in calculating directly the subsidence of PBM 68 for the period April 7, 1931—January 4—12, 1934. 1. Subsidence of PBM 68 with respect to Hol- lywood E—ll for the period April 7, 1931— January 4—12, 1934, accordingly, is com- i puted here through calculation of the average rate of subsidence of PBM 68 over the intervals of measurement immediately preceding and immediately following this 2.75-year period. a. Subsidence ol' PBM 68 (in it) October 29. 1926-Apri1 7, 1931 --. (A)0.905 ft; (B)1.007 ft (V.D.) January 4—12, 1934— October 13—25, 1943 __________ (A)0.619 ft; (B)0.679 ft (IV.C.) Time interval b. The average rate of subsidence of PBM 68 over the two collective intervals is calcu- lated to have been: (A) 0.905 ft + 0.619 ft 4.44 yr + 9.78 yr (B) 1.007 ft + 0.679 ft 4.44 yr + 9.78 yr ‘ 011% my“ c. Subsidence of PBM 68 with respect to Hollywood E—ll for the period April 7, 1931—January 4—12, 1934 is calculated to have been: (A) (2.75 yr) (0.1071 ft/yr) = 0.295 ft, (B) (2.75 yr) (0.1185 ft/yr) = 0.326 ft. IX. April 7, 1931-October 1943. A. Subsidence of PBM 68 with respect to Hol- lywood E—11 between April 7, 1931, and October 1943 may be computed directly through a comparison with the subsidence at the site of LA. County bench mark BM M4. 1. According to Hayes (1943, p. 11—12), BM M4, a chiseled cross set in an iron bolt at the southeast corner of Standard Oil Co. Stocker 10 derrick (LA. County level book 302, p. 199), located about 600 feet south- southwest of the LaBrea Avenue—Overhill Drive intersection, subsided 0.517 foot between 1931 and October 1943. Hayes’ statement implies that this subsidence was with respect to LA. County BM 2 (at Fairview Avenue and Overhill Drive), but the datum wasunspecified. ’ a. It is assumed that Hollywood E—ll has subsided with respect to BM 2 at a constant rate of 0.0018 ft/yr (V.B.2.a.). Hollywood E—ll, accordingly, is calcu- lated to have subsided about (12.5 yr) (0.0018 ft/yr) = 0.023 ft with respect to BM 2 between April 7, 1931, and October 1943; it is thus concluded that BM M4 subsided 0.517 ft — 0.023 ft = 0.494 ft with respect to Hollywood E—ll during the same period. b. Inasmuch as the site ofBM 4 has undergone subsidence with respect to Hollywood E—11 since 1950 at a rate roughly 1.098 times that which obtained at the site of BM M4 (Hayes, 1955, fig. 1; Hayes, 1959, fig. 1; Walley, 1963, fig. 1), the ratio ofthe subsidence of PBM 68 to the subsidence of BM M4 should have exceeded that ofPBM 68 to BM 4 by the same factor. c. Therefore, adoption of the post-1950 ratios of subsidence of PBM 68 to subsidence of BM 4 (V.A.5.), times a correction factor of = 0.1071 ft/yr, 112 1.098, for the subsidence of PBM 68 to the subsidence of BM M4, permits the follow- ing calculations of subsidence of PBM 68 with respect to Hollywood E—11 for the period April 7, 1931, to October 1943: (A) (0.494 ft) (1.651) (1.098) = 0.896 ft, (B) (0.494 ft) (1.841) (1.098) = 0.999 ft. B. Regrettably, the apparently excellent corres- pondence between the figures for the subsid- ence of PBM 68 during the period 1931—43 determined through a comparison with the subsidence at PBM 31 (IV.C.; VIII.A.) and those determined through a comparison with the subsidence at BM M4 (IX.A.1.c.) almost certainly is spurious. This arises from the fact that Hayes’ figure of 0.517 ft was determined through a direct comparison between the 1931 adjusted elevation ofBM M4 as given by LA. County and the 1943 adjusted elevation of BM M4 as given by the Department of Water and Power: 443.154 ft (L.A. County level book 302, p. 199) —442.637 ft.(DWP field book 2769, p. 64) 0.517 ft. Since the above figure does not provide for a difference in datums, it is valid only to the extent that the two datums converge. 1. Calculation of the subsidence of BM M4 with respect to BM 2 for the period 1931—43 may be made, however, through a comparison between either the observed or adjusted differences in elevation between BM M4 and BM 2 for 1931 and 1943. a. Computation of April 7, 1931, observed difference: 443.235 ft BM M4 (L.A. County level book 302, p. 198) (L.A. County level book 302, p. 196) —186.785 ft BM 2 256.450 ft Computation of April 7, 1931, adjusted difference: 443.154 ft BM M4 (L.A. County level book 302, p. 199) (L.A. County level book 302, p. 197) —186.731 ft BM 2 256.423 ft. b. Computation of October 1943, observed difference: 442.605 ft BM M4 (DWP fieldbook 2769, p. 23, 64) —186.464 ft BM 2 (DWP fieldbook 2769, p. 17, 66) 256.141 ft. Computation of October 1943, adjusted difference: RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 442.637 ft BM M4 (DWP fieldbook 2769, p. 64) —186.510 ft BM 2 (DWP fieldbook 2769, p. 66) 256.127 ft. c. Employment of the observed and adjusted differences in elevations between BM 2 and BM M4 shows that between April 7, 1931, and October 1943 BM M4 subsided with respect to BM 2 as follows: Observed: 256.450 ft (1931) —256.141 ft (1943) 0.309 ft. Adjusted: 256.423 ft (1931) —256.127 ft (1943) 0.296 ft. 2. Subsidence of BM M4 with respect to Hol- lywood E—11 may be computed by correct- ing for the estimated subsidence of H01- lywood E—11 with respect to BM 2 between April 7, 1931, and October 1943. a. Hollywood E—11 is assumed to have sub- sided at a constant rate of 0.0018 ft/yr with respect to BM 2 (see V.B.2.). b. Accordingly, Hollywood E—11 subsided ap- proximately (12.5 yr) (0.0018 ft/yr) = 0.023 ft with respect to BM 2 between April 7, 1931, and October 1943. c. Subsidence of BM M4 with respect to Hollywood E—11 for the period April 7, 1931, and October 1943 thus is computed to have been: Observed: 0.309 ft —0.023 ft = 0.286 ft, Adjusted: 0.296 ft —0.023 ft = 0.273 ft. 3. Therefore, adoption of the post-1950 ratios of subsidence of PBM 68 to subsidence ofBM 4 (V.A.5.), times a correction factor of 1.098, for the subsidence of PBM 68 to the subsidence of BM M4, permits the following calculations of subsidence of PBM 68 with respect to Hollywood E—11 for the period April 7, 1931, to October 1943: (A) (0.286 ft) (1.654) (1.098) = 0.520 ft (0.273 ft) (1.654) (1.098) = 0.496 ft, (B) (0.286 ft) (1.841) (1.098) = 0.578 ft (0.273 ft) (1.841) (1.098) = 0.552 ft. C. Because the figures for the subsidence of PBM 68 with respect to Hollywood E—ll for the period 1931—43 determined through a com- parison with the subsidence at BM M4 are roughly 0.41 ft less than those determined through a comparison with the subsidence at PBM 31 and (indirectly) BM 4, a question exists as to which set of figures should be accepted. 1. Those derived through a comparison with APPENDIX D 1 13 PBM 31 are considered the more accurate for the following reasons: a. PBM 31 is a monument bench mark, greater period April 7, 1931, to October 1943 is computed to have been no more than 0.286 ft (IX.B.3.). Assuming a whereas BM M4 was simply a cross in an iron bolt set in an oil derrick and thereby more subject to disturbance. The probably undisturbed state of PBM 31, moreover, is corroborated by the almost precisely constant elevation difference maintained between PBM 31 and adjacent bench mark PBM 30 (Baldwin) from 1934 to the present (DWP filecards for PBM 31 and PBM 30). b. The period of observation covering both PBM 68 and PBM 31 has been much greater than that covering both PBM 68 and the site of BM M4. c. The comparison with PBM 31 is based entirely on measured elevation changes at PBM 31, whereas the comparison with BM M4 is based in part on approximate elevation changes at the site of BM M4 deduced from the isobase maps for 1950— 54, 1954—58, and 1958—62. d. An apparent aberration exists in the sub- sidence recorded for another bench mark (BM M2) set at the same time BM M4 was established. According to Hayes (1943, p. 12), BM M2, located 165 ft north of Slauson Avenue and 630 ft west of the Mansfield Drive centerline (LA. County level book 302, p. 197), subsided 0.538 ft between 1931 and 1943. The subsidence ofBM M2 with respect to Hollywood E—ll may have been about 0.23 ft less, as was the case with BM M4, thereby reducing the apparent subsidence at BM M2 to about 0.31 ft. Nevertheless, since 1950 subsidence in the vicinity of this bench mark has ranged between 0.000 ft/yr and 0.017 ft/yr, so that it should have subsided ‘ a maximum of 0.2 ft between 1931 and l 1943. i e. The approximate ratio of subsidence at the site of BM M4 to that at PBM 31 since , 1950 has ranged as follows: 1950—54; 0.94 1954—58; 1.06 1958—62; 1.09. , Yet between January 1934 and October 1943 subsidence of PBM 31 with respect . to Hollywood E—11 is computed to have § been 0.331 ft (IV.B.2.), whereas subsid- ence of BM M4 for the considerably l uniform rate of movement at BM M4 between 1931 and 1943, the ratio of subsidence at BM M4 to subsidence at PBM 68 for the period January 1934 to October 1943 is computed to have been approximately 0.223 ft/O.331 ft=0.67, almost the inverse of that which has obtained since 1950. This profound di- vergence in the 1934—43 ratio strongly suggests that for the period 1931—43, measured subsidence at at least one of these two points (PBM 31 or BM M4) was aberrant. Subsidence with respect to Hollywood E—11 at the site of BM M4 has averaged about: 1931—43; 0023 ft/yr 1950—58; 0.070 ft/yr (IX.B.2.; Hayes, 1955, fig. 1; Hayes, 1959, fig. 1). Subsidence of PBM 31 with respect to Hollywood E—ll has averaged about: 1934—43; 0.034 ft/yr 1950—58; 0.069 ft/yr (IV.B.2., IV.A.). According to these figures, then, the average subsidence of PBM 31 increased by a factor of 2.02 between the periods 1934—43 and 1950— 58, whereas the average subsidence at the site ofBM M4 increased by a factor of3.04 between the roughly comparable periods 1931—43 and 1950—58. Since an accelera- tion in subsidence of the magnitude suggested by the latter figure in particu- lar greatly exceeds any measured in- crease in subsidence in the northern Baldwin Hills since 1943, the subsidence measured at BM M4 between 1931 and 1943 was more likely aberrant than that measured at PBM 31 between 1934 and 1943. The probable validity of the 0.034 ft/yr figure for the average rate of subsidence of PBM 31 between 1934 and 1943 may be demonstrated in the following manner: 1934—43: Subsidence of PBM 31 with respect to Hollywood E—l 1 between January 1934 and October 1943 (IV.B.2.) is computed to have averaged 0.331 ft/9.75 yr : 0.034 ft/yr. 1939—43: 114 Subsidence of PBM 31 with respect to Hollywood E—11 between November 29, 1939, and October 13, 1943 (DWP filecard for PBM 31) is computed to have averaged 0.171 ft/3.89 yr = 0.044 ft/yr. 1934—39: Subsidence of PBM 31 with respect to PBM 71 (W—169) between January; 1934 and November 1939 may be computed by assuming that the move- ment of PBM 71, with respect to the corrected US. Coast and Geodetic Survey datum adopted by Hayes (1943, p. 13—14), remained constant between 1934 and 1943. Movement of PBM 71 with respect to the corrected US. Coast and Geodetic Survey datum for this period is reported to have been +0.011 ft (Hayes, 1943, p. 14); its movement during the period January 1934 to November 1939, accordingly, is calcu- lated to have been (0.011 ft) (5.9 yr/9.75 yr)=0.007 ft. Since PBM 31 subsided about 0.222 ft with respect to the corrected US. Coast and Geodetic Survey datum during this same period (Hayes, 1943, fig. 5), PBM 31 appa- rently subsided about 0.222 ft + 0.007 ft = 0.229 ft with respect to PBM 71 between 1934 and 1939. Adoption ofthe 1943—62 average rate of subsidence at Hollywood E—ll with respect to PBM 71 (IV.B.1.a.) indicates that PBM 31 subsided approximately 0.229 ft - (5.9 yr) (0.0075 ft/yr)=0.185 ft with respect to Hollywood E—ll between January 1934 and November 1939. Subsidence of PBM 31 with respect to Hollywood E—11 between January 1934 and November 1939, accordingly, is com- puted to have averaged 0.185 ft/5.9 yr = 0.031 ft/yr. Since the average rates of subsidence of PBM 31 for these three separate periods, no one of which depends on measured elevations common to all three intervals, remained roughly uni- form throughout the period 1934—43, it is concluded that the aberrant ratio of subsidence of BM M4 to subsidence of PBM 31 for the period 1934—43 is attrib- utable to an aberration in the move- ment of BM M4 rather than PBM 31. RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA APPENDIX E Determination of subsidence of PBM 68 with respect to PBM 58. I. Since 1911. A. The 1911 elevation of PBM 68 (fig. 8) has been derived through a comparison with 8—32 as fixed in the 1934 adjustment (see appendix C). Subsequent elevations of PBM 68 have been calculated through subtraction of the subsid- ence at PBM 68 since 1911; the subsidence with respect to PBM 58 (fig. 8) has been computed through algebraic addition of the subsidence at PBM 68 with respect to Hol- lywood E—l 1 (appendix D, III.) to the subsidence at Hollywood E—11 with respect to PBM 58 (appendix C, PBM 40, II.A.2., II.D.4.; DWP fieldbook 2769, p. 27, 37; DWP filecard for PBM 40; DWP filecard for PBM 58). 1. Dates of elevation measurements at PBM 58 do not accord precisely with those at PBM 68. However, because Hollywood E—11 has sub- sided only slightly with respect to PBM 58 since 1939, any elevation changes that Hol- lywood E—ll may have undergone with respect to PBM 58 over periods of less than 2 months duration are considered negligible. , - Cumulative Date Masai/[non Of subsidence (in it) 0‘ 5?ng 11/1911 __________________________________ 319.568 10/25/1943 ________________________________ 317.616 1.952 10/31/1946 ________________________________ 317.178 2.390 4/11/1950 ________________________________ 316.762 2.806 6/5/1950 __________________________________ 316.754 2.814 9/28/1954 _________________________________ 316.118 3.450 10/7/1958 ________________________________ 315.585 3.983 6/15/1962 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 315.166 4.402 II. January 4—12, 1934—October 13—25, 1943. A. Subsidence of Hollywood E—ll with respect to PBM 58 is calculated to have proceeded at an average rate of 0.01098 ft/yr between 1939 and 1962 (appendix C, PBM 40, II.D.2.b.). 1. Accordingly, between January 4—12, 1934, and October 13—25, 1943, Hollywood E—11 is calculated to have subsided (9.75 yr) (0.01098 ft/yr) = 0.107 ft with respect to PBM 58. B. PBM 68 is calculated to have subsided 0.619 ft with respect to Hollywood E—11 between January 4—12, 1934, and October 13—25, 1943 (appendix D, IV.C.). C. Therefore, subsidence of PBM 68 with respect to PBM 58 for the period January 4—12, 1934, to October 13—25, 1943, is calculated to have been: 0.107 ft + 0.619 ft = 0.726 ft. APPENDIX F III. October 29, 1926—April 7, 1931. A. Hollywood E—ll is calculated to have subsided approximately (0.01098 ft/yr) (4.5 yr) = 0.049 ft (appendix C, PBM 40, II.D.2.b.) between Oc- tober 29, 1926, and April 7, 1931. . PBM 68 is calculated to have subsided 0.905 ft with respect to Hollywood E—ll between Oc- tober 29, 1926, and April 7, 1931 (appendix D, V.D.). . Therefore, subsidence of PBM 68 with respect to PBM 58 for the period October 29, 1926, to April 7, 1931, is calculated to have been: 0.049 ft + 0.905 ft = 0.954 ft. IV. November 29, 1939—October 13, 1943. A. Hollywood E—11 is calculated to have subsided (3.87 yr) (0.01098 ft/yr) = 0.042 ft (appendix C, PBM 40, II.D.2.b.) with respect to PBM 58 between November 29, 1939, and October 13, 1943. . PBM 68 is calculated to have subsided 0.320 ft with respect to Hollywood E—11 between November 29, 1939, and October 13, 1943 (appendix D, VI.A.1.). . Therefore, subsidence of PBM 68 with respect to PBM 58 for the period November 29, 1939 to October 13, 1943, is calculated to have been: 0.042 ft + 0.320 ft = 0.362 ft. V. January 4—12, 1934—November 29, 1939. A. The subsidence of PBM 68 with respect to PBM 58 for the period January 4—12, 1934, to November 29, 1939 may be calculated by difference. 1. a. Subsidence of PBM 68 between January 4—12, 1934, and October 13—25, 1943, is cal- culated to have been 0.726 ft. b. Subsidence of PBM 68 between November 29, 1939, and October 18, 1948, is calculated to have been 0.362 ft. 2. Assuming that the average elevation of PBM 68 for the period October 13—25, 1943, matched that which obtained on October 13, 1943, subsidence of PBM 68 with respect to PBM 58 for the period January 4—12, 1934, to November 29, 1939, is calculated to have been: 0.726 ft — 0.362 ft = 0.364 ft. VI. April 7, 1931—January 4—12, 1934. A. The subsidence of PBM 68 with respect to PBM 58 over the period April 7, 1931, to January 4—12, 1934, is computed here through calcula- tion ofthe average rate ofsubsidence of PBM 68 over the intervals ofmeasurement immediately preceding and immediately following this 2.75-year period. 115 B. The average rate of subsidence of PBM 68 with respect to PBM 58 over the intervals October 29, 1926—April 7, 1931, and January 4—12, 1934— October 13—25, 1943, is calculated to have been: 0.954 ft + 0.726 ft = 0.1181 ft/yr. 4.44 yr + 9.78 yr 1. Therefore, subsidence of PBM 68 with respect to PBM 58 for the period April 7, 1931 ~ January 4—12, 1934, is calculated to have been: (2.75 yr) (0.1181 ft/yr) = 0.324 ft. APPENDIX F Derivation of June—July 1910 elevations of PBM 68 and PBM 67 with respect to 8—32. The June-July 1910 elevations of PBM 68 (identified alternatively as DD—-see fig. 8) and PBM 67 (triangulation monument Inglewood D—1; adjacent to bench mark HH—see fig. 8) are developed here through the medium of topographic control surveys carried out by the Los Angeles Investment Company. NOTE—June—July 1910 stake elevations of points adjacent to LAIC bench marks DD and HH were derived through a comparison with the elevation of a bench mark located at Centinela and Eucalyptus Avenues, Inglewood (LAIC fieldbook 7, p. 2). The authority for the starting elevation of 137.973 ft at the Centinela-Eucalyptus bench mark has been given simply as: “Datum = City of Inglewood City of Los Angeles +0013” (LAIC fieldbook 7, p. 2). Although perusal of pre-1911 City of Inglewood fieldbooks failed to confirm the existence of a City of Inglewood bench mark at Centinela and Eucalyptus, the starting elevation of 137.973 ft is accepted provisionally here as having been derived from a City of Inglewood basic control point. The elevation of the Centinela-Eucalyptus bench mark is assumed to have remained unchanged in elevation with respect to 8—32 for the following reasons: 1. Elevation changes with respect to S—32 (or its approximate equivalents) in the vicinity ofthe Centinela-Eucalyptus bench mark, based on precise leveling carried out prior to 1939, averaged about +0.01 ft/yr (Grant and Sheppard, 1939, p. 302); those based on precise leveling carried out between 1949 and 1955 averaged about —0.01 ft/yr (fig. 6). We conclude, accordingly, that the relatively small positive elevation changes that have accrued in this area have been roughly balanced by comparably small negative changes. 2. The datum correction applied to the pre-1925 LABE elevation of S~32 in order to bring it into conformity with the 1934 elevation assigned to 8—32 by the US. Coast and Geodetic Survey is +5.809 ft (see appendix C, PBM 68); the datum correction applied to pre-1956 elevations of City of Inglewood bench marks (it is assumed that these bench marks have remained stable with respect to each other over the relatively limited area of Inglewood) in order to bring them into conformity with the elevations assigned to common bench marks by the US Coast and Geodetic Survey (which has held S—32 reset fixed in elevation since 1936—LABE Precise Bench Mark Index, p. 25) is +5.77 ft (Inglewood Municipal Code, Section 7101; 7/17/56). Because the 1910 elevation of the Centinela-Eucalyptus bench mark reportedly departed from that determined through a comparison with the pie-1925 LABE datum by only 0.013 ft, and because the datum 116 corrections determined for both 8—32 and City of Inglewood bench marks through comparison with US. Coast and Geodetic Survey elevations of these points (established subsequent to 1933) are very nearly the same, it is likely that, since 1910 at least, 8—32 and the Centinela-Eucalyptus bench mark have changed with respect to each other by no more than a few hundredths of a foot. If 8—32 and the Centinela-Eucalyptus bench mark may be treated as having remained unchanged in elevation with respect to each other since 1910, it follows that the City of Inglewood datum correction employed to bring the City of Inglewood bench mark elevations into conformity with those determined by the US. Coast and Geodetic Survey may be applied validly at any time after 1910 regardless of when the datum correction was actually made. PBM 68 (identified alternatively as DD). 1. June—July 1910 elevations ofa 2X2 stake set 10 ft east of DD, with respect to the City of Inglewood elevation of the Centinela-Eucalyptus bench mark, have been given as 315.675 ft and 315.66 ft (LAIC fieldbook 7, p. 3, 64), respectively, for an average elevation of: 315.675 ft+ 315.660 ft 2 II. Datum correction. A. The 1910 elevation of the 2X2 stake set 10 ft east of DD with respect to 8—32 as fixed in the 1934 adjustment may be computed through the addition of the standard datum correction applied to all pre-1956 elevations of City of Inglewood bench marks (see prefatory note): 315.668 ft June—July 1910 elevation of 2x2 stake adjacent to DD with respect to the City of Inglewood elevation of the Centinela-Eucalyptus bench mark. + 5.770 ft City of Inglewood datum correction 321.438 ft. III. Monument-stake elevation difference. A. Concrete monument DD and the 2><2 stake set 10 ft east ofDD are assumed to have remained unchanged in elevation with respect to each other. B. The elevation difference between DD and the 2X2 stake set 10 feet east of DD may be determined as follows: = 315.668 ft. 315.420 ft 19110bserved elevation of2 x2 stake marked 315.675 (DWP fieldbook . 1458, p. 29) ‘ «313.760 ft 1911 observed elevation of DD(DWP 1 fieldbook 1458, p. 29) (This is Within two-tenths of a foot of the ground elevation differ- ence between these two points today.) IV. The JuncLJuly 1910 elevation of PBM 68 (DD) ‘ with respect to 8—32 as fixed in the 1934‘ 1.660 ft RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA adjustment, as determined through the medium of Los Angeles Investment Company topographic control circuits, accordingly, is calculated to have been: 321.438 ft 1910 2X2 DD stake elevation with respect to S—32 — 1.660 ft 2X2 stake elevation minus DD __ monument elevation 319.778 ft. PBM 67 (triangulation monument Inglewood D—l; adjacent to Monument HH). I. June—July 1910 elevations ofa 2X2 stake set 10 ft north of HH have been given as 378.218 ft, 378.37 ft, and 378.24 ft (LAIC fieldbook 7, p. 10, 57, 74), respectively, for an average elevation of: 378.218 it + 378.37 ft + 378.24 ft = 378.276 ft. 3 II. Datum correction. A. The 1910 elevation of the 2X2 stake set 10 ft north of HH with respect to 8—32 as fixed in the 1934 adjustment may be computed through the addition of the standard datum correction applied to all pre—1956 elevations of City of Inglewood bench marks (see prefatory note): 378.276 ft June—July 1910 elevation of 2X2 stake adjacent to HH with respect to the City of Inglewood elevation of the Centinela-Eucalyptus bench mark + 5.770 ftCity of Inglewood datum correction 384.046 ft. III. PBM 67-HH 2X2 stake elevation difference. A. Concrete monument HH, the 2 X2 stake set 10 ft north of HH, and PBM 67 (approximately 40—50 ft north—northwest of HH) are assumed to have remained unchanged in elevation with respect to each other. B. The approximate elevation difference between HH and the 2x2 stake set 10 ft east of HH may be determined as follows: 1. Concrete monument HH was set flush with the ground surface (William Ball, Los Angeles Investment Co., oral commun., 1965). a. The top of the 34-inch iron pipe to which subsequent elevations have been referred stands about 0.20 ft above its concrete base. 2. The natural ground surface in the immediate area of HH is smooth and very flat. It is assumed, as a first approximation, that the 1910 ground elevations at HH and the 2 X2 stake were identical. APPENDIX G 3. LAIC plane table sheet 9, dated August 13 to 24 (1910?), shows the ground elevation at a pinpoint 10 ft north of HH at 378.3 ft (that is, within a few hundredths of a foot of the stake elevation adjacent to monument HH), so that it is probable that the 2 X 2 stake was set approximately flush with the ground surface. 4. The 1910 elevation of HH, accordingly, is assumed to have been roughly 0.20 ft above the elevation of the 2X2 stake set 10 ft to the north of HH. C. The elevation difference between HH and PBM 67 may be determined as follows: 375.635 ft 1951 observed elevation ofHH(LAIC fieldbook 201, p. 4) —375.275 ft 1951 observed elevation of PBM 67 (LAIC fieldbook 201, p. 4) 0.360 ft. D. The PBM 67—HH 2X 2 stake elevation differ- ence accordingly is computed to have been: 0.360 ft — 0.20 ft = 0.160 ft. IV. The approximate June—July 1910 elevation of PBM 67 (triangulation monument Inglewood D—l; adjacent to monument HH) with respect to 8—32 as fixed in the 1934 adjustment, as determined through the medium of Los Angeles Investment Company topographic control circuits, accordingly, is calculated to have been: 384.046 ft 1910 HH 2X2 stake elevation with respect to 8—32 — .160 ftHH 2 X2 stake elevation minus PBM 67 monument elevation 383.886 ft. APPENDIX C Determination of subsidence of PBM 67 with respect to Hollywood E—l 1. I. Since 1910. A. Calculated with respect to Hollywood E—ll as fixed in elevation since 1910. 1. The 1911 elevation of Hollywood E—ll has been derived through a comparison with 8—32 as fixed in the 1934 adjustment and is calculated to have been 470.772 ft (appendix C, PBM 40). Accordingly, 470.772 ft + [(1.4 yr) (0.00841 ft/yr + 0.01098 ft/yr) = 0.027 ft (see appendix C, PBM 40, II.C., II.D.)] — 470.304 ft = 0.495 ft has been added to all elevations derived from Hollywood E—11 as fixed at 470.304 ft (DWP filecard for PBM 67) in order to obtain their elevations with respect to 117 Hollywood E—ll as fixed in elevation since June—July 1910. 2. The approximate J une—J uly 1910 elevation of PBM 67 has been derived through a compari- son with S—32 as fixed in the 1934 adjustment and is calculated to have been 383.886 ft (appendix F, PBM 67). 3. The October 25, 1943, elevation of PBM 67 was not measured; it has been calculated through extrapolation backward to 1943 of the average rate of subsidence at PBM 67 between 1946 and 1950 (DWP filecard for PBM 67). Comparison with the rate of subsidence at PBM 68 suggests that this calculated value for the subsidence of PBM 67 probably is several hundredths of a foot too large (that is, the calculated 1943 elevation is several hundredths of a foot high). Cumulative Elevation of subsidence Date PBM 67 of PBM 67 (in ft) (in ft) 6»7/1910 __________________________________ 383.886 10/25/1943 ________________________________ 382.355 1.531 10/31/1946 ________________________________ 381.872 2.014 4/10/1950 381.337 2.549 10/6/1954 380.588 3.298 10/23/1958 ________________________________ 380.029 3.757 2/13/1963 ________________________________ 379.562 4.324 APPENDIX H Calculation of maximum subsidence in the northern Baldwin Hills since 1911 with respect to Hollywood E—11. NOTE—Calculation of the maximum subsidence in the northern Baldwin Hills may be closely approximated by assuming that PBM 122 (fig. 8) is essentially coincident with the point of maximum subsidence. Although the actual center of subsidence in the Baldwin Hills apparently has shifted slightly from time to time, PBM 122 is the only bench mark within the Baldwin Hills that has been observed through more than a single quadrennial measurement period that, since 1950 at least, has been subsiding at a rate no less than 90 percent of the maximum measured rate of subsidence. 1. November 1911—October 1943. A. Subsidence between December 1917 and Oc- tober 1943, at the low point of a topographic saddle (herein referred to as BM “‘saddle”) located approximately 725 ft N76°E of PBM 122, was computed by Hayes (1943, fig. 6) to have been approximately 4.2 ft. 1. This computation of subsidence at BM “sad- dle,” however, was based on the following assumptions: a. The elevation of an unspecified topographic saddle (from which the 1917 elevation was derived) remained unchanged between 118 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA 1911 and 1917 (DWP fieldbook 1579, p. 4—5). b. The datums employed in the 1917 and 1943 derivations of the elevation at BM “saddle” were identical. 2. Because the first assumption is not necessar- ily valid and the second assumption is clearly invalid, the estimated subsidence of 4.2 ft at BM “saddle” between 1917 and 1943 is apparently in error by an unknown factor. 3. Subsidence at BM “saddle” with respect to Hollywood E—11 between November 1911 and October 1943 may be deduced only by making the following assumptions: a. Any change in elevation at BM “saddle” with respect to PBM 68 between October 25, 1943 and December 9, 1943 was negligible. This assumption is required because the 1943 elevation at BM “saddle” was derived from that of PBM 68 (DD) on December 9, 1943 (DWP fieldbook 2769, p. 74—75). b. PBM 68 and BM “saddle” remained un- changed in elevation with respect to each other between 1911 and 1917. This assump- tion is necessary because neither a 1911 measured elevation at BM “saddle” nor a 1917 measured elevation of PBM 68 (with respect to some independent control point outside this immediate area) is known to exist. B. Subsidence at BM “saddle,” with respect to DD, between December 1917 and October 1943 was approximately 4.2 ft — 2.6 ft = 1.6 ft (Hayes, 1943, fig. 6). Because these two points are assumed to have remained unchanged in elevation with respect to each other between 1911 and 1917, subsidence at BM “saddle” with respect to DD between November 1911 and October 1943 must also have been 1.6 ft. 1. Subsidence of PBM 68 with respect to Hol- lywood E—ll between November 1911 and October 25, 1943 is computed to have been 1.672 ft (app. D, 111.). a. Subsidence at BM “saddle” with respect to Hollywood E—ll between November 1911 and October 25, 1943 accordingly is com- puted to have been: 1.672 ft + 1.6 ft = 3.272 ft. C. Subsidence at the site of PBM 122 since 1950 has exceeded that at BM “saddle” by the following approximate factors: 1950—54; 1.24 (Hayes, 1955, fig. 1) 1954—58; not estimated owing to error in 1954—58 map (Hayes, 1959, fig. 1; DWP filecard for PBM 122) 1958—62; 1.23 (Walley, 1963, fig. 1). 1. The average rate of subsidence of PBM 122 with respect to Hollywood E—ll accordingly has exceeded that at BM “saddle” by the following factor: 1.24 + 1.23 . 2 D. Adoption of the above ratio of subsidence of PBM 122 to subsidence at BM “saddle” permits the following calculation of subsidence of PBM 122 with respect to Hollywood E—ll between November 1911 and October 25, 1943: (1.235) (3.272 ft) = 4.04 ft. E. Alternatively, subsidence at the site of PBM 122 with respect to Hollywood E—ll between November 1911 and October 1943 may be calculated through a direct comparison with subsidence at PBM 68. 1. PBM 68 and PBM 122 subsided with respect to Hollywood E—ll between 1950 and 1958 (PBM 122 was not recovered in 1962) as shown below (DWP filecards for PBM 68 and = 1.235. PBM 122). PBM 68 PBM 122 PBM 68 PBM l2? Time interval Subsidence Time interval Subsidence (inli) Iinfti 41150—9 28 54 (4 yr 5 mo 2‘2 wk) ,, 9 28 54—10 7 58 6 75(L9‘29’54 (4yr3 m0 3 wk) ..__ 9 2954—93068 0.633 1.397 0.885 14 yr 1% wk‘ ,,,,,,, .469 1.372 14 yr! .............. .644 41150—107 58 617x5049f30/58 {8yr6mol ,,,,, 1.102 1.387 18yr3m03wk11." 1.529 2. As shown in the center column above, PBM 68 and PBM 122 subsided at proportionately constant rates during the period 1950—58. Therefore, subsidence of PBM 122/ subsidence of PBM 68 with respect to Hollywood E—ll (including a correction for the minor difference in the increments of time over which subsidence at the two bench marks has been measured) between 1950 and 1958 averaged: 1.529 ft + 0.033 ft 1.102 ft _ 1'417' 3. Adoption of the 1950—58 ratio of subsidence of PBM 122 to subsidence of PBM 68 for the period 1911—43 permits the following calcu- lation of subsidence at the site of PBM 122 with respect to Hollywood E—ll for the period November 1911 to October 25, 1943: (1.417) (1.672 ft) = 2.37 ft. 4. This lower figure for the 1911—43 subsidence at PBM 122 seems to be corroborated through a comparison with the approxi- mate subsidence at PBM 67 between 1910 and 1943. APPENDIX I a. The average rate of subsidence at PBM 122/average rate of subsidence at PBM 67 for the period 1950—58 is calculated to have been approximately 1.200 (DWP filecards for PBM 122 and PBM 67). b. The approximate subsidence at PBM 67 with respect to Hollywood E—ll between June—July 1910 and October 25, 1943 is calculated to have been 1.531 ft (app. G); this figure is almost certainly low, but probably by no more than 0.5 ft. c. Adoption of the 1950—58 ratio of subsidence at PBM 122 to subsidence at PBM 67 permits the following calculation of sub— sidence of PBM 122 with respect to Hollywood E—l 1 between June—July 1910 and October 25, 1943: (1.200) (1.531 ft) = 1.84 ft. II. October 1943—March 1950. A. The average annual rate of subsidence of PBM 122 with respect to Hollywood E—11 for the period June 7, 1950—September 30, 1958, is computed to have been: 1.529 ft/8.308 yr = 0.184 ft/yr (DWP filecard for PBM 122). B. The rate of subsidence of PBM 68, as deter— mined from its subsidence chart (Walley, 1963), for the period 1943—50 was less than that for the period 1950—58 by a factor of 0557/0663 = 0.840. 1. Accordingly, if it is assumed that the rate of subsidence at the site of PBM 122 for the period 1943—50 was diminished by the same factor, the average annual rate of subsid- ence at the site of PBM 122 for the period 1943—50 may be computed as follows: (0.184 ft/yr) (0.840) = 0.155 ft/yr. C. Therefore, subsidence at the site of PBM 122 with respect to Hollywood E—ll between October 1943 and March 1950 is calculated to have been: (6.417 yrs) (0.155 ft/yr) = 0.99 ft. III. March 1950—August 1954. A. Subsidence of PBM 122 with respect to Hol— lywood E—ll for the period June 7, 1950— September 29, 1954, is reported to have been 0.885 ft (DWP filecard for PBM 122). 1. Subsidence of PBM 122 with respect to Hollywood E—ll for the slightly greater period March 1950—August 1954, accord- ingly, is assumed to have been approxi— mately 0.89 ft. IV. August 1954—October 1958. A. Subsidence of PBM 122 with respect to Hol— 119 lywood E—ll for the period September 29, 1954—September 30, 1958, is reported to have been 0.644 ft (DWP filecard for PBM 122). 1. Subsidence of PBM 122 with respect to Hollywood E—11 for the 2-month period August 1, 1954—October 1, 1954 is coma puted to have been: (0.644 ft/4 yr) (1/6 yr) = 0.027 ft. 2. Subsidence of PBM 122 with respect to Hollywood E—11 for the period August 1954—October 1958, accordingly, is calcu- lated to have been: 0.644 ft + 0.027 ft = 0.67 ft. V. October 1958—August 1962. A. PBM 420, located approximately 500 ft west of the site of PBM 122, showed the greatest measured subsidence of any point in the northern Baldwin Hills between 1958 and 1962, during which time it reportedly sub- sided with respect to Hollywood E—11 at an average rate ofO. 143 ft/yr (Walley, 1963, p. 5). 1. Adoption of the average annual rate of subsidence of PBM 420 for the period 1958—62 as the average annual rate of subsidence at the site of PBM 122 for this same period permits the following calcula- tion of subsidence at the site of PBM 122 with respect to Hollywood E—ll for the period October 1958—August 1962: (3.833 yr) (0.143 ft/yr) = 0.55 ft. VI. August 1962—January 1964. A. Subsidence at the site of PBM 122 between 1962 and 1964 is assumed to have continued at the rate that prevailed between 1958 and 1962. 1. Therefore, subsidence at the site of PBM 122 with respect to Hollywood E—ll for the period August 1962—January 1964 is com- puted to have been: (1.417 yr) (0.143 ft/yr) = 0.20 ft. VII. November 1911—January 1964. A. Maximum subsidence at the site of PBM 122 with respect to Hollywood E~11 between November 1911 and January 1964 is calcu— lated to have been approximately: (1) 4.04 or (2) 2.37 .99 .99 .89 .89 .67 .67 .55 .55 .20 .20 7.34 ft 5.67 ft. APPENDIX I Comparative 1910 and 1917 elevations within the area 120 RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA of differential subsidence centering in the northern Baldwin Hills. I. 1910 elevations. A. Elevation control surveys emanating from a City of Inglewood bench mark located at Centinela and Eucalyptus Avenues were established in the northern Baldwin Hills by the Los Angeles Investment Company in June and July of 1910 (prefatory note, app. F). 1. Resultant elevations have been recorded in Los Angeles Investment Company fieldbook 7. 2. Additional 1910 elevations (apparently de- rived from side shots based on the leveling described in LAIC fieldbook 7), measured to the nearest tenth of a foot, were recorded at selected saddles and knolls within the northern Baldwin Hills (LAIC Hill Tract, sheets 1 and 2, October 1910). II. 1917 elevations. A. Elevation control surveys emanating from the previously determined elevation of a topo- graphic saddle within the northern Baldwin Hills (and apparently supplementary to 1911 leveling recorded in DWP fieldbook 1458) were established in the northern Baldwin Hills by the Los Angeles Department of Water and Power in December, 1917 (DWP fieldbook 1579). 1. Resultant elevations have been recorded in Los Angeles Department of Water and Power fieldbook 1579. 2. Additional 1917 elevations (apparently de- rived from side shots based on the leveling described in DWP fieldbook 1579), meas- ured to the nearest tenth of a foot, were recorded at selected saddles and knolls above the BOO—foot contour in the northern Baldwin Hills on Los Angeles Department of Water and Power “topographical field map No. D—1769 dated November, 1911” (Hayes, 1943, p. 15, fig. 6). a. That the indicated elevations are indeed the product of 1917 rather than 1911 leveling derives from the following analysis by Hayes (1943, p. 15): “A minute examina— tion of the topographic field map No. D-1769, dated November 20, 1911 tends to show that the portion of topography mapped above the 300-foot contour eleva- tion was done by a different topographer than that which was mapped below the BOO—foot elevation, and probably at a much later date. The style of mapping 3 along the northeasterly side of the [old Centinela] reservoir site is distinctly different from that of the lower portion. The original pencil numerals, still recog- nizable in the upper portion of the field map, agree precisely with the lettering in fieldbooks containing level circuit and triangulation control surveys conducted at the reservoir site in 1917. It has been assumed, based on convincing evidence, that the reservoir site above the 300-foot elevation was mapped about December 1917.” III. Comparative elevations. A. The only bench mark common to both the 1910 and the 1917 leveling of which we have knowledge, is concrete monument DD (LAIC fieldbook 7, p. 3 and DWP fieldbook 1458, p. 10, 29—see app. F. III; DWP fieldbook 1579, p. 5), or what is now known as PBM 68. 1. Although bench mark "LAI” (fig. 8) was surveyed in connection with the 1917 leveling (DWP fieldbook 1579, p. 4), both earlier and later elevations on the iron pipe extension to which the 1917 leveling has been referred, remain unknown (for exam- ple, DWP fieldbook 2769, p. 63 dated 10/29/43). a. Thus, the 1917 record elevation of the top of a 3-in iron pipe set on a concrete base marked “L.A.I. Co.” has been given as 312.23 ft (DWP fieldbook 1579, p. 4), whereas the 1917 elevation of bench mark LAI read from topographic map D—1769 (Hayes, 1943, fig. 6) was approx— imately 306 ft. The 1917 record (314.24 ft) and contoured elevations of concrete monument DD, on the other hand, agree almost precisely (DWP fieldbook 1579, p. 5; Hayes, 1943, fig. 6). Hence we con- clude: (1) that the 1917 record elevation of LAI was measured on the top of a 3—inch iron pipe that stood an unknown number of feet above the top of the con- crete base; and (2) that the 1917 mea- sured elevation difference between LAI and DD affords a very poor basis for de- termining any differential movements that may have occurred between these identifiable concrete monuments during periods preceding or following 1917. b. Support for the preceding conclusion de- rives from the following analysis: (1.) The 1910 elevation of a temporary APPENDIX I l 2 1 bench mark identified simply as a “2" x 2” hub set 10 ft north of corner N.W., near GG” has been given as 309.302 ft with respect to DD as fixed at 314.015 ft (LAIC fieldbook 7, p. 3; DWP fieldbook 1458, p. 29). It is as- sumed: (1) that the hub was set so as to be no lower than the ground eleva- tion of the identified northwest corner; and (2) that “corner N.W.” is identical with the position of LAI as shown on topographic map D—1769. The second assumption is supported by the following considerations: (a.) A comparison of topographic map D—1769 with Los Angeles Invest- ment Company Hill Tract sheet no. 2, dated October 1910, shows by in- spection that LAI and a corner identified on sheet no. 2 as 117 + 14.6 are almost certainly coinci- dent. (b.) The distance HH—N.W. Corner has been given as 2,286.80 ft by the Los Angeles Investment Company (LAIC Hill Tract calculation work- sheet). The distance HH—LAI mea- sures 2,263 ft on a photostat copy of mpa D—1769 (Hayes, 1943, fig. 6); correction for known distortion of the photostat indicates that this distance would measure 2,273 ft on a stable-base copy. Furthermore, if the bar scale appended in 1943 is read as 1” = 200’ (as seems to have been the intent), the distance HH—LAI measures 2,284 ft on the photostat copy. Hence, “117 + 14.6” is almost certainly identical with “N.W. Corner”; thus LAI and NW. Corner are equally certainly coin- cident. 2. All of the evidence tabulated above indicates that the 1917 elevation of concrete monu- ment LAI as (opposed to the 3-inch iron pipe extension) was probably less than 310 feet and certainly several feet below the record elevation of312.23 ft (with respect to DD as fixed at 314.24 ft). Hence, the 1917 record elevation of LAI is of no value for compara- tive purposes unless it can be shown that any earlier or later elevations of LAI were measured on the top of the same 3-inch pipe alluded to in the 1917 field notes. B. 1910 and 1917 elevation differences between DD and four identifiable knolls or saddles, above the 300-foot contour and within the now-recognized subsidence bowl, may be deduced from the record elevations of DD and elevations recorded or estimated to the nearest tenth of a foot on Los Angeles Investment Company Hill Tract map sheets 1 and 2 (1910) and Los Angeles Department of Water and Power topographic map D—1769 (1917). These four topographic features are located as follows with respect to DD (see Hayes, 1943, fig. 6): (A) 3,105 ft N. 34.8° W. (B) 1,910 ft N. 43.2° W. (C) 2,228 ft N. 15.2° W. (D) 1,740 ft N. 66° W. 1. Record elevations of DD are: a. 1910—314.015 ft (LAIC fieldbook 7, p. 3; DWP fieldbook 1458, p. 29). b. 1917—314.24 ft (DWP fieldbook 1579, p. 5). 2. 1910 elevations of the four identified topo- graphic features read from Los Angeles Investment Company Hill Tract sheets 1 and 2, are as follows: (A) 319.8 ft (estimated) (B) 3271 ft (C) 327.9 ft (D) 331.1 ft. a. Thus, the 1910 elevation difference be— tween DD and the indicated topo- graphic features were: (A) 319.8 ft — 314.015 ft = 5.785 ft (B) 327.1 ft — 314.015 ft = 13.085 ft (C) 327.9 ft - 314.015 ft = 13.885 ft (D) 331.1 ft — 314.015 ft = 19.085 ft. 3. 1917 elevations of the four identified topo- graphic features read from Los Angeles Department of Water and Power topo- graphic map D—1769 (Hayes, 1943, p. 15, fig. 6), are as follows: (A) 320.0 ft (B) 327.2 ft (C) 328.1 ft (D) 333.0 ft. a. Thus, the 1917 elevation differences be- tween DD and the indicated topographic features were: (A) 320.0 ft — 314.24 ft = 5.76 ft (B) 327.2 ft - 314.24 ft = 12.96 ft (C) 328.1 ft — 314.24 ft = 13.86 ft (D) 333.0 ft — 314.24 ft = 18.76 ft. 4. Elevation changes with respect to DD, be— tween 1910 and 1917 at the four identified 122 points were, accordingly: (A) 5.785 ft — 5.760 ft = 0.025 ft (B) 13.085 ft — 12.960 ft = 0.125 ft (C) 13.885 ft — 13.860 ft = 0025 ft (D) 19.085 ft — 18.760 ft = 0.325 ft. a. The only seemingly significant elevation i change that occurred at any of these 3 points between 1910 and 1917 was that at D. However, because this knoll is a very subdued topographic feature (see Hayes, 1943, fig. 6), it is unlikely that precisely ; the same point could have been recovered during successive levelings. Hence, the apparent elevation change recorded at D is probably less meaningful than that measured at the other three points. 5. Elevation changes between 1950 and 1962 l (with respect to DD or PBM 68) at the four identified topographic features (as deduced from pl. 4) averaged: (A) 0.033 ft/yr or 0.231 ft/7 yr (B) 0.044 ft/yr or 0.340 ft/7 yr (C) 0.017 ft/yr or 0.119 ft/7 yr (D) 0.014 ft/yr or 0.098 ft/7 yr. 6. Because even this crude analysis indicates that points A, B, and C underwent relative elevation changes ranging from only 0.025 ft through a maximum of 0.125 ft between 1910 and 1917, yet subsided by at least several times these amounts over compara- ble subsequent periods, it is likely that little, if any, differential subsidence was underway in the northern Baldwin Hills during the period 1910—17. APPENDIX J Calculations of average increase in effective pressure in an unlayered equivalent of the Vickers zone. I. The average change in effective pressure (Ap’) owing to liquid-level decline through the full thickness of an unlayered, decompressd equivalent of the Vickers zone may be calculated by use of a formula modified from Poland and Davis (1969, p. 193—196): Ap’ 2 37(1 —n+nf) (23—21)/2, ‘ where l W = unit weight of the liquid, ‘ n = average porosity of the reservoir sand, nf = liquid retained in pore space, expressed in percent of total volume, , 23 : initial elevation of liquid level, and 21 = final elevation of liquid level. NOTE—The expression derived by Poland and Davis (1969, p. l 193—196) is divided by 2 here because their equation permits ‘ RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA calculation of the increase in effective pressure within the saturated part ofthe column only, whereas our objective is to obtain an average or distributed value over the entire column (that is, one equivalent to a uniformly developed increase over this same column during artesian head decline or general decompression). Incremental values of the average or distributed increase in effective pressure over the entire column may be obtained through: (1) calculations of the average increase in effective pressure attributable to liquid-level decline through a lower part (22 — 21, where 22 = some intermediate elevation between 23 and 21) of the column for pertinent values ofz2, times that fraction of the column through which the drop has been effected (22 — 21 — 23 — 21); and (2) subtraction of (a) successive values of Ap’ ob- tained through the assignment of successively smaller values to 22 plus (b) the sum of successive, previously calculated increments of Ap’ from the total Ap’ calculated from a reduction of the liquid level through the full column height (23 — 21). II. An approximate value for W may be calculated directly by averaging the stock tank density of the pure oil phase (0.9403), deduced from the 1954 API gravity given by Oefelein and Walker (1964, p. 510), with that of the brine (1.023), deduced from the salinity value given by the California Division of Oil and Gas (1961, p. 577), in accordance with the produced-liquid ratio that obtained at the end of the primary or natural depletion stage; this ratio is estimated to have been 185,000,000 bbls (oil)/267,000,000 bbls (brine). Thus the average specific gravity = 0.990 and yf = 0.429. The porosity, n, for the Vickers east zone has been given by Oefelein and Walker (1964, p. 511) as 0.35, but values provided by T. H. McCulloh (written commun., 1966) suggest that 0.30 is a more realistic figure for the zone as a whole. If, as a first approxima- tion, it is accepted that the retained brine—oil ratio is the same as the produced brine-oil ratio, the liquid retained in place (nf) may be calculated in turn from the estimated original oil in place (2067 bbls/acre X 73,500 acre ft = 151,900,000 bbls) in the Vickers east zone and comparison with the estimated production of oil (33,300,000 bbls) through primary or natural depletion (Oefelein and Walker, 1964, p. 511). Thus, inasmuch as about 78.07 percent ofthe oil has been retained in place, 7;,» may be taken as (0.30)(0.7807) = 0.234. The average thickness through which liquid—level decline is considered to have been operative (that is 33 - 21) has been estimated from the lithologic log presented in figure 2 at about 1,650 feet. This figure has been obtained from the summation of all of the sand units contained within the Vickers and In- vestment zones, plus all ofthe shale units 5 ft or less in thickness. The thin shales have been included with the sands because their compac- tive response to a given pressure increase over APPENDIX K time intervals of a year or more is believed to approximate that of the sands. Exclusion of all shale units, however, would decrease this 1,650-foot figure by a maximum ofonly about 10 percent. NOTE—It is assumed here that the in situ oil density has remained unchanged during its production. The relatively low reservoir temperature of 100°F, the very low original solution GOR of 0.09 Mcf/bbl (Oefelein and Walker, 1964, p. 511), and the generally low measured reservoir pressures (figs. 33 and 34) tend to support this assumption. In any case, ifthe reservoir oil underwent any significant increase in density during the productive history ofthe Vickers zone, it probably occurred during the pre-1930 major decompression (and degassing) period. Because this initial period was one in which liquid-level decline could only have just begun, any oil density increase should have been of minimal significance to the model developed here. If, on the other hand, the in situ oil density declined somewhat during depletion, it is doubtful that the analogy drawn here with liquid-level decline in an unconfined water system would be . seriously compromised, for any density drop would operate in the same sense as the liquid-level decline: both would result in a buoyancy ‘ loss and, therefore, an increase in effective pressure. For a given volume of produced oil, however, the magnitudes of this increase might differ. If, for example, n/r—> n or 0, then the production of 50 percent ofthe recoverable fluid accompanied by a 50 percent decline in liquid level would result in a systemic or average increase in effective pressure amounting to 75 percent of that resulting from 100 percent depletion. The production of an equivalent stock tank volume accompanied by a uniformly distributed 50 percent decrease in fluid density would increase the effective pressure by only 50 percent. The produced ratio developed at the end of the primary depletion stage is utilized here because it provides a reasonable index of the average liquid composition over a period during which the liquid may be considered to have declined to its lowest levels. If the volume produced in response to secondary recovery efforts is disregarded, this ratio, together with the volumes ofoil and brine produced and the year during which primary recovery should have ceased, may be estimated from the natural oil depletion to 1954 (26,200,000 bbls) and the estimated ultimate natural recovery (33,300,000 bbls) given by Oefelein and Walker (1964, p. 511) for the east block only. Because 145,000,000 bbls ofoil had been produced from the entire Vickers zone by 1954, and ifit is assumed that 78.5 percent (26,200,000/33,300,000) of the naturally recoverable oil had been produced from the eastern Vickers zone by the end of 1954, natural depletion should have ceased with the production of 185,000,000 bbls of oil. This figure was reached ‘ in 1966 (Conservation Committee ofCalifornia Oil Producers, 1967, p. P), by which time the cumulative net liquid production was roughly 452,000,000 bbls. 1H. Calculations of Ap’ developed through buoyancy loss or liquid-level decline are tabulated in table 10. It is assumed that the decompression stage ended at the beginning of 1930, corres- ponding to the abrupt deceleration in the 1 decline of reservoir pressure (figs. 33 and 34), and that succeeding pressure losses were associated with liquid-level decline. The per— cent liquid-level decline is based on the assumptions: (1) that this decline began in 1930 at the end of the decompression stage, after the production of 68,460,301 bbls of oil 123 and 10,388,340 bbls of water; and (2) that liquid level would have declined 100 percent by the end of the primary or natural depletion stage, which is estimated to have occurred in 1966 with the production of 185,000,000 bbls of oil. APPENDIX K Estimates of compaction of the Vickers zone. I. The most direct approach to the calculation of reservoir compaction has been described by Gilluly and Grant (1949, p. 511—519). These writers have computed "compression moduli” from compression measurements on a series of sand cores taken from the Wilmington field, which they have then used (in conjunction with measured pressure losses and producing sand thicknesses) to calculate the expected compac- tion of the several major Wilmington zones over a specified time interval. The compression mod- ulus (a negative quantity) is conceptually simi- lar to Young’s modulus and is defined as: _ _ P8 —P0, EC (compressmn modulus) :3; Lo where P3 = ultimate stress (in the solid framework), P0 = original stress (in the solid framework), Ls = final length of core, L0 = original length of core; its utilization assumes a linear relation between stress and strain. A. Among the Wilmington test data developed by Gilluly and Grant, those of the Tar-Ranger zone are most reasonably applied to the Vickers zone, for in terms of average depth (2,200—2,500 ft) and average age (late Miocene to early Pliocene) (California Divi- sion of Oil and Gas, 1961, p. 687), the Tar- Ranger more closely matches the Vickers than do any of the other zones considered by Gilluly andGrant (1949, p. 512, 514). Thus, if the average reservoir fluid pressure loss is 790 psi (fig. 34), the cumulative average thickness of the producing sands is 1,650 feet (see app. J), and the most representative compression modulus (Ee) is [—] 146,000 psi (see Gilluly and Grant, 1949, p. 514), the cal— culated change in thickness of the Vickers zone generated in response to a total loss of reservoir pressure is given as 124 TABLE 10.——-Calculations of the average increase in effective pressure a unlayered equivalent of the Vick RECENT SURFACE MOVEMENTS IN THE BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA ttributed to decompression and liquid-level decline through an ers zone of the Inglewood oil field Vickers zone production Percent estimated Reservoir pressure Increase in effective pressure (Ap'l net liquid produced during cumulative Interval Oil lbblsl Water lbblsl Net liquid lbblsl liquid-level decline , . Due to total Apr interval interval interval interval -1‘330' Eg‘f‘iiiggt demfiulfretgsion l‘qduelgfig’e] lpsn cumulative cumulative cumulative cumulative lpsii lpsil (psi! lpsil $3” 9/1924—1/1926 ,,,,,,,,,, 18,377,716 589,993 18,967,709 ,,,,,, 232 ,,,,,, E-fi 18,377,716 589,993 18,967,709 400 558 232 E : 1/1926—1/1930 ,,,,,,,,,,, 50,082,585 9,798,347 59,880,932 ,,,,,, 360 ,,,,,, gfi 68,460,301 10,388,340 78,848,641 142 198 592 1/1930vl/1935 ,,,,,,,,,, 23,870,141 16,857,341 40,727,482 10.91 ,,,,,, 68 92,330,442 27,245,681 119,576,123 1091 108 149 660 1/1935—1/1940 __________ 11,015,445 12,595,442 23,610,887 633 ,,,,,, 36 g)” 103,345,887 39,841,123 143,187,010 17.24 100 139 696 s 1/1940—1/1944 ,,,,,,,,,, 11,456,307 19,608,000 31,064,307 8.33 ,,,,,, 43 a”: 114,802,194 59,449,123 174,251,317 25.57 91 128 739 ,E 1/19441/1950 __________ 17,324,437 51,285,000 68,609,437 18.39 ______ 79 E 132,126,631 110,734,123 242,860,754 43.96 62 86 818 E 1/1950~1/1954 ,,,,,,,,,, 12,956,708 41,770,000 54,726,708 14.67 ,,,,,, 47 3 145,083,339 152,504,123 297,587,462 58.63 42 60 865 i" 1/19541/1958 1111111111 11,989,000 41,295,068 53,284,068 14.28 ,,,,,, 33 79 157,072,339 193,799,191 350,871,530 72.91 ,,,,,,,,,,,, 898 :6" 1/195&1/1962 __________ 11,174,000 26,370,472 37,544,472 10.05 ,,,,,, 14 5 168,246,339 220,169,663 388,416,002 82.96 ,,,,,,,,,,,, 912 1/1962vl/1964 __________ 6,968,000 18,266,024 25,234,024 6.76 ,,,,,, 6 175,214,339 238,435,687 413,650,026 89.72 ____________ 918 1/1964—6/1966 .......... 9,785,661 28,564,313 38,349,974 10.28 ,,,,,, 4 185,000,000 267,000,000 452,000,000 100.00 ,,,,,,,,,,,, 922 L L (PS — Po) (L0) sediments extending 1,850 ft below sea level 0 S _ _Ec (to the approximate center of the Vickers (790) (1650) zone); plus (2) the nearly dry weight of a col- = _(_1 46 000) umn of sediments extending 300 ft above sea ’ . u = 8 93 ft. level (to a height roughly matchlng that of II. A second approach to the calculation of reservoir the average surface elevation 0f the In- compaction stems from modern soil mechanics glewood 011 field). The below sea level pres— and is based on one—dimensional, drained sure 1ncrement may be computed d1rectly consolidation tests. Thus, each of the one or from an express10n presented by Gllhfly and more relatively straight-line segments of a Grant (1949’ p. 502—904) and the overburden standard e-log p curve (fig. 44) is characterized lgcrement derlves dlrectly from conSIdera- by a slope identified as the “compression index” tlons 0f average sedlment dens1ty and poros- (Taylor, 1948, p. 217—218). Taylor (1948, p. 1ty; thus, 286—288) has derived an expression permitting 0.65 x 2,7 x 62.5 x 1850 +035 x 64 x 1850 + calculation of compaction through use of meas- p 2 _ 144 ured comp ress1on indices and other pertinent 0.65 X 2.7 x 62.5 X 300 properties and changes in the system. This expression is given as: 2H _ pu - mil figfi 0.4350, where Pu = total consolidation or settlement, 2H1 = initial thickness, el = initial void ratio, p2 = final average intergranular pressure, p1 = initial average intergranular pressure, CC = compression index. A. The initial reservoir thickness (2H1) of the Vickers zone is again taken as 1,650 ft (app. J). The final average intergranular pressure (p2) may be obtained directly from: (1) the saturated weight of an unbuoyed column of . = 2 ' 144 192 p81 The initial aVerage intergranular pressure (p1) consists simply of the final average intergranular pressure less the initial aver- age reservoir pressure of 790 psi; thus, p1 = 1,922 — 790 = 1,132 psi. The initial void ratio (el) and compression index (Cc) must be read directly from the test results. 1. Because we have no test data from the Inglewood oil field, we have prepared assumed e-logp curves for the Vickers zone based on the results of test data developed for the Wilmington oil field and a Bolivar APPENDIX K 125 0'6 I I I I I I I I I r 1 Bolivar Coast; :21 g-0.366 Wilmington; e1 =0.362 0.5 - _ RECOMPRESSIONAL CURVES \ \ M - - _ ‘ - \ \ 04 — ‘ ‘ ‘ - - - ‘\‘\ . _ ' ‘ - \\ BolIvar Coast - \ / WIImIngton ‘t-o-+Cc=0.032 E BoIIvar Coast CFO-036 E 0.3 - _ Q Wilmington 9 VIRGINAL CURVES 0.2 — Cc=0.237 _ C¢=0.304 0.1 - _ 0,0 I I I I l I I l I I I I 15 100 1000 10,000 PRESSURE, IN POUNDS PER SQUARE INCH FIGURE 53.-—-—Assumed e—log p curves for the Vickers zone of the Inglewood oil field. Values of CC for the Virginal range assumed to match those for “average” 2,000—4,000-foot Wilmington sand and 3,100-foot Bolivar Coast sand. Values of CL. for the recom- pressional range assumed to match unloading portion of e—log p Coast oil field (fig. 53). The initial in situ void ratios at 1,132 psi were in each case derived from a projection of the recompres- sional slope at 15 psi and an average mea- sured (laboratory) void ratio of 0.428 (or porosity of 0.30). Utilization of the recom- pressional parts of the curves, which derive from experimental loading and (or) unload- ing of the samples, should lead to minimum ultimate compaction figures; utilization of the Virginal parts should lead to maximum ultimate compaction figures. B. Acceptance of the above data as representative of the Vickers zone leads to the following extreme values for the ultimate expected compaction of this zone developed in response to a total loss of reservoir fluid pressure: 1. Recompressional compaction: 8.71 ft (Bolivar Coast) 9.80 ft (Wilmington). 2. Virginal compaction: 82.7 ft (Bolivar Coast) 64.6 ft (Wilmington). curve for “average” 2,000—4,000-foot Wilmington sand and av- erage of unloading and reloaded cycles in the 1,000—3,000 psi range for 3,100—foot Bolivar Coast sand. Data from Allen and Mayuga (1970, p. 415) and van der Knaap and van der Vlis (1967, p. 89). C. Alternatively, compaction may be calculated from the same basic data through use of the expression: =3: X H, 1 +e where AH = change in thickness, Ae = change in void ratio between initial and final loads, e = initial in situ void ratio, and H = original thickness. Thus, 1. Recompressional compaction: 7.26 ft (Bolivar Coast) 10.9 ft (Wilmington). 2. Virginal compaction: 84.6 ft (Bolivar Coast) 65.4 ft (Wilmington). 3. Differences between these figures and those calculated from Taylor’s formula are at- tributed to an inherent imprecision in the measurement of Ae (fig. 53). ‘t‘zGPo 691- 496—1976 PROFESSIONAL PAPER 882 IOR UNITED STATES DEPARTMENT OF THE INTER PLATE 1 GEOLOGICAL SURVEY FORMATION OIL LITHOLOGY THICK- PERIOD EPOCH Sp Resis _ NESS, IN DESCRIPTION' AND STAGE ZONE tivity FEET Poorly, interbedded sands, gravels, and conglomerates. Gray to brown, 1 0 yellowish brown and rusty, ill sorted and commonly crossbedded. t° Fine to coarse sands with interbeds of gravel and occasional silt beds to 1 foot. Common iron-oxide staining. Pebbles and cobbles are angular to rounded, consisting mostly of granitic material with some slate and brown shale fragments. Rests unconfcrmably on lnglewood Formation. Well-interbedded sands, silts, and clays. Predominately sand and silt. Varies from light gray to yellowish gray to reddish brown in part. Fine to medium grained with scattered coarse grains. III sorted and dirty. Friable. Occasional iromoxide cementing, and in lower portion occa- sional thin limestone streaks and nodules. San Pedro Inglewood Pleistocene QUATERNARY _7 _ 7 __ 7 _ 7 __ ' ' I I Claystone, grayish blue to gray. Massive with occasional thin lenses of sand and gravel. Fossiliferous. Some carbonaceous material, occa- Upper sional small limestone nodules and limonitic concretions. Sand and Oil Sand, gray to dark brown where oil saturated. Interbedded occasionally with gray to greenish. gray claystone. Sands fine to coarse, becoming locally pebbly. Dirty, ill sorted. Loose and poorly consolidated, crumbly. Massive. Claystones are massive with occa- sional carbonaceous pods and local laminations of sand. Also gener- ally firrn. Sand percentage varies from 10 percent at crest of field to over 50 percent on flanks. Investment Middle Pico Upper Pliocene Lower Interbedded Oil Sand and gray shale with occasional interbeds of sandy shale. Sands fine to medium grained, ill sorted, angular to sub- rounded grains, slightly clayey, dark-brown oil staining. Shale dark gray with micaceous laminations. Firm and tough. Scattered forams throughout, few fossil fragments. Rare high-angle fractures. Occa- sional lime-cemented sandstone streaks to 1 foot. N well bedded. Section approximately 60 percent sands. Vickers Upper Interbedded Oil Sands and gray shales with occasional interbeds of sandy shale and thin lime-cemented sands. Shales occasionally laminated and streaked with fine sand. Sands are fine to locally coarse grained, ill sorted, firm to easily friable. Locally very dirty with abundant carbonaceous fragments. Generally massive. Shales dark gray becoming very sandy and silty with depth. Firm to locally hard and compact. Well bedded with good dips where laminated and streaked with fine sands. Flindge Interbedded Oil Sands and dark-gray siltyto sandy shales. Sands fine to coarse grained with rare gray shale inclusions and irregular lamina- tions. Locally very carbonaceous. Massive except where laminated or thinly interbedded with shale. Flare thin lime-cemented streaks. Shale dark gray and commonly very silty and sandy. Common streaks and inclusions of sand. Hard and compact. Tough. Pliocene Upper Flubel Repetto Lower Interbedded sands, Oil Sands, and dark-gray shales with occasional interbeds of laminated shale, siltstone, and lime-cemented sand- stone. Sands fine to coarse grained with common pebbly streaks. Dirty, ill sorted. Shales dark gray. Locally very sandy and micaceous. Local floods of shell fragments. Irregular streaks and inclusions of hard gray sand. Few steep fracture planes. Local floods of car- bonaceous wood fragments. Hard and compact. Forams. Middle Lower Rubel Interbedded and mottled sands. Oil Sands, shales, and siltstones with occasional thin lime—cemented streaks. Bedding poor to good with common mottling. Sands fine to coarse, hard,dirty, ill sorted.quarlz- ose. Shales dark gray, hard, micaceous, with local floods of shell fragments. Occasional thin fine sand streaks and irregular paper-thin laminae. Few steep slickensided fracture surfaces. Section generally tight and predominately shaly, particularly in lower 200 feet. Upper Moynier Sandstone and Oil Sand interbedded with Siltstone, shale, and lime- cemented sandstone strea ks. Occasional thinly laminated shales and Siltstones. Sands are gray to dark brown depending on oil saturation, very fine and silty to fine grained near top grading locally to medium grained toward bottom. Scattered ferro-mags and feldspar grains. Clayey in part. Dirty, ill sorted. Generally massive except where crossbedded. Firm but friable, hard where lime cemented. Siltstone and shale dark gray, hard, slightly calcareous, micaceous, with scat- tered forams. Occasionally well bedded but generally massive ap- pearing. Up to 30 feet thick. Rare thin bentonite beds and streaks. Lower Lower Moynier TERTIARY Shale and sandy shale, dark grayish brown. Locally interbedded and laminated with fine-grained sand and silts. Earthy texture. Generally massive except where bedded. Common slickensided fracture sur- faces at high angles and parallel to bedding planes. Local pods and irregular lenses of hard micaceous sand. Shale is hard, massive, and micro micaceous. Delmontian Laminated shale, locally thinly interbedded with siltsfone and sand- stone. Laminae composed of fine sands and silts. Shale dark brown, occasionally mottled, micaceous. Rare, massive limestone streaks. Forams. Common high-angle fractures. Sands generally less than 1 foot, massive, firm to difficultly friable, appear tight, moderately well sorted, fine grained. Bradna Upper Miocene Puente Sandstone, gray, fine to medium grained with local floods of coarse grains. Quanzose, with minor mica. Grains subangular to sub- rounded. Fair to ill sorted. Dirty. Tight appearing. Massive. Haird. City of lnglewood Mohnian Nodular shale, dark brown to black with numerous light-tan to buff phosphatic nodules. Punky. Local floods of forams. Flare streaks of bentonite. Abundant bituminous matter throughout. Fissile, hard. Nodular shale Sandstone, interbedded with Siltstone, shale, and rare basalt streaks. 200 Sands fine to coarse. arkosic, scattered ferro—mags. Poorly sorted, to dirty, massive, hard to locally well cemented. Igneous material light 700 gray to black (porphyritic). Siltstones and shales dark brown to black, fissile, hard. Appear cherty. Occasional thin tuff beds. Sentous Luisian Interbedded massive sandstones, conglomerates. and dark brown to black shales; includes numerous intrusive and extrusive volcanic rocks. Mostly calcic andesite flows, tufts, and breccias with occa— sional diabase and andesite sills and dikes. Sands vary from fine to 1500+ coarse grained with local grit floods. Common carbonaceous material and calcite-filled veins. All hard and dense. Middle Miocene Topanga Flelizian Deepest penetration in field approximately 1,500 stratigraphic feet into Relizian sediments and volcanics in 3.0. Co. Baldwin Cienega No. 105. Thickness of section below this point and depth to basement ? unknown. ‘Descriptions of rock units are presented as furnished by Standard Oil Company of California and have not been edited to conform to US. Geological Survey standards or nomenclature. Composite log drawn at scale of 1 inch = 400 feet using type sections from S. 0. Co. wells Vickers 1- 41 ,1—63,2—1 2, 2 —18,2—28, Bradna No.3 , Baldwin Cienega No. 105, and L. A. l. 1—88. Permission to publish granted by Standard Oil Company of California, February 1966. UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY 118°35’ 30’ 25’ | l l O O SANTA MONICA MOUNTAINS Q \X\\\ \\ o \\ <90 ~ O (8) 8%) PROFESSIONAL PAPER 882 PLATE 3 EXPLANATION EARTHQUAKE EPICENTERS OOOOQ 1—1.9 2—2.9 3—3.9 4-4.9 5—5.9 Magnitude scale Q "A Class B Class C Cl Specially investigated Location probably accurate Location probably accurate within 3 miles within 10 miles Quality of location NOTE: Epicenters located to nearest minute of latitude and longitude. Where more than one epicenter is given for same position, additional epicenters are offset slightly from in- strumental location. On this map such a situation can be inferred from overlapping of circles representing epicenters. For locally intense concentrations of a given type, total number of epicenters represented by number contained within circle 118°35’ 30’ 25’ Base from US. Geological Survey 1:250,000 Los Angeles, 1959; San Bemardino, 1958; Long Beach, 1957; Santa Ana, 1959 7 KILOMETRES 34°00’ O — 33°25’ l l | 50’ 45’ 117°40’ Compiled from records of the Seismological Laboratory, California Institute of Technology, as tabulated by C. F. Richter, C. R. Allen, J. M. Nordquist, and P. St. Amand MAP OF THE EARTHQUAKE EPICENTERS IN THE LOS ANGELES BASIN AREA, CALIFORNIA, JANUARY 1, 1934, TO MARCH 31, 1963 PROFESSIONAL PAPER 882 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PLATE 4 1 18°22'30" 1 18°22’30" I I a I I V I O O EXPLANATION EXPLANATION —0.06 —0.06 Isobase line Isobase line Showing average annual elevation change, Showing average annual elevation change, in feet. Contour interval 0.01 foot per m feetDashed in areas of poor control. RODEO RD year RD Contour Interval 0.01 fgot per year . U \ ' o o . ’ o . I . :.___\ +9— H ~e—e—UH \ . . Bench mark \ Earth crack \ 0 Dashed where approximately located. \ '00 ’ U, upthrown side; D, downthrown side \ A A’ \ \ Line of profile showing horizontal \ . . strain and horizontal displacement . 0 See figures 16 and 45 ° \ / . . \¢(o Bench mark “I; ‘2: O o O I \ . . \ O \ o \ \ - AHoIIywood E—11 . \ O O O . O ‘2? "1' \0. \0 LAI ' \o "7 ‘75 \ .76‘ (g: 0 \0 ‘75 \0 >2) STOCKER 8T STOCKER ST . ’6’ 3 0.,9 \ \ $3 0 PBM 122 0 ~02 (’3 ° r <2? (v ‘1‘ —0.19 \ I i? % . PBM 71 . o . Q ' . PBM 71 0' 76’ '7 . / / _ ,,,,, _ 34000' e , __ \0 ® \ ...- 34900' 400‘ _. 34 0° 4'? A PBM 67 e . . 3 \O,’ \ . 6‘ \ \ ‘0. ,5 . STOC R 87 I o PBM 68 \ ‘0, 7 3 Y \ \o. 72 \ \ \ \ \ \ ‘009 \0. 77 \ \ \ \ \00 \ \ —0.10 . - 8 \ \0' 7 \ \ \ \ o —o.11 . \ \ \ ‘0 07 ... _/ 0 \ BM 4 ' w —v’ 009 1’ S? ' \ \ \ \ \ \ 3701 \0 \ ' 6‘ m \ \ —0 06 * _._—— 2 .08 BM M4 2Q 5) \\ \ . “ —« (3’3 \ b 0‘07 \\ o E \ \ \\\_0'05—__‘__________—- S \0-06‘ . ’9 O \ \ ___ cu \ \ —— —0.04 _ / ”I s . \ '5 \004 ’ D \ \ \ ,- .— V \ —o.03 v ——-— T"’ 11 —0.02 o b o ‘0.01 b ‘ . % 5 I . SLAUSON , SLAUSON AVE , AVE 4 m o o “T” / ° \ I , ... g \a; S as \m 52’ :n q ‘33 T F T § 3, 1000 0 1000 FEET g 1000 1| . . I) r1000 EE < l I I I I I I u m I I I I I \I i \ 250 o 250 METRES 5?, 250 o 250 METRES fl) \ a; I I I I 11502230" - - “802930" Modified from Hayes (1959, fig. 1). Elevation changes measured iggmcflgygilgifffiafifi.III)6IEII\eV\(/)z(i)t(1iogcll11angcs measured wuh with respect to bench mark Hollywood 13—1 1; Isobase configura- tion based on approximately twice as many bench marks as were AVERAGE ANNUAL ELEVATION CHANGES, 1950 - 54 available for the per10d1950-54(see map at left) DISTRIBUTION OF EARTH CRACKS AS OF 1958, AND AVERAGE ANNUAL ELEVATION CHANGES, 1954—58 1 18°22'30” 1 18°22'30” I . . l O O EXPLANATION — —0.06 —— . EXPLANATION Isobase line \ —0 06 \ Showing average annual elevation change, I ' \ in feet, Contour interval 0.01 foot per Isobase line year / . RODEO_ RD . 1. Showing average annual elevation change, \ ‘ RODEO RD 1 1 64 ft - _ o ' _ ' - . in feet. Contour interval 0.01 foot 9 . 'r W per year \ I Horizontal movement vector 1 1.64 ft Measurement interval shown in paren- ( 936—61) theses Horizontal movement vector D Measurement interval shown in paren- -e—e— H eve—e— thesis Earth crack 9—9 H —eP—9—e- Dashed where approximately located. U, up- U thrown Slde,‘ D. do wn thro wn szde 0 Earth crack . o 0 Dashed where approximately located. . \ U, upthrown side; D, downthrown side Bend" mark .\ O ( \ Bench mark \ . Hollywood E—1 1A 0 O 0 ° I i O . . O ' \ 0 . i o . \Qo 06‘ 0‘ o . i i . . g: . . O Y O V LAI ' 51" (Baldwin Aux.) Q7 ’ STOCKER ST 0 ‘ o 0 STOCKER ST . 737.7 ‘\. PBM 31 000 3 I . . G (Baldwm Aux.) . a. ‘ “ o if -<'» <2» 9 O ' ‘4, ‘0 . o B . U D . o elV O . v 3400' r, , ”- o ..... _ 34600' 34°00‘ ... a " 34 00 0 xi u 0 \ ., .. . \ 8T0 R 87' " n _1) \ ‘ n \ . .. 0 . 0 1 0 ~ " " -<"9 ’0- ' ‘ (,9 ‘99 0 ' ' 79 I? ‘ 6‘7 a .. \ ~0-75 «I u " o 4 I . (Inglewood E—1) ,0.‘ 0 +0.01 é? 012 a: 2 ’ ' 2 $ 0 11 (i) > ’ ' )> E 0.10 § 09 E /O' E E): 0.0% D / 0-01 ‘ / 6 > fig >< 6 0 )> /0‘ o . < O SLAUSON §LAUSON . _ . ‘ . , . AVE ... _ . _ a O. ' (’—' \ (__ O O . O (>3 . o . ° ./ g o ' ° El 51 < o 3 1000 o 1000 FEET S o 1000 FEET Lil Q'.‘ I I. . I ' I I I 3 .1 l I J \J a? / Q 250 o 250 METRES é o 250 METRES I2 99 \\ <0 \ ' I I “822130" Elevation changes from Walley (1963, fig. 1); measured with re- 11802280” Elevation changes calculated forgesricéds “$193ng r031 t?" I“; 30 e spect to bench mark Hollywood 13—1 1. Isobase configuration zearsfi mealiu'rred Iivghlrgezsgescgntgedré (sgzsteiny b :19; de 01: d221, y based on approximately 50 percent more bench marks than were enc 'lmdall) Ll 3A 1 C t D‘ t fC : t En ineer available for the perlod 1954—58 (see map, above right). Horlzon- 3316111; Hafiz: tall: :Semthrtlsyfyro 13113116: AnZEIIesyCougn ty (Sin-gt locations from City Of Los Angeles Bureau Of Engineering, 53311121123281???tizrfiitgegfsgggurgzfifl)gastfiigfgesoumes Dept. oi County Engineer (1961b); Alexander (1962); Calif. Pramagte map used by Dfepartrnent Of Water and (1964 pl. 16); measured with respeci to base line east of the Dept. Water Resources (1964, pl. 16); measured with respect ower or presentation 0 evehng data Baldwin Hills to base line east of the Baldwin Hills E'STR'BUT'ON OF EARTH CRACKS AS OF 1962’ AVERAGE ANNUAL ELEVAT'ON CHANGES 1958' 52’ DISTRIBUTION OF EARTH CRACKS AND AVERAGE ANNUAL ELEVATION CHANGES AS OF JUNE 1961, AND HORIZONTAL MOVEMENTS DU RING VARIOUS PERIODS, 1934—63 AND HORIZONTAL MOVEMENTS FOR VARIOUS PERIODS, 1934—63 MAPS OF THE NORTHERN BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA, SHOWING APPROXIMATE PATTERN OF AVERAGE ANNUAL ELEVATION CHANGES, HORIZONTAL MOVEMENTS, AND DISTRIBUTION OF EARTH CRACKS DURING VARIOUS PERIODS, 1934—63 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY \77;\ Q BaIdIivin-Cienega 27 PROFESSIONAL PAPER 882 PLATE 2 118°22’30" EXPLANATION Structural features shown in red based on observations of G.B. Moody, Stande Oil Company of California; \\ D. H. Hamilton; and personnel of the Los Angeles \\\ Department of Water and Power and California De- ‘\\ partment of Water Resources \ \ \\ I 70 \\ ———— \\\ Fault, showing dip \ ‘\\ Dashed where approximately located \\\\ _ ——————————— \\\ Inferred or hypothetical fault \ \ \\\ ll u \ \\\ \\\ Earth crack RODEO RD \\ Dashed where approximately located. U, upthrown side; \ ‘ \ D, downthrown side / ’ \ ‘ s5 \ I L “ \\\ Strike and dip of joint \ \x 55 / ‘ \ ——I— / I ‘\ Strike of vertical joint \ / l‘ \ \‘x 80 ‘| I 70 y/ I \ ‘x\ ._L ‘ l i / ‘\ \ Strike and dip of small fault \ I x \ . I i / ‘I O ‘I | / / ‘I \ Oil well / \ \ x ‘I l I / \ \\ ‘ \ \ I. II / I \ . Q” I V ‘ \ \ Injector well | / \ \ \x \ I I / \‘ \\ ~\\\ \ 6‘ I I / ‘ t \ “\ 255325-28" I \ /XIII \ g .1954 ~ i l/ \ i l’ \/\\‘~\\ Pilot waterflood \ 12 s l 7 \ I 46 / \ x I \ g \ \ I I \ I / \\ I / \I m \ \ T‘ \ \ 9 I { f]. \ I y \ l \ . x... \\ \ //XI 53' \\ \ LIT/“A \\\ \\ \“ _/ / \\\ \\ “ 537/ $ I, // \\ Q \ ‘x A 70“. \ ‘ 76 I / / x {8/ \ \\ I, “ L I x \ ~ \\ \ ,’ ‘I \E Area of l // l \\ \\ \\ I/ II \\\:\ figure 27 I’ u [/ \\\ \ K\ I, I r / \\ 45 y |‘ \ / D U / \\ [I 86 || \ ‘ ll 5X ‘1 X / \ I \ \ [I It \ I \ I \ , l: \\ I, \\ I I ’i \ II \ i \ I \ {70 3h \ \ l V\ I? \ \ I /I \ 734 x \ l I \ \\ ' I \ \ I + \ I I \ ‘ I I I I I _..§I.. 34000 ”A » 34°OO’ / /’/ // \ I. " 'I " x”/ / u I, II ’ $0“ U . ,, /’/ r \ \ ’/ l I“ z / O 73A x’ O / O\ x/ I: // Stocker 5 O\ ,x’ m / O /’ (21:7 / e // E ’/ ED 2 D 33 3% b x >- < m SLAUSON AVE t... ‘t M £3 \l 02) <( E 1000 0 1000 FEET I I I l I \J I I ' ' I I 0:. 250 0 250 METRES % I 118°22’30” Street locations from City of Los Angeles Bureau of Engineering, drainage map used by Department of Water and Power for presentation of leveling data Based chiefly on surface mapping by R. 0. Castle, 1958—59 (Castle, 1960) Structural features shown in red based on observations of G. B. Moody, Standard Oil Company of California; D. H. Hamilton; and personnel of the Los Angeles FAULTS, JOINTS, AND EARTH CRACKS IN THE NORTHERN BALDWIN HILLS, LOS ANGELES COUNTY, CALIFORNIA, AS OF FEBRUARY 1964 [’0 v. 3 DISCRIMINATION OF ROCK TYPES AND ALTEIRED AREAS IN NEVADA BY THE USE OF ERTS IMAGES PREPARED IN COOPERATION WITH THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION \/ GEOLOGICAL SURVEY PROFESSIONAL PAPER 883 DISCRIMINATION OF ROCK TYPES AND DETECTION OF HYDROTHERMALLY ALTERED AREAS IN SOUTH-CENTRAL NEVADA BY THE USE OF COMPUTER-ENHANCED ERTS IMAGES By LAWRENCE C. ROWAN, PAMELA H. VVETLAU FER, ALEXANDER F. H. GOETZ, FRED C. BILLINGSLEY, and JOHN H. STEWART GEOLOGICAL SURVEY PROFESSIONAL PAPER 883 Prepared in cooperation with the National Aeronautics and Space Administration A detailed description of the development and application of a remote-sensing technique for geologic exploration UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1974 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director For sale by the Superintendent of Documents, US. Government Priming Ofiice Washington, DC. 20402 A Price $155 Stock Number 2401—02544 CONTENTS Page Abstract ________________________________________________________________ 1 Introduction _____________________________________________________________ 1 ERTS—1 Multispectral Scanner _______________________________________ 2 Visible and near-infrared reflectance of rocks and minerals ______________ 2 Acknowledgments ____________________________________________________ 4 Computer image enhancement _____________________________________________ 4 Digital methods _______________________________________________________ 5 Geometric corrections ________________________________________________ 6 Contrast stretching ___________________________________________________ 6 Atmospheric effects __________________________________________________ 6 Ratioing ____________________________________________________________ 6 Display products ____________________________________________________ 7 Geology of the study area _________________________________________________ 7 Rock units __________________________________________________________ 7 Geology of the Goldfield mining district _________________________________ 9 Structural geology ___________________________________________________ 12 Geologic interpretation of images _________________________________________ 15 Standard MSS images ________________________________________________ 15 Stretched MSS images _______________________________________________ 17 Color-infrared composites _____________________________________________ 17 Stretched-ratio images ___________________________ .- ___________________ 19 Color-ratio composites ____________________________ {_ ___________________ 21 Analysis of color-ratio composite __________________ ‘._ ___________________ 21 Discussion ___________________________-__________; ___________________ 29 Summary and conclusions _____________________________ if __________________ 33 References cited __________..____.._______________..___31 _________________ 34 ILLUSTRATIONS Page FIGURE 1. Diagram showing multisp‘ectral scanner ground-scan pattern _____ 2 2. Graphs showing visible and near—infrared reflectance spectra for selected mafic and felsic rocks _______________________________ 3 3. Flow diagram showing sequence of steps used in processing comi- puter-compatible tapes and the five image products generated _- 5 4. Schematic histogram showing contrast stretching of digital numbers for a typical ERTS MSS scene ______________________________ 6 5 ERTS mosaic of Nevada showing locatiOn of study area _________ 8 6. Geologic map of study area ___________________________________ 10 7. Map showing areas of alteration in the Goldfield mining district _- 12 8. Color aerial photograph of part of the Goldfield mining district __- 13 9. NASA Skylab color photograph of part of study area ___________ 14 10. Standard unenhanced ERTS MSS images of study area __________ 16 11. Standard ERTS MSS image of study area for band 7 ___________ 18 12. Map showing major mining districts in study area ______________ 19 13. Linearly stretched ERTS MSS images of study area ____________ 20 14. Linearly stretched ERTS MSS band 7imageof study area _______ 22 15. Color-infrared composite of study area _________________________ 23 16. Linearly stretched-ratio ERTS MSS images of study area ________ 24 17. Color-ratio composite of south-central Nevada __________________ 26 18. Maps showing distribution of anomalous color patterns represent— ing altered outcrops in the study area. Inset is alteration map of Goldfield district ___________________________________________ 30 19. Map showing major mining districts in study area ______________ 31 20. Graph showing reflectance spectra for alteration minerals ________ 32 III IV CONTENTS TABLE Page TABLE 1. Ratios calculated for MSS bands for selected mafic and felsic rocks and alteration minerals ______________________________________ 29 DISCRIMINATION OF ROCK TYPES AND DETECTION OF HYDROTHERMALLY ALTERED AREAS IN SOUTH-CENTRAL NEVADA BY THE USE OF COMPUTER-ENHANCED ERTS IMAGES By LAWRENCE C. ROWAN, PAMELA H. WETLAUFER, ALEXANDER F. H. GOETz 1, FRED C. BILLINGSLEYl, and JOHN H. STEWART ABSTRACT A combination of digital computer processing and color compositing of ERTS Multispectral Scanner (MSS) images has been used to detect and map hydrothermally altered areas and to discriminate most major rock types in south- central Nevada. The technique is based on enhancement of subtle visible and near-infrared reflectivity differences asso— ciated with variations in bulk comp0sition. MSS spectral bands are ratioed, picture element by picture element, by computer and are subsequently contrast stretched to enhance the spectral differences. These stretched-ratio values are used to produce a new black-and-white image which shows the subtle spectral-reflectivity differences and concurrently minimizes radiance variations due to albedo and topography. Additional enhancement is achieved by preparing color com- posites of two or more stretched-ratio images. Color varia- tions seen in these color-ratio composites represent spectral- reflectance differences. The choice of MSS bands for ratioing depends on the spectral-reflectance properties of the surface materials to be discriminated. For south-central Nevada, the most effective color-ratio composite for discriminating between altered and unaltered areas and among the regional rock units was pre- pared using the following color and stretched-ratio image combination: blue for MSS 4/5, yellow for MSS 5/6, and magenta for MSS 6/7. In this composite, mafic rocks, mainly basalt and andesite, are white whereas felsic extrusive and intrusive rocks are pink. The felsic rocks are especially nota- ble because they have a large intrinsic albedo range, which commonly prevents their discrimination from mafic rocks in other types of images and photographs. Altered areas are represented by green to dark-green and brown to red-brown patterns in the color-ratio composite. Except for two areas, the green areas represent hydrother- mally altered, commonly limonitic rocks. The dark-green, brown, and red-brown patterns are less prevalent. Dark- green areas are limonitic and limonite-free altered rocks. Areas that are brown in the color-ratio composite have been studied in less detail, but they appear to be predominantly light-colored hydrothermally altered volcanic rocks. The red- brown pattern represents limonite-free, silica-rich light- colored volcanic rocks that have conspicuous alteration in two areas and questionable alteration in two other areas. Altered outcrops mapped from the color-ratio composite 1Jet Propulsion Laboratory, California Institute of Technology, Pasa- dena, Calif. show a pronounced coincidence with known mining areas. In the Goldfield mining district, the most productive in the study area, the degree of agreement between the green pat- terns and the previously mapped alteration zone is striking. These altered areas are not apparent on the individual MSS images, color-infrared composites, or color photographs ob- tained from NASA’s Skylab. Therefore the technique used in this study appears to have important applications in mineral-resources exploration and regional geologic map- ping. Future research should focus on refinement of this technique, especially on defining more clearly the relation- ships between visible and near-infrared spectral reflectivity and mineralogical composition and on testing the technique in a variety of geologic settings and environmental conditions. INTRODUCTION The first Earth Resources Technology Satellite (ERTS—1) provides an important new tool for geo— logic exploration in the form of small-scale multi- spectral visible and near-infrared images. These im- ages, which show large areas under nearly constant lighting conditions, already have been applied to a wide variety of geologic problems ranging from de- tection and delineation of fault zones and volcanic centers to studies of coastal erosion and sediment transport. Most applications, however, have relied mainly on photointerpretation of these synoptic views rather than on multispectral-reflectance analy- sis. Regional morphologic features are commonly quite conspicuous, but visible and near-infrared spectral-reflectance differences among rocks are usu- ally small and therefore not readily apparent through visual examination of the images. A technique which combines digital computer processing and color compositing has been devised for enhancing subtle spectral-reflectivity differences. This technique has been applied to part of an ERTS—1 image of south-central Nevada with em- , phasis on the Goldfield mining district. Analysis has I focused on discrimination of the geologic materials, 1 2 DISCRIMINATION 0F ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES especially in mineralized areas, on the basis of visi- ble and near-infrared spectral-reflectivity differ- ences. This report presents the geologic interpreta- tion and evaluation of the resulting processed images. Brief descriptions are given of the ERTS-1 mission profile and imaging subsystem, the general nature of the visible and near-infrared spectral reflectivity of rocks, and the techniques used. ERTS—l MULTISPECTRAL SCANNER ERTS—1 was launched by the US. National Aero- nautics and Space Administration (NASA) on July 3, 1972, and is stabilized in a near-polar orbit ap- proximately 907 km above the earth. The satellite contains two imaging systems, the Multispectral Scanner (MSS) and the Return Beam Vidicon (RBV), which record reflected visible and near— infrared radiation. A third system, the Data Collec- tion System (DCS), receives and relays data from earth—based monitoring instruments. The sun-syn- chronous orbit allows 14 orbits each day and cover- age of the same area every 18 days at the same local solar time, which is 0942 hours at the equator. Data for North America, Hawaii, and Iceland are transmitted directly to the nearest of three NASA receiving stations—Greenbelt, Md., Goldstone, Calif, and Fairbanks, Alaska. Images of selected areas be- yond the reception capability of these stations are recorded on tape and transmitted at a later time, but tape-recorder malfunctions have limited the coverage of such areas. Although the RBV was turned off in August 1972 after an electronic malfunction, the MSS has re- corded thousands of images that have high spatial resolution and radiometric fidelity. Solar energy re- flected from the Earth’s surface is measured in four spatially registered spectral bands through the same . optical system. Band Wavelength. um MSS 4 _______________________________ 0.5—0.6 MSS 5 _______________________________ .6- .7 MSS 6 _______________________________ .7—— .8 MSS 7 _______________________________ .8—1.1 The analog electronic signal, along with internal calibration measurements, is transmitted to the ground where it is digitized and formatted into a digital data stream. Geometric and radiometric cali- bration is achieved in a ground-based digital com- puter. The MSS scans cross-track (west to east) swaths 185 km wide, imaging six scan lines across in each of the four spectral bands simultaneously (fig. 1). This scanning provides continuous coverage along each orbital track. The data are converted to pic- MSS OPTICS Scan mirror(oscillates 6 Detectors nominally :2.88°) per band (24 total) —; Note: Active scan is west to east 6 Lines per scan per band % Path of spacecraft travel FIGURE 1.—Multispectral Scanner ground-scan pattern. Schematic diagram shows the relations between space- craft attitude and image geometry (U.S. Natl. Aeronau- tics and Space Admin., Goddard Space Flight Center, 1971). torial images and are framed at the Goddard Space Flight Center, Greenbelt, Md., with a 10-percent forward-lap between adjacent scenes. Side-lap de- pends on latitudinal position; it ranges from about 14 percent at the equator to 50 percent at lat 54° N. or S. Each frame covers approximately 34,200 sq km. Spatial resolution for the images averages about 80 m but is appreciably higher for high-contrast linear features. VISIBLE AND NEAR-INFRARED REFLECTANCE OF ROCKS AND MINERALS Our understanding of the relationships between mineralogical composition and visible and near— infrared spectral reflectivity is based mainly on published laboratory measurements (Hunt and Salis- bury, 1970; Ross and others, 1969; Hunt and others, 1971a,b; 1973a,b; 1974a,b). All these measurements were made on crushed, homogeneous, and generally unaltered samples. Although application of these data to analysis of MSS images of large geologically complex areas is made difficult by several factors, especially scale differences and surface—state condi- tions, the laboratory data do provide a framework for initial investigations. Analysis of these laboratory spectra show that electronic transitions in constituent metal ions result REIFLEICTANCE 0F ROCKS AND MINERALS 3 in broad optical absorption bands in the ultra-violet, visible and near-infrared wavelengths. For example, iron, the most common transitional metal ion, has conspicuous ferrous and ferric absorption bands centered at about 1.0 and 0.92 am, respectively, and several closely spaced weaker bands between 0.40 and 0.55 am (Hunt and Salisbury, 1970). Other transitional metal ions that give rise to absorption bands include copper, titanium, chromium, and man- ganese (Hunt and others, 1971a,,b). Absorption bands due to vibrational processes in water and hy- droxyl molecules also occur in the near-infrared wavelengths, but the only one of these bands within the response range of the MSS is centered at about 0.95 pm. Absorption bands are commonly quite intense and therefore result in conspicuous reflectance minima, predominantly in ferromagnesian and hydrous min- eral spectra. Diagnostic individual spectral features, however, are generally subdued beyond recognition by addition of anhydrous nonferrous minerals such as quartz and feldspar to form polymineralic rocks. The shape of rock spectra are nonetheless still af- fected by the absorption bands. For example, the reflectance of mafic and ultramafic rocks changes very little between 0.4 and 1.1 ,um (fig. 23). In con- trast, felsic-rock reflectance, which is generally af- fected less by absorption bands, increases continu- ously throughout this range, although at a slower rate between 0.70 and 1.1 gm than at shorter wave- lengths (fig. 2A). The slopes of reflectance curves for rocks with intermediate composition are typi- cally between those of felsic and mafic rocks (Ross and others, 1969). As we will discuss later, the spectra for unaltered rocks (fig. 2) and altered rocks generally have significantly different shapes. Differences in spectral shape can be used to dis- tinguish among geologic materials and, in some cases, to place general bounds on their bulk compo- sition. Several factors—including impurities both in the crystal lattice and on the surface of the rocks, atmospheric conditions, and system calibration— oomplicate both of these efforts. Sur‘ficial weather- ing products such as limonite and clay minerals are especially important as they obscure the original rock surface. The characteristic spectral shapes for the rock (and soil) units can be derived from the MSS data to provide the basis for compositional estimates, al- though spectral details are somewhat subdued by the breadth of the MSS bands, especially band 7. Un- known atmospheric efl'ects and system-calibration complications preclude obtaining absolute spectral reflectivities at this time. The field spectral measure- 50 I I I I I I I ,_ 50 — Z LIJ o E 40 — D. E LIJ 30— o E ’— o 20 — _ LIJ _l L LIJ “ 10 — - O I I I I I I I 0.5 0.6 0.7 0.8 0.9 1.0 1.1 WAVELENGTH, IN MICROMETERS A 60 I I I I I I I ,_ 50 — _ Z LIJ 8 m 40 — _ Q. E ui 30 — ._ o z \ Iit "“ ‘\_ 15 8 20 — -\—’\_—_ 9 _ E’ f x s LLI 0: 10 — _. 13 0 I I I I I I I 0.5 0.6 0.7 0.3 0.9 1.0 1.1 WAVELENGTH, IN MICROMETERS B FIGURE 2.—Visible and near-infrared reflectance spectra. Spectra of samples with grain sizes in the 420- to 500mm range (modified frOm Ross and others, 1969). A, Selected , felsic rocks, rhyolite (12), granite (14), rhyolite (4), granodiorite (2), showing increasing reflectance. B, Se- lected mafic rocks, serpentinite (15), gabbro (9), peri- dotite (8), and basalt (13), showing overall decreasing reflectance. Dashed line where inferred. ments needed for absolute MSS calibration are pres- ently being made, although adequate data are not yet available. On the other hand, absolute calibration is not required for simple discrimination that depends mainly on relative reflectance differences among rock types. Rock (and soil) units can be distin- guished on the basis of very subtle reflectance difier- ences, even though the absolute spectral reflectivities 4 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES and gross lithologies cannot yet be determined from the MSS data. ACKNOWLEDGMENTS This study was supported by the US. National Aeronautics and Space Administration under con- tract No. S—70243—AG to the U.S. Geological Survey and Contract No. NA57—100 to the Jet Propulsion Laboratory, California Institute of Technology. Sev- eral colleagues made many useful suggestions during the course of this study, and we are especially grate- ful to Kenneth Watson, Terry Offield, and Allan Kover of the US. Geological Survey, who reviewed the manuscript. Alan Gillespie, Jet Propulsion Lab- oratory, did most of the computer processing. Allan Kover developed the diazo processing technique used in preparing the color-ratio composites. COMPUTER IMAGE ENHANCEMENT Development of image-processing techniques has been greatly stimulated during the last 10 years by the widespread use of imaging devices in planetary and, more recently, terrestrial remote sensing. En- hancement techniques now range from the relatively simple single-band contrast enhancement to two- dimensional filtering in spatial or Fourier domain to complex cluster analysis, sometimes coupled with ratioing of spectral bands. The picture data can be taken from film images by scanning densitometry or, as in the case of the ERTS MSS, taken directly from computer~compatible tap-es (CCT). Taperecorded digital data are prefer- able because on film accuracy is lost in recording radiometric information and is further degraded by duplication, and scanning introduces additional noise into the signal. Other advantages of using the tapes for analysis include considerable analytical flexibil- ity, reproducible results, and relatively reasonable costs. Film methods were used in one of the earliest successful attempts (Whitaker, 1965) to discrimi- nate rock units on lunar photographs on the basis of spectral reflectivity. In the apparently uniform rego- lith of Mare Imbrium, two basaltic lava flows were distinguished in a black-and-white composite pro— duced by masking blue and infrared wavelength telescopic photographs. Using a similar approach, but manipulating digitized multiband telescopic photo- graphs in the computer, a method was devised for analyzing Apollo orbital multiband photographs (Billingsley and others, 1970; Goetz and others, 1971). An extension of this technique, using a pho- tographic ratio method, was developed by Yost, An- derson, and Goetz (1973). During this same general period, Vincent and Thomson (1972) were ratioing thermal—infrared spectral images to detect emissivity variations related to chemical and mineralogical dif- ferences. These results, along with the evaluation of laboratory spectra described in the previous section, made clear the considerable potential of ratioing for multispectral analysis of ERTS data (Rowan and Vincent, 1971). Ratioing is an effective method for distinguishing among rock types because the main spectral differ- ences in the visible and near-infrared spectral re- gions are found in the slopes of the reflectivity curves; individual absorption bands are broad and weak and therefore cannot be used in most cases for discrimination of rock type on the standard MSS images. In addition, areas of interest geologically generally have some vertical relief. The ratioing process removes first-order brightness effects due to topographic slope and allows attainment of higher image contrast through additional processing. On the other hand, terrain effects are highly disturbing in color-additive displays or in analysis by clustering methods based solely on brightness. Although digital computer processing ultimately proved to be necessary for this study, attempts were made to use more rapid Visual and optically assisted techniques. Visual comparison of the MSS bands of many Nevada scenes resulted in only a few places where band-to-band differences could be related to rock type. For example, widespread volcanic rocks in the northern Antelope Range and Schell Creek Range in White Pine and Elko Counties are con- spicuously darker in the near-infrared bands than in the Visible bands (ERTS frame No. E—1053—17533, not shown). Enhancement by color-additive viewing is mainly useful for determining vegetation distri- bution. Although discrimination of rock units in the study area is not substantially improved by this method, color-additive techniques have proved more useful than simple comparison of individual black- and-white MSS images in other areas. Attempts to enhance spectral-reflectance differ- ences by compositing a negative of one spectral band and a positive of another, as described by Whitaker (1965), were also generally unsuccessful. Of the many problems, the most serious were the general lack of enhancement actually achieved and the intro- duction of photographic processing errors that were of the same order of magnitude as the spectral- reflectance differences. In order to make the spectral- reflectance differences visible, a very high film con- trast is necessary. At high-contrast levels, however, COMPUTER IMAGE ENHANCEMENT INPUT- CCTS Formatting, cleanup, and calibration __ Atmospheric correction Ratio Histogram Histogram Histogram evaluation evaluation evaluation Linear Linear Linear stretch stretch stretch SkeviE Histogram evaluation Linear stretch Color separation and compositing Color separation and compositing l l OUTPUT OUTPUT OUTPUT Standard Stretched Stretched MSS image MSS image ratio image Collor-stretched- . ratio composite compOSIte OUTPUT OUTPUT Color-infrared FIGURE 3,—Flow diagram showing the sequence of steps used in processing computer-compatible tapes and the five image products generated. some important information is lost in the nonlinear part of the film response curve. Therefore, in gen- eral, purely optically assisted methods of analysis appear to have a somewhat limited value for geo- logic multispectral analysis. DIGITAL METHODS Various techniques have been developed for digi- tal processing of images. Only those relevant to dis- crimination among rock materials will be discussed here. The steps in the enhancement of the M88 images are outlined in the flow diagram in figure 3. The dynamic range of the M88 is encoded to 64 brightness levels. Application of system calibration to take care of nonlinearities results in approxi— mately 80 brightness levels, coded to seven-bit accu- racy. The digital numbers (DN) on the tape repre- sent data values that are linear with brightness and range from 0 to 127. For convenience in using exist- ing computer programs, the M88 data have been expanded into eight bits, resulting in a DN range of 0 to 255. Future references to DN values Will refer to the eight-bit range. Because the application of M88 on-board calibra- tion data at the National Data Processing Facility, Goddard Space Flight Center, is not perfect, residual variations manifest themselves as a striping pattern repeated at six-line intervals. In unenhanced small- scale photographic prints, this banding is not very noticeable, but after computer enhancement and en- largement, the lack of perfect radiometric calibra- tion is disturbingly apparent. Methods for reducing the striping pattern have been described by Billings- ley and G‘oetz (197 3) and require lengthy processing. For each MSS scene, four CCT’s are required, each containing one-fourth of a frame. If the area of interest spans an area covered by more than one CCT, strips can be reassembled or concatenated. 6 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES GEOMETRIC CORRECTIONS The ERTS MSS is a point-scanner device that has the scanning trace perpendicular to the downtrack direction of the spacecraft (fig. 1). Therefore, the rotation of the Earth during acquisition of each set of progressive lines of one picture will cause a lat- eral skewing of the area covered on the ground. This skewing is a function of latitude. Because the data are recorded on film using an orthogonal grid pat- tern, each successive scan line must be shifted hori- zontally within the grid to compensate for the skew- ing. The resulting output picture is in the form of a parallelogram. An additional correction is needed to compensate for a higher sampling rate in the scan-line direction than in the downtrack direction. This distortion can be compensated for by reformatting the picture ele- ments (pixels) either in the computer or during the analog film recording. We have chosen to make this correction at the latter stage of processing. CONTRAST STRETCHING The MSS system is designed to cover a large dy— namic range in scene brightness to respond to the effects of sun angle and albedo variation as the space— craft covers the globe. Consequently the brightness range of any one image will generally occupy only part of the available dynamic range, resulting in a low-contrast image. In reconstructing an image from the digital data, it is therefore desirable to stretch the DN range to increase the contrast. Stretching begins by forming a histogram plot of the number of pixels per DN value (fig. 4). The brightness values above and below which no appreciable data exist can then be located and used as stretch limits. The stretch may be linear or nonlinear. A linear stretch increases the scene contrast uni- formly over the dynamic range of the output prod- uct. The stretch limits determined from the histo- gram are placed at the extreme points of the dynamic range (that is, 0 to 255 DN values), and the other points are spaced linearly between these end points (fig. 4). In a nonlinear stretch, such as a cube-root stretch, the cube root of each DN value is taken. The result— ing DN range is linearly stretched as above. This procedure increases local scene contrast in the dark areas at the expense of contrast in the brightest areas. In an exponential stretch, the inverse occurs. There does not seem to be a general rule of thumb that can be app-lied to all images in determining the required stretch parameters. Care must be taken to see that useful raw data at the extremes of the DN range are not saturated and lost. Part to be stretched (I r-"—'fl _ L|J 1‘] m 2 3 3 Z Lu O 5 Lu 5 E 2' o E a: O 0 Z DIGITAL NUMBER (DN) FIGURE 4,—Schematic histogram showing the distributions of digital numbers (DN) for a typical ERTS MSS scene before contrast stretching (solid line) and after linearly stretching (dashed line) a part of the DN range. ATMOSPHERIC EFFECTS The effects of absorption and scattering in the atmosphere vary among the different types of en— hanced images. When the images are simply stretched to increase contrast, no effect is noted. If color composites are made from the stretched images, however, the relative color balance will be affected by the atmospheric scattering. The greatest effect is seen in the formation of ratios. Because A+£1 A 3+6, 3' where 61 and 62 are the additive atmospheric-scatter— ing components in bands A and B, the scattering term must be removed. The value for the atmospheric-scattering compo- nent can be determined by locating the lowest DN values in the image. These Values will normally occur over water or in cloud shadows. In a study area in Arizona (Goetz, 1974), measurements of ground-reflected radiation made before, during, and after the passage of a small (about 300-m-diameter) fair-weather cumulus cloud, showed a reduction in reflected intensity by a factor of 5—6 during cloud passage. From these data We can anticipate that, to first order, most of the light received from the dark shadows is in fact atmospherically scattered sun- light. Therefore, corrections are made by subtracting the appropriate band-dependent values, determined from cloud shadows in each band, from each pixel DN value. Other methods of determining the band- to-band values may be used. The atmospheric cor- rections are applied to the data before skewing, stretching, and ratioing. RATIOING In the ratioing process, two spectral band images that have been corrected for atmospheric effects are divided pixel by pixel. The resultant image will show COMPUTER IMAGE ENHANCEMENT the variations in the slopes of the spectral-reflectivity curves between the two wavelength bands. Differ- ences in albedo are suppressed, however, and very dissimilar materials easily separable on a standard photographic image may become inseparable on a ratio image because their spectral-reflectivity slopes are similar. On the other hand, a distinct advantage of this method is that one type of material will ap- pear the same or similar in a ratio image regardless of the local topographic slope angle. The ratio image generally shows a narrow histo- gram of DN values and may therefore be contrast stretched to enhance the visibility of the spectral differences. The type of stretch used, whether linear or nonlinear, as discussed, above, will determine which areas in the image are most strongly en- hanced. For instance, a linear stretch will result in the visual enhancement of dark areas (low DN values in the original ratio image) and light areas (high DN values in the original ratio image). Other types of stretches will enhance other DN value ranges in the original ratio image. The error introduced by scattering is greatest for low-reflectance targets. It is highest in band 4, where the scattering component may make up as much as 50 percent or more of the recorded bright- ness level. Band 7 has the lowest scattering compo— ‘ nent. Although atmospheric absorption can play an im- portant role in the form of apparent interband radi- ance variations, we are not able to separate these effects from variations in the M88 absolute calibra- tion, done before we received the tapes. Band 7, spanning the 0.95-um water band, might be expected to be affected most severely by atmospheric absorp- tion. Residual errors, most easily detected on ratio images in highly sloped and shadowed regions, may result either from improper atmospheric correction or from the fact that such areas are illuminated mainly by the blue sky and reflections from sur- rounding terrain; if this is the case, the atmospheric absorption and scattering calculated from other re- gions is not appropriate for these areas. DISPLAY PRODUCTS The computer—enhanced images are recorded on black-and-white film with a flying-spot cathode-ray tube recorder. These 70-mm transparencies can be printed on paper or combined in a color-additive process, using either a viewer, color-negative stock, or diazo transparencies. The color combination of ratio images provides the photointerpreter with a Vivid display akin to a classification map. GEOLOGY OF THE STUDY AREA The surficial character of the study area (figs. 5, 11) makes it an ideal choice for analysis of ERTS spectral data. The topography of the test site is varied, ranging from smooth-textured alluvial basins to rugged ranges and a large mesa. Vegetation is sparse, covering 10—20 percent of the desert valleys where sagebrush is dominant, and is substantially denser only in the higher ranges where piiion pine, juniper, and grasses are predominant. Although vegetation type and distribution can sometimes re- flect geology, minimal vegetation was considered preferable for these initial evaluations so that sur- ficial features and rock units would not be obscure-d. The most important characteristics of the terrain are the widespread hydrothermal alteration and the broad compositional range of Tertiary igneous rocks, which provide an excellent opportunity for testing the discrimination potential of the M88 images. ROCK UNITS Widespread Tertiary volcanic and intrusive rocks cover approximately 95 percent of the surface of the study area not covered by alluvium (fig. 6). Pre- cambrian and Paleozoic rocks are exposed only locally and are shown as a single unit in figure 6. Mesozoic plutonic rocks, mainly quartz monzonite in composition, are also undifferentiated in figure 6 be- cause of their limited distribution in the study area. The Tertiary units exceed 6,000 m in thickness in a composite section; tuffs of rhyolitic, dacitic, and quartz latitic composition are the most common. Lava flows and intrusive rocks of similar composi- tions and of andesite and basalt are also Widespread (Cornwall, 1972). Although sedimentary rocks are subordinate in the Tertiary sequence, Miocene tuffa- ceous sedimentary rocks are common in the central and east-central parts of the area (fig. 6). The sources for the tuffs and flows are thought to have been as many as 9 or 10 volcanic centers, several of which are within the study area (Ekren and others, 1971). Especially noteworthy are the Black Moun- tain and Timber Mountain calderas. The Black Mountain caldera, in the southeastern corner of the study area, was the source for the Thirsty Canyon ash-flow and ash-fall tuff (unit Tt3, fig. 6) which underlies much of the southern half of the area. Tuffs derived from the larger Timber Mountain cal- dera southeast of the study area are prominent in the west-central and southwestern parts of the study area. In addition, the Goldfield mining district is a volcanic center (Albers and Cornwall, 1968) and is thought to be a resurgent caldera (Albers and Klein- hampl, 1970). The volcanic and intrusive rocks of DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES 100 MILES J l 100 KiLOMETERS 0—0—0 GEOLOGY OF THE STUDY AREA 9 FIGURE 5.—ERTS mosaic made with MSS band 5 (0.6—0.7 ,um) images of the State of Nevada showing location of study area. Prepared by Aerial Photographers of Ne- vada, Reno-Stead Airport, Nev. the Goldfield mining district are restricted to that district. The Quaternary units consist of surficial deposits and sporadic outcrops of basalt flows and cinder cones (fig. 6). The basaltic deposits are conspicuous because of their low reflectivity relative to the adj a- cent materials. The surficial units, however, include complexly related alluvium, colluvium, desert wash and landslide deposits, playa materials, and, on the western edge of the area, a single exposure of bedded clay and silt (unit Qts, fig. 6). With the ex- ception of the playa deposits, which are character- ized by reasonably uniform composition and high reflectivity, these surficial deposits are lithologically heterogeneous. This compositional heterogeneity, as well as grain size, surface coatings, and vegetation- cover variations, gives rise to large spectral-reflect- ance differences. Although the processing techniques described in the previous section appear to be po- tentially useful for mapping these materials, the surficial deposits present a formidable analytical problem because of their large extent and the transi- tional nature of boundaries. The rest of this discus- sion will exclude the surficial deposits; emphasis will be placed on the Tertiary units, especially where they have been hydrothermally altered. The unaltered Tertiary volcanic and intrusive rocks have from very high to low albedos, but these variations are not a reliable guide to composition. For example, although most of the silicic rocks have high to intermediate albedos, the widespread rhyo- litic Thirsty Canyon Tuff appears dark enough on the images, as well as in the field, to be mistaken for a rock of intermediate or even mafic composition. The unaltered rocks in the study area have a wide variety of muted colors, the most common being brown and gray, with green, yellow, and pink tints. Alteration by the introduction of hydrothermal fluids and by subsequent weathering has resulted in hydration and oxidation of the Tertiary volcanic host rocks. The end products range from high-albedo clay-rich rocks, which may be locally silicified, to variably colored limonitic rocks. All the major alter- ation products are present in the Goldfield mining district, which is the most productive and best known altered zone in the study area. GEOLOGY OF THE GOLDFIELD MINING DISTRICT The Goldfield mining district is principally com— posed of Miocene volcanic rocks overlying Ordovician shale and chert and Mesozoic granitic rocks (Allbers and Stewart, 1972) (fig. 6). The middle Tertiary units include air-fall and ash-flow tuff along with flows and intrusive bodies of andesite, dacite, rhyo- dacite, quartz latite, and rhyolite (Cornwall, 1972). Upper Tertiary basalt and welded tuft locally cap these units (Ashley, 1970). Alteration and minerali- zation are extensive, especially in the lower Miocene andesite and dacite, the primary ore-bearing rocks. Ashley (1970) described two types of alteration. The older deuteric or propylitic alteration varies con- siderably, each variation characterizing a single vol- canic unit. According to Ashley and Keith (1973), however, the chemical changes in most of these rocks have probably been quite limited. The younger in- tense hydrothermal alteration is more conspicuous and has a similar character in all rock units. Harvey and Vitaliano (1964) and Ashley and Keith (1973) described three mineralogically distinct zones of hy- drothermal alteration. In order of decreasing altera- tion, silicified rocks with associated alunite, and kaolinite give way to illite-kaolinite—bearing argil- lized rocks, which grade into montmorillonite-bear- ing argillized rocks having surficial coatings of limonite and jarosite resulting from oxidation. Limonite is also common in the first two zones. The silicified and argillized rocks have a bleached ap- pearance except where stained red and yellow by limonite and jarosite. Figure 7 shows the general limits of the alteration zones which cover more than 38.4 sq km (Ashley, 1970). A color aerial photograph of part of the Goldfield district shows the distinctive complex mosaic of bleached clay-rich rocks and of brightly colored limonitic areas interspersed with the unaltered rocks (fig. 8). Feature A (fig. 8), an unaltered upper Ter- tiary basalt cap, appears dark gray; this basalt can also be identified on the alteration map of the Gold- field district (A, fig. 7) and on the enhanced images discussed later. Surrounding the basalt cap is the oreabearing hydrothermally altered andesite and da- cite, ranging from shades of light gray to red brown and brown. The red-brown hues dominate in the altered rocks. The purple-blue outcrop of unaltered latite to the northwest (B, fig. 8; B, fig. 7) can easily be distinguished from the prong of altered andesite and dacite on its southeastern border (C, fig. 8; C, fig. 7), but the northern limit of the altered rocks is difficult to determine in the color photograph. Farther east, some dark-brown-gray unaltered dacite (D, fig. 8; D, fig. 7) stands out from the nearby altered andesite and dacite. Although individual outcrops can be classified properly, the boundary of the hydro- thermal alteration is difficult to define at this scale, mainly because visible color is not entirely diagnostic. 10 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES 116°09’ 117°08’ 38°00 37°14’ ‘ ‘ 116°28' 117°27' 10 IOMILES l | 10 KILOMETERS o—-o GEOLOGY OF THE STUDY AREA 11 CORRELATION OF MAP UNITS QUATERNARY O:t 6: m. . o y Pliocene QUATERNARY AND TERTIARY 6: to 17: m.y. Miocene TERTIARY 17: to 34: m.y. Oligocene UNCONFORM/TY - }MESOZOIC UNCONFORMITY PALEOZOIC i w PRECAMBRIAN DESCRIPTION OF MAP UNITS Qa ALLUVIAL DEPOSITS (QUATERNARY) QTb BASALT FLOWS (QUATERNARY AND TERTIARY) QTs SEDIMENTARY ROCKS (QUATERNARY AND TERTIARY)—Mostly lake deposits Tgr GRANITIC ROCKS (PLIOCENE T0 OLIGOCENE)—Mostly quartz monzonite and granodiorite Tt3 WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS (PLIOCENE AND MIOCENE)—Locally includes thin units of air—fall tuff and sedimentary rock Tt2 WELDED AND NONWELDED ASH-FLOW TUFFS (MIOCENE AND OLIGO- CENE)—Locally includes thin units of air—fall tuff and sedimentary rock Tr3 RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS (PLIOCENE AND MIOCENE) Tr2 RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS (MIOCENE AND OLIGOCENE) Ta3 ANDESITE FLOWS AND FLOWS OF INTERMEDIATE COMPOSITION (PLI- OCENE AND MIOCENE) Ta2 ANDESITE FLOWS AND FLOWS OF INTERMEDIATE COMPOSITION (MIO- CENE AND OLIGOCENE) Tba ANDESITE AND BASALT FLOWS (PLIOCENE AND MIOCENE) Tb BASALT FLOWS (PLIOCENE AND MIOCENE) Tob OLDER BASALT FLOWS (MIOCENE AND OLIGOCENE) Tts ASH-FLOW TUFFS AND TUFFACEOUS SEDIMENTARY ROCKS,UNDIVIDED (PLIOCENE AND MIOCENE) T53 TUFFACEOUS SEDIMENTARY ROCKS (PLIOCENE AND MIOCENE)—Locally includes minor amounts of tuff T52 TUFFACEOUS SEDIMENTARY ROCKS (MIOCENE AND OLIGOCENE)—Lo- cally includes minor amounts of tuff Tri RHYOLITIC INTRUSIVE ROCKS (PLIOCENE TO OLIGOCENE) Tmi INTRUSIVE ROCKS OF MAFIC AND INTERMEDIATE COMPOSITION (PLI— OCENE TO OLIGOCENE) Mzgr GRANITIC ROCKS (MESOZOIC)—Mostly quartz monzonite and granodiorite pCPz LIMESTONE, DOLOMITE, SHALE, SILTSTONE, QUARTZITE, SANDSTONE, CHERT, AND METAMORPHIC ROCKS (PALEOZOIC TO PRECAMBRIAN) FIGURE 6.—Geologic map of the study area. From a map of a larger area compiled by John H. Stewart and J. E. Carl- son, U.S. Geological Survey; Tertiary units older than Tt2 are not present in the study area. 12 DISCRIMINATION 117°15’ OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES 117°10’ Kendall Mtn 5 37°45’ - ‘ Goldfield ' Myers Mtn ., EXPLANATION Argillized areas Surface projection of ore-bearing areas (from Ransome, 1909, and Searls, 1948) \ , " ESMERALDA g a / NYE co 9 Base from US. Geological Survey Goldfield 1952, and Mud Lake 1952 O———O FIGURE 7.~—Map showing areas of alteration in the Goldfie Area within dashed line is approximate limit of color aerial photograph in figure 8. Alteration contacts by J. P. Albers. H. R. Cornwall. and R. P.Ashley, 2M|LE$ 1966 1 | l 1 | 2 KILOMETERS 1d mining district (modified from Jensen and others, 1971). A, unaltered upper Tertiary basalt cap; B, unaltered latite; C, hydrothermally altered andesite and dacite; D, unaltered daoite. Although many of the rock units in the study area have characteristic colors or combination of colors, they are too muted to be consistently shown on small- scale orbital-altitude color photographs. Comparison of an excellent color photograph obtained from the 8190 photographic experiment (fig. 9) with the dis- tribution of the main rock types (fig. 6) illustrates this point. The appearance of the rocks in this photo- graph is dominated by albedo, which is not a reliable guide to rock type (for example, the dark-appearing Thirsty Canyon tuff, Tt3). Color differences are es- pecially difficult to discern in the low-albedo rocks. Except for a few small limonitic altered areas southeast of Stonewall Mountain (A, B, and C, fig. 9), which appear red brown, the mineralized areas are not distinctive in the Skylab photograph. For example, the Goldfield district appears mottled and slightly rust colored in a few places (D, fig. 9), but similar characteristics are also seen in unaltered areas, such as the northwest end of the Cactus Range (E, fig. 9). These characteristics are not diagnostic of altered areas. This preliminary evaluation sug- gests that small-scale photographs such as the Sky- lab example, although useful for morphological and structural studies, are not adequate for detecting and mapping mineralized areas. STRUCTURAL GEOLOGY Northwest-trending ranges bounded by normal faults reflect the characteristic Basin and Range ter- rain of the study area. High-angle normal faults bound the Cactus and Kawich Ranges and the north- ern and western margins of Stonewall Mountain (fig. 11) ; movement along these faults began in Mio- GEOLOGY OF THE STUDY AREA w» *5 M L Ioloo“ l‘xlzo‘OO'Eser» L 1 g‘ L l , w l l 200 r 110 600 800 METERS “at, V: FIGURE 8.—~C010r aerial photograph of part of the Goldfield mining district: A, unaltered upper Tertiary basalt cap; B, unaltered latite; C, hydrothermally altered andesite and daeite; D, unaltered dacite. Photographed June 2, 1968,f0ir the U.S. Geological Survey. Ektachrome film type 2448. 14 DISCRIMINATION 0F ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES 0 10 MILES I 1 I J | o l 10 KlLOMETERS Q \~\ FIGURE 9.—NASA Skylab 8190 photograph of part of the study area showing (A—C) alteration areas southeast of Stonewall Mountain, (D) mottled appearance of Goldfield mining district, (E) similar mottled appearance of an unaltered area, and (F) basalt cap in the Goldfield area. Photographed June 3, 1973. Ektachrome film type 50356. GEOLOGIC INTERPRETATION OF IMAGES 15 cene time. Although in many areas the Tertiary units are highly faulted and tilted, large areas of fiat-lying and undisturbed Tertiary rocks also occur (for example, Pahute Mesa in the study area). The Precambrian and Paleozoic rocks were folded and thrust faulted mainly during Mesozoic orogeny. Right-lateral shearing of these and more recent rocks along the shear zone known as Walker Lane has resulted in mountain ranges of diverse trend. The volcanic centers mentioned above may be re- lated to this shear belt (Ekren and others, 1971), which cuts in a northwest direction across the south- ern half of the study area. The structural features are not shown in figure 6 so that lithologic differ- ences can be emphasized. The geology of the Goldfield district is consistent with that of an early Miocene volcanic center (Al- bers and Cornwall, 1968). The concentric zones of successively younger formations and the alteration pattern form an east-trending elongated ellipse, and a zone of grabenlike subsidence also extends east- ward. The belts of more or less linear silicified ledges may be indicative of a rim fracture system (Albers and Stewart, 1972). GEOLOGIC INTERPRETATION OF IMAGES Using the procedures previously described, five processed image sets (fig. 3) have been produced from the basic digital MSS tape of the south-central Nevada study area. Listed in order of increasing enhancement of spectral-reflectance information, the MSS image products are: ( 1) standard unenhanced images, (2) stretched images, (3) stretched color- infrared composites, (4) stretched-ratio images, and (5) colorastretched-ratio composites (hereafter re- ferred to as color-ratio composites). STANDARD MSS IMAGES The standard MSS images distributed by the NASA Date Processing Facility at Goddard Space- flight Center are of low to moderate contrast; con- sequently the level of detail is low for both bright and dark objects. In the northeast part of the Octo- ber 3, 1973, ERTS frame No. E—1072—18001 (fig. 10), materials with low and high albedos, such as mafic rocks and playa deposits, respectively, are dis- tinguished easily, but little detail can be discerned within these areas. Furthermore, few differences are detectable through band-to-band comparison, except in vegetated areas, which are dark in the visible bands and light in the near-infrared bands. This general lack of band-to-band contrast testifies to the subtlety of the spectral differences among the rock types. The small magnitude of the spectral differ- ences, along with the low scene contrast of the standard images, seriously limits their value for rock-type discrimination. Image contrast for the rocks and soils of the study area, as well as for most areas examined in Nevada and southern California, appears to be highest in the MSS image for bands 6 and 7, in figure 11 at a scale (if 1:500,000. However, although most of the playas are easily distinguished from clouds and other features in the area on the basis of shape and texture, little confidence can be placed in most other distinctions. For example, several dark areas are quite prominent, but the compositions of the rocks in those areas range from rhyolitic to andesitic to basaltic. The two large dark patches south-south- west of Mud Lake (A) are basaltic and andesitic in composition, but three minor outcrops of tuffaceous sedimentary rocks (T33, fig. 6) occur in the north- ernmost dark area. The three small dark spots (B) on the northeastern margin of the Cactus Range are basalts, whereas the larger dark area (C) slightly to the south represents part of a mafic intrusive body. East of the Cactus Range, andesite makes up the low hills (D) that are dark on the image. The areal extent of these andesitic outcrops is exagger- ated on the image because of the presence of a talus apron around the outcrop. Approximately 12 km south of Tolicha Peak is a series of basalt flows (E), Whose boundaries do agree well with the geologic map. Although some subtle reflectivity differences among the mafic rocks exist on the image, variations are not consistent enough to allow discrimination, for example, among andesites, basalts, and the mafic intrusive body with any degree of confidence. Not all dark areas are indicative of mafic rocks, however. The most prominent dark area on the standard MSS image in the southeastern corner represents the previously mentioned Thirsty Canyon tufl' (Tt3) and a rhyolite (Tr3) (fig. 6). Only the southernmost circular area is basalt (Black Butte), and it is indistinguishable from the dark—appearing tuff and rhyolite north of it. Tuffaceous sedimentary rocks that crop out within the dark area southwest of Mud Lake are also indistinguishable from the neighboring andesite and basalt. In addition, a few small exposures of Precambrian and Cambrian rocks (F) appear dark on the image. Therefore rock-type discrimination on this standard MSS image is severly limited even if only a two-component classification system of mafic and felsic rocks is used. In general, felsic rocks vary in tone on the image from medium to light gray. Discrimination of rock units within this tonal range of gray is rarely pos- sible in any band, especially as the alluvium in the 16 DISCRIMINATION 0F ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES M88 6 M88 7 25 MILES A .— O——O I 25 KILOMETERS GEOLOGIC INTERPRETATION OF IMAGES 17 FIGURE 10.——Standard unenhanced MSS images of the study area for bands 4—7 (scale 121,000,000). Vegetation is 4 brighter in the image for band 7, especially in the Kawich Range (upper right), than it is in that for band 5. Imaged October 3, 1973, northeast part of ERTS frame No. E—1072—18001. image appears as very similar gray levels. Isolated outcrops can be discriminated, however, as in the rhyolitic rocks and tufi‘aceous sediments (G) on the westernmost margin of the Cactus Range. Nevertheless, on Pahute Mesa, the dark pattern on the image correlates only locally with the mapped distribution of tuff and rhyeolite. Major mineralized areas, as indicated by the 10- cations of mines and mining districts (fig. 12), are not distinguishable on the image. The largest, the Goldfield district, is a uniform light gray, and the image gives no indication of the extensive altera- tion zone there. Other altered areas are also in- distinct. STRETCHED MSS IMAGES The stretched MSS images of the study area (fig. 13) show substantially more scene contrast and spa- tial detail than do the standard images. The in- creased scene contrast, a direct result of the stretch- ing process, allows slightly improved discrimination of rock types. The stretched images have been gen- erated directly from the digital tapes with the re- sult of an apparent increase in spatial resolution (fig. 14). The standard images (fig. 10), on the other hand, have passed through several photographic re- productive processes after their generation from the tapes, processes that have caused a loss of some resolution. The most apparent improvement of rock—type dis- crimination in figure 14 is the separation of the basalt (fig. 13, A) and the mafic intrusive (fig. 13, B) in the Cactus Range on the basis of the generally lower albedo of the basalt. Other limitations on dis— crimination of mafic rock types, however, as de- scribed for the standard images, also apply to the stretched images. In addition, discrimination among the felsic rock units, particularly in the Pahute Mesa area, is not improved through stretching the images. Comparison of the four images of figure 13 with the known mineralized areas (fig. 12) shows that the mineralized areas southeast of Stonewall Moun- tain (C) and north of the Cactus Range mafic in- trusive body (B) are distinctive and bright in all the stretched MSS images. The Cuprite district (D) is notably brighter than it is in the standard images. Nevertheless, confusion could still arise in discrimination between these bright areas and other highly reflective areas such as the tutfaceous sedi- ments south of the Goldfield district (E, fig. 13) and, in some places, alluvium (F, fig. 13). Although the Goldfield district stands out better in the stretched than in the standard images (fig. 10) because of the increased contrast, most of the mineralized areas are not prominent in the stretched images. In gen- eral, although scene contrast and apparent spatial resolution are increased, stretching of the radiance data without additional enhancement results in only slightly better discrimination of the geologic mate- rials of this area. COLOR-INFRA RED COM POSITES Color composites can be prepared either by trans- mitting filtered light through the positive film transparencies or by combining color separates such as those made with diazo foils. For example, the color—infrared composite shown in figure 15 was pre- pared using blue, green, and red filters and positive transparencies for stretched MSS bands 4, 5, and 7, respectively. Colors in this composite are directly related to the film densities in the positive trans— parencies. Hence, vegetation is red in this composite because the high reflectivity of Vigorous vegetation in MSS band 7 compared with MSS bands 4 and 5 results in a relatively low density in the MSS band 7 transparency. In the study area, the color-infrared composite is most useful for discrimination of vegetated areas (fig. 15). The darkest red, and therefore the densest vegetation, occurs in the Kawich Range and on Stonewall Mountain. Additional red tinges are ap- parent on Gold Mountain, on parts of Pahute Mesa, and north of Monitor Peak. These sparsely vege- tated areas cannot be detected easily on the black- and-white stretched MSS images. Color-infrared composites appear to offer little improvement over the stretched MSS images for discrimination of rock types. All the points of con- fusion among the felsic, intermediate, and mafic rock types described for the standard and stretched images are also present in this color composite. Al- though some of the known limonitic areas, such as southwest of Quartz Mountain (A) and north of Monitor Peak (B), are light orange brown (fig. 15), the other altered areas are not distinctive. The light- orange-brown color, suggesting high reflectance in the MSS bands 5 and 7 compared with the MSS band 4, is consistent with limonite spectra discussed later. Nonetheless, color-infrared composites do not appear 18 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES 10 MILES l o~—«— o I 10 Kl LOM ETERS GEOLOGIC INTERPRETATION OF IMAGES 19 FIGURE 11.—Standard ERTS MSS image of the study area for band 7 (scale 1:500,000) showing some of the main ‘ physiographic features in the study area. A, andesite and basalt south-west of Mud Lake; B, three basalt outcrops east of the Cactus Range; C, mafic intrusive rock; D, hills of andesite; E, basalt flows 12 km south of Tolicha Peak; F, dark-appearing Precambrian and Cambrian outcrops; G, rhyolite and tuff'aceous sediments on westernmost margin of the Cactus Range; H, basalt cap in the Goldfield mining district. to offer a reliable means for detecting hydrothermal- ly altered areas. STRETCHED-RATIO IMAGES From the previous discussions, it is clear that the spectral-reflectance differences among rock types and between altered and unaltered rocks are general- ly too small to be detected by visual comparison of the MSS images or through analysis of color-in- frared composites. Ratioing of the spectral bands, however, provides additional means for enhancing spectral differences. Although ratioing alone is ade- quate to show large differences, such as those be- tween the visible and near-infrared bands for vigor- ous vegetation, stretching is also necessary for ade- quate enhancement of the typically subtle spectral- reflectance differences found among most geologic materials. The resultant images represent a visual display of the differences between the bands in slope of the spectral-reflectance curve of each geologic unit. Used in combination, ratioing and stretching offer a powerful means for discriminating rock types and alteration zones. In the stretched-ratio images shown in figure 16, the linear stretches used have been selected to show maximum scene contrast rather than to relate film density to the DN values. Hence, the ratio range selected for stretching and the amount of stretch applied to each ratio image are different. Relative spectral reflectivity, therefore, cannot be determined directly from these particular stretched-ratio images because corresponding gray levels among the images do not represent equal DN ratio values. Within each of the images in figure 16, the ex- tremes of the 16-step gray scale (not shown) repre- sent the largest spectral-reflectivity differences. The darkest areas in each stretched-ratio image are those for whichthe denominator of the ratio is greater than the numerator. Conversely, the numerator is greater than the denominator for the lightest areas. For example, the largest differences in reflectance between bands for vegetation are shown in the im- ages for ratios 5/6 and 5/7 (vegetation very dark) and for ratio 4/5 (vegetation extremely light). ’5: x x x x 11 X X Hannapa x ’1‘ Elfendale X Golden Arrow xx)? ,5: Eden xx ’§( x S1lver Bow xx xx not xxx xx ’Si‘x Klondyke x Mellan Goldfield x , xx x xxx . xx xx X x Cactus Sprlng G ld x“ "x xx 0 Reed )& ’55:: Xxxxxx x ’fxxx >§< ”Cuprite x ’2‘ Jamestown x x H xx Stonewall x ’6‘ x Quartz Mountain x x x); Clarkdale 10 MILES 10 O 10 KILOMETERS FIGURE 12.—Major mining districts in the study area. Data from Kral (1951), Albers and Stewart (1972), Cornwall (1972); J. H. Stewart (written commun., 1973); F. J. Kleinhampl (written commun., 1973). ><, approximate location of mine or prospect. More variation Within the playas is shown in the stretched-ratio images than in the previous single- band enhanced images in which no variation is ap- parent. Mud Lake and the southernmost playa (A) are most notable. Within all the stretched-ratio im- ages, however, the playas can be confused with other geologic materials. Mafic rocks (B, fig. 16) appear very light and dis- tinctive in the images for MSS 4/5, 4/6, and 4/7, but discrimination is still problematic. For example, ba- saltic and andesitic rocks are indistinguishable, and in the image for MSS 4/5 the mafic rocks can be confused with vegetation and with the felsic rocks (C) on Pahute Mesa. Felsic rocks do not stand out in the stretched-ratio images. Most appear as me- dium tones of gray, although the felsic rocks on Pahute Mesa are dark in the image for MSS 5/7 and can, in this image, be discriminated from the lighter mafic rocks. 20 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES M88 7 2J5 MILES I 25 KILOMETERS GEOLOGIC INTERPRETATION OF IMAGES , 21 FIGURE 13.——Linearly stretched ERTS MSS images of the study area for bands 4—7 (scale 111,000,000). Selected { DN ranges for stretch are: MSS 4, 56—108; MSS 5, 54— 121; MSS 6, 53—111; and MSS 7, 44—96. A, three basalt outcrops east of Cactus Range; B, mafic intrusive; C, mineralized areas southeast of Stonewall Mountain; D, Cuprite district; E, bright tufi’aceous sediments south of the Goldfield district; F, bright alluvial areas. Most of the hydrothermally altered areas are in— distinct in the standard MSS and stretched MSS im- ages and in the stretched color-infrared composites. The Goldfield mining district (fig. 12), although the largest producing district in the study area, is espe- cially inconspicuous in these image products (figs. 10, 13, 15). In the stretched-ratio images, however, the Goldfield district shows a pattern (fig. 16, MSS 4/5, 4/6, 4/7, 5/6) that, as we will discuss next, is nearly identical with the altered area mapped by Jensen, Ashley, and Albers (1971). Although the Goldfield district and many other known altered areas are apparent on the stretched- ratio images, they cannot be discriminated from other areas with similar gray tones. The gray levels of the playas especially appear to be nearly identical with those of the altered areas. COLOR-RATIO COMPOSITES Color-compositing techniques offer an efl‘icient means for combining blackwand-white stretched-ratio images for discrimination of rock types. Whereas two spectrally different areas may be nearly indis- tinguishable in a black-and-white stretched-ratio image, proper color combination of two or more images permits discrimination on the basis of color differences. Discrimination is increased not only be- cause information from several ratio images is com.- bined but also because the human eye is capable of discriminating two orders of magnitude more hue values than values of gray. Color-ratio composites constitute the most useful image product for geo- logic analysis generated during this study. A large number of color and ratio image combina- tions is possible. Ideally, selection of stretched-ratio images for compositing should be based on the spec- tral reflectivities of the materials of interest, but spectral data for the study area are too limited to provide an adequate basis for specific selection. Therefore, 70-mm positive transparencies of the six stretched-ratio images were combined in a color- additive viewer to determine the combinations most useful for discriminating the main rock types and altered areas. Analysis of combinations of two stretched-ratio images and two color filters, from a choice of red, blue, and green, showed that no single two-compo- nent composite examined could provide adequate dis- crimination among major rock types, altered areas, vegetation, and playas. The most common problem involved difficulty in distinguishing the altered zones from the playas and some alluvial areas. Further- more, in combinations in which the altered areas are detectable, some of the major rock types are not distinctive. Three-component composites (three stretched-ratio images and three color filters) have more overall discrimination potential than do the two-component composites, but discrimination be- tween the altered areas and the playas and alluvium remains a problem. Another color-compositing technique was tried in an effort to circumvent these problems. Color-ratio composites were prepared using diazo transparen- cies. Because in the diazo process the most intensely exposed parts of the image are “burned off” upon development, no color is contributed by areas that are clear (for example, DN = 0) in the transparency. Conversely, high film density results in intense color in the diazo-color separates. It is important to under- stand that the end product of this technique does not represent the reverse of the color-additive method. That is, a composite of negative transparencies made in a color-additive viewer would not be the same as a positive-transparency composite produced using the diazo process. An optimum combination for geologic analysis of the study area was determined using the diazo process. Although all the innumerable possible color combinations and stretched-ratio—image combina- tions have not been evaluated, the most effective three-component color-ratio composite for discrimi- nating between altered and unaltered areas and among the regional rock units was prepared using the following color and stretched-ratio image com- bination: blue for MSS 4/5, yellow for MSS 5/6, and magenta for MSS 6/7. Note that these ratios involve all four MSS bands. ANALYSIS OF COLOR-RATIO COMPOSITE The color-ratio composite shown in figure 17 was analyzed initially by studying available geologic maps and 1:250,000~scale black-and-white photomo- saics to determine which rock units should be dis- tinguishable and to identify problem areas to be checked in the field. Several regional geologic studies have been conducted previously in this area, most notably those of Cornwall (1972), Albers and Stew- 22 DISCRIMINATION OF ROCKS AND ALlTERED AREAS BY USE OF ERTS IMAGES FIGURE 14.——Linearly stretch-ed ERTS MSS image for band 7 of the study area (scale 1:500,00‘0). Note the excellent resolu- tion of the image as evidenced by discrimination of the secondary roads (A) and the main road (B) that passes through Goldfield and south—southeast past Stonewall Mountain. Also note the basalt cap (C) in the Goldfield mining district. OF IMAGES GEOLOGIC INTERPRETATION 10 MILES l 10 KILOMETERS .— O——O FIGURE 15.—Color-infrared composite of study area made up of linearly stretched images of ERTS MSS bands 4, 5, and 7 with blue, green, and red filters, respectively (scale 1:500,000). A and B are limonitic areas southwest of Quartz Moun- tain and north of Monitor Peak, respectively. Prepared by the Jet Propulsion Laboratory, tion with the us. Geological Survey. Pasadena, Calif., in coopera- 24 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES M88 5/6 10 0 10 20 MILES l 1 l l A I ' I l l 10 O 10 20 KILOMETERS GEOLOGIC INTERPRETATION OF IMAGES 25 MSS 5/7 MSS 6/7 FIGURE 16.—Linear1y stretched—ratio ERTS MSS images of the study area (scale 1:1,000,000) showing (A) variation in Mud Lake and southernmost playa, (B) mafic rocks, and (C) felsic rocks on Pahute Mesa. Selected ratios and DN ranges for stretch are: MSS 4/5, 116—161; MSS 4/6, 125—184; MSS 4/7, 156-222; MSS 5/6, 125—168; MSS 5/7, 152—205; MSS 6/7, 135—178. art (1972), and Ekren and others (1971), but a map based on a compilation by John H. Stewart and J. E. Carlson, US. Geological Survey, of the State of Nevada is the most useful single map because it integrates all these previous studies (fig. 6). In addi- tion, the original compilation scale of 1:500,000 is especially compatible with analysis of ERTS images. Three field evaluations, each 1 week long, were aided appreciably by overflying the area before working on the ground. Black-and-white aerial photographs at a scale of 1:62,500 also proved to be nearly indis- pensable for orientation and for distinguishing out- crops and surficial deposits. In the color-ratio composite (fig. 17), mafic rocks are generally White, felsic rocks are pink, playas are blue, and vigorous vegetation is orange. Limonitic areas are green to yellow green, and essentially limonite-free hydrothermally altered areas range from green to brown and, more rarely, to red brown. Clouds are a dark pink brown, and cloud shadows are white; topographic shadows are also White. Most mafic rocks can be discerned easily on the image. They appear white, usually accompanied by small patches of pink. In places, such as immediately southwest of Mud Lake (A, fig. 17) , some of the pink patches associated with the white area are clearly due to the presence of tuffs and tufi'aceous sediments, but in other areas the pink is probably related to residual soil formed on mafic rocks. These light-pink- oolored soils are exemplified by Malpais Mesa south— west of Goldfield (B, fig. 17), the basalt approxi- mately 6 km north of Tolicha Peak (B, fig. 17 ), and the basalt northeast of the Kawich Range (B, fig. 17 ) ; they are probably felsic in composition either because the mafic minerals have been decomposed and leached, leaving a residuum consisting mainly of slightly weathered feldspar, or because a veneer of felsic eolian material overlies the basalt. Some discrepancies between the map units (fig. 6) and the color-ratio composite may be accounted for by talus deposits, as mentioned previously. Unfortunately, several other rock units besides mafic rocks also appear white, although not consist- ently so. The two White spots northeast of Mud Lake (C, fig. 17 ) are dark—gray to black Paleozoic lime- stone and c‘h‘ert (Cornwall, 1972), and a white strip north of Gold Mountain (D, fig. 17) is dark-green- gray siltstone and very fine grained quartzite of Pre- cambrian and Cambrian age (Albers and Stewart, 1972). The eastern part of the white square area DISCRIMINATION OF ROCKS AND AL ERED AREAS BY USE OF ERTS IMAGES IOMILES 10 KILOMETERS GEOLOGIC INTERPRETATION OF IMAGES 27 FIGURE 17.—Three-component color-ratio composite of south- central Nevada (scale 1:500,000) made from diazo—color 4 separates showing limonitic and hydrothermally altered areas (green to brown), playas (blue), mafic rocks (gen- erally white), felsic volcanic and intrusive rocks (pink), and vigorous vegetation (orange). Clouds are dark pink brown and cloud shadows white. Prepared from ERTS MSS data by the U.S. Geological Survey in cooperation with the Jet Propulsion Laboratory, Pasadena, Calif. EROS Data Center ID No. ER—l—CC—SOOO. A, Pink patches of felsic volcanic intrusive rocks southwest of Mud Lake. B, Light-pink-colored soils formed on mafic rocks north of Tolicha Peak and northeast of the Kawich Range. C, Two white pre-Mesozoic elliptical features northeast of Mud Lake. D, White pre-Mesozoic strip north of Gold Mountain. E, Pre-Mesozoic part of the white square west of Stonewall Mountain. Western part is alluvium. F, White topographic effects on northeastern part of Stone- wall Mountain. G, Orange-pink outcrops of Thirsty Canyon rhyolitic tuffs and flows, which appear dark on the other images and photographs evaluated. H, Two blue areas representing mine tailings north and northeast of Goldfield. I, Green outcrop of slightly ferruginous sandstone of the Harkless Formation. J, Green appearing highly bleached Gold Crater area. K, Green circular area of mafic intrusive body 20 km north- west of Mud Lake. L, Brown area of rhyolite and tuff‘aceous sediments in west- ern Cactus Range. M, Two red-brown areas west of Stonewall Mountain. N, Two red-brown areas near Tolicha Peak. 0, Basalt cap mentioned in figures 8 and 14. west of Stonewall Mountain (E, fig. 17) is part of an undifferentiated Paleozoic unit (fig. 6). The west- ern part is presumably talus. Additional problems in discriminating mafic rock types are the white-appearing cloud shadows and topographic effects—for example, the thin white areas northeast of Stonewall Mountain (F, fig. 17). Examination of the stretched MSS images (figs. 13 and 14), however, makes identification and discrimi- nation of these nongeologic features straightfor— ward. Dark pink, brown pink, and orange pink are char- acteristic of felsic rocks on the image. Light vegetap tion cover causes the orange tone but it appears that rock reflectance, and therefore rock-type variation, can be seen if the vegetation cover is light, as on Pahute Mesa. 0n the other hand, where vegetation is dense, as on the Kawich Range and on Stone- wall Mountain, speotral differences reflecting rock type are not recorded. These areas appear a very dark orange. In general, the agreement between pink hues and the distribution of felsic rocks shown in the geo- logic map is quite striking. Most impressive is the orange-pink hue of the Thirsty Canyon tuffs and flows (TB and Tr3, fig. 6; G, fig. 17). Because the surface of these rocks has a low albedo, they are easily confused with the mafic volcanic rocks both on the other images evaluated and in the field. Rati- oing minimizes albedo effects, however, so that dis- crimination of these felsic rocks from mafic rocks is possible on the color-ratio composite. The orange pink in figure 17 indicates that the general shape of the visible and near-infrared reflectance spectra of these felsic rocks must be very similar to that of the other felsic rocks. In general, however, the older tufts (Tt2) and flows (Tr2) are less uniform on the color-ratio composite than units Tt3 and Tr3. Playas are easily discriminated from the altered rocks. The only blue areas in figure 17 that are not playas are two small patches representing mine tailings, north and northeast of Goldfield (H, fig. 17 ). In addition, variation within and among playas is much more pronounced in the color-ratio com- posite than in any of the previously enhanced prod- ucts. The southernmost playa and Mud Lake show the most variation, presumably because of composi- tional and perhaps grain-size differences. One of the principal objectives of this study was to evaluate the potential of the MSS data for detect- ing hydrothermally altered areas. Although none of the previous image products seems to have much potential for discriminating altered areas, these areas can be identified with a high degree of confi- dence in the threeacomponent color-ratio composite shown in figure 17. Figure 18 shows the distribution of altered outcrops based on a very general four- color classification of anomalous color patterns in figure 17. Black-and-white aerial photographs at a scale of 1:62,500 were used to exclude areas of alluvium. In general, the green to yellow-green pattern in the color-ratio composite (fig. 17) represents pre- dominantly limonitic outcrops. The largest anomaly is the green pattern representing the alteration zone in the Go-ldfield mining district (fig. 18). In fact, the agreement between the altered zone as defined by Jensen, Ashley, and Albers (1971) (fig. 18, inset) and the green pattern in figure 18 is very striking. The largest discrepancies occur in the western part of the district, where many mine dumps obscure the surface, and in the area beyond the southern border, 28 DISCRIMINATION OF ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES which was not mapped by Jensen, Ashley, and A1- bers. Although the altered area consists of several different alteration products, the G-oldfield district is represented by a fairly uniform green in figure 17. As mentioned previously, however, the red-brown hue of the limonite dominates the overall appear- ance of the complex mottled pattern (fig. 8) of the alteration zone. On the basis of this observation and of brief evaluation of several other areas, Rowan (1973) concluded that all green areas were predominately limonitic. More detailed field examination showed, however, that included in this color pattern are two or three areas that are altered but that have little or no limonitic surface stain. For example, the Gold Crater area (J, fig. 17) is very highly bleached and has only a few limonite-stained outcrop-s on the lower slopes. Most of the outcrops that are green on the composite were checked in the field, and with the exception of two areas, all proved to be hydro- thermally altered. One of these exceptions is the out- crop of slightly ferruginous sandstone and siltstone of the Harkless Formation (I, fig. 17), which is in- cluded in the undifferentiated Precambrian-Paleozoic map unit (p6 P2) of figure 6. This formation occurs only in the west-central and southwestern part of the study area. The other exception is an area that is neither limonitic nor obviously altered. The rock unit in this area, about 20 km northwest of the center of Mud Lake (K, fig. 17 ), is mapped as a Tertiary mafic intrusive body (Tmi, fig. 6). Most of the material in the crudely circular light-green area in figure 17 is alluvium derived from the intrusive body repre- sented by darker green hills in the southwestern part of the circular area. Although a few fragments of the alluvium are limonite stained, the greenish- gray outcrops appear on the ground to be generally free from ferric iron surface stains. This still enig- matic area will be the subject of future coordinated petrographic and spectral analyses. Most of the other altered areas are dark green to brown in the color-ratio composite (figs. 17 and 18). The dark-green areas, all of which were examined in the field, are confined to the southern half of the area. The rocks themselves in these areas are typic- ally pink to red, tan, yellow, and gray mottled, altered Tertiary volcanic rocks. The dark green in figure 17 represents both limonitic and limonite-free altered areas, although less limonite is generally present than in the light-green category. Brown areas in the color-ratio composite are more numerous than dark-green areas and have not been examined as thoroughly. The materials in the brown areas appear to be made up of light-colored Tertiary volcanic rocks, some of which are glassy and pumi- ceous. Limonite—free areas predominate, but some limonite may be present. In the Silver Bow district, the only brown area checked in detail on the ground, hydrothermal alteration is evident. Other brown areas checked from the air, such as those on the southeastern and southwestern margins of the Ka- wich Range, are light-colored volcanic rocks, but the presence of hydrothermal alteration could not be de- termined. Ekren and others (1971), however, stated that the light colors of the tufi’aceous sediments in the large brown area in the western Cactus Range (L, fig. 17) typify zeolitized, silicified, or argillized rocks. Several dark-green to brown areas proved to be alluvium that is limonite stained. Weathering of the many exposed surfaces of the small fragments re- sults in the formation of abundant ferric oxide. The MSS, therefore, records the characteristic spectrum of limonite (Hunt and others, 1971a; Rowan, 1972) for these weathered but not hydrothermally altered materials. A few altered areas appear red brown in the color- ratio composite. The two areas west of Stonewall Mountain (M, fig. 17 ) and the two areas near To- licha Peak (N, fig. 17 ) were examined in the field, and in all four places the rocks are nearly white silica-rich Tertiary volcanic rocks with no limonite present. The rocks west of Stonewall Mountain have been lightly altered by epithermal activity to very fine grained silica, whereas the Tolicha Peak vol- canic rocks are very glassy tuffs without any obvious hydrothermal alteration. Assessment of the color-ratio composite indicates that green, dark green, brown, and red brown, which seem to represent, in that order, predominantly limonite—stained rocks to highly bleached and argil- lize-d rocks, are generally indicative of hydrothermal alteration. Comparison of the areal distribution of mining districts (fig. 19) and the color anomalies (fig. 18) substantiates this conclusion, even though figure 19 represents only a general map of the mines and prospects. Some mines and prospects were omitted necessarily in areas of high mine density. Most of the major mining districts—Goldfield, Cactus Spring, Antelope Springs, Gold Reed, Gold Crater, Wilson’s Camp, Trappman’s Camp, and Well- ington—have concentrations of green to yellow green and dark green. A few green areas apparently do not have mines or prospects, although they con- sistently represent areas of altered rocks. Brown and red brown dominate the Silver Bow, Golden Arrow, Cuprite, and Hannapah districts, in some of which hydrothermal alteration is evident. Several brown and red-brown areas have no evidence of mining, a1- GEOLOGIC INTERPRETATION OF IMAGES 29 TABLE 1,—Ratios calculated for MSS bands for selected mafic and felsic rocks and alteration minerals of figures 2 and 20, respectively Sample Number MSS 4/5 MSS 5/6 MSS 6/7 Mafic rocks 13 1.05 1.03 1.06 1.07 1.01 .99 1.01 1.01 1.05 Serpentinite ____________________ 15 1.04 1.05 1.07 Felsic rocks Rhyolite (pink) _________________ 0.79 0.92 0.96 Rhyolite (gray) ________________ .96 .96 .98 Granite ________________________ .89 .94 91 Granite _________________________ 97 .98 92 Granodiorite ____________________ 92 .94 97 Alteration minerals Limonite (goethitic) ____________ ...._ 0.61 0.72 0.94 Limonite (hematitic) ____________ _ .49 .85 .95 Jarosite _________________________ _ 78 .99 1.27 Montmorillonite _________________ - 65 .84 1.07 Alunite ________________________ __- 66 .88 .97 Kaolinite _______________________ ___ 93 .98 .99 DISCUSSION though they are generally concentrated in areas of past mining activity. Considerably more work needs to be done to evaluate all the brown and red-brown areas fully. Two mining districts, Eden and Stonewall, are noteworthy because anomalous colors are not present (figs. 17, 19). In these districts, the spectral-reflec- tivity information is probably obscured by vegeta- tion and topographic shadows, respectively, but there is little surface indication of alteration in the vicin- ity of the Stonewall district (R. P. Ashley,written commun., 1973). Anomalous colors are not shown in figure 18 for the Mellan district because the area that appears green in figure 17 is mainly alluvium. The southwestern part of the area is also important because, although many mines are present (fig. 19), the areal density of colors indicative of hydro- thermal alteration is obviously lower than in most of the other mining districts. The main geological difference between this general area and the rest of the anomalously colored areas appears to be the prevalence of Mesozoic and Precambrian-Paleozoic rocks. The ore bodies occur as vein deposits associ- ated with the Mesozoic intrusive rocks in this area, and the surface area of alteration is very much smaller than in the altered Tertiary volcanic rocks. Hence, higher spatial resolution may be needed to detect the alteration in an area such as this. The general correlation between the color anoma- lies (fig. 18) and the known mining-district loca- tions (fig. 19) indicates that color-ratio composites should be especially valuable as a means of recon- naissance mapping for mineral exploration in well- exposed areas. Color-anomaly maps such as figure 18 can be used for selection of specific targets for detailed geologic, geochemical, and geophysical anal- yses. One of the ultimate objectives of this investiga- tion is to derive quantitative spectral-reflectivity information from the MSS images and to use these data for making estimates of the bulk composition of surface materials. Although this objective is not presently feasible because of inadequate calibration data, the spectral differences seen as color variations in the color-ratio composite (fig. 17) can be evalu- ated qualitatively by considering laboratory spectra that appear to be reasonably representative of the surface materials. As discussed previously, visible and near-infrared reflectance spectra for mafic and felsic rocks (fig. 2) have generally different shapes. Although data for only a few of the rock types present in the study area are included in figure 2, a general idea of the anticipated differences can be gained through com- parison of these spectra. A useful method for mak- ing such comparisons is examining calculated ratio values based on the width of the MSS bands used in processing the color-ratio composite (MSS 4/5, 5/6, and 6/7). These ratio values are not representative of the absolute MSS values because of undetermined effects of the solar spectrum and of atmospheric variations, but the calculated ratio values can be useful for comparative purposes. In general, ratios for the felsic rocks are less than unity, whereas the mafic rock ratios are greater than unity (table 1). Comparison of the basalt with the two rhyolite spectra shows that the ratios for basalt are ap- proximately 7—12 percent higher, except in the MSS 4/5 ratio for the pink rhyolite (table 1) where the difference is about 25 percent. These low percentage values attest to the subtlety of the spectral differ- ences among even very different rock types. It is DISCRIMINATION OF ROCKS AND AL‘TERED AREAS BY USE OF ERTS IMAGES 10 MlLES l 10 KILOMETERS o-—o ' \~\ Mud Lake . H 7‘: o '4. 0 ' ‘- '7 2a. . " a E o \ o o g C 3.! . ' . o . ' 0. 0 a o. g 0" I I O \l'. I r . .‘.l . ’ O ' ’. "' :. / ALTERED AREAS IN STUDY AREA FIGURE 18.—Distributi0n in the study area of anomalous c brown. and brown (from fig. 17). These color patterns represen Goldfield district by Jensen, Ashley, and Albers (1971) at the same scale. olor patterns, classified by four colors—green, dark green, red t altered outcrops. Inset is an alteration map of the GEOLOGIC INTERPRETATION OF IMAGES 31 Xx x x x x Hannapah x xxx x x Ellendale x X xx x‘ X Eden Golden Arrow x x X x; X Silver Bow Xx xxx xx ’9ng Klondyke XX xxx X x x x Mellan x x x x x Goldfield x x Cactus S rin X xxxx X X xx x X P g "x X x X X x . G ld Reed x a)! X X X A telo S ln s o X X xx X X X xxx X X x X n pe pr g X x Xx Wellington x X Wilson’s Camp xXxx X X )1 x x xx , x Gold Crater Xx Jamestown x Trap pman S Camp xxxx Cuprite x x xx Stonewall x xx x x x x x x x x x x x x Homsilver xx x Quartz Mountain x xx x‘x x x x X x x X x x >8 Xx x § X x X xxfix X Clarkdale x X XX X X X Xx X x x xx x 10 o 10 MILES X X xx X xx)“ T°k°p l I I l x xxx l I | I x x’): 10 o 10 KILOMETERS FIGURE 19.-—Major mining districts in the study area (scale 1:500,000 Cornwall (1972), J. H. Stewart (written commun., ). From Kral (1951), Albers mate location of mine or prospect. 1973), F. J. Kleinhampl (written commun. and Stewart (1972), , 1973). X, approxi- 32 DISCRIMINATION 0F ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES not surprising, therefore, that some form of com- puter processing is necessary to enhance the spectral signatures of mafic and felsic rocks in the standard ERTS images. Additional computer processing, per- haps using cube-root stretch of the ratio values to increase scene contrast in the dark areas in the stretched-ratio images, might permit further dis- crimination between, for example, basalts and andesites. Evaluation of the altered areas is more difficult because spectroradiometric studies have not been conducted on altered rocks. A few laboratory spec- tra, however, have been published for most of the main minerals that constitute the Goldfield altera- tion zone, including limonite, montm-orillonite, alunite, kaolinite, and jarosite (fig. 20). Comparison 80 I I I I I I I Kaolinite z”, 70 — Alunite — / . . '_ 60 _ MontmorIllonIte _ Z Lu 0 E 50 — _ a. E / lg 40 _ Hematitic limonite — Z :5 o 30 — _ 111 _I L 111 n: Goethitic limonite 10—- ~ Jarosite \\ ‘——-’ ’ 0 I I I I I I I 0.5 0.6 0.7 0.8 0.9 1.0 1.1 WAVELENGTH, IN MICROMETERS FIGURE 20.—Reflectance spectra for alteration minerals. Data for montmorillonite and kaolinite from Hunt and Salisbury (1970), alunite and jarosite from Hunt, Salis- bury, and Lenhoff (1971b), goethitic limonite from Rowan (1972), hematitic limonite obtained in place at Goldfield (A. F. H. Goetz, written c0mmun., 1973). of the ratios calculated for these spectra and for the mafic rocks (table 1) shows that the MSS 4/5 values for the alteration products are signifi- cantly lower than those for mafic rocks and that the MSS 5/ 6 ratios are slightly lower. Therefore these alteration products should be very distinctive where they occur in areas underlain by mafic rocks. Com- parison with the felsic-rock ratios indicates that geothitic and hematitic limonite, alunite, and m~ont~ morillonite should be distinguishable from felsic rocks because of their lower MSS 4/5 ratios and somewhat lower MSS 5/6 ratios. The jarosite MSS 4/5 ratio is only slightly lower than the felsic-rock ratios; however, the MSS 6/7 ratio for jarosite is markedly higher than the largest value for the felsic rocks, so this ratio could be used for discrimination purposes. The ratios shown in table 1 for kaolinite resemble those for the felsic rocks of figure 2, and it is doubtful that such small differences could be dis- tinguished in a color-ratio composite. However, as Ashley (1970) pointed out, illite and alunite are associated with kaolinite in the more intensely al- tered zone at Goldfield. Both of these minerals might, as the uniform green of the color-ratio composite at Goldfield indicates, subdue the effects of the kao- linitic spectral reflectivity and result in low ratios. Although altered and unaltered rocks are dis- criminated with a high level of confidence in the color-ratio composite, limonitic and limonitehfree hydrothermally altered areas do not appear to be dis- tinguishable at this stage of the analysis. Although this distinction does not appear to be economically important in the study area because metallization occurs in both types of areas, it could be important in areas where limonite is not particularly diagnos- tic of hydrothermal alteration. The calculated ratios in table 1 suggest that the MSS 4/5 ratio should provide the best opportunity for distinguishing bleached argillized and limonitic altered rocks, espe- cially where the limonite is hematitic rather than goethitic. In addition, higher spectral resolution and bands at longer wavelengths, such as those provided by the NASA Skylab multispectral scanner (8192), should significantly aid in discriminating these ma- terials and in estimating the mineralogical makeup of the surface materials. The above discussion illustrates the critical need for a clearer definition of the relationship between mineralogical composition and visible and near— infrared spectral reflectivity of altered and unaltered rocks. Ideally, in situ spectroradiometric measure- ments, at several scales and coordinated with de- tailed sampling for subsequent mineralogical analy- sis, should be made in a variety of geologic settings and environmental conditions. An important use for these in situ measurements is formulation of spec- tral-reflectivity standards that take into account varying surface-state conditions. The standard areas should be of different albedos but nearly uniform SUMMARY AND CONCLUSIONS 33 over large areas, and the spectral information should be collected at the same time as the satellite over- flight so that atmospheric conditions are similar. Spectral-reflectance standards acquired in this fash- ion could be used to normalize all the DN values in the M88 images, provided that atmospheric trans- mission and path-radiance are uniform over the run. Then quantitative spectral-reflectivity information could be extracted directly from the DN values for any surface unit. SUMMARY AND CONCLUSIONS The results of this study show that most of the major rock units and altered and unaltered areas in the study area can be separated on the basis of visi- ble and near-infrared spectral-reflectivity differences recorded from satellite altitude. Because these differ- ences are mainly due to slight variations in the slopes of the spectra, they are not detectable through visual or optically assisted techniques. Digital ratio- ing of the M88 bands and subsequent stretching to increase the contrast are necessary to enhance these differences. Although the basic spectral information is contained in the stretched-ratio images, color- ratio composites, especially combinations of three ratio images, appear to be the best means of display for geologic visual interpretation as an aid in min- eral-resources exploration and regional geologic mapping. For discrimination of hydrothermally altered areas and of regional rock (and soil) units in the study areas, the optimum color-ratio composite ap- pears to be a combination of diazo-color transpar- encies having the following ratio images and colors: blue for MSS 4/5, yellow for M88 5/6, and magenta for M88 6/7. In this composite (fig. 17), mafic rocks are generally distinguishable from felsic rocks de- spite their similar albedos in some places. Details within playas are best seen in the color-ratio com- posite. Some of the most important practical limita- tions, however, include erroneous identification of basalt as felsic rocks where soil overlies areas of the basalt, and lack of discrimination thus far of ba- saltic and andesitic rocks. Hydrothermally altered areas appear as anoma- lous color patterns (fig. 17) within the volcanic rocks on the color-ratio composite. Comparison of known mining-district locations and clusters of anomalous colors, ranging from green and dark green to brown and red brown, shows good agree- ment in the widespread Tertiary volcanic rocks. In the Goldfield mining district, for example, very striking agreement was found between the anoma- lous green pattern and the map of the altered area by Jensen, Ashley, and Albers (1971). However, the density of anomalies compared with that of the mines is not as high in the southwestern part of the study area where the alteration and mineralization are associated with intrusion of pre-Mesozoic rocks rather than with the Tertiary volcanic rocks. In spite of the few discrepancies, the color-anomaly map showing the distribution of altered areas (fig. 18) should be very useful for identifying sites where detailed geological, geochemical, and geophysical analyses should be made during mineral-resources exploration. In general, the green to dark-green color pattern in this color-ratio composite represents predomi- nantly limonitic areas, which except for two cases, are hydrothermally altered. All green areas in the composite are not limonitic however. Several green areas, as is well illustrated in the Gold Crater area, are essentially limonite-free argillized volcanic rocks. Red-brown areas in the color-ratio composite commonly appear to be silica-rich light-colored vol- canic rocks. In the Cuprite district, the red-brown col-or correlates very well with the silicified zone in which hydrothermal alteration has taken place, but the red-brown areas near Tolicha Peak are very glassy tuffs without any obvious hydrothermal al- teration. Brown areas, though studied in less detail than the other color anomalies, generally seem to represent light-colored volcanic rocks, with hydro- thermal alteration present at least in the Silver Bow district. The presence of hydrothermal activity in other brown areas could not be determined at this time. Although adequate spectroradiometric measure- ments are not yet available for defining the relation- ships between the mineralogical composition and spectral reflectivity of the surface materials, analysis of laboratory spectra suggests that ratio differences of 7—12 percent between the felsic and mafic rocks may be shown in the color-ratio composite. Compari- son o-f the ratios calculated for unaltered rocks and alteration minerals common to the 'Goldfield district shows that in general the altered rocks should be dis- criminable, especially in the M88 4/5 ratio. The inability to distinguish between limonitic and limonite-free hydrothermally altered areas is be- lieved to be due to the similar general shapes of limonite and nonferrous alteration minerals and to the low spectral resolution and absence of spectral bands beyond 1.1 pm in the M88. Higher spectral resolution images of the area, especially recorded 34 DISCRIMINATION 0F ROCKS AND ALTERED AREAS BY USE OF ERTS IMAGES beyond 1.1 nm, should provide adequate discrimina- tion between limonite and the nonferrous alteration minerals. Additional computer processing of the MSS data may also aid in distinction of materials. Because the studies described here have been di- rected towards areas of outcrop, surficial deposits have received very little attention; even a cursory examination of the color—ratio composite, however, shows considerable spectral information for these materials, which should be useful for study of these areas. An interesting result pertaining to these sur- ficial deposits is that a thin coating of ferric iron apparently forms on the fragments derived through weathering of some felsic rocks, thereby causing the anomalous green color on the color-ratio composite in some alluvial areas. The exclusion of these areas from the color-anomaly map is important because they are not hydrothermally altered. Refinement and further testing of these computer- processing and geologic-interpretation techniques are necessary for realizing the full potential in geologic exploration. An especially critical need at this stage is for in situ spectroradiometric measure- ments coordinated with detailed sampling for sub- sequent mineralogical analysis in a variety of geo- logic and environmental conditions. Additional computer—processing techniques that deserve consideration include cluster analysis and automatic classification. However, the advantage of interpreting a color-ratio composite over using a pure classification scheme, such as the LARSYS method (Landgrebe, 1971), is that the analyst can take into account many other factors, such as the distinction between outcrop and surficial deposits, before delineating boundaries among units. An addi- tional advantage of the ratio method used in this study is that computer-processing time is reduced by a factor of 100 or more below the time for the LARSYS classification scheme, with an accompany- ing substantial cost saving. Nevertheless, considera- tion should be given to such classification schemes as well as to both supervised and unsupervised cluster- analysis techniques. Although many questions have been left unan- swered by this report, the results indicate that geo- logic exploration can benefit substantially by the use of digital computer processing of visible and near- infrared MSS images. Limitations imposed by the low spatial and spectral resolutions of the ERTS—1 MSS must be overcome in subsequent satellite sys- tems so that the results can be applied to larger scale problems. In the meantime, in order to define the effects of spatial resolution and intervening at- mosphere, visible and near-infrared spectral data should be collected from aircraft platforms, proc- essed in a manner similar to that applied to these ERTS images, and analyzed in conjunction with existing geologic maps, field study, and spectral- reflectivity information. REFERENCES CITED Albers, J. P., and Cornwall, H. R., 1968, Revised interpreta- tion of the stratigraphy and structure of the Goldfield district, Esmeralda and Nye Counties, Nevada [abs]: Geol. Soc. America Spec. Paper 101, p. 285. Albers, J. P., and Kleinhampl, F. J., 1970, Spatial relation of mineral deposits to Tertiary volcanic centers in Ne- vada: U.S. Geol. Survey Prof. Paper 700—0, p. Cl—CIO. Albers, J. P., and Stewart, J. H., 1972, Geology and mineral deposits of Esmeralda County, Nevada: Nevada Bur. Mines and Geology Bull. 78, 80 p. Ashley, R. P., 1970, Evaluation of color and color infrared photography from the Goldfield mining district, Es- meralda and Nye Counties, Nevada: U.S. Geol. Survey open—file report, 36 p. Ashley, R. P., and Keith, W. J., 1973, Geochemistry of the altered area at Goldfield, Nevada, including anomalous and background values for gold and other ore metals: U.S. Geol. Survey open-file report, 117 p. Bancroft, G. M., and Burns, R. G., 1967, Interpretation of the electronic spectra of iron in pyroxenes: Am. Min— eralogist, v. 52, nos. 9-10, p. 1278—1287. Billingsley, F. C., and Goetz, A. F. H., 1973, Computer tech- niques used for some enhancement of ERTS images, in Friden, S. G., and others, compilers and editors, Sym— pOsium on significant results obtained from the Earth Resources Technology Satellite—1. Volume I—Technical Presentations, Section 13: U.S. Natl. AeronautiCS and Space Admin. SP—327, p. 1159—1168. Billingsley, F. G., Goetz, A. F. H., and Lindsley, J. N., 1970, Color differentiation by computer image processing: Photog. Sci. and Engineering, v. 14, no. 1, p. 28—35. Cornwall, H. R., 1972, Geology and mineral deposits of southern Nye County, Nevada: Nevada Bur. Mines Geol. Bull. 77, 45 p. Ekren, E. B., Anderson, R. E., Rogers, C. L., and Noble, D. C., 1971, Geology of northern Nellis Air Force Base Bomb- ing and Gunnery Range, Nye County, Nevada: U.S. Geol. Survey Prof. Paper 651, 91 p. Goetz, A. F. H., 1974, Quality and use of ERTS radiometric information in geologic applications: Ann. Conf. Appli- cation Remote Sensing Arid Land Resources and En- vironment 4th, Tucson, Ariz. Nov. 14—16, 1973. (In press). Goetz, A. F. H., Billingsley, F. G., Yost, E., and McCord. T. B., 1971, Apollo 12 multispectral photography experiment, in Levinson, A. A., ed., Proceedings of the Second Lunar Science Conference, Houston, Texas, January 11—14, 1971: Cambridge, Mass, MIT Press, v. 3, p. 2301—2310 (Geochim, et Cosmochim, Acta, Supp. 2). Harvey, R. D., and Vitaliano, C. J., 1964, Wall-rock altera— tion in the Goldfield district, Nevada: Jour. Geology, v. 72, no. 5, p. 564—579. Hunt, G. R., and Salisbury, J. W., 1970, Visible and near- infrared spectra of minerals and rocks—I. Silicate min— REFERENCES CITED 35 erals: Modern Geology, v. 1, no. 4, p. 238—300. Hunt, G. R., Salisbury, J. W., and Lenhofl", C. J., 1971a, Visi- ble and near-infrared spectra of minerals and rocks— III. Oxides and hydroxides: Modern Geology, v. 2, no. 3, p. 195—205. 1971b, Visible and near-infrared spectra of minerals and rocks—IV. Sulphides and sulphates: Modern Geol- ogy, v. 3, no. 1, p. 1—14. 1973a, Visible and near-infrared spectra of minerals and rocks—VII. Acidic igneous rocks: Modern Geology, v. 4, p. 217—224. 1973b, Visible and near-infrared spectra of minerals and rocks—VI. Additional silicates: Modern Geology, v. 4, p. 85—106. 1974a, Visible and near-infrared spectra of minerals and rocks—VIII. Intermediate igneous rocks: Modern Geology (In press). 1974b, Visible and near-infrared spectra of minerals and rocks—IX. Basic and ultrabasic igneous rocks: Mod- ern Geology (In press). Jensen, M. L., Ashley, R. P., and Albers, J. P. 1971, Primary and secondary sulfates at Goldfield, Nevada: Econ. Geol- ogy, v. 66, p. 618—626. Kral, V. E., 1951, Mineral resources of Nye County, Nevada: Nevada Univ. Bull., v. 45, no. 3 (Geology and Mining Ser. no. 50), 223 p. Landgrebe, D. A., 1971, Systems approach to the use of re- mote sensing: Purdue Univ., Lab. Application Remote Sensing, LARS Inf. Note 041571, 40 p. Ransome, F. L., 1909, The geology and ore deposits of Gold- field, Nevada: U.S. Geol. Survey Prof. Paper 66, 258 p. Ross, H. P., Alder, J. E. M., and Hunt, G. R., 1969, A sta- tistical analysis of the reflectance of igneous rocks from 0.2 to 2.65 microns: Icarus, v. 11, no. 1, p. 46-54. Rowan, L. C., 1972, Near-infrared iron absorption bands: Applications to geologic mapping and mineral explora- tion: Annual Earth Resources Program Rev., 4th, Hous- ton, Tex., 1972, p. 60—1 to 60—18. 1973, Iron-absorption band analysis for the discrimi— nation of iron-rich zones: U.S. Geol. Survey open-file report, 23 p. Rowan, L. C., and Vincent, R. K., 1971, Discrimination of iron-rich zones using visible and near-infrared spectral analysis [abs]: Geol. Soc. America, Abs. with Programs, v. 3, no. 7, p. 691. Searls, Fred, Jr., 1948, A contribution to the published in- formation on the geology and ore deposits of Goldfield, Nevada: Nevada Univ. Bull., V. 42, no. 5 (Geology and Mining Ser. no. 48) 24 p. U.S. National Aeronautics and Space Administration, God- dard Space Flight Center, 1971, Data users handbook [for Earth Resources Technology Satellite]: U.S. Natl. Aeronautics and Space Admin., Goddard Space Flight Center Doc. 7ISD4249 [loose-leaf, variously paged]. Vincent, R. K., and Thompson, F. J., 1972, Discrimination of basic silicate rocks by recognition maps processed from aerial infrared data, in Seventh Internat. Symposium on Remote Sensing of Environment, Proc., V.1: Ann Arbor, Mich., Univ. Michigan, Inst. Sci. and Technology, Willow Run Laboratories, p. 247—252. [Whitaker, E. A.] 1965, Colors and the mesa-structure of the maria, in Heacock, R. L., and others, Ranger VII, Part II, Experimenters’ analyses and interpretations: Cali- fornia Inst. Technology, Jet Propulsion Lab. Tech. Rept. 32—700, p. 29—39. White, W. B., and Keester, K. L., 1966, Optical absorption spectra of iron in rock-forming silicates: Am. Miner- alogist, v. 51, nos. 5—6, p. 774—791. Yost, E., Anderson, R., and Goetz, A. F. H., 1973, Isolumi— nous additive color method for the detection of small spectral reflectivity differences: Photog. Sci. and Engi- neering, v. 17, p. 117—182. 0 U.S. GOVERNMENT PRINTING OFFICE : I974 O—553i533 BACK COVER: Mosaic of the State of Nevada prepared by Aerial Photographers of Nevada, Reno-Stead Airport, Nev., from NASA ERTS images for band 5 FRONT COVER: Part of the mosaic of the conterminous United States compiled by the Soil Conservation Service of the US. Department of Agriculture from NASA ERTS images for band 5 ":9: ‘79 U 7 DAY Carboniferous Biostratigraphy, Northeastern Brooks Range, Arctic Alaska GEOLOGICAL SURVEY PROFESSIONAL PAPER 884 P4301975 @fi'fi Carboniferous Biostratigraphy, Northeastern Brooks Range, Arctic Alaska By AUGUSTUS K. ARMSTRONG, US. Geological Survey, and BERNARD L. MAMET, University of Montreal, Montreal, Canada GEOLOGICAL SURVEY PROFESSIONAL PAPER 884 Eleven microfossil assemblage zones are recognized in two sections of Carboniferous rocks in the northeastern Brooks Range, correlated with six other previously described sections, and tied to the Cordilleran and Eurasian standards UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON:1975 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress Cataloging in Publication Data Armstrong, Augustus K. Carboniferous Biostratigraphy, northeastern Brooks Range, Arctic Alaska. (Geological Survey Professional Paper 884) Bibliography: p. 23—25. Includes index. Supt. of Docs. No.: 119.16z884 1. Geology, Stratigraphic—Carboniferous. 2. MicropaleontologyiAlaska—Brooks Range. 3. Stratigraphic correlation— Alaska'Brooks Range. 1. Mamet, Bernard L.,j0int author. 11. Title. 111. Series: United States. Geological Survey. Professional Paper 884. QE671.A7 557.3’083 [551.7’5] 75-619053 For sale by the Superintendent of Documents, US. Government Printing Office Washington, DC. 20402 Stock Number 024-001—02667-8 CONTENTS Page Page Abstract __________________________________________________ 1 Kongakut River section ____________________________________ 4 Introduction ______________________________________________ 1 Biostratigraphy __________________________________________ 7 Acknowledgments ________________________________________ 2 Microfaunal assemblage zones __________________________ 7 Stratigraphy ______________________________________________ 2 Microfossil list ________________________________________ 9 Endicott Group ________________________________________ 2 Biota of the lagoonal facies, Alapah Limestone, Kongakut River Kekiktuk Conglomerate ____________________________ 2 section ___________________________________________________ 16 Kayak(?) Shale ____________________________________ 2 Regional correlations ______________________________________ 17 Lisburne Group ______________________________________ 2 Endicott Group ________________________________________ 17 Wachsmuth and Alapah Limestones ________________ 2 Lisburne Group ______________________________________ 19 Wahoo Limestone __________________________________ 4 References cited __________________________________________ 23 Clarence River Section ____________________________________ 4 Index ____________________________________________________ 27 ILLUSTRATIONS Page FIGURE 1. Index map of northern Alaska, and location of sections described in this report ______________________________________ 2 2. Regional stratigraphic correlation chart of the Lisburne Group of arctic Alaska ______________________________________ 3 3. Stratigraphic column of the Clarence River section 71A—1,2, northeastern brooks Range and explanation of lithologic and paleontologic symbols used in this report ________________________________________________________________________ 5 4. Photomicrographs of carbonate rocks and microfossils,‘ Clarence River section 71A—1, 2, and Kongakut River section 71A—3 _______________________________________________________________________________________________________ 6 5. Photograph of outcrops of Wahoo Limestone on the Clarence River __________________________________________________ 7 6. Photograph of Corwenia jagoensis Armstrong in the Atokan age beds of Wahoo Limestone _____________________________ 7 7. Stratigraphic column of the Kongakut River section 71A—3, 4, 5, 6, northeastern Brooks Range ______________________ 8 8. Photograph of the outcrop of the lower part of the Kongakut River section __________________________________________ 9 9. Photomicrographs of carbonate rocks and microfossils, Kongakut River section 71A—3 _________________________________ 0 10. Photomicrographs of carbonate rocks and microfossils, Kongakut River section 71A—3, 4 _______________________________ 12 11. Photomicrographs of carbonate rocks and microfossils, Kongakut River section 71A—4, 5 _______________________________ 14 12. Graphs showing the distribution of microfossils in lagoonal facies of Kongakut River section __________________________ 18 13. Carboniferous biostratigraphic correlation chart, northeastern Brooks Range, Alaska ________________________________ 20 14. Photograph of stromatolites in the Alapah Limestone from the Plunge Creek section 70A—4 ___________________________ 22 15. Location map of Clarence River section 71A—1, 2 ___________________________________________________________________ 23 16. Location map of Kongakut River section 71A—3, 4, 5, 6 ____________________________________________________________ 23 III CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA By AUGUSTUS K. ARMSTRONG1 and BERNARD L. MAMET2 ABSTRACT Two sections of Carboniferous rocks were measured in the northeastern Brooks Range, arctic Alaska, and correlated with six other sections previously described. The section on the Clarence River is 739 m thick. Endicott Group sandstones and gray shales at the base of the section are 175 m thick and are Viséan (Meramecian) in age. They are overlain by 564 m of Lisburne Group carbonate rocks of Viséan (lower Chesterian) and Namurian-Westphalian (upper Chesterian, Morrowan, and Atokan) age. The base of the 1,062-m- thick section on the Kongakut River is not exposed. The basal rocks of the Endicott Group are more than 341 m thick and are Viséan (Meramecian) in age. They are overlain by 721 m of Lisburne Group rocks of Viséan and Namurian (Meramecian and Chesterian) age. The Permian and Triassic Sadlerochit Formation unconformably overlies these Chesterian carbonate rocks. Within these two sections, 11 microfossil assemblage zones are recognized. They are correlated with six other sections in the northeastern Brooks Range and tied to the Cordilleran and Eurasian standards. The lower part of the Alapah Limestone in the Kongakut River section from 369 to 692 m represents shallow lagoonal sedimentation with a biota characterized by abundant calcispheres of the genera Calcisphaera, Parathurammina, and Vicinesphaera. Lithologic studies reveal that the Lisburne Group carbonate rocks on the northeastern Brooks Range were deposited in shallow water on a slowly subsiding shelf. During brief and possibly cyclic periods carbonate sedimentation exceeded subsidence and formed regional and local intertidal to supratidal carbonate deposits. INTRODUCTION In 1971 Armstrong and J. T. Dutro, J r., measured and sampled the Clarence River Section, and Armstrong, 1US. Geological Survey. 2University of Montreal, Montreal, Canada. H. N. Reiser, W. P. Brosgé, and R. L. Detterman measured and sampled the Kongakut River section. These sections are described in this report and are correlated with three stratigraphic sections previously described by Armstrong, Mamet, and Dutro (1970) and three sections described by Mamet and Armstrong (1972) from the northeastern Brooks Range. A foraminiferal zonation for the Lisburne Group in the central and eastern Brooks Range was established by Armstrong, Mamet, and Dutro (1970) and extended by them (1971) to the Lisburne Group of the Lisburne Hills and sea cliffs of northwestern Alaska. A detailed systematic study and illustrations of the Carboniferous microfossils of the Lisburne Group are given by Mamet (in Armstrong and Mamet, 1975) with discussions of their stratigraphic and geographic ranges. This report extends this microfossil zonation of the Lisburne Group to the Franklin and Romanzof Moun- tains of northeastern Alaska. The correlated sections project in an east-West direction along the north flank of the Brooks Range, from Clarence River near the Canadian boundary west to the Sadlerochit Mountains, south of the Canning River to Marsh Fork, then finally east to the Romanzof Mountains in the northeastern Brooks Range with a line east to the Kongakut River (figs. 1, 2). The carbonate rock classification used in this report is that of Dunham (1962). A detailed historical review of stratigraphic studies of the Lisburne Group can be found in Bowsher and Dutro (1957) and Armstrong, Mamet, and Dutro (1970). 1 170° CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA 164° 158° 152° 146° 140° 50 I 0 50 100 MILES l I \ Point Barrow . 0C 50 0 50 100 KlLOMETRES EAN 70° BEAUFORT NAVAL PETROLEUM RESERVE NO. 4 Prudhoe Bay State No 1 68A- 4A, 4B Measured sections and3 3 H69“ 1 GBAVS stratigraphic correla- = Sadlerochit Mts [ions described in \ Shublik Mts Romanzof Mts this report 70A»4. 5 Franklin Mts 70A—2, 3 Cape Lisburne Point Hope 71A—3 70M; 7 4' 5' 6 ARCTIC NATIONA 68" Cape Thomson Mountains \ ‘/\ ‘ \ ' BROOKS N onlak I \ . % Baird Moumains “we“ \ 09 Long 0““‘5IY‘5 RANGE Shainin Lake 5‘5““ Mountalns “Q“? * Location maps. figs. l5 and I6 I l l \ 71A—1, 2 L\ f\/\WILDLIFE RANGE \‘ \Vfi/d IN Nvo 15 331 V fl— v’av FIGURE 1.—Index map of northern Alaska, and location of sections described in this report. ACKNOWLEDGMENTS We thank the Naval Arctic Research Laboratory (Barrow), Office of Naval Research, for its logistical support of fieldwork in the summers of 1968, 1969, 1970, and 1971. We are grateful to our colleagues, J. Thomas Dutro, Jr., and William J. Sando, who helped in the preparation of the manuscript and provided critical review. STRATIGRAPHY ENDICOTT GROUP Kekiktuk Conglomerate.—— Brosgé, Dutro, Mangus, and Reiser (1962) named the basal sandstone beneath the Kayak(?) Shale in northeastern Alaska the Kekik— tuk Conglomerate. The type section is on Whistler Creek, near the Neruokpuk Lakes. They found only indeterminate plant fragments within the formation and assigned it a Late(?) Devonian or Mississippian age, but they believed that it represents the basal conglom- erate of the overlapping Mississippian sequence. Re- gionally, the Kekiktuk lies unconformably on strata ranging in age from Precambrian to Middle Devonian (Dutro and others, 1972). The base of the Kekiktuk Conglomerate is a pebble or cobble conglomerate grading upward to coarse-grained beach or near-shore deposits that in turn commonly grade upward into finer grained paralic sediments. The contact between the Kekiktuk Conglomerate and the overlying Kayak(?) Shale is generally gradational. Kayak(?) Shale—Mississippian dark-gray to black shales lie beneath carbonate rocks of the Lisburne Group throughout the eastern and central Brooks Range. Bowsher and Dutro (1957, p. 6) named these rocks the Kayak Shale, from the type locality on the south side of Mount Wachsmuth, east of Shainin Lake in the Endicott Mountains. The Kayak Shale at its type locality is Early Mississippian in age. Adjacent to and east of the Canning River, in the Arctic National Wildlife Range, a similar black shale occurs between the Kekiktuk Conglomerate and the Lisburne Group. Brosgé, Dutro, Mangus, and Reiser (1962, p. 2185) stated “this shale is at least in part of Late Mississip- pian age.” They added, “Because of geologic structure, this shale can not be mapped continuously into the type Kayak. It might therefore be a discrete unit entirely younger than the Kayak and separated from the Kayak by a disconformity with the Mississippian rocks.” Following Brosgé, Dutro, Mangus, and Reiser (1962), the shales in the area of this report are called Kayak (?) Shale. LISBURNE GROUP Wachsmuth and Alapah Limestones.—In the Shainin Lake area, Endicott Mountains, Bowsher and Dutro (1957, p. 3, 4, 6) recognized two new formations Within the Lisburne Limestone and raised the Lisburne to group rank. The lower formation is the Wachsmuth Limestone, and the overlying one is the Alapah Limestone. Armstrong, Mamet, and Dutro’s (1970, figs. 3, 4) study indicates that on the basis of microfossils the age of the Wachsmuth at its type section is late Osagean (Zone 8) through Meramecian (Zone 12). They found that the Alapah Limestone contains microfaunas of STRATIGRAPHY 66915 ueadoma ueueudisaM ueunweN uegsm uegsgeumoi \ auoxsemn uadaw 9 l9 'V‘E ”VLL g 19AM )nxefiuo» 3 : dnms suinqsn a a g § § :12 euoisswn ’ euoysawn uedsw F 00 a ' w z ‘L-VLL u M iaAgH acumen _ dnma ewnqsn '0 8 fi :5 euoisamn auozsemn uedelv .: mg 9—, '3 V1 'H "N ll ‘J. '01 058 ‘l '°N 0(7qu 3 %§ as 91938 KEEI souprud Z a 9 Lu -001 a g M nH V dnmg euinqsn 2 euoisewn ‘ euozsauin uedew . ovum L S’VOL siw ,ozuemoH dnoig auinqsn " eumssLuI—u v1 53 ‘ aumsewn uedew (UHWUJ °' quM *SHQEM 1', E'Z'VOL m JD 912 E >1 i H W dnon) eumqsn fl & E 8 u auoisamn I euolsamn uedew ‘— a) c oouEM E E” w 9 ‘v-vot 5 § 1.1 ABMH Suguueg ._ E ”I m anJQ aumqsn m 2 SUOISGUJH OOH? M I euozsewn uedew l'VSS 'SIIN $!U0019IPES walseM dnng awnqsn eumsewn DoueM ‘ aumsamn uedew iaAgu enooqoa dnms eanqsn ’- 8.5 3 E 9291 >I!||!>DI _"'_ 6 3% anJE) emnqsn fi. 5 31 a a ‘3 o ‘L‘ E '— | on 5 ._ E: 5 _. D a) .n .. c J: o) l g E (Lssmmna s @553 -§ ég 52 t0 5 3‘7 “,8. g :0 pumusmoe 61% 35°, 1;, m9_E9_ gg_ m. g-%- 755 - g UJOJJSE'WE“ 1.3 Eng 55 E 33 233 01%}; E8 ngBI a” E” $6.5 WWIWW 53 raw {,3 2' 5g 2%; §§E 2% £541 8 a 2‘23 :7. Ecg§ 33 3 2E 3%5 five as gage; E EM m fuse» “a E; 2% m5 Ei‘ ( g g a a a; a 2‘3 9» j 33 is U I w w 2. uoueuuod Q g a 0 .E N p. g S 8 :> u. o g m E 6 euoysawn qedE'V euozsemn uinwsuoeM | l anJ 1 0 < drlOJE) eanqsn °' § :1 “Olleuuod uoueuuod J]- § : Ll-VEQ iorves fe-v99 g l ”"1502 MEJOSEN g 3 suouaas sums-1 adeo g |_.__._ g g g E E D: dnma aanqsn o} E f) 3 ‘5 a 2 ° 8 4., J. § v- E D g I E (1| : $2 5 st-vaeuouoes % lagl a '2': g ‘5 Heels >19!N Lanes g 35 g 0’ E fi (~- (I R 5 € E LL | I «L B o . l '9'; g 3 x I 4 9 N o. s. .9 ‘6 ewes Houses 5 | dnms I c § g E M6310 MN WON =5 9'. aumqsn J g; B * +— 5: ' { 9W2 .- a m o h u“; ('5 II: V m N 3; 9 a) .1, afielqmesse [euneimogw N N * '- .— '- * '- v- .- to c a) c 3‘ w a: up a: w o c n) 95 mg 535 gag-figs .g 25 5; if» as. uoneuucnueUuuoomw gé 60%; 52% g Egg 5 E 3% 3 as FIS§§ 33 23% gé x J :, a j u? E L? I if 2 3 j J 3 j in: seues Imam/mid wxow . uegiaiseuo uagoemmew uesfieso saHES alpplw JBMU1 Jsddn JGMO'l NVINVA mexsfis ’IASNNEd NVIddlSSISSIW FIGURE 2.—Regional stratigraphic correlation chart of the Lisburne Group of arctic Alaska. 4 CARBONIFEROUS BIOSTRATIGRAPHY, N ORTHEASTERN BROOKS RANGE, ARCTIC ALASKA Meramecian (transition of Zones 12 and 13) through Chesterian (Zone 19) ages. Wahoo Limestone.—Brosgé, Dutro, Mangus, and Reiser (1962, p. 2 191—2 192) described the type section of the Wahoo Limestone near Wahoo Lake as containing carbonate rocks of both Pennsylvanian(?) and Permian age. In the area of this report, the Wahoo Limestone as mapped by Reiser, Dutro, Brosgé, Armstrong, and Detterman (1970) may contain carbonate rocks of Late Mississippian (very latest Chesterian) and Early and Middle Pennsylvanian age (Morrowan and Atokan). The Pennsylvanian limestones overlie Mississippian carbonate rocks without a recognizable hiatus. The boundary between the two systems and the zones within them are based on microfaunal assemblages. The beds of Atokan age are unconformably overlain by Late Permian arenaceous limestones, sandstones, and con- glomerates in the lowest part of the Sadlerochit Formation. CLARENCE RIVER SECTION At the outcrops of the Carboniferous rocks on the Clarence River (fig. 3) the oldest unit, the Kekiktuk Conglomerate, rests with a marked unconformity on arenaceous lower Paleozoic limestones (H. N. Reiser, oral commun., 1973). The basal 3 m of the Kekiktuk Conglomerate is gray to dark-gray sandstones, siltstones, and thin coal beds in 0.3- to 0.5-meter-thick beds. Above this basal unit, the Kekiktuk Conglomerate is 97 m of dark-gray shales, arenaceous limestone nodules in dark-gray shale, and gray to pale-yellow-brown thin siltstones and sandstones with thin coal beds. Minor amounts of interbedded thin gray argillaceous limes- tones are present, and a foraminifer-crinoidal packstone occurs 37.8 m above the base (fig. 4A). The contact of the Kekiktuk Conglomerate with the overlying Kayak(?) Shale is picked above the last thin coal bed at about the lOO-m level. The Kayak(?) Shale consists of thin-bedded dark-gray shales, siltstones, and argillaceous fine-grained sandstones. Some thin-bedded siltstones and sandstones are reddish brown owing to hematitic cement. The contact of the Kayak(?) Shale with the Alapah Limestone is covered by a talus slope and is arbitrarily picked at about 175 In (fig. 3). The carbonate rocks of the Lisburne Group in this section are commonly altered by tectonic stress, and affected horizons are shown in figure 3. The first good outcrop of the Alapah Limestone, found at 198 m above the base, is gray dolomite, formed by 5- to 10-micrometre-size dolomite rhombs, with abundant and well-developed birdseye structures, small litho- clasts, stromatolites, and calcite pseudomorphs of gypsum (fig. 4B). The stromatolite zone is 15 to 17 m thick. The sedimentary structures clearly indicate a well-developed intertidal to supratidal facies. Above the intertidal to supratidal facies, exposures are poor (fig. 3) until about 308 m above the base where typical Alapah crinoidal-bryozoan wackestones and packstones with nodular gray cherts are found. Detrital quartz sand is rare as is dolomite above the 250—m level, except for 1- to 3-m-thick dolomite beds at the 371- and 396-m level. The dolomite is formed by dolomite rhombs in the 20- to 30-micrometre size. The Alapah-Wahoo contact is put at the first occurrence of massive limestone and pale-yellowish-orange interbeds at 425 m above the base. The Wahoo Limestone (fig. 5) is composed partly of tectonically stressed foraminifer-ooid grainstones (fig. 4C), coarse-grained foraminifer-ooid lump grainstones (fig. 4D, E, F), bryozoan-crinoid packstones and wacke- stones, lime mudstones and pale-yellowish-orange- weathering argillaceous thin-bedded dolomites. Detri- tal quartz, 50- to 100-micrometre size, is common in the dolomites. Large colonial corals are common in the upper part of the Wahoo Limestone (fig. 6). The highest beds of the Wahoo Limestone are arenaceous packstone followed by 2 m of yellowish- orange-weathering, arenaceous, bryozoan-crinoid wackestone. In the carbonate rocks the detrital quartz sand is 0.1—0.2 mm in size and rounded. The carbonate rocks of the Wahoo Limestone are ‘lnconformably overlain by Permian grayish-brown argillaceous cal- careous siltstones and sandstones of the Sadlerochit Formation. KONGAKUT RIVER SECTION The Carboniferous section south of the Kongakut River (figs. 7, 8) is well exposed except that the lower part of the Kayak(?) Shale and older beds are cut out by a fault and covered by tundra. The Kayak(?) Shale from the base to 134 m is dark-gray fissile shale with a few 3- to lO-cm-thick argillaceous beds and lenses of brown to gray siltstone and fine-grained sandstone. From 134 to 341 m the Kayak(?) Shale is an alternating series of dark—gray shales and dark-gray argillaceous spiculitic lime mudstones and wackestones (fig. 4G, H. 7, 9A). A black, argillaceous lime mudstone with nodular to bedded chert is present from 192 to 223 m. It is very siliceous and spiculitic and contains fragments of bryozoans and echinoderms. This unit is dolomitic in zones with abundant 50- to 100-micrometre-size dolomite rhombs. The contact of the the Kayak(?) Shale with the Alapah Limestone is gradational. The lower part of the Alapah Limestone (fig. 7) from 342 to 571 In is an argillaceous, coralliferous, thin- bedded foraminiferal-algal-bryozoan-echinoderm wackestone and packstone (figs. 9B—H, 10A—D). From S'l‘RA'l‘lGRAPHY 5 l- - | V dk . _ _ A7 dk i." 3 § .- .- I +: W 9y 300_ 9y § 5 35 g o u.— *- o . g; E _ - ' ‘ I % —eI—x 5 ‘ g5 i 3% I “P Q I P 2 9y g 3:5 0 %< l/ 'T‘ E '76 i D 21 o E _ 5 - - 7v - v 2 739a , 9r P 5'" ,. 21 L“ V/ ‘/l 275— g = say 500 ‘0 z w 0 3- % dk _ 9‘ E v - _ 9V 725 Fig -‘f: t_| M U u- P 12 9V — 4c — — _ — yel § dk '7 '- — ‘3 A1 9y : ‘ _‘ _ —‘ W '3 '3 Sm,“ E _. 17.;7P D x blk < .5 - _ a) . 3| § it - Y -‘ 7: 7 - 250— > __ 9V 3 - wk ‘1 2 +1 * H P - vo' A8 3 475— ,- -* M 20 7 5 g D 16' 0mg dk 700 -v ; 2 — a: g l-l- ul- l P A2 4— 9y " w 5 yel E g ”k 3 A6 §i# 5,; § D 1000: P E gy '1 <7: 1 cm 21 say 20 —v coal w .QA _ 1“ Stress yel 225 g; D _ 2' s75- — “7““ I: D dk 13% p gy A34“- w W ., , - mg 4, 4, — __ __ dk Explanaflonofllmologic P Stress W yel m («I7») AW QY andpalaormloglc symbols -0— CV i“ _H m m D 1 CD Tl W F}; f“ mm fin“ . 1o \ :D /7‘ * D 200— m. . Anhd ' l/ T“ & ”I“ ‘ p m a: l T -* P g i 425— V *I 1 L 650_ <7 3 l 4- a:. say mo 90 1’? lpvl w a a: | m 19 mm L p L 3 I '1‘ - 7k 2 A5 yol- 0-0: fl G 3 - + I- W "W - _ ‘3 E Fir 9* O'—E— 21 T -+- f Wonly SM 3 g 15 6:9“.‘2 W - . , O o ' ——— “"99 ‘3 E -8' ma ' o 2! G VP H P E 9v —7*—7—175*- an?!“ E J g 99.1.?“ Stress 4°0- - ‘\ 2 I W. W ‘flgflm' cw 625 "‘ ‘¢"""®"y' E yel .— 0 § _Ve m ffl. P 0 J_ CARBONATE PARTICLES . L ,x—— OTHER THAN FOSSILS r . . A7 Coalodpartldco lo lo (3 G sue - W s. M =. ‘1- JL D __si - .. <- ‘8 m m "d W'W mi}; 4< | * w - T‘f‘w -le A4 Tk sm 0 else + 03° - . gy — 'I ‘0“ ~—-——— 375 -- *‘ P mk flap—i— Superflclal E / ¢ V‘ w Granule ‘ CD ould © __ D ”—4. _ PM” 60° .l*.q~:*| P - a Pebble 0 ® - el 0 e (E5l 3“ 5 o | *‘ P "‘— E smsumsronsgossn. P IOL m |* '1‘ B g f *4'IM _ 3 m .9 7% la a G] G a 3‘ mm Fusullnld Echinodevm T 4: m [ m — o e ’T‘ la 9 o] l 9‘ § Calcareous Solitary Bryozoen ‘9 l9 9 P .+: ; gy 3'98! coral |0 0| 5 35°' 3 x w <7 5755‘ ~0- -0— A7 tress I fr‘ 7“ P Sponge Colonlal Bimbpod gy ‘— spleule ooval ~— 6% B Q X 0— * Abundant smaller Pemnod Osvaoode yal - 47%.- T loramlnlfer - - 17 A3 9y TEXIURE W t I fil- M-Limormdebne Slim-ml: M __ 1.5.," w-Wnekeetone recrynalllzaflon _AL°__ ] l D-Dolomne gy 325 ~ ———— 003' p _ pm xln — Crystalline 21 yel' é 3-9..mm Anhd-Anhydrlta _ — 5 E Sednmnary strumrea M 93' g — u. G) A. a I ‘ p __ IA. *1 5 Birdseye Crossoeddlng l . D 5 yel -)< P 9’ . dk x o l g ’0- L W Interdam Galena muuompha r "' 1 W blk olgwoum FIGURE 3.—Clarence River section, 71A—1, 2, northeastern Brooks Range, and explanation of lithologic and paleontologic symbols used in this report. 6 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA FIGURE 4.—Phobomicrographs of carbonate rocks and microfossils, Clarence River section 71A—1, 2 and Kongakut River section 71A—3. Location shown in figures 3 and 7. BIOSTRATIGRAPHY 7 571 to 576 m above the base superficial coated ooids and pelletoid packstones and abundant microfossils are present (figs. 10E-—F). The Alapah Limestone above 600 m is much less argillaceous, light gray in color, and composed primarily of echinoderm-bryozoan-algae- foraminiferal-brachiopod wackestones and packstones. Lesser amounts of lime mudstones and dolomitic beds are present. Detrital quartz sand is very rare. Ooid beds are found at 685 and 775 m, and grainstones and packstones composed of bryozoans and crinoids are not uncommon (figs. 7, 100, G, H, 11A—F). Above 900 m to 1,025 m the Alapah is a light-gray, massive bryozoan— echinoderm packstone and grainstone, with minor amounts of wackestone and dolomites (fig. 11G, H). Above the 400-m level, dolomite is generally present in the form of 30- to 70-micrometre rhombs. The Alapah Limestone from 1,031.5 to 1,062 m is arenaceous bryozoan-echinoderm wackstones, packstones, grainstones, and cherty dolomites. The dolomite is formed by 30- to 50-micrometre size dolomite rhombs. FIGURE 4.—— Bar scale = 0.5 mm, A—F, Clarence River section. A, Recrystallized crinoid-foraminifer packstone. Pressure solution is widespread and foraminifer tests are partially dissolved; Eoforschia sp., E ndothyra sp., and Earlandia of the group E. clavatula (Howchin) are present. Univ. Montréal 271/6, section 71A—2+124 ft; 37.8 m above the base, Kayak Shale(?) (lateral equivalent of the Wachsmuth Limestone), Zone 12 (or slightly younger?), upper Salem age equivalent, middle Viséan. B, Calcite pseudomorphs of gypsum in a fine-grained microdolomite, former pelletoidal wackestone. Univ. Montréal 271/11, section 71A— 2+660 ft; 201.2 m above the base, Alapah(?) Limestone, zone undetermined (Zone 15 or 16?), upper Meramec or lower Chester age equivalent, late Viséan. C, Tectonically stressed foraminifer- ooid grainstone. Univ. Montreal 271/2, section 71A—2+1,600 ft; 487.7 m above the base, Wahoo Limestone, Zone 20, Morrow age equivalent, late Namurian. D, Early cemented lump grainstone. Neoarchaediscus incertus (Grozdilova and Lebedeva) and algal fragments are present. Univ. Montreal 270/37, section 71A—1 +590 ft; 560.8 m above the base, Wahoo Limestone, Zone 21, Atoka age equivalent, early Westphalian. E, A typical coarse-grained foraminifenooid lump grainstone of the middle part of the Wahoo Limestone. Pseudostaffella sp., Eoschubertella sp., Globiualvulina sp., and Endothyra sp. are partly coated and mud filled. Echinoid spines, pelmatozoan plates, and algae are present. Univ. Montréal 270/27, section 7 lA—l +345 ft; 635.5 m above the base of the section, Zone 21, Atoka age equivalent, early Westphalian. F, Detail of E showing two sections of Eoschubertella yukonensis (Ross). Univ. Montreal 270/32, as fig. 4E, G, H, Kongakut River section. G, Two sections of Stacheia skimoensis Mamet and Rudloff in a crinoid— bryozoan packstone. Note the excellent preservation of the thalli, in spite of the widespread and extensive epitaxial overgrowth. Univ. Montréal 274/30, section 71A—3 +565 ft; 172.2 m above the base, Kayak Shale(?/ interfingering with Wachsmuth Limestone, Zone 12, upper Salem age equivalent, middle Viséan. H, Chertified, layered radiolarite. Univ. Montréal 274/36, section 71A—3+695 ft; 211.8 m above the base, Kayak Shale(?), zone undetermined (Zone 13 or 14?). upper Meramec age equivalent, middle to late Viséan. FIGURE 5.—Outcrops of Wahoo Limestone on the Clarence River. View east. The Permian and Triassic Sadlerochit Formation unconformably overlies bryozoan-crinoid wackestones of the Alapah Limestone. BIOSTRATIGRAPHY MICROFAUNAL ASSEMBLAGE ZONES The microfaunal assemblage zones used in this study have been used by Mamet and Gabrielse (1969), Mamet and Mason (1968), and Mamet (1968) to correlate the Carboniferous of western Canada with the Carbonifer— ous of the northern Cordillera of the United States (Sando and others, 1969). Armstrong, Mamet, and Dutro (1970, 1971) and Mamet and Armstrong (1972) also used these zones to correlate the Lisburne Group of the eastern and central Brooks Range and the Lisburne Hills region of northwestern Alaska. Detailed systema— tic descriptions, stratigraphic and geographic distribu- tions, and illustrations of the microfossils of this report FIGURE 6.—Corweniajagoensis Armstrong in the Atokan age beds of Wahoo Limestone, 635 m above the base of the Clarence River section 7 1A—1, 2. The exterior of the corallum is partly silicified. The scale is 15 cm long. CARBONIFEROUS BIOSTRATIGRAPHY, N ORTHEASTERN BROOKS RANGE, ARCTIC ALASKA (1962) RN97 SeCllOn thology (Kongakul 71A4, 4. 5, 6 Formalron Cumulative thickness Sedimentary color. slmcture. and accessory Carbonate classification of Dunham Microvossil zone and age Sadleroch ll Formation Fermlan a m o 3 9 o a. E 3 fl 4 Alapah leestone Lisburne Group Alapah leeslone Lusbume Group Alapah Limestone Cheslenan Melameaan Lisburne Group Alapah Lumeslone Splculbles ,rwn l l [ll]— '1th a mull 7’ | | «a ~< Splcullles Endum Group Kayakm Shale MerameCIan Endlooll Group Kayakfi) Shale Splculllfi <1 Splcumes See «g a lor explanation ov lllhologlc and paleon- lologic symbols FIGURE 7.— Kongakut River section, 71A—3, 4, 5, 6, northeastern Brooks Range, arctic Alaska. are given by Mamet (in Armstrong and Mamet, 1975). Microfossil lists for the eastern Sadlerochit Moun- tains section 68A—4A, 4B and the Egaksrak River section 68A—5 can be found in Armstrong, Mamet, and Dutro (1970), and for the western Sadlerochit Moun- tains section 69A—1, Plunge Creek section 70A—4, 5, Marsh Fork section 70A—2, 3, and the Syncline section 7OA—6, 7 in Mamet and Armstrong (1972). The Clarence River section 71A—1, 2 and Kongakut River section 71A—3, 4, 5, 6 are new, and the microfossil lists are given below. The microfacies of Alaska, as in most of the Taimyr-Alaska foraminiferal realm (Mamet, 1962, Mamet and Belford, 1968; Mamet and Skipp, 1970), are generally poor in foraminifers and algae. Within the sections of the Lisburne Group of northeastern Alaska studied in this report, 1 1 foraminiferal assemblages can be recognized and correlated with the Cordilleran and Eurasian Carboniferous zonations (Sando and others, 1969). BIOSTRATIGRAPHY 9 FIGURE 8.—Outcrop of the lower part of the Kongakut River section, showing the well—exposed upper part of the Kayak(?) Shale and the lower part of the Alapah Limestone. View east. Wood and Armstrong (1975) give a detailed analysis of the petrography and diagenesis of the Lisburne Group carbonate rocks in sections 69A—1 and 68A—4A,B for the Sadlerochit Mountains and the Plunge Creek section 70A—4, 5. Microfossil list Clarence River section A—1 (120—140 ft); 36.6—42.7 111 Calcisphaera laevis Williamson Calcisphaera pachysphaerica (Pronina) Dainella sp. Dainella anivikensis Mamet in Armstrong and Mamet Earlandia of the group E. clauatula (Howchin) Earlandia vulgaris (Rauzer-Chernoussova and Reitlinger) Endothyra sp. E ndothyra of the groupE. bowmani Phillips in Brown emend Brady Endothyra of the group E. similis Rauzer-Chernoussova and Reitlinger Eoendothyranopsis sp. Eoendothyranopsis of the group E. spiroides (Zeller) Eoforschia sp. Globoendothyra sp. Globoendothyra of the group G. baileyi (Hall) Globoendothyra of the group G. tomiliensis (Grozdilova in Lebedeva) Stacheia sp. Stacheia skimoensis Mamet and Rudloff Stacheoides sp. Age: Zone 12 or slightly younger, middle Viséan, upper Salem age equivalent. A—2 (790 ft); 240.8 m Calcisphaera sp. cf. Neoarchaediscus sp. Age: Zone 16i or younger, late Viséan, lower Chester age equivalent or younger. A—3 (1,010—1,205 ft); 307.8—3673 m Arc/zaediscus sp. Archaediscus of the group A. krestounikovi Rauzer- Chernoussova Archaediscus krestovnikovi Rauzer-Chernoussova Asteroarchaediscus sp. Asteroarchaediscus baschkiricus (Krestovnikov and Teodorovitch) Calcisphaera laevis Williamson Calcisphaera pachysphaerica (Pronina) Earlandia sp. Earlandia clauatula (Howchin) Earlandia of the group E. vulgaris (Rauzer-Chernoussova and Reitlinger) Endothyra sp. E ndothyra of the group E. bowmani Phillips in Brown emend Brady Globoendothyra sp. Neoarchaediscus sp. Planospirodiscus sp. Priscella sp. Priscella of the group P. prisca (Rauzer-Chernoussova and Reitlinger) Stacheia sp. Stacheoides sp. Tetrataxis sp. Zellerina sp. Age: Zone 17, early Namurian, middle Chester age equivalent. A—4 (1,230—1,250 ft); 374.9—381 m Archaediscus sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Asteroarchaediscus sp. Biseriella sp. Calcisphaera sp. Earlandia sp. Endothyra sp. Globoendothyra sp. Neoarchaediscus sp. Planospirodiscus Sp. Priscella sp. Zellerina sp. Age: Zone 18, early Namurian, upper Chester age equivalent. A—5 (1,380—1,400 ft); 420.6—426.7 m Archaediscus sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Asteroarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus (Krestov- nikov and Teodorovitch) Calcisphaera sp. Calcisphaera pachysphaerica (Pronina) Earlandia sp. Endothyra sp. Neoarchaediscus sp. Planospirodiscus sp. Priscella sp. Priscella of the group P. prisca (Rauzer-Chernoussova and Reitlinger) Pseudoammodiscus sp. Quasiarchaediscus sp. 10 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA FIGURE 9.— Photomicrographs of carbonate rocks and microfos sils, Kongakut River section 71A—3. Location shown in figure 7. BIOSTRATIGRAPHY I 11 Quasiarchaediscus rugosus Brazhnikova Zellerina sp. Age: Zone 19, middle Namurian, uppermost Chester age equivalent. A—6 (1,410—1,550 ft); 4298—4724 In Archaediscus sp. Asphaltina cordillerensis Mamet Asteroarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus (Krestov- nikov and Teodorovitch) Biseriella sp. Biseriella of the group B. parva (Chernysheva) Calcisphaera sp. Earlandia sp. Eostaffella sp. Globivalvulina sp. Millerella sp. Neoarchaediscus sp. Planoendothyra aljutovica (Reitlinger) FIGURE 9.—Bar scale = 0.5 mm. A—H, Kongakut River section. A, A partially silicified brachiopod shell in a dark mudstone. The spines have been preferentially silicified. Univ. Montreal 275/5, section 71A—3.+790 ft; 240.8 m above the base, Kayak(?) Shale, Zone 14, St. Louis age equivalent, early late Viséan. B, Recrystallized foraminiferal-algal packstone. Calcispheres (Calcisphaera sp., Parathurammimz, sp., Vicinesplwera sp.) and Foraminifera [Glo- boendothyra sp., Eoendothyranopsis sp., Earlandia of the group E. clavatula (Howchin), cf. Skippella? sp., and Endothyra sp.] are abundant. Univ. Montréal 275/7, section 71A—3+1,210 ft; 368.8 In above the base, Alapah Limestone, Zone 175, Ste. Genevieve age equivalent, middle late Viséan. C, Detail of 9B. Axial sections of two gigantic Eoendothyranopsis? robustus (McKay and Green) in a slightly recrystallized packstone. Note the feeble pseudochomata. Univ. Montréal 275/10, section 71A—3+1,210 ft; 368.8 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. D, Recrystallized algal-pelletoidal packstone. Pseudoissinella alaskaensis Mamet and Rudloff and Kamaena sp. are intertwined and probably formed a continuous mesh throughout the sediment. Calcispheres are widespread. Univ. Montreal 275/28, section 71A—3 + 1,340 ft; 408.4 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. E, Medium-grained, poorly sorted crinoid-foraminifer-brachiopod grainstone. Eoendothyranopsis of the group E. ermakiensis (Lebedeva), Endothyra sp., Earlandia sp., Earlandinella sp., and Planoendothyra sp. are conspicuous. Univ. Montreal 275/30, section 71A—3+1,350 ft; 411.5 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. F, Detail of a pelletoidal-Calcisphaera packstone. Two Calcisphaera pachy- sphaerica (Pronina)are present. Though foraminifers present in this facies are mud filled, the interior of the calcispheres is usually a clear clean cement. Univ. Montreal 275/40, section 71A—3+ 1,380 ft; 420.6 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. G, Recrystallized, poorly sorted crinoid-bryozoan-brachiopod—foraminifer packstone with a gigantic Globoendothyra of the group G. globulus d’Eichwald (note the characteristic continuous differentiated wall structure [clear layer]). Univ. Montreal 276/1, section 71A—3+1,400 ft; 426.7 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. H, Calcisphere-pelletoidal-algal grainstone. The "rectangular” clear calcite ghosts are recrystallized thalli of Pseudoissinella and of kamaenid algae. Univ. Montréal 276/2, section 71A—3+1,43O ft; 435.9 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. Planospirodiscus sp. Stacheoides sp. Stacheeinae Zelierina sp. Age: Zone 20, late Namurian, Morrow age equivalent. A—7 (1,700—2,100 ft); 5181—6401 in Asphaltina sp. Asphaltina cordillerensis Mamet Asteroarchaediscus sp. Asteroarchaediscus baschkiricus (Krestovnikov and Teodorovitch) cf. Biseriella? sp. Calcisphaera sp. Climacammina sp. Earlandia sp. Eoschubertella sp. Very abundant Eoschubertella yukonensis (Ross) Globivalvulina sp. Globivalvulina of the group G. bulloides (Brady) cf. Millerella sp. Neoarchaediscus incertus (Grozdilova and Lebedeva) Palaeotextularia sp. Planoendothyra sp. Planospirodiscus sp. Planospirodiscus taimyricus Sossipatrova Pseudocornuspira sp. Pseudoendothyra sp. Very abundant Pseudoendothyra britishensis Ross Pseudoglomospira sp. Pseudostaffella sp. Abundant Stacheoides sp. Tetrataxis sp. Tuberitina sp. Zellerina sp. Age: Zone 21, Westphalian, Atoka age equivalent (very abundant fusulinid fauna). A—8 (2240—2390 ft); 6828—7285 In Asphaltina sp. Asteroarchaediscus sp. Asteroarchaediscus baschkiricus (Krestovnikov and Teodorovitch) Calcisphaera sp. Endothyra sp. Earlandia Sp. Eoschubertella sp. Very scarce Globivalvulina sp. Globivalvulina of the group G. bulloides (Brady) Neoarchaediscus sp. Neoarchaediscus incertus (Grozdilova and Lebedeva) Planospirodiscus sp. Planospirodiscus minimus (Grozdilova and Lebedeva) Planospirodiscus taimyricus Sossipatrova Pseudoendothyra sp. Tetrataxis sp. Tuberitina sp. Zellerina sp. Age: Zone 21, Westphalian, Atoka age equivalent (very scarce fusulinid fauna). Kongakut River section B—l (440—595 ft); 134.1—181.4 In Calcisphaera sp. Earlandia of the group E. vulgaris (Rauzer-Chernoussova and Reitlinger) CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA 12 FIGURE 10.—— Photomicrographs of carbonate rocks and micro fossils, Kongakut River section 71A—3, 4. Locations shown in figure 7. BIOSTRATIGRAPHY 13 Endnthyru sp. Emh>th~vmnvllu sp. (Illiboc’lzdot/rvra sp. (;l()ht)(’ll({()fh_\’l‘(1 ot'the group G. bailovi (Hall) (llobtwndollu'ra pan/a (Vissarionoval Prisca/la Sp. Psvudoammodiscus Sp. Shir/win 5p. Star/win skimoonsis Mamet and Rudloff Stacheoides sp. Age: Zone 12. early middle Viséan. upper Salem age equivalent. B—2 (730—865 ft); 2225—2637 m Brunsia sp. Brunsia Ienensis Bogush and Yuferev Calcisp/mera Sp. Endothyra sp. Endothyra ofthe groupE. bowmani Phillips in Brown emend Brady Globoendothyra sp. Planoarchaediscus sp. Priscella sp. Pseudoammodiscus sp. Stacheoides sp. FIGURE 10.— Bar scale = 0.5 mm. A—H, Kongakut River section. A, A partially mud-filled Globoendothyra of the group G. globulus d’Eichwald showing the differentiated wall structure (cl ear layer). Univ. Montreal 276/3, section 71A—3+1,515 ft; 461.8 In above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. B, Poorly sorted, recrystallized foraminifer- brachiopod-crinoid packstone. Foraminifers are Eoendothyranop— sis? robustus (McKay and Green), Globoendothyra paula (Vis— sarionoua), and Endothyranopsis sp. Ostracodes, pelecypods calci- spheres, and pellets are also present. Univ. Montréal 276/32, section 71A—3+ 1,680 ft; 512.1 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Visean. C, Eoendothyranopsis cf. E. thompsoni (Anisgard and Campau) in a pelletoidal wackestone. Mud and lumps have a tendency to form aggregates. Calcispheres (Calcisphaera sp., Parathurammina Sp), pelecypods ostracodes, brachiopods, and algae are also present. Univ. Montréal 276/34, section 71A—3+ 1,710 ft; 521.2 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. D, Endothyranopsis compressus (Rauzer- Chernoussova and Reitlinger). Univ. Montréal 277/15, section 71A—3+1,840 ft; 560.8 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. E, Recrystallized algal-pelletoidal packstone. lntertwined filaments of Pseudoissinella sp. associated with pelecypods. Calcisphaera sp., Vicinisphaera sp. and crushed endothyrids are present. Univ. Montreal 277/16, section 71A—3+1,895 ft; 577.6 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. F, Same facies as the preceding figure with abundant endothyrids, globoendothyrids, and endothyranopsids. Univ. Mon- tréal 227/21, section 71A—3+1,925 ft; 586.7 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. G, A unique record of the algae Ungdarella in the late Viséan. Univ. Montréal 277/25,section 71A—3+1,970 ft; 600.5 m above the base, 63 X, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. H, Medium—grained, poorly sorted, foraminifer-lump grainstone. Eoendothyranopsis macrus (Zeller) is particularly abundant. Univ. Montreal 227/29, section 71A—4+ 120 ft; 646.2 m above the base, 25 X, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. Age: “Brunsin f'acies," probably Zone 14?, early late(?) Viséan, St. Louis age equivalent. E3 \1.170—1,190ft);356.6—362.7 m Brmzsia sp. Brunsia Ienensis Bogush and Yuferev Calcisphaera sp. Diplosphaerina sp. Earlandia sp. Endothyra sp. Endothyra ofthe group E. bowmani Phillips in Brown emend Brady Endothyra of the group E. similis Rauzer-Chernoussova and Reitlinger Eoendothyranopsis sp. Eoendothyranopsis of the group E. pressus (Grozdilova in Lebedeva) Eoendothyranopsis of the group E. ermakiensis (Lebedeva) Eaendothyranopsis scitulus Toomey Globoendothyra paula (Vissarionova) Priscella sp. Pseudoammodiscus sp. S tacheia sp. Age: Zone 14, early late Viséan, St. Louis age equivalent. B—4 (1,210—1,900 ft); 3688—5791 In Archaediscus sp. Archaediscus of the group A. krestounikovi Rauzer- Chernoussova Archaediscus of the group A. moelleri Rauzer-Chernoussova cf. Banffella? sp. Brunsia sp. Calcisphaera laevis Williamson Calcisphaera pachysphaerica (Pronina) Diplosphaerina sp. Earlandia of the group E. clavatula (Howchin) Earlandia of the group E. vulgaris (Rauzer—Chernoussova and Reitlinger) Earlandinella sp. Endothyra sp. Endothyra ofthe groupE. bowmani Phillips in Brown emend Brady Endothyra of the group E. similis Rauzer-Chernoussova and Reitlinger Eoendothyranopsis of the group E. ermakiensis (Lebedeva) Eoendothyranopsis cf. E. utahensis (Zeller) Eoendothyranopsis? robustus (McKay and Green) Eoendothyranopsis cf. E. thompsoni (Anisgard and Campau) Eoforschia sp. Epistacheoides sp. Eotuberitina sp. Globoendothyra of the group G. globulus d’Eichwald Globoendothyra paula (Vissarionova) Issinella? sp. Kamaena sp. Kamaena index (von Meller) Scarce Kamaena lahuseni (von Moller) Scarce Koninckopora Sp. Very scarce Koninckopora inflata (de Koninck) One specimen Palaeocancellus sp. Parathurammina sp. Parathurammina of the group P. cushmani Suleimanov Parathurammina of the group P. suleimanovi Lipina Planoendothyra sp. Priscella sp. Priscella devexa Rauzer-Chernoussova Priscella prisca (Rauzer-Chernoussova and Reitlinger) 14 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA FIGURE 11.— Photomicrographs of carbonate rocks and microfossils, Kongakut River section 71A—4, 5. Location shown in figure 7. BIOSTRATIGRAPHY Pseudoammodiscus sp. Pseudoissinella sp. Pseudoissinella alaskaensis Mamet and Rudloff Radiosphaerina sp. Skippella? sp. Stacheoides sp. Tetrataxis sp. Vicinesphaera sp. Yukonella sp. Very scarce Age: Zone 15, middle late Viséan, Ste. Genevieve age equivalent. B—5 (1,960—2,260 ft); 5974—6888 In Archaediscus sp. Brunsia sp. Calcisphaera laevis Williamson Calcisphaera pachysphaerica (Pronina) Earlandia sp. Earlandia of the group E. clavatula (Howchin) Earlandia of the group E. vulgaris (Rauzer-Chernoussova and Reitlinger) Endothyra sp. E ndothyra of the groupE. bowmani Phillips in Brown emend Brady Endothyra of the group E. similis Rauzer-Chernoussova and Reitlinger Endothyranopsis sp. Endothyranopsis compressus (Rauzer-Chernoussova and Reitlinger) FIGURE 11. —Bar scale = 0.5 mm. Kongakut River section. A, Poorly sorted, medium— to coarse-grained foraminifer-algal-crinoid-lump grainstone. A micritized, crushed Yukonella sp. is associated With numerous Endothyra of the group E. bowmani Phillips in Brown emend Brady. Univ. Montréa1277/35, section 71A—4+250 ft; 685.8 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. B, Same facies as A, but with Koninckopora inflata (de Koninck) associated with Endothy- ranopsis compressus (Rauzer-Chernoussova and Reitlinger) and Planoendothyra sp. Univ. Montréal 277/34, section 71A—4+250 ft; 688.8 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. C, Same facies as A, but with the enigmatic Paracalligelloides sp. associated with crushed Endothyra sp. and Priscella sp. Univ. Montréal 277/36, section 7 1A—4+250 ft; 688.8 m above the base, Alapah Limestone, Zone 15, Ste. Genevieve age equivalent, middle late Viséan. D, A heterocoral Hexaphyllia sp. in a slightly recrystallized calcispherid-rich wackestone (Calcisphaera sp., Vicinesphaera sp.). Univ. Montréal 278/2, section 71A—4+500 ft; 762 m above the base, Alapah Limestone, Zone 16i, lower Chester age equivalent, late Viséan. E and F', A poorly sorted, slightly recrystallized foraminifer-crinoid-calcisphere-pellet packstone. Abundant Pseudoendothyra sp. are mixed with Calcisphaera laevis William— son, Calcisphaera pachysphaerica (Pronina), Vicinesphaera sp., Parathurammina sp., Brunsia sp. and Priscella sp. Univ. Montreal 278/3 and 278/5, section 71A—4+510 ft; 765.1 m above the base, Alapah Limestone, Zone 161, lower Chester age equivalent, late Viséan. G, A partially mud-filled thallus(?) of Asphaltina cordil- lerensis Mamet. Crinoid plates have extensive epitaxial over- growth. Some pellets are present. Univ. Montreal 278/11, section 71A—5+370 ft; 917.5 m above the base, Alapah Limestone, Zone 165, lower Chester age equivalent, latest Viséan. H ,Asteroarchaediscus of the group A. baschkiricus in a fine- to medium-grained well-sorted grainstone. Univ. Montréal 278/15, section 71A—5+280 ft; 944.9 m above the base, Alapah Limestone, Zone 17, middle Chester age equivalent, early Namurian. 15 Endothyranopsis of the group E. crassus (Brady) Eoendothyranopsis macrus (Zeller) Eoendothyranopsis of the group E. ermakiensis (Lebedeva) Eoendothyranopsis? robustus (McKay and Green) Epistacheoides sp. Globoendothyra of the group G. globulus d’Eichwald ”'Irregularina” sp. Kamaena sp. Kamaena lahuseni (von Moller) Koninckopora sp. Scarce Koninckopora inflata (de Koninck) Very scarce Paracalligelloides sp. Parathurammina of the group P. cushmani Suleimanov Parathurammina of the group P. suleimanovi Lipina Planoendothyra sp. Priscella sp. Priscella prisca (Rauzer-Chernoussova and Reitlinger) Pseudoammodiscus sp. Pseudoissinella alaskaensis Mamet and Rudlofl‘ Stacheoides sp. Ungdarella sp. Yukonella sp. Yukonella bamberi Mamet and Rudloff Vicinesphaera Sp. Age: Zone 15, middle late Viséan, Ste. Genevieve age equivalent. B—6 (2,320—2,520 ft); 707.1—768.1 m Archaediscus s . Archaediscus of the group A. krestovni/aovi Rauzer- Chernoussova Archaedisczfs krestovnikovi Rauzer-Chernoussova Archaediscus koktjubensis Rauzer-Chernoussova Archaediscus of the groupA. moelleri Rauzer—Chernoussova Brunsia sp. Cclcisphaera laevis Williamson Calcisphaera pachysphaerica (Pronina) Earlandia sp. Endothyra sp. E ndothyra of the group E. bowmani Phillips in Brown emend Brady Eostaffella sp. Eotuberitina sp. Epistacheoides sp. Globoendothyra sp. Neoarchaediscus sp., primitive Parathurammina sp. Priscella sp. Pseudoammodiscus sp. Pseudoendothyra sp. Pseudoglomospira sp. Tetrataxis sp. Zellerina sp. Zellerina discoidea (Girty) Age: Zone 16i, late Viséan, lower Chester age equivalent. B—7 (2,700 ft); 823 m Archaediscus sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Archaediscus krestovnikovi Rauzer-Chernoussova Archaediscus koktjubensis Rauzer-Chernoussova Calcisphaera sp. Endothyra sp. Eostaffella sp. Priscella sp. Pseudoammodiscus sp. 16 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA Pseudoendothyra Sp. Zellerina sp. Zellerina discoidea (Girty) Age: Zone 16i, late Viséan, lower Chester age equivalent. B—8 (2,760—3,000 ft); 8412—9144 In Asphaltina cordillerensis Mamet and Rudloff Archaediscus Sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Archaediscus of the groupA. moelleri Rauzer-Chernoussova Calcisphaera sp. Diplosphaerina sp. Earlandia sp. Endothyra sp. Neoarchaediscus sp. Neoarchaediscus parvus (Rauzer-Chernoussova) Neoarchaediscus regularis (Rauzer-Chernoussova) Planospirodiscus sp. Pseudoammodiscus sp. Pseudoendothyra sp. cf. Planoendothyra? sp. Tetrataxis Sp. Zellerina sp. Age: Zone 165, latest Viséan, lower Chester age equivalent. B—9 (3,070—3,140 ft); 9357—9571 In Archaediscus sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Archaediscus krestounikovi Rauzer-Chernoussova Asphaltina Sp. Asteroarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus (Krestov- nikov and Teodorovitch) Asteroarchaediscus gnomellus Brenckle Calcisphaera sp. Earlandia sp. Endothyra of the group E. bowmani Phillips in Brown emend Brady Endothyra cf. E. excellens (Zeller) Neoarchaediscus sp. Planospirodiscus sp. Pseudoendothyra sp. Pseudotaxis sp. Stacheoides sp. Tetrataxis sp. Zellerina sp. Age: Zone 17, earliest Namurian, middle Chester age equivalent. B—10 (3,320—3,460 ft); 1,011.9—1,054.6 m Archaediscus sp. Archaediscus of the group A. krestovnikovi Rauzer- Chernoussova Archaediscus of the groupA. moelleri Rauzer-Chernoussova Asphaltina sp. Asphaltina cordillerensis Mamet Asteroarchaediscus sp. Asteroarchaediscus of the group A. baschkiricus (Krestov- nikov and Teodorovitch) Biseriella sp. Biseriella parva (Chernysheva) Calcisphaera laevis Williamson Earlandia sp. Endothyra sp. Endothyra of the groupE. bowmani Phillips in Brown emend Brady Eostaffella sp. Neoarchaediscus sp. Neoarchaediscus incertus (Grozdilova and Lebedeva) Planospirodiscus Sp. Planospirodiscus taimyricus Sossipatrova Pseudoglomospira sp. Zellerina sp. Age: Zone 18, early Namurian, upper Chester age equivalent. BIOTA OF THE LAGOONAL FACIES, ALAPAH LIMESTONE, KONGAKUT RIVER SECTION The lower part of the Alapah Limestone in the Kongakut River section from 369 to 692 m suggests very shallow lagoonal sedimentation. The facies is strikingly similar to other Carboniferous carbonate lagoons of the Cordillera, for example, the Carnarvon Member, Mount Head Formation, Alberta (which has similar age, Zone 15) of the Tournaisian Shunda Formation in Alberta and British Columbia (Petryk and others, 1970). The biota is characterized by a great abundance of cal- cispheres; the genera Calcisphaera, Parathurammina, and Vicinesphaera are the most widespread. These calcispheres are usually observed as single, discrete spherules and show little trace of abrasion. The fragile parathuramminid spines are rather well preserved, particularly where they are coated by algal dust. The nature of calcispheres is a controversial subject. It is, however, reasonable to assume that most of them are calcified cysts of algal spores. When they are in situ, they usually form clusters around poorly calcified thalli (see for instance Radiosphaera, pl. 10, fig. 14, in Mamet and Rudloff, 1972). This clustering habit was already noticed in the calcispheres of the Shunda Formation by Stanton (1963); it is rarely observed in the calcispheres of the Alapah Limestone. Calcispheres also occur in the form of a crown with octameral symmetry; a habit observed among Calcisphaera (Mamet, 1973). All these smooth calcispheres are finely perforated and have no aperture. They are, therefore, not foraminifers, or probable foraminifers?, as is suggested by most Russian authors (Suleimanov, 1945; Lipina, 1950; Reitlinger, 1957, 1960; Bogush and Yuferev, 1962, 1970; Pronina, 1963; Aizenberg and others, 1966; Brazhnikova and others, 1967, Menner and Reitlinger, 1971), an attribu- tion accepted by Conil and LyS (1964), Loeblich and Tappan (1964), and Hallett (1970). On the other hand, the nature of the spinose parathuramminid calcispheres remains debatable. Veevers (1970) published a unique photograph of a “cluster of united cells” from the Famennian Button Beds of Australia, he attributed them, with doubt, to sporangia of Uva Maslov. It is clear, however, that his figure 1, plate 31, represents an in situ cluster of Vicinesphaera, which is closely similar to a cluster REGIONAL CORRELATIONS 17 of Radiosp/zacra. Probably neither Calcisphaera nor Vicinesphaera should be considered foraminifers. Since Vicinesphaera and Parathummmina are close- ly related, the latter genus might also be removed from the Protozoa. Up to now, no cluster ofParathurammina has been observed, and the "cells” are always disarticu— lated. This is true for the specimens from the entire Kongakut River section where the genus abounds. However, the distribution of the algal cyst Calcisphaera and the parathuramminids is strikingly similar. Eighty-six samples collected throughout the entire column of lagoonal sediments were analyzed for distribution of Vicinesphaera, Calcisphaera, Para- thurammina, true foraminifers and Pseudoissinella, and Kamaena. The results of this analysis (fig. 12) show a very close relation between the distribution of smooth and spinose calcispheres, while no correspondence is observed with the other taxa. For more than 305 m of fine-grained pelletoidal carbonate rocks, the ratio of spinose calcispheres to smooth calcispheres is remarka- bly constant and varies from one-half to one— third. The ratio of Parathurammina to Vicinesphaera is also very constant. Such relations are also conspicuous in the Carnarvon Member of the Mount Head Formation in Alberta and in the Black Marbles of Dinant (VIa) in Belgium. This close relationship may be the result of mechani- cal sorting. Indeed, spinose and smooth calcispheres have similar ranges of diameter and of wall thickness. Thus, this worldwide similar association is by no means proof that they have the same biological origin, and algal cysts could very well be mixed with monolocular foraminifers. Until in situ clusters of Parathurammina, similar to those of Radiosphaera or Vicinesphaera, are found, the question remains unanswered. REGIONAL CORRELATIONS ENDICOTT GROUP The Kekiktuk Conglomerate is absent, owing either to nondeposition or to faulting at the base, from the bottom of section 69A—1, in the west end of the Sadlerochit Mountains (fig. 13). The Kekiktuk Con- glomerate is absent owing to nondeposition from the eastern Sadlerochit Mountains section BSA—4A, 4B. At the Kongakut River section 71A—3, 4, 5, 6, it is not exposed and is covered by tundra. The Kekiktuk Conglomerate is well exposed at the base of section 71A—2 on the Clarence River. Here the Kekiktuk rests with angular unconformity on lower Paleozoic (Ordovician or Silurian) arenaceous lime- stone and is about 100 m thick. It consists of basal‘ quartz-pebble conglomerate, black carbonaceous shales, nodular limestones and siltstones, and light- gray and brown, thin-bedded quartz sandstone and siltstones and is overlain by the dark-gray Kayak(?) Shale. The section 70A—7 on the north flank of the large synclinorium east of the Aichilik River contains about 30 m of quartzite conglomerates, sandstones, and shales. The Kekiktuk Conglomerate in section 70A—2, near the junction of Marsh Fork and the Canning River, is at least 61 m thick. It unconformably overlies the greenish—gray slates and phyllites of the Neruokpuk Formation. The lower 38 m of the Kekiktuk Conglom- erate is medium- to massive-bedded pebble conglom- erates and sandstones, with quartz and hematite cement. The upper 23 m consists of medium- to thin-bedded quartz sandstone, dark—gray siltstones, dark-gray shales, and thin coals. At the base of section 70A—4, near the Canning River, the Kekiktuk rests with angular unconformity on metamorphic rocks of the Neruokpuk Formation and is about 10 m thick. It consists of basal quartz—pebble conglomerate, black carbonaceous shales, and 5 m of strongly crossbedded light-gray quartz sandstone. The Kayak(?) Shale is thin, about 15 m thick, in the western Sadlerochit Mountains. In section 69A—1 this brownish-gray calcareous unit rests unconformably on dolomites of Devonian age. The overlying basal beds of the Alapah Limestone are lower Chesterian in age, and the thin Kayak(?) Shale is probably lower Chesterian age. In section 70A—4, about 43.5 km to the south (fig. 13), the unit thickens markedly and is older; it contains microfossils of Meramecian, Zone 11, age. Approximately 372 m thick, the Kayak(?) is a sequence of dark-gray shales, thin-bedded argillaceous lime mudstones, dolomites, and thin-bedded dark-gray to black cherts. The upper 30 to 40 m of the unit becomes progressively more calcareous upward, and the contact with the Alapah Limestone is gradational. The Kayak(?) Shale, 18 km to the southeast in section 70A—2, is only about 183 m thick. The predominant rock type is dark-gray shale, with only minor amounts of thin-bedded sandstones, siltstones, and yellow-weathering thin-bedded limestone. The base of the unit is gradational with the Kekiktuk Conglomerate, which contains abundant plant remains. The dark-gray shales of the Kayak(?) Shale change abruptly to the dark-gray bedded spiculitic cherts and dolomites of the Wachsmuth Limestone. In the Clarence River section 71A—1 (figs. 3, 13) the Kayak(?) Shale contact with the Alapah Limestone is not exposed. The Kayak (?) Shale is about 75 m thick and is composed of dark-gray shales, nodular and lenticular interbeds of thin limestones, and brown to 18 63* 507 37* 317 25— CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA Viz incxphuzm sp. 50~ Calcunhuem sp. Pm'ul/Im‘ammiml sp. (l’urulhummminu and Vimm'w/Im’ru) NUMBER OF SPECIMENS PER SQU :1E CENTIMETRE 25* ramminwm 75* 627 50% 377 25‘ 12— 0,2 Pwuduixsinellu 5p. and Kumuwm sp. Metres above base of Kongakut River section 1210 368.8 1290 393.2 1320 402.3 1330 405.4 1340 408.4 1360 414.5 1380 420.6 1390 423.7 1400 426.7 1410 429.8 1350 411.5 1250 381 1430 435.9 1485 452.6 1495 455.7 1505 458.7 1515 461.8 1525 464.8 1530 466.3 1540 469.4 1550 472.4 1560 475.5 1570 478.5 1590 484.6 1600 487.7 1630 496.8 1470 448.1 1640 499.9 1650 502.9 1620 493.8 1710 521 2 1720 524.3 1680 512.1 1690 515.1 1 580 481 .6 1 660 506 1 670 509 Thin section sample No. and footage No. i 1315 400.8 1 3 9.. E 1700 5182 > a. l Section No. FIGURE 12.—Distribution of Vicinesphaera, Calcisphaera, Parathurammina, true foraminifers, Pseudoissinella, and Kamaena in the pale-yellow-brown siltstones and sandstones. The Kayak(?) is not exposed at the Egaksrak River section 68A—5. It is absent at the east end of the Sadlerochit Mountains where thin beds of sandstone of the Itkilyariak Formation (Mull and Mangus, 1972; Arm- strong and Mamet, 1974) rest directly on the Neruok- puk Formation. Pelletoid-ooid grainstones with micro- fossils of Zone 16s, Chesterian, age overlie these thin sandstone beds. _ The composite section, 70A—6 and 70A—7, of the Kayak(?) Shale about 135 km east of section 70A—2 is about 442 In thick; the lower 137 m is dark-gray shale of smooth and spinose calcispheres; no correspondence is observed with a few thin lime mudstone beds and nodules. Above this segment is 92 In of highly siliceous, argillaceous, cherty, gray and dark-gray dolomites and limestones. The upper 213 m of the unit is calcareous dark-gray shale and thin~bedded argillaceous dark-gray coral- liferous limestones. The contact with the basal Alapah Limestone is gradational. The lower part of the Kayak(?) Shale is not exposed in the Kongakut River section (71A—3, 4, 5, 6; figs. 7, 13). The upper part is a dark—gray shale with thin siltstone interbeds followed by thin-bedded argillaceous and chert spiculitic lime mudstones and wackestones. The REGIONAL CORRELATIONS M /\'~\ 19 W 8 Vir'i‘nesnhui’m 5p. R Foruminifrru Culr'isphuem sp. Pumlhurummiml 5p. (Punllhurumminu and Virmacp/meru) — 175 - 150 7125 7100 W 75 f 50 — 25 —75 —62 —50 737 a2?) ~12 Pseudvixxim'lla Sp. and Kamnmu 5p. 70 ? i ii; ms? wwhI‘mmlmm‘qmmmfipwhnwtn‘znwmhwmm 'TfTNmQ‘QV‘V‘QW‘nQ Ndn'v—m‘m'é’ys'aidn' ajév'commwm h ommmv—devrxomwaiw'mmw'qimmm'v— assagasfissssfissssssss§s§aasassasazasgassssasss oooln ocomo «2min 09mm0§o o 0 00°00 0° 2z£k§§ssses§§sss§smsas 8”98838288§;§§§33g3§§35 FF__-F_-__F_F_re_r__-—-F i . 71A43—> —>71A—3—> —>71A—4~—> —>71A—4—> lagoonal facies of the Kongakut River section from 368.8 to 691. 9 In abov e the base. Note the close relation between the distribution with other taxa. Eighty-six samples were studied in thin section. beds in the middle part of the Kayak(?) Shale contain microfossils of Zone 12, and in the upper part of the Kayak(?) Shale of Zone 13/14, Meramecian, age. LISBURNE GROUP Because most of the carbonate rocks of this study are younger than Zone 12, the Wachsmuth carbonate facies is poorly represented. The interval from 244 to 450 m of section 7OA—2 is considered to be a possible Wachsmuth equivalent. Likewise, the intervals from 140 to 220 min the Kongakut River section, 130 to 400 m in section 70A—4, and 160 to 220 m in section 70A—6, 7 may represent Wachsmuth equivalents. The base of the Lisburne Group is diachronous in the area of this study. In the southern series of east to west sections that run from the Kongakut River section 71A—3, 4, 5, 6 west to Marsh Fork section 70A—2, 3 and then north to the Plunge Creek section 70A—5, the contact between the Kayak(?) Shale and the Lisburne Group occurs in Zones 12 to 15 in Meramecian rocks. In the Sadlerochit Mountains 50 km to the north, the basal Alapah Limestone is in Zone 16, or 16s, Chesterian. At Egaksrak River section 68A—5, 75 km to the east, 20 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA 10 0 10 20 SOKILOMETRES a? - _ g 1. I 5 7:: _ g; ._ 5 vi .2 ‘7"; :8: .3 2 r, L; E. 23152 “a is :3 ~3§§ =5 e c c: a E c x N gg >-_ (2899. E c an: N 5-9 V' c '1 M = c '1 m = as .2 Mas= E '1 38 = 3 5 Tu '“ "’ E .—‘ ‘0 '_. '0 la 3 x E 0 (m6 "' - w v- " 3 aé-aw' 3 243 geeks gage-33 §§'é%e ‘0 a E g *2 8 K g 5 g :33 g i- E g E :5, 38 g Bracliiopoda fauna of E i E 5 ‘9 T: _ S '- 5 g E > 5 early Kazanian (early ,5 ‘ . .5 ’— . Sadlerochit Formation i— _ Late Permian) age . ‘ ‘700 ‘H 2400 . 21 ° ,5": 21 Wahoo Limestona_ ‘ 21 4507—1500 _* ‘ 21 Foraminiferal iauna ol 3507 L3 r‘ 500 i ’1 r - 20 Atokan (Middle 700 — ~c: ‘ 4‘” _H_ "q" ' Pennsylvanian) age . 1500 4007 -- - 20 _ 450 — ~— ‘ _ 300‘1000 J 21 _ \ 650 a a 1 1* 20 ._ - 18 W __ - o n 5 8 c 2000 4007 A 3? 2° 'g g g 600 a 25“ $00 * 3 -— 3 ° 21 ’ ' 300 1035 E ‘8’ »0 350— $19 /f 13 S c 550 a 200 — / ._ H i. 1,, a. on , E - i.' "r “L ‘4 g . 21 2507 : 7b °° a 21 / 5007 I 20 300— %( z 5 500 — . 20 1507 ‘J - ’69, “’6 ' a S ' - 250a 200a 698 o a 1500 70A—4 E 450 7 | 150- 500 1 w auuu Wahoo 200* ' r' 65 90° ‘ _, Limestone 400 — - - '- - °’ " 16i 8 L-A’apa" ‘ N - . N "hast fl! 150_ 100 _ aso— - 3 °"9 2 350 — . .3 o a. - - - . 9 g; g covered 100a 50‘ ~- - 800a E E . # «3-W- :. § soo~‘°°° 5'°P° - X m. ..l f: 2 V , l “i. 0“® Shale — 2500 _ 2 o a 507 I “‘36 “ 750 . . g < 250 7 7 113i *§6;0«\\; ow i ‘2 Alapah 06‘ q" a ‘ 15 Imaiifiliaisuiraidg laoias, Stromatoliies Limes‘One— 7 0 90“) 700‘ ‘7! 200 — or and calcite psaudomorphs ol gypsum .u_. 7 g 16 ,, Kayakl'?) 2 § 9_//' Shaka Neruokpuk Formation 650~ mi «‘5 g x 2000 W ‘ § : , SSA—5 600 \fl .1: _‘“¥"" Egaksrak River 8 From Armstrong, Mamet, x§ E and Dulro (1970) and 5507 3‘32 5 Armstrong (1972b) :2 5 ‘ SBA—4A, 4B 500 7 0 _ 0 Kek'k‘l‘k 0° lomerale Eastern Sadlerochit Mls Lower Paleozoic From Armstrong, Mamet, Iimestonas and Dutro (1970) 1500 450~ GSA—1. 7OA—5. 7OA42,3, 70A—6, 7 . . Weslem Sadlerochit Mts See figure 3 for explanation ol lithologic From Mamet and 400 a - and paleontologic symbols Armstrong (1972) 1470 144a me 3507 I l 1 3004000 Prudhoe N 3‘” ARCTIC Bedded cheri 250* 0054” \ Bum/0,, 2007 150* 50° Bedded chart ‘ 70° ‘5 '5:- 100* i \ § _ ABA-4A. 4a a, so — r2 Sadlarochit Mts \ L Shublik Ms \J 7 M P 3 K. \ / 0 0 \ P— ‘— ~ \‘ \\ Zr 70A—4, 5 Franklin Mountains 53:32:23; 71A—1 1 Front oi Brooks Range 7OA—2. 3 \ m < f g i; / §°" E E 1 l / Philip Smith 0 2° 3° M'LES i 45 EL 0 Mountains w ,//71A—3,4, 5. 6 g 69 FIGURE 13.—Carboniferous biostratigraphic correlation REGIONAL CORRELATIONS 21 3 ‘5 E g ‘a'z' o 3 E W 3 5 § 9 E E :3: "E g E 4'3 ". g S E 5 § g S E “ O 5 ’ N E ‘9 = E ’ = a a _-E. .32 5 £21: 5, a- 3:9 HM - "’ 2 S g a“ 3 o “‘ 5 3 3 A (n o 2 g 8 (D , § g E 5 ‘3 g " E o 8 E § § .- g 's u. 5 {.9 § . 5 .9 .§ 1‘: .9 E i ‘5 E 3 IQ .: E Sadlerochlt \ 19: IE 2 E g is .5 '— Formation 1- r— 1050 3500 . 2507 f , 21 400 — 21 . 18 A _ r_- . I h It 1000- 2000 rag: 1 __*{ 4°00 [5” a, $5- “ L 507 ' I 1200— IILII 20 If“? I [T v .5 500 ,V" 21 _ _ 0° $7 950- 17 15°- #5}! o “1"". 1150« $59. 1 1:1" 21 0* /1 I III; ? 3000 163 1 L _ [H 900- a 100* v u- m o 1 k ': III g 1100~ _I I _‘, _ g l- -_ —% 3 : :‘-::. 350— 5 50— mII_.J_ e E 3500 — _ . ~ 1' A 3 E ‘5 1050 A - 1‘ 3 E E * . ' . . E 2 1a -. 800- 0— 0 c I: 3 _ a 1000 — . ‘6' ‘5 250°" Del-'91- : E 750' 2c I 3 a. E I 11.. _ _ 2 = u _ 3 q 950 A - - e c 13 / f‘ a: E 0 .g .2 E 3 o g 5 8 3000 A: I g m 9007 if _ § 2 4-9 -I of — 9 - 2 < ’ t 17 IQ 850 — : _ . W 3 ' . I I J 1 aoo~ ',_ _'m . eoo — A I" 163 Jr 4‘ 2500 2500 - " h - _.1 750— Is: ’5: 75° ‘ - ‘71—‘11 1 ‘0‘ ' 1 1; , fl 0§§° A '3'}- ' 700 ‘ 7 n- I (p ‘ 700 _ [*l- \ 6‘ . II—Ir \ 1500—..p|_*- — we 6K, _5 ' ’ _ I’l'l 1 ¢P§ 450‘ ".._ ' ‘ :1. ' ‘5‘ 650 — I 573 J94? ‘ _ " Z 650— - ,- '7 '1 ' T 1? - — - I 400- _ *‘ ‘ 2000— - -’ i » 600* . a _ _ _ 15 Intertidal to 5015?de 13cm? ' ' ‘ ' I I | I A cm“ ”39““ 8’ fades OIAIEW 350‘ 3 I 14 E . # , _ _- 1 possible reglonal oorrela- _ _ - morphs 0' gypsum \\550 ’Zsslone . g flan _ — _ _ _ ~—— 1 . \i ‘— — _ __ — — x 9 Lagoonal fades of Napah Lamestone\ — 99° 0 g Arglllaceous-spiculiflc lor- #13—_ 15 Lagoon-Ia] fades 01A \ —_ __ «5: \0° amlnifor-calclsphevic bry- 5°0_ ‘apah “meshing 500 " — _ é «'9 '50 ozoan-palmatozoan pack- _ * \ - 4;? \> go slonas-waokestanos Al 4 15 oxéfdfi apah leastn 13 , 1500 We 1. .4236- ‘5°° — —% 450 _ +9“ 0 smulM'l) Limestone . Washsrnuthn) Limestone k _ .' r .2 #1 Q 400— - i 9 13 40° * 5 g , «a E x: 0 fl » a; g , \ o 350 7 35° ¢\\‘(‘ “9‘3 3“" E 1‘ (1“ 6A 9!: — «1° 19“ 9% Bedded Q6 chart r1 1 1 l . 137 200 7 150 7 500 ' - — 100 , Kaye-11(7) Sm ‘\ Keklktuk Couglarnem. —‘ 50 _ W L1 % _ ‘ 0 ~ 0 Takinuk Coai, plant remains. and m———— Ieavss Interbedded wiih Neruokpuk Formation shales. sandstones. and (pge-Mississlppian conglomerates metamomhlc rocks) chart, northeastern Brooks Range, Alaska. 22 neither the Alapah Limestone nor the Kayak(?) Shale is exposed. On the north flank or the Brooks Range adjacent to the Canadian border, 50 km to the east, where the contact of the Alapah Limestone with the Kayak(?) Shale is covered by talus, the contact is probably near the Meramecian-Chesterian boundary. During Meramecian time, the sediments that now form the Sadlerochit Mountains stood as an island or positive area to the shale and shallow-water carbonate sediments being deposited east, west, and south of it. By earliest Chester time, Alapah Limestone deposi- tion extended over the whole region, including the Sadlerochit high, and the area northwestward to Prudhoe Bay (Armstrong and Mamet, 1974; Armstrong, 1974). The Alapah Limestone varies in thickness, It is generally thinnest in the Sadlerochit Mountains—only 335 m thick on the west end and 278 m on the east end. Armstrong and Mamet (1974) report a thickness about 290 m in the subsurface at Prudhoe Bay (fig. 2). At the Clarence River section it is about 260 m thick. The sections to the south are thicker, at Plunge Creek section 70A—4, 5, the Alapah is at least 640 m thick and at the Syncline section 70A—6, about 670 m thick. At the Kongakut River section 71A—3, 4, 5, 6, its original thickness is unknown (fig. 13) because it is cut by the pre-Permian erosion surface, but its remaining thick- ness is still about 457 m. In general, the Alapah is relatively thick in the central part of the northeastern Brooks Range, thins towards the north flank of the range, and becomes' younger at its base. A highly characteristic rock type referred to as the lagoonal facies occurs in the southern series of sections in the lower part of the Alapah Limestone, Zone 15. It is a thin-bedded dark-gray argillaceous-spiculite-forami- niferal-calcisphere-bryozoan-pelmatozoan wackestone and packstone. It is about 70m thick at the Plunge Creek section 70A—4, 5 and extends eastward to the Kongakut River section 71A—3, 4, 5, 6 where it is 260 m thick. The beds at the Plunge Creek section 70A—4, 5 are overlain by gray dolomites that contain well-developed stromatolites (fig. 14) and those at the Marsh Fork section by dolomites with abundant calcite pseudomorphs of gypsum. The basal beds of the Alapah Limestone at the Clarence River section 71A—1, 2 (figs. 3, 13) are dolomites that have very well developed stromatolites, birdseye structures, lithoclasts, and abundant calcite pseudomorphs of gypsum. These beds were deposited in an intertidal to supratidal environ- ment. The suggested correlation of these lower Chester- ian carbonate regressive facies is shown in figure 13. The Wahoo Limestone in the west end of the Sadlerochit Mountains is only about 122 m thick; at the east end of the Sadlerochit Mountains it is 241 m thick. CARBONIFEROUS BIOSTRATIGRAPHY, N ORTHEASTERN BROOKS RANGE, ARCTIC ALASKA FIGURE 14.—-Well-developed and large stromatolites in the Alapah Limestone, 510 m above the base of the Plunge Creek section 70A.4. The scale is 15 cm long. The eastward thickening of the Sadlerochit high is apparent at the Egaksrak River section 68A—5 where the Wahoo is 381 m thick, and adjacent to the Canadian border at the Clarence River section 71A—1, 2 where it is 3 14 m thick. The Wahoo Limestone on the north flank of the Brooks Range is primarily pelmatozoan-bryozoan wackestone, packstones and grainstones and ooid packstones and grainstones with minor amounts of pale—yellow-weathering dolomites and calcareous arenaceous shales. The ooid facies is generally absent in the southern set of sections studied in the Franklin and Romanzof Mountains. Here the unit is from 183 to 275 m thick, and it consists of medium- to massive-bedded, gray to light-gray, slightly crossbedded pelmatozoan-bryozoan wackestone and packstones, and minor amounts of grainstone. Beds of thin dolomite and superficial ooid packstones are present sporadically. In the southern set REFERENCES CITED 23 141°30’ N ”7"»; O. \\ (90 Buy Deman'ation VUVNVD l T2 30 ’1 z z SEILVLS (131an ———-—|—_— R43E 5 MILES 5 KILOMETRES FIGURE 15—The Clarence River section 71A—1, 2 in northeastern Brooks Range. of sections, chert within the Wahoo is typically nodular and light gray to brown and generally occurs in the lime—mud—rich (micritic) beds. The contact between the Wahoo and Alapah Limestones is generally sharp, marked by the darker gray, thinner bedded lime mudstones and wackestones and packstones of the underlying Alapah Limestone. ' The various horizons (fig. 13) containing stromato- lites, birdseye structures, microdolomites, and calcite pseudomorphs of gypsum alternate with thick se- quences of bryozoan-crinoid wackestones and ooid packstones and grainstones; the whole sequence was deposited in shallow water on a slowly subsiding platform. The intertidal to supratidal beds indicate that, at times, carbonate production on the platform exceeded rates of subsidence. The Sadlerochit Formation of Permian and Triassic age unconformably overlies limestones of Atokan age, except at the Kongakut River section 71A—3, 4, 5, 6, where it overlies the Upper Mississippian Alapah Limestone. Detterman (1970) reports that the basal Echooka Member of the Sadlerochit Formation contains a brachiopod fauna of early Kazanian, earliest Late Permian age. The unconformity between the Wahoo 142°30' R40E #~+ Z R41E R40E R41E 69° 7 71A—3. 4, 5 00" 5 MILES 5 0 5 KILOMETRES FIGURE 16.—-Th. Kongakut River section 71A—3, 4, 5, 6 in northeastern Brooks Range. Limestone and Sadlerochit Formation represents a hiatus of Des Moinesian through Leonardian and possibly lower Guadalupian time. Where the Sad— lerochit lies unconformably on the Alapah, the hiatus includes all of Pennsylvanian time and part of the uppermost Chesterian. Armstrong, Mamet, and Dutro (1970) and Mamet and Armstrong (1972) illustrated the westward thinning of Atokan carbonate rocks in the Sadlerochit Mountains. Mamet and Armstrong (1972) and Armstrong (1972) reported that at many localities the highest few feet of Atokan carbonate rocks beneath the Sadlerochit For- mation shows evidence of vadose weathering in the form of enlarged vertical joints and vugs filled with a clay similar to terra rossa. The basal beds of the Echooka Member of the Sadlerochit Formation are conglomer- ates or conglomeratic sandstone formed partly of rounded chert and limestone pebbles and cobbles derived from the underlying Wahoo Limestone. Figures 15 and 16 are detailed graphic locations of the measured sections, Clarence River (71A—1, 2) and Kongakut River (71A—3, 4, 5, 6). REFERENCES CITED Aizenberg, D. C., Brazhnikova, E. V., and Rostovceva, L. F., 1966, On the CI‘a Zone of the Donetz basin, in The fauna of the lowest part of the Tournaisian in the Donetz basin [in Russian]: Akad. Nauk Ukrain. SSR Inst. Geol. Nauk, p. 3—42, 18 pls. 24 Armstrong, A. K., 1972, Pennsylvanian carbonates, paleoecology, and rugose colonial corals, eastern Brooks Range, arctic Alaska: US. Geol. Survey Prof. Paper 747, 19 p., 16 figs., 8 pls. [1973]. 1974, Carboniferous carbonate depositional models, prelimi- nary lithofacies and paleotectonic maps, arctic Alaska: Am. Assoc. Petroleum Geologists Bull., V. 58, no. 4, p. 646-660. Armstrong, A. K., and Mamet, B. L., 1974, Carboniferous biostratig- raphy, Prudhoe Bay State No. 1 to northeastern Brooks Range, arctic Alaska: Am. Assoc. Petroleum Geologists Bull., v. 58, no. 4, p. 621—645. 1975, Microfacies, microfossils and corals. Lisburne Group, arctic Alaska: US. Geol. Survey Prof. Paper 849. Armstrong, A. K., Mamet, B. L., and Dutro, J. T., Jr., 1970, Foraminiferal zonation and carbonate facies of the Mississippian and Pennsylvanian Lisburne Group, central and eastern Brooks Range, Alaska: Am. Assoc. Petroleum Geologists Bull., v. 54, no. 5, p. 687—698, 4 figs. . 1971, Lisburne Group, Cape Lewis—Niak Creek, northwestern Alaska, in Geological Survey research 1971: US. Geol. Survey Prof. Paper 750-B, p. B23—B34, 9 figs. Bogush, O. I., and Yuferev, O. V., 1962, Foraminifera and stratigraphy of the Carboniferous deposits in Kara-Tau and Talaskiy Ala-Tau [in Russian]: Akad. Nauk SSSR Sibirsk. Otdeleniye Inst. Geologii i Geofiziki, p. 1—234, 9 pls. 1970, Foraminiferida, in The Carboniferous of the Omolon and southwestern Kolyma Massif [in Russian]: Akad. Nauk SSSR Sibirsk. Otdeleniye Inst. Geologii i Geofiziki, Bull. 60. p. 68—74. Bowsher, A. L., and Dutro, J. T., J r., 1957, The Paleozoic section in the Shainin Lake area, central Brooks Range, Alaska: US. Geol. Survey Prof. Paper 303—A, 39 p., 6 pls., 4 figs. Brazhnikova, N. E., Vakartchuk, G. I., Vdovenko, M. V., Viniitchen- k0, L. V., Karpova, M. A., Kolomietz, Ia. I., Potievskaia, P. D., Rostovceva, L. P., and Chevtchenko, G. D., 1967, Marker micro-faunistic horizons of the Carboniferous and the Permian of the Dniepr-Donetz basin [in Russian]: Izdat. "Naukova Dumka,” Kiev, p. 1—224, 59 pls. Brosgé, W. P., Dutro, J. T. Jr., Mangus, M. D., and Reiser, N. H., 1962, Paleozoic sequence in eastern Brooks Range, Alaska: Am. Assoc. Petroleum Geologists Bull., v. 46, no. 12, p. 2174—2198. Conil, R., and Lys, M., 1964, Matériaux pour l’étude micro- paléontologique du Dinantien de la Belgique et de la France (Avesnois). Pt. I, Algues et Foraminiféres; Pt. 2, Foraminiféres: Louvain Univ. Inst. Geol. Mem., v. 23, 335 p., 42 pls. Detterman, R. L., 1970, Sedimentary history of the Sadlerochit and Shublik Formations in northeastern Alaska, in Adkison, W. L., and Brosgé, M. M., eds., Proceedings of the geological seminar on the North Slope of Alaska: Am. Assoc. Petroleum Geologists, Pacific Sec., Los Angeles, p. 0-1—0-13, 9 figs. Dunham, R. J ., 1962, Classification of carbonate rocks according to deposition texture, in Classification of carbonate rocks—A symposium: Am. Assoc. Petroleum Geologists Mem. 1, p. 108—121. Dutro, J. T., Jr., Brosgé, W. P., and Reiser, H. N., 1972, Significance of recently discovered Cambrian fossils and reinterpretation of Neruokpuk Formation, northeastern Alaska: Am. Assoc. Pe- troleum Geologists Bull., v. 56, no. 4, p. 803-812. Hallett, D., 1970, Foraminifera and algae from the Yoredale "Series” (Viséan-Namurian) of northern England: Congres Avanc. Strat. Carbonifére, Geme, Sheffield, 1967, Compte Rendu, p. 873—885. Lipina, O. A., 1950, Foraminifera from the Upper Devonian of the Russian platform [in Russian]: Akad. Nauk SSSR Geol. lnst. Trudy 119, no. 4, p. 110—132, 3 pls. Loeblich, A. R., Jr., and Tappan, H., 1964, Protista, Pt. C, in Moore, R. C., ed., Treatise on invertebrate paleontology: Geol. Soc. America and Kansas Univ. Press, p. 1—900. CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA Macqueen, R. W., Bamber, E. W., and Mamet, B. L., 1972, Lower Carboniferous stratigraphy and sedimentology of the southern Canadian Rocky Mountains: Internat. Geol. Cong, 24th, Guidebook, Excursion 0-17, p. 1—62. Mamet, B. L., 1962, Remarques sur la microfauna de Foraminiféres du Dinantien: Soc. Géol. Belgique, v. 70, no. 2, p. 166—173. 1968, Foraminifera, Etherington Formation (Carboniferous), Alberta, Canada: Canadian Assoc. Petroleum Geology Bull., v. 16, no. 2, p. 167—179. 1973, Microfaci‘es viséens du Boulonnais (Nord): Rev. Micro- paléontologie, v. 16, no. 2, p. 101—124, 5 pls. Mamet, B. L., and Armstrong, A. K., 1972, Lisburne Group, Franklin and Romanzof Mountains, northeastern Alaska, in Geological Survey research 1972: US. Geol. Survey Prof. Paper 800—0, p. 0127—C144, 10 figs. Mamet, B. L., and Belford, D., 1968, Carboniferous Foraminifera, Bonaparte Gulf basin, northwestern Australia: Micropaleontolo- gy, V. 14, no. 3, p. 339—347. Mamet, B. L., and Gabrielse, H., 1969, Foraminiferal zonation and stratigraphy of the type section of the Nizi Formation (Car- boniferous systems, Chesterian Stage), British Columbia: Canada Geol. Survey Paper 69—16, p. 1—21, 6 figs. Mamet, B. L., and Mason, D., 1968, Foraminiferal zonation of the lower Carboniferous Connor Lake section, British Columbia: Canadian Assoc. Petroleum Geologists Bull., v. 16, no. 2, p. 147—166. Mamet, B. L., and Rudloff, B., 1972, Algues carbonif‘eres de la partie septentrionale de 1’Amérique du Nord: Rev. Micropaléontologie, v. 15, no. 2, p. 75—114, 10 pls. Mamet, B. L., and Skipp, B. A., 1970, Preliminary foraminiferal correlations of early Carboniferous strata in the North American Cordillera, in Colloque sur la stratigraphie du Carbonifére: Liege Univ. Cong. et Colloques, v. 55, p. 327—348. Menner, V. V., and Reitlinger, E. A., 1971, Foraminiferal provin- cialism during the Middle and Upper Devonian in the Siberian platform [in Russian]: Akad. Nauk SSSR Voprosy Mikropaleon- tologii, v. 14, p. 25—34. Mull, C. G., and Mangus, M. D., 1972, Itkilyariak Formation: New Mississippian Formation of Endicott Group, Arctic Slope of Alaska: Am. Assoc. Petroleum Geologists Bull., v. 56, no. 8, p. 1364—1369, 6 figs. Petryk, A. A., Mamet, B. L., and Macqueen, R. W., 1970, Preliminary foraminiferal zonation, Rundle Group and uppermost Banff Formation (Lower Carboniferous), southwestern Alberta: Cana- dian Assoc. Petroleum Geology Bull., v. 18, no. 1, p. 84—103. Pronina, T. V., 1963, Carboniferous foraminifers of the Berezovo Series in the eastern slope of the southern Ural Mountains, in Papers on the problems of stratigraphy, no. 7, Stratigraphy and fauna of the Paleozoic of the Ural Mountains [in Russian]: Akad. Nauk SSSR Ural. Fil., Geol. Inst. Trudy 65, p. 119—176, 7 pls. Reiser, H. N., Dutro, J. T., Jr., Brosgé, W. P., Armstrong, A. K., and Detterman, R. L., 1970, Progress map, geology of the Sadlerochit and Shublik Mountains [Alaska]: US Geol. Survey open-file map, scale 1:63,360. Reitlinger, E. A., 1957, Devonian spheres of the Russian platform [in Russian]: Akad. Nauk SSSR Doklady, v. 115, no. 4, p. 773—776. 1960, Characteristic microscopical organic remains of the Ozerko-Khovansk Formation: Akad. Nauk SSSR, Geol. Inst. Trudy, Bull. 14, p. 135—179, 3 pls. Sando, W. J., Mamet, B. L., and Dutro, J. T., Jr., 1969, Carboniferous megafaunal and microfaunal zonation in the northern Cordillera of the United States: U.S.Geol. Survey Prof. Paper 613—E, 29 p., 7 figs. Stanton, R. J ., 1963, Upper Devonian calcispheres from the Redwater and South Sturgeon Lake reefs, Alberta, Canada: Canadian REFERENCES CITED 25 Australia: Australia Bur. Mineral Resources, Geology and Geophysics Bull. 116, p. 174—188, 22 pls. Wood, G. V., and Armstrong, A. K., 1975, Diagenesis and stratigraphy of the Lisburne Group limestones of the Sadlerochit Mountains and adjacent areas, northeastern Alaska, US. Geol. Survey Prof. Paper 857, 47 p. Assoc. Petroleum Geology Bull. v. 11. no. 4. p. 410—418. Suleimanov, l. S.. 1945. Some new species ofsmall Foraminifera from the Tournaisian of the Ishimbaevo oil-bearing region [in Russian]: Akad. Nauk SSSR Doklady. v. 48. no. 2, p. 124—127. Veevers. J. J.. 1970. Upper Devonian and Lower Carboniferous calcareous algae from the Bonaparte Gulf basin, northwestern Page A Acknowledgments ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Alchilik River Alapah Limestone ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 age ,,,,,,,,,,,,,,,,,,,, 2, 4, 17, 19 ‘ ______ 1 6 carbonate regressive facies ,,,,,,,,,,,,,,,,, 22 Clarence River section ,,,,,,,,,,,,,,,,,,,, 4, 22 contact ,,,,,,,,,,,,,,,,,,,,,,,, 4, 17, 18, 22, 23 correlation ,,,,,,,,,,,,,,,,,,,,,,,, __,_ 19, 22 deposition __________________________________ 22 dolomite ,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 4, 7, 22 Egaksrak River section ,,,,,,,,,,,,,,, 19, 22 facies ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 4, 16 Kongakut River section _ 4, 7, 16, 22, 23 lagoonal facies ,,,,,,,,, 22 lithology , _, , ,,,,, 4, 7 microfossils _____________________________ 2, 7 northeastern Brooks Range ________________ 22 ooid beds ___________________________________ 7 Plunge Creek section ________________________ 22 Sadlerochit Mountains ,,,,,,,,,,,,,,,,,,,, 19, 22 stromatolite zone __________________________ 4 subsurface ,,,,,,,, . 22 Syncline section , , ,,,,,,,, 22 thickness __________________ wackestone and packstone ,,,,,,,,,,,,,,,,,, 4 Alaska, microfacies ______________________________ 8 northeastern ____________________________ 1, 2, 8 northwestern ___________________________ 1, 7 alaskaensis, Pseudoissinella ,,,,,,,,,, Algae ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 7, 8, 13 kamaenid Algal cysts _ Algal spores __________ aljutovica, Planoendothyra ,,,,,,,,,,,,,,,,,,,,,, 11 aniuikensis, Dainella ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9 Archaediscus koktjubensis ,,,,,,,,,,,,,,,,,,,,,, 15 krestounikovi ____________________ 9, 13, 15, 16 moelleri ___________________________ 13, 15, 16 Sp ______________________________ 9, 11, 13, 15, 16 Arctic National Wildlife Range _____________ 2 Asphaltina cordillerensis v, 11, 15, 16 sp ____________________________ 11, 16 Asteroarchaediscus baschkiricus ,,,,,,,, 9, 11, 15, 16 gnomellus ______________________________________ 16 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9, 11, 16 B baileyi, Globoendothyra ,,,,,,,,,,, bamberi, Yukonella ______________ Banffelu sp ______________________________________ 13 baschkiricus, Asteroarchaediscus ________ 9, 11, 15, 16 Biostratigraphy ________________________________ 7 Biota, lagoonal facies __________________________ 16 Biseriella parua ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 16 sp ,,,,,,,,,,,,,,,,, _ 9, 11, 16 Black Marbles, Dinant, Belgium _____ 17 bowmam', Endothyra. ,,,,,,,,,, , 9, 13, 15, 16 Brachiopod ____________________ 11, 13 Brachiopod fauna _______________________________ 23 britishensis, Pseudoendothyra ___________________ 11 Brooks Range ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 2, 7, 22 INDEX [Italic page numbers indicate both major references and descriptions] Page Brunsia facies ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 Brunsia lenensis __________________________________ 13 sp ,,,,,,,,,,,,, , 13, 15 Bryozoans ,,,,,,,,,,,,, _ 4, 7 bulloides, Globiualvulina , - 11 Button Beds, Australia ,,,,,,,,,,,,,,,,,,,,,,,,,, 16 C Calcisphaera ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16, 17 distribution ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 17 laeuis__1, _________________________ 9, 13, 15,16 pachysphaerica ,,,,,,,,,,,,,,,,,, 9, 11, 13, 15 sp ,,,,,,,,,,,,,,,, 9,11, 13,15,-16 Calcispheres ,,,,,,,,,,,,,,,, 11, 13, 16 Alapah Limestone ,,,,,,,,,,,,,,,,,,,,,,,,, 16 Shunda Formation , W, 16 Canning River ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 2, 17 Carbonate rock classification _____________________ 1 Carbonate rocks, Sadlerochit Mountains ,,,,,,,,, 23 Carboniferous microfossils ,,,,,,,,,,,,,,,,,,,,,,,, 1 Carboniferous rocks, northern Cordillera, United States ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 7 western Canada ,,,,,,,,,,,,,,,,,,,,,,,, 7 Carboniferous zonations, Cordilleran ,,,,,,,,,,,,, 8 Eurasian ,,,,,,,, 8 Carnarvon Member, Mount Head Formation, Alber- Clarence River ,,,,,,,,,,,,,,,,,,,,,,,, 1, 4 Clarence River section___, __________________ 1, 4, 9 Alapah Limestone ___________________ 4, 17, 22 correlation graphic location _____ Kayak(?) Shale ,,,,,,,,,,,,,,,,,,,,, Kekiktuk Conglomerate microfossil list ,,,,,,,,,,,,,,,,,,,,,,,,,, 8, 14 Wahoo Limestone _ _____________________ 4, 22 clauatula, Earlandia ,,,,,,,,,,,,,,,,,, 7, 9, 11, 13, 15 Climcwammina sp Coal beds ,,,,,,,,,,,,,,,,,,,,,,,,,, 4 compressus, Endothyranopsis ,,,,,,,,,,,,,,,,,, 13, 15 Corals, colonial ,,,,,,,,,,,,,,,,,,,,,,,, Cordillera ________________________ cordillerensis, Asphaltina ,_ Correlations, regional ______________ crassus, Endothyranopsis ,,,,,,,,,,,,,,,,,,,,,,, 15 Crinoid plates ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 15 Crinoids ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 7 cushmani, Parathurammina ,,,,,,,,,,,,,,,,,, 13, 15 D Dainella aniuikensis ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9 sp ________________________________________ 9 Detterman, R, Li, cited ,,,,,,,,,,,,,,,,,,,,,,,,, 23 deuexa, Priscella ,,,,,,, ____ H 13 Dinant, Black Marbles, Belgium V, 17 Diplosphaerina sp ,,,,,,,,,,,, __ 13, 16 discoidea, Zellerina ________ Dolomites, Clarence River section ,,,,,,,,,,,,,, 22 Devonian ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 17 Marsh Fork section _________________________ 22 Plunge Creek section _______________________ 22 Dunham, R. J ., cited ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 Page E Earlandia clauatula ,,,,,,,,,,,,,,,,,, 7, 9, 11, 13, 15 vulgaris ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9, 11, 13, 15 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,, 9, 11, 13,15, 16 Earlandinella sp Echinoderms ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, Echinoid spines _________ Echooka Member, Sadlerochit Formation ,,,,,,,,,, 23 Egaksrak River section, Alapah Limestone _, 19, 22 Kayak(?) Shale W, ....... __ 18, 19, 22 microfossil list ,,,,,,,,,,,, 8 Wahoo Limestone ______ Endicott Group ______________________________ 2, 17 regional correlations ,,,,,,,,,,,,,,,,,,,,, 17 Endicott Mountains ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Endothyra bowmani ____________________ 9, 13, 15, 16 excellens ____________ similis , sp ,,,,,,,, ,_ 7, 9,11, 13, 15, 16 Endothyranella sp ________ 13 Endothyranopsids ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 Endothyranopsis compressus __________________ 13, 15 crassus ______________________________________ 15 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Endothyrids ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 Eoendothyranopsis ermakiensis ,,,,,,,,,,,, 11, 13, 15 spiraides thompsoni ________________________________ 13 utahensis __________ sp ,,,,,,,,,,,,,,, Eoforschia sp » ,,,,,,,,,,,,,,,, Eoschubertella yukonensis sp ,,,,,,, Eostaffella sp , Eotuberitina sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Epistacheoides sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 ermakiensis, Eoendothyranopsis ,,,,,,,,,,,, 11, 13, 15 excellens, Endathyra ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16 F, G, H, I Foraminifera ,,,,,,,,,,,,,,,,,,,,,,,,, 8, 11, 16, 17 assemblages , Fossils, plants ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2, 17 Franklin Mountains ,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 22 Globivaluulina bulloides ,,,,,,,,,,,,,,,,,,,,,,,,,, 11 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 7, 11 Globoendothyra baileyi ,,,,,,,,,,,,,,,,,,,,,, 9, 13 globulus ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 13, 15 paula .u tomiliensis sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9, 11, 13, 15 Globoendothyrids ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 glabulus, Globuendothyra ,,,,,,,,,,,,,,, 11, 13, 15 gnamellus, Asteroarchaediscus _._ ,,,,,,,,,,,,,, 16 Gypsum ,,,,,,,,,,,,,,,,,,,, 4, 22, 23 Heterocoral __,, ___ 15 Hexaphyllia sp ...... 1,, 15 incertus, Neoarchaediscus , 1 7, 11, 16 index, Kamaena ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 28 CARBONIFEROUS BIOSTRATIGRAPHY, NORTHEASTERN BROOKS RANGE, ARCTIC ALASKA Page inflate, Koninckopora ,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Introduction ______________________________________ 1 Irregularina sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 15 Issinella sp' ____________________________________ 13 Itkilyariak Formation ,,,,,,,,,,,,,,,,,,,,,,,,,,, 18 K Kamaena ____________________________________ 11, 17 index ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 'lahuseni ________________________________ 13, 15 5]) ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 13, 15 Kayak Shale ____________ age __________________ type locality ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Kayak(?) Shale . ______ 2 age 1.- ,,,,, ",1 , 2, 17 Clarence River section _ 1 4, 17 composite section ____________________________ 18 contact ______________________ 2, 4, 17, 18, 19, 22 correlation 1.. disconformity ,,,,,,,,,,,,, eastern Sadlerochit Mountains _______________ 18 Egaksrak River section ,,,,,,,,,,,,,, 18, 19, 22 geologic structure ,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Kongakut River section ,,,,,,,,,,,,,,,, 4, 18, 19 lithology ____________________________ 2, 4, 17, 18 microfossils __________________________ 17, 18, 19 western Sadlerochit Mountains ______________ 17 Kekiktuk Conglomerate ,, __________ 2 age __________________ 1, 2 Clarence River section __________ _ 4, 17 coal beds ,,,,,,,,,,,,,,,,,,,, 1 4, 17 contacts ________________________________ 2, 17 correlation _________________________________ 17 eastern Sadlerochit Mountains _______________ 17 Kongakut River section ,,,,,,,,,,,,,,,,,,,,,, 17 lithology stratigraphy , type section ___________ western Sadlerochit Mountains ,,,,,,,,,,,,, 17 koktjubensis, Archaediscus ______________________ 15 Kongakut River ________________________________ 1, 4 Kongakut River section __________________ 1, 4, 11, 19 Alapah Limestone ________________ 4, 7, 16, 22, 23 biota ,,,,,,,,,,,,,,,,,,,, correlation ___ 1 graphic location ,,,,,,,,,,,,,,,, 23 Kayak(?) Shale _________ _ 4, 18, 19 Kekiktuk Conglomerate ,,,,,,,,,,,,,,,,,,,,,, 17 lagoona] facies ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 22 microfossil list ,1" _____________________ 8, 16 Sadlerochit Formation ,,,,,,,,,,,,,,,,,,,, 7, 23 Wachsmuth Limestone equivalent ,,,,,,,,,,,, 19 Kaninckopora inflate ______________________ 13, 15 sp ________________________ 13, 15 krestounikoui, Archaediscus ____________ 9, 13, 15, 16 L laevis, Calcisphaera ,,,,,,,,,,,,,,,,,,,, 9, 13, 15, 16 Lagoonal facies, Alapah Limestone ____________ 16, 22 Lagoons, carbonate, Carboniferous ,,,,,,,,,,,,,,,, 16 lahuseni, Kamaena ,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 lenensis, Brunsia ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 Limesmnes, Awkan age ,1 23 Paleozoic ________________________________ 4, 17 Pennsylvanian ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 4 Lisburne Group ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1,2, 19 carbonate rocks, altered ,,,,,,,,,,,,,,,,,,,, 4 contact ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2, 19, 22 correlation ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 7, 1.9 diagenesis ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9 foraminiferal assemblages ,,,,,,,,,,,,,,,,,,, 8 foraminiferal zones ,,,,,,,, 1 microfossils, Carboniferous ,,,,,, 1 petmgraphy ,,,,,,,,,,,,,,,,,,,, 9 regional correlations ,,,,,,,,,,,,,,,,,,,,,,,, 19 stratigraphic studies ,,,,,,,,,,,,,,,,,,,,,,,,,, 1 Lisburne Hills ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 7 Lisburne Limestone ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Page M macrus, Eoendothyranopsis ,,,,,,,,,,,,,,,,, 13, 15 Marsh Fork ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 17 Marsh Fork section, Kayak(?) Shale ,,,,,,,,,, 1. 19 microfossil list ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 8 Microfaunal assemblage zones ,,,,,,,,,,,,,,,,,, 7 Microfacies, Alaska ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 8 Microfossil list ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9 Clarence River section _________ 8, 14 eastern Sadlerochit Mountains section, ,1 8 Egaksrak River section ,,,,,,,,,,,,, H 8 Kongakut River section ____________________ 8, 16 Marsh Fork section ,,,,,,,,,,,,,,,,,,,,,,,, 8 Plunge Creek section ,,,,,,,,,,,,,,,,,,,,,,,,, 8 Syncline section ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 8 western Sadlerochit Mountains section ,,,,,,,, 8 Microfossils, Alapah Limestone ,,,,,,,,,,,,,,,,,, 2, 7 Carboniferous ,,,,,,,, 1. 1 Franklin Mountains ,,,,,,,,,,,,,,,,, 1 Kayak(?) Shale ,,,,,,,,,,, 1 17, 18, 19 Lisburne Group ,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 Romanzof Mountains ,,,,,,,,,,,,,,,,,,,,,,,,, 1 Wachsmuth Limestone _______________________ 2 Wahoo Limestone ,,,,,,,,,,,,,,,,,,,,,,,,,, 4 M illerella sp __________________________________ 1 1 minimus, Planospirodiscus ,,,,,,,,,,,,,,,,,,,,, 1 1 moelleri, Archaediscus ___________________ 13, 15, 16 Mount Head Formation, Carnarvon Member, Alberta __________________________ 16, 17 Mount Wachsmuth ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 N, O Neoarchaediscus incertus ,,,,,,,,,,,,,,,,,, 7, 11, 16 paruus ,,,,,,,,,,,,,,,,,,,,,,,,,,,,, regularis ,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16 Sp ,,,,,,,,,,,,,,,,,,,,,,,, 9, 11, 15, 16 Neruokpuk Formation ,,,,,,,,,,,,,,,,,,,,, 17, 18 Neruokpuk Lakes ______________________________ 2 Ooids ,,,,,,,,,, w. 7 Ostracodes ....... 9, 11, 13, 15 13 pachysphaerica, Calcisphaem _ _ 1 Palaeocancellus sp ____________ Palaeotextularia sp _ Paracalligelloides sp _ Parathurammina ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16, 17 cushmani ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Kongakut River section ,,,,,,,,,,,,,,,,,,,,,, 17 suleimarwui ______________________________ 13, 15 5p _- ,,,,,,,,,,,,,,, 11, 13, 15 Parathuramminids, distribution ,,,,,,,,,,,,,,,,,, 17 parva, Biseriella ______________________________ 11, 16 paruus, Neoarchaediscus ,,,,,,,,,,,,,,,,,,,,,,, 16 regularis, Neoarchaediscus ,1 16 paula, Globoendothyra _______ H 13 Pelecypods ,,,,,,,,,,, __ 13 Pellets ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Pelmatoman plates ,,,,,,,,,,,,,,,,,,,,, Planoarchaediscus sp ,,,,,,,,,, Planoendothyra aljutouica ,,,,,,,,,,,,,,,,,,,,,,,, 11 Sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 13, 15, 16 Planospirodiscus minimus ,,,,,,,,,,,,,,,,,,,,,,,, 11 taimyricus __________ ._ 11, 16 _ 9, 11, 16 “-1 22 Kayak(?) Shale ,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 19 lagoonal facies ,,,,,,,,,,,,,,,,,,,,,,,,,,, 22 microfossil list ,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 8 pressus, Eoendothyranopsis ,,,,,,,,,,,,,,,,,,,,,, 13 prisca, Priscella ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 9, 13, 15 Priscella deuexa ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13 prisca ,,,,, 9, 13, 15 sp ,,,,, 9, 13, 15 Protozoa __,, ,. 17 Prudhoe Bay ,,,,,,,,,,,,,,,,,,,,, 22 Pseudoammodiscus sp ,,,,,,,,,,,,,,,,,,,,,, 9, 13, 15 Page Pseudocornuspira sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11 Pseudoendothyra britishensis sp ,,,,,,,,,,,,,,,,,,,,, Pseudoglomospira sp ,,,,,,, 11, 15, 16 Pseudaissinclla ,,,,,,,,,, ”W 11, 17 alaskaensis ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 15 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 13, 15 Pseudostaffella sp ,,,,,,,,,,,,,,,,,,,,,,,,,,, 7, 11 Pseudutaxis sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16 Q, R Quasiarchaediscus rugosus _______ __ 11 sp ,,,,,,,,,,,,,,,,,,,,, , 9 Radiolarite ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 7 Radiosphaera ,,,,,,,,,,,,,,,,,,,,,,,,,, a ,,,,,, 16, 17 Radiosphaerina sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 15 regularis, N eoarchaediscus paruus ,,,,,,,,,,,,,,,, 16 robustus, Eoendothymnopsis ,,,,,,,,,,,,,, 11, 13, 15 Romanzof Mountains ,,,,,,,,,,,,,,,,,,,,,,,,,, 1, 22 rugosus, Quasiarchaediscus ,,,,,,,,,,,,,,,,,,,,,, 11 S Sadlerochit Formation _______________ 4, 7, 23 Clarence River section ___ 4 contact ,,,,,,,,,,,,,,,,,,,,,,,, H 23 correlation ,,,,,,,,, Echooka Member __- Kongakut River section ,,,,,,,,,, Sadlerochit high ____________________ Sadlerochit Mountains ________________ 1, 17, 22 carbonate rocks ,,,,,,,,,,,,,,,,,,,,, 23 eastern section, diagenesis ___________________ 9 microfossil list,,__ petrography ,,,,,,,,,,,,,,,,,,,,,, Meramecian time ,,,,,,,,,,,,,,,,,,,,,,,, western section, diagenesis ,,,,,,,,,,,,,,,,,,, 9 microfossil list ,,,,,,,,,,,,,,,,,,,,,, petrography __,, scitulus, Eaendothyranopsis ,,,,,,,,,, Shainin Lake ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Shainin Lake area ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 2 Shale, black ______________ _. 2 Shunda Formation, Alberta 1 ,,,,, 16 British Columbia ,,,,,,,,,, 16 similis, Endothyra ,,,,,,,,,,,,,,,,,, W, 9, 13, 15 skimoensis, Stacheia ,,,,,,,,,,,,,,,,,,,,, 7, 9, 13 Skippella sp _____________________ 11, 15 spiroides, Eoendothyranopsis ,,,,,,,,,,,,,,,,,,,,, 9 Stacheeinae ,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11 Stacheia skimoensis _, sp ______________ __ 11,, 9, 13 Stacheoides sp ______________________ 9, 11, 13, 15, 16 Stratigraphy 1-- ,,,,,,,, 2 Stromatolites ____________ suleimanovi, Parathurammina ___________ 1 13, 15 Syncline section, Alapah Limestone ,,,,,,,,,,,,, 22 microfossil list ,,,,,,,,,,,,,,,,,,,,, Synclinorium, Aichilik River __________ T, U, V Taimyr—Alaska foraminifera ,,,,,,,,,,,,,,,,,,,,,, 8 taimyricus, Planospirodiscus ,,,,,,,,,,,,,,,,,, 11, 16 Terra rossa ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 23 Tetrataxis sp ______________________ thompsoni, Eoendothyranopsis , tomiliensis, Globoendothyra Tuberitina sp ,,,,,,,,,, Ungdarella 111111111111111111111111111111111111 13 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 15 utahensis, Eoendothyranopsis ,,,,,,,,,,,,,,,,,, 13 Uva ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16 Vadose weathering, carbonate rocks ______________ 23 Veevers, J. J., cited ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16 Vicinesphaera ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 16, 17 sp ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 11, 13, 15 vulgaris, Earlandiu ,,,,,,,,,,,,,,,,,,,, 9, 11, 13, 15 Page W Wachsmuth Limestone __________________________ 2 age ________________________________________ 2 carbonate facies lithology __________________________________ 17 microfossils _________________________________ 2 stratigraphic equivalent- __ A 19 type section _____________ __ 2 Wahoo Lake _______ __ 4 Wahoo Limestone ______________ age __________________________________________ 4 INDEX Page Wahoo Limestone—Continued Clarence River section ____________________ 4, 22 contact ________________________________ 4, 23 correlation ,,,,,,,,,,, 22, 23 eastern Sadlerochit Mountains“ _____ 22 Egaksrak River section ___________ 22 lithology __________________________________ 4, 22 microfossils ___________________________ ___ 4 northern Brooks Range ____________________ 22 ooid facies _______________________________ 22 thickness _________________________________ 22 type section __________________________________ 4 U.S. GOVERNMENT PRINTING OFFICE: 1975-0-689-909/53 Wahoo Limestone—Continued western Sadlerochit Mountains Whistler Creek yukonensis, Eoschubertella _________ Zellerina discoidea ________________ 15, 16 Sp __________ 9, 11, 15, 16 76 701w a , v. ,6” * Summary of 1972‘ Oil and Gas Statistics» For Onshore and Offshore Areas of 151 Countries GEOLOGICAL SURVEY PROFESSIONAL PAPER 885 M H , ”if; \‘IW; if» ”‘w-n 5&3 ‘ W L, gixx, [Up 1,9134 7 ‘ Summary of 1972 Oil and Gas Statistics For Onshore and Offshore Areas of 151 Countries By SHERWOOD E. FREZON GEOLOGICAL SURVEY PROFESSIONAL PAPER 885 Data on oflshore and onshore production, reserves, resources, exploration activity, and imports and exports of oil and natural gas for 1972 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1974 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 74-600102 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, DC. 20402 - Price $2.70 . Stock Number 2401-02518 CONTENTS Page Page Introduction _______________________________________ 1 Data tabulated by country—~Continued Purpose _______________________________________ 1 Equatorial Guinea ______________________________ 45 Countries included ______________________________ 1 Ethiopia ________________________________________ 46 Presentation of data ____________________________ 1 Fiji _____________________________________________ 47 Use of data ____________________________________ 1 Finland ________________________________________ 48 Sources of information and acknowledgments ___- 2 France _________________________________________ 49 Data tabulated by country __________________________ 2 Gabon __________________________________________ 50 Explanatory notes _______________________________ 2 Gambia ________________________________________ 51 Definitions and abbreviations _______________ 2 German Democratic Republic ____________________ 52 Geographic and geologic data _______________ 2 Germany, Federal Republic of ___________________ 53 Oil and gas statistics _______________________ 3 Ghana _________________________________________ 54 Afghanistan ___ - ______ ___ __ 5 Greece _________________________________________ 55 Albania ________________________________________ 6 Guatemala _____________________________________ 56 Algeria ________________________________________ 7 Guinea _________________________________________ 57 Angola ___________~-_--___--_g __________________ 8 Guyana ________________________________________ 58 Argentina ______________________________________ 9 Haiti __________________________________________ 59 Australia _______________________________________ 10 Honduras ______________________________________ 60 Austria _- _____ - _______ 11 Hungary ________________________________________ 61 Bahamas _______________________________________ 12 Iceland ________________________________________ 62 Bahrain ________________________________________ 13 India __________________________________________ 63 Bangladesh ______________________________________ 14 Indonesia ______________________________________ 64 Barbados _______________________________________ 15 Iran _____________________________________________ 65 Belgium ________________________________________ 16 Iraq ___________________________________________ 66 Belize __________________________________________ 17 Ireland ________________________________________ 67 Bhutan ________________________________________ 18 Israel __________________________________________ 68 Bolivia ______ ___ __ ___- ___ 19 Italy ___________________________________________ 69 Botswana ______________________________________ 20 Ivory Coast ____________________________________ 70 BraZil _________________________________________ 21 Jamaica ________________________________________ 71 Brunei _________________________________________ 22 Japan __________________________________________ 7 Bulgaria _______________________________________ 23 Jordan _________________________________________ 73 Burma _________________________________________ 24 Kenya _________________________________________ 74 Burundi ________________________________________ 25 Khmer Republic ________________________________ 75 Cameroon ______________________________________ 26 Korea, Democratic People’s Republic of __________ 76 Canada ________________________________________ 27 Korea, Republic of _____________________________ 77 Central African Republic ________________________ 28 Kuwait ________________________________________ 78 Chad ___________________________________________ 29 Laos ___________________________________________ 79 Chile ___________________________________________ 30 Lebanon _______________________________________ 80 China . Lesotho ________________________________________ 81 People’s Republic of China __________________ 31 Liberia ________________________________________ 82 Republic of China (Taiwan) ________________ 32 Libyan Arab Republic ____-_______-__________;__ 83 Colombia ________________________________________ 33 Lichtenstein ____________________________________ 84 Congo __________________________________________ 34 Luxembourg ____________________________________ 85 Costa Rica _____________________________________ 35 Malagasy Republic _____________________________ 86 Cuba ___________________________________________ 36 Malawi ________________________________________ 87 Cyprus _________________________________________ 37 Malaysia _______________________________________ 88 Czechoslovakia _________________________________ 38 Maldives _______________________________________ 89 Dahomey _______________________________________ 39 Mali ___________________________________________ 90 Denmark _______________________________________ 40 Malta __________________________________________ 91 Dominican Republic ____________________________ 41 Mauritania _____________________________________ 92 Ecuador _______________________________________ 42 Mauritius ______________________________________ 93 Egypt __________________________________________ 43 Mexico __________________________________________ 94 El Salvador ____________________________________ 44 Mongolia _______________________________________ 95 III IV CONTENTS Page Page Data tabulated by country—Continued Data tabulated by country—Continued Morocco _______________________________________ 96 Sri Lanka ______________________________________ 127 Mozambique ____________________________________ 97 Sudan _________________________________________ 128 Nauru _________________________________________ 98 Swaziland ______________________________________ 129 Nepal __________________________________________ 99 Sweden ________________________________________ 130 Netherlands ____________________________________ 100 Switzerland _____________________________________ 131 New Zealand ___________________________________ 101 Syrian Arab Republic ___________________________ 132 Nicaragua ______________________________________ 102 Tanzania _______________________________________ 133 Niger __________________________________________ 103 Thailand _______________________________________ 134 Nigeria ________________________________________ 104 Togo ___________________________________________ 135 Norway ________________________________________ 105 Tonga __________________________________________ 136 Oman __________________________________________ 106 Trinidad and Tobago ___________________________ 137 Pakistan _______________________________________ 107 Tunisia ________________________________________ 138 Panama ________________________________________ 108 Turkey _________________________________________ 139 Paraguay ______________________________________ 109 Uganda _________________________________________ 140 Peru ___________________________________________ 110 Union of Soviet Socialist Republics _____________ 141 Philippines ______________________________________ 111 United Arab Emirates __________________________ 142 Poland _________________________________________ 112 United Kingdom ________________________________ 143 Portugal _______________________________________ 113 United States __________________________________ 144 Portuguese Guinea _______________________________ 114 Upper Volta ____________________________________ 145 Qatar __________________________________________ 115 Uruguay _______________________________________ 146 Romania _______________________________________ 116 Venezuela ______________________________________ 147 Rwanda ________________________________________ 117 Viet-Vam, Democratic Republic of _______________ 148 San Marino ____________________________________ 118 Viet-Nam, Republic of __________________________ 149 Saudia Arabia _________________________________ 119 Western Samoa _________________________________ 150 Senegal ________________________________________ 120 Yemen Arab Republic (San'a) __________________ 151 Sierra Leone ___________________________________ 121 Yemen, People’s Republic of (Aden) _____________ 152 Singapore __________________ _____________________ 122 Yugoslavia _____________________________________ 153 Somalia ________________________________________ 123 Zaire __________________________________________ 154 South Africa ___________________________________ 124 Zambia ________________________________________ 155 Southwest Africa (Namiba) _____________________ 125 Summary tables _____________________________________ 156 Spain __________________________________________ 126 References _________________________________________ 163 TABLES Page TABLE 1. Coastal and shelf characteristics, by continents, of countries bordered by oceans or inland seas ______________ 156 2. Oil production. proved reserves, and potential resources ___________________________________________________ 157 __________________________________________ 160 3. Natural gas production, proved reserves, and potential resources SUMMARY OF 1972 OIL AND GAS STATISTICS FOR ONSHORE AND OFFSHORE AREAS OF 151 COUNTRIES By SHERWOOD E. FREZON INTRODUCTION PURPOSE The purpose of this report is to present data con- cerning the exploration, production, reserves, resources, and world trade of oil, natural gas, and petroleum products for 151 countries for the year 1972. The com- pilation, from diverse sources, should prove useful to those interested in the world’s petroleum economy. In its intent and content this report is an update of similar data presented by Albers and others (1973). COUNTRIES INCLUDED The 151 areas included in this report were selected because of their participation, in the petroleum econ- omy of the world and because of their interest in the development of mineral resources, including petroleum, on the continental margins of the world. Most of the areas are independent countries, and for convenience the areas are collectively referred to as countries. In reporting commodity data from many areas it seems advisable to maintain, in some part of the re- port, the integrity of data from the areas from which they are received. The degree of certainty and the completeness of commodity data varies for each area and frequently is highly variable for adjoining areas. To combine the data from two such areas, and present it as data from a single area, would be completely misleading and therefore is avoided. The 151 countries are chosen solely because petro- leum and trade data are available for them. The in- clusion of any name on the list is not intended to convey any official attitude regarding their political status. The list includes 119 of the 120 countries in- cluded in the report of Albers and others (1973) and 32 new areas, and includes most areas bordering the continents, as well as the larger islands of the world. PRESENTATION OF DATA The data for the 151 countries are presented in individual tables. Each table contains geographic and geologic information for the onshore and offshore areas of the country as well as production, reserve, resource, and trade data of oil, gas, and petroleum products. At the end of this report certain of the data in the country tables is presented in the summary form, with countries arranged by continents. The continents are North America, South America, Europe, Asia, Africa, and Oceania, as listed in “Status of the Worlds Nations” (US. Department of State, 1969b). The Soviet Union is listed under a separate heading (Europe and Asia). The coastal and margin geogra— phy and geology of each of those countries bordered by oceans and inland seas are given in table 1. Pro- duction, cumulative production, proved recoverable re- serves, and potential resources for all the 151 countries of the report are given for both oil (table 2) and gas (table 3). USE OF DATA The data presented here reflect the degree to which a country currently participates in the production, re- fining, consumption, and trade of hydrocarbons. The accuracy of the data permits comparisons between countries with an acceptable degree of assurance. The resource and reserve estimates are useful in de- termining the future ability of a country to participate in the economy, but they must be used with caution. Reserve estimates are transitory numbers subject to upward change with new discoveries and downward change resulting from production. Resource estimates are less accurate because in many areas they are based on a minimum of information and are highly con— jectoral. The transitory and interpretive nature of re- serve and resource estimates, combined with the com— plexity of political and economic factors, reduce the certainty of any predictions made using reserve and resource data. 2 SOURCES OF INFORMATION AND ACKNOWLEDGMENTS The primary sources of available information used in this report were dispatches of the U.S. Department of State and publications of the US. Bureau of Mines. Where information from these sources was unavailable or insuflicient, data were obtained from the published sources listed in the references. Specific sources of data are not given in the report, but all data are derived from the references. The geographic and geologic data for the 119 coun- tries of Professional Paper 817 (Albers and others, 1973) used in this report were compiled by E. G. A. Weed and J. I. Tracey, J r.; similar data for the re- maining countries were compiled by the author. The resource potential of each of the countries was deter- mined by S. P. 'Schweinfurth. The author is indebted to J. P. Albers and A. B. Coury for numerous discussions and helpful sugges— tions. made during the time of compiling this report. Their previous experience in preparing Professional Paper 817, and their work in soliciting the Department of State data made it possible for the author to pre- pare the report in the shortest possible time. DATA TABULATED BY COUNTRY EXPLANATORY NOTES DEFINITIONS AND ABBREVIATIONS The meaning of abbreviations and the definitions of some terms used are presented here rather than on the tables for the individual countries. The American system of numerical punctuation is used: periods indicate decimal points, and commas separate units of thousands. The American numbering system is used; thousand = 103, million = 106, billion = 109, and trillion = 1012. Abbreviations used are as follows: NA—not available, information probably exists; O—zero quantity; Negl—negligible, less than one-tenth (10“) of designated unit; SI—shut in, well capable of producing oil or gas but not on production for the current year; >—greater than; <——less than. Distances and areas are given in nautical miles. The relation between nautical miles and other generally used distance and area] measurements are as follows: 1 nautical mile = 1.15 statute miles 1.85 kilometers 1 square nautical mile = 1.32 square statute miles 3.43 square kilometers The term oifshore is used in a more restricted sense than by the oil and gas reporting media. Offshore waters are defined as 1) waters along shores facing high seas, or 2) waters along shores of relatively con- fined seas through which an international boundary exists. Bodies of water surrounded by one nation or in- land sea are not regarded as offshore waters. Following this definition,wells drilled or producing in Lake Mara— caibo in Venezuela or the Caspian Sea in the Soviet Union are assigned to the onshore classification. Quantities of oil generally are reported in barrels of 42 gallons or in metric tons. In the tables quantities are reported in both units of measurement, and the two quantities represent the same amount of oil. The number of barrels in a metric ton of oil is dependent on the specific gravity of the oil. The following list, prepared by the U.S. Bureau of Mines (1974), gives the number of barrels in a metric ton of oil from B b ls p er metric Bbla per metric Mongolia _ Morocco _ Netherlands Neutral Zone ___________ New Guinea ______ 7 468 New Zealand Nigeria __ 7.410 Norway __ 7.444 Oman ___- 7 390 People's Republic of bins. _____________ Republic of China (Taiwan) Colombia _____________ . Cu :1 __________________ . Czechoslovakia __ . _ Denmar _____ . _ Ecuador ___ . _ Egypt _____ . Tunisia - - France ______ . Turkey -- Gabon Republic ......... . United Arab Emirates ___ Germany, West _________ 7.223 United Kingdom ________ 7.279 Hungary _____ . United States ___ _ 7.418 India U.S.S.R. ___ 7.350 Indonesia __ Venezuela -_ 7.00:) ran _______ Yugoslavia _ ______ 7.407 Iraq ___________________ Zaire __________________ 7.478 Israel various world areas. This list was used to convert quantities of produced and exported oil from one unit of measurement to the other. Imported oil, and oil from countries not shown on the list, were converted from one to the other quantity using the world aver- age of 7.3 barrels per metric ton. Quantities of natural gas are reported in cubic feet or cubic meters. One cubic meter is equivalent to 35.3 feet. GEOGRAPHIC AND GEOLOGIC DATA Category: Soley for the convenience of presenting in- formation in this publication categories have been designated for each country that indicate the rela- tion between the country and any coastal waters present. The four categories are: landlocked, shelf- ~ SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 3 locked, open shelf, and archipelago. Landlocked countries have no access to coastal waters. Shelf— locked countries have access to seabed areas which have superjacent waters that are no deeper than 200 meters. Open shelf countries have access to areas deeper than 200 meters. Archipelago indicates that the country is an island or islands on a shelf area. The map “Boundaries of separate seabed areas of contrasting topographic gradients” (U.S. Depart- ment of State, 1971) was used to determine these categories. Bordering water body: The sixteen major water bodies named in this report are the Pacific, Atlantic, Indian, and Arctic Oceans; the Mediterranean, Adriatic, South China, Caribbean, East China, Japan, North, Red, Black, and Baltic Seas; the Persian Gulf, and Gulf of Mexico. These names are listed for each country in order of decreasing length of coastline. Coastal length: The length of the coastline facing the sea, exclusive of irregularities, is given in nautical miles. Data are from “Sovereignty of the sea” US. Department of State, 1969a). Shelf and margin: The continental shelf is defined as the area between the shore line and the 200-meter isobath. The outer edge of the continental margin generally lies between the 200‘meter and the 3,000 meter isobaths. Areas are given in square nautical miles, and the data is from “Sovereignty of the seas” (U.S. Department of State, 1969a). Geology: Two rock types, sedimentary and crystalline, are used to describe the geology. Where both rock types occur the first type listed comprises more than 50 percent of the area. If the country borders an ocean or sea, the rock types for coastal onshOre and offshore areas are given; for landlocked countries the rock types present in the whole country are listed. The source of this data is McKelvey and Wang (1970). OIL AND GAS STATISTICS Production in 1972: Oil production is reported in bar- rels and metric tons; gas production is reported in cubic feet and cubic meters. Natural gas production is gross production, which includes flared, vented, reinjected, and marketed gas. Cumulative production: Total cumulative production is for the years indicated. It includes previously re- ported cumulative production (Albers and others, 1973) to which 1972 production is added. Proved recoverable reserves: Reserves are identified deposits of oil and gas known to be recoverable. The quantities cited here are the estimated remaining reserves available as of 12/31/72. Potential resources (ultimate recoverable resources): Potential resources are quantities of crude oil and natural gas that are believed to be present in sedi— mentary rocks in areas that have not been explored or only partly explored. Because the estimates of these resources are based on a minimum of geo- logic information, their accuracy is largely depen- dent on the estimation procedures. The actual quan- tities of these resources that will be discovered is dependent on the intensity of exploration programs. These programs are in turn a function of petroleum industry technology and the economics of petroleum supply and demand. Each potential resource estimate is given as a numerical rating that represents a range of the quantity of oil and gas believed to be present. The use of a specific quantity is avoided in order to prevent any implication of a misleading degree of precision, accuracy, or certainty of the estimate. The quantities of oil and gas assigned to the various categories is shown below. Quantity of oil or gas Category Billions of barrels Trillions of cubic feet I ____________ 1,000 -—10,000 1,000 —10.000 II ___________ 100 — 1,000 100 — 1,000 III __________ 10 — 100 10 — 100 IV ___________ 1 —— 10 1 - 10 V ____________ 0.1 - 1 0.1 - 1 VI ___________ 0.01- 0.1 0.01~ 0.1 O ____________ <0.01 <0.01 The quantity of oil and gas in each category varies from that in adjoining categories by orders of 10. Thus the quantity in any single category is ten times smallerthan the next larger category and ten times greater than the next smaller category. The 0 category does not indicate 0 quantity; countries in the zero category could produce, if feasible, sev- eral million barrels of oil. The methods used to compute potential resources estimates are based on the work of Hendricks (1965). Historical data useful in defining potential resources include exploration, drilling and field development information, reserve estimates, and production ef- forts. For the United States these data, as 'well as geologic information, are abundant and the estimates are relatively accurate. At the present time, for ex- ample, the United States has reached a cumulative production slightly greater than 100 billion barrels of oil, which falls in the lower part of its assigned category II. For areas and countries with little or no his- torical petroleum data, resource estimates were made by comparing the area with geologically similar areas in the United States where potential resources SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES were known. It was assumed that geologically simi- lar areas had similar resource potential. Therefore the quantity of,oil in each was dependent upon its relative size. With these assumptions the resources of the unknown area could be estimated. After determining the potential resources for all areas within a country the oil-in-place and the gas- in-place were totaled. Not all this estimated oil and gas is recoverable because of economic and techno- logical reasons. Therefore the in-place quantities were reduced by an amount equivalent to an estimated fractional recovery factor to produce the ultimate recoverable reserves. These quantities determined the potential resource category. Number of wells completed in 1972: In this table the wells drilled in 1972 are classified as onshore or offshore and as exploratory or production depending upon the purpose for which they were drilled. Wells drilling at the end of the year are not included in the tabulation: wells started in earlier years and completed in 1972 are included, unless noted. The depth of water in which offshore wells are drilled is indicated as greater than 200 meters (>200 m) or less than 200 meters (<200 m). The 200-n1eter depth is equivalent to about 100 fathoms or 660 feet. Exploratory wells are drilled to find deeper pro— duction zones in known fields, or to find production in areas where none exists. Production wells, on the other hand, are drilled to encounter producing zones in known fields. Producing wells as of 12/31/72: Producing wells in- clude both pumping and flowing oil wells and gas wells. Generally the number of producing gas wells is not available. Offshore concessions licensed as of 12/31/72: A con- cession is here defined as an offshore area in which exploration activities can be conducted. The permit or license is the formal permission from the rele— vant agency in the country to conduct exploration activities. The best source of this information is the maps published in the annual Foreign Developments issue of the Bulletins of the American Association of Petroleum Geologists. Offshore exploration expenditures in 1972: Little in- formation on such expenditures is generally avail- able. The names and nationalities of companies in- volved in such exploration are known. The amounts expended by these companies are often not known; therefore the symbol NA is used frequently in these tables. Imports and exports in 1972: Imports of oil, natural gas, and petroleum products are reported in actual quantities. The three-part division of commodities more accurately reflects the activity of a country in the production, refining, consumption, and trade of petroleum hydrocarbons. As in other tables, qualiti- ties of oil and gas are reported in two units of meas- urements. Quantities of products are reported in only one unit and no equivalent is given. This fact is indicated by a + sign in the headings of the columns. For those countries where two entries ex- ist in the products columns, the reporting source has reported quantities of liquids in gallons, and quan- tities of solids in metric tons. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES AFGHANISTAN Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ - Negl _ _ _ Negl Negl _ _ _ Negl Cumulative production . (1971—72) __________ Neg] ___ Negl Negl ___ Negl Proved recoverable reserves (12/31/72) _ 90 ___ 90 12 ___ 12 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 91.3 ___- 91.3 2.6 ___ 2.6 Cumulative production (1967—72) __________ 428 ___- 428 12 ___ 12 Proved recoverable reserves (12/ 31 / 72) _ 5.000 ____ 5,000 142 ___ 142 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ IV ___ IV IV __- IV Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA ___- ___- ___- NA NA Development _ NA NA ___- ____ ___- NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Ofi'shore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ . Percent } Not applicable. Im orts and ex orts of oil roducts and natural as in 1972: P p 9 P a g Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 2.9 0 0 0 Exports _______ 0 0 0 0 91.3 2.6 6 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS; 151 COUNTRIES \ ALBANIA Category: Open shelf. Margin: Area to 3,000-m depth, 3,600 sq Bordering water body: Adriatic Sea. nautical miles. Area to 200 nautical Coastal length: 155 nautical miles. miles, 3,600 sq nautical miles. Shelf area to 200-m depth: 1,600 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 15 0 15 2.2 O 2.2 Cumulative production (1933—72) _________ 97 O 97 14.2 0 14.2 Proved recoverable reserves (12/31/72) _ 90 O 90 13.6 0 13.6 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ NA 0 NA NA 0 NA Cumulative production (1933—72) __________ NA 0 NA NA 0 NA Proved recoverable reserves (12/31/72) _ 300 0 300 8.4 0 8.4 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III IV III IV IV IV Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory _ - NA NA NA NA NA NA NA Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: Onshore, NA; Ofl'shore, NA; Total, NA. Ofl'shore concessions licensed as of 12/31/72: Not applicable. Ofl'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA 0 NA NA Percent _______________ NA 0 NA NA Imports and exports of oil,'pr0ducts, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA NA NA NA Exports _______ NA NA NA NA NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ALGERIA Category: Open shelf. Margin: Area to 3,000-m depth, 13,600 sq Bordering water body: Mediterranean Sea. nautical miles. Area to 200 nautical Coastal length: 596 nautical miles. miles. 40,000 sq nautical miles. Shelf area to 200-m depth: 4,000 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 400 0 400 52 0 52 Cumulative production (1944—7 2) __________ 3,318 0 3,318 430 0 430 Proved recoverable reserves (12/31/72) _ 11.800 0 11,800 1,532.5 0 1,532.5 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 107.8 0 107.8 3.1 0 3.1 Cumulative production (1957—72) __________ > 1.708 0 > 1,708 > 48 0 > 48 Proved recoverable reserves (12/31/72) _ 105.900 0 105,000 3,000 0 3,000 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Cate or ____________ II 0 II II 0 H g y Number of wellscompleted in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory _- 9 1 0 O 0 9 1 Development _ 70 53 0 0 0 70 53 Producing wells as of 12/31/72: Onshore, 574; Offshore, 0; Total, 574. Ofl'shore concessions licensed as of 12/31/72: None licensed; state assumed control of industry in 1971. Offshore exploration expenditures in 1972: Local U.S. Companies of Y companies companies other countries Gm ernment Amount _____________ 0 0 0 NA Percent ______________ 0 0 0 NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 3.4 0 0 0 0 Exports _______ 364.4 47.4 2.1 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ANGOLA Category: Open shelf. Margin: Area to 3,000-m depth, 65,900 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 806 nautical miles. miles. 147,600 sq nautical miles. Shelf area to 200-m depth: 19,500 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 4.9 46.5 51.4 0.7 6.4 7.1 Cumulative production (1958-72) _________ 56.9 124.5 181.4 8 17 25 Proved recoverable reserves (12/31/72) _ NA NA 1,200 NA NA 166.7 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ NA 40.3 >403 NA 1.1 > 1.1 Cumulative production (1958—72) _________ NA >403 >40.3 NA >1.1 >1.1 Proved recoverable reserves (12/31/72) _ NA NA 1.400 NA NA 39.7 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ IV IV IV III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 7 3 8 0 2 15 5 Development _ 11 NA 8 0 NA 19 15 Producing wells as of 12/31/72: Onshore. 57; Offshore, 101; Total, 158. Offshore concessions licensed as of 12/31/72: Eight concessions; all Within 200~m depth. Four onshore and offshore; five completely offshore. Concessions licensed to five companies or consortia. Offshore exploration expenditures in 1972: Local US. Companies of V Y companies companies other countries (’0‘ ernment Amount _____________ NA NA NA ‘ NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 3-4, 0 NA NA Exports _______ 49.2 0 2.1 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ARGENTINA Category: Open shelf. nautical miles. Area to 200 nautical Bordering water body: Atlantic Ocean. miles, 339,500 sq nautical miles. Coastal length: 2,120 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 232,200 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. talline. Margin: Area to 3,000-m depth, 484,100 sq Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 158.4 0 158.4 22.7 0 22.7 Cumulative production (1908—72) __________ 2.0557 0 2,055.7 313.7 0 313.7 Proved recoverable reserves (12/31/72) _ >2,500 NA >2,500 >357.7 NA >357.7 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 268.7 0 268.7 7.6 0 7.6 Cumulative production (1960—72) __________ 2,835.4 0 2,835.4 83.6 0 83.6 Proved recoverable reserves (12/31/72) _ 6,700 NA 6,700 190 NA 190 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore ‘Total Onshore Offshore Total Category ____________ III III III III III III Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory _- 106 20 0 0 0 106 20 Development _ 509 389 0 0 0 509 389 Producing wells as of 12/31/72: Onshore, 5,660; Offshore, 0; Total, 5,660. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of G 7 t companies companies other countries 0‘ ernmen Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet . meters Imports _______ 10.9 1.5 4.8 0 34.6 0.9 Exports _______ .2 Neg] 1.4 0 0 0 10 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES AUSTRALIA Category: Open shelf. Margin: Area to 3,000-m depth, 1,445,400 Bordering water bodies: Pacific Ocean, In- sq nautical miles. Area to 200 nautical dlan Ocean. miles, 2,043,300 sq nautical miles. Coastal length: 15,091 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 661,600 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oifshore Total Production in 1972 _-_ 29 114 143 3.6 14.8 18.4 Cumulative production (1964—72) _________ 108.6 257.2 365.8 14.1 33.5 47.6 Proved recoverable reserves (12/ 31/ 7 2) _ NA NA 2,082 NA NA 268 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 68.2 31.4 99.6 1.9 0.9 2.8 Cumulative production (1965—72) _________ 147.7 93.8 241.5 4.2 2.6 6.8 Proved recoverable reserves ( 12/ 31/72) _ NA NA 37,700 NA NA 1,068 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III III II II II Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 50 3 36 0 7 86 10 Development __ 32 17 14 0 12 46 29 Producing wells as of 12/31/72: Onshore, NA; Oifshore, NA; Total, 474. Offshore concessions licensed as of 12/31/7 2: No information. ' Offshore exploration expenditures in 1972: Local~ U.S. . Companies of Government companies companies other countries ‘ Amount _____________ NA NA NA 0 Percent ______________ NA N A NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons , feet meters Imports _______ 65.3 0 24.5 0 0 0 Exports _______ . 4 O 16.2 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES AUSTRIA Category: Landlocked. Shelf area to 200-111 depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 17.3 __- 17.3 2.5 ___ 2.5 Cumulative production (1933—72) _________ 502 ___ 502 73 __- 73 Proved recoverable reserves (12/31/72) _ 184.5 ___ 184.5 26.7 ___ 26.7 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 ___ 70.6 -__ 70.6 2.0 ___ 2.0 Cumulative production (1930—72) _________ 1,105 ___ 1,105 31 ___ 31 Proved recoverable reserves (12/31/72) _ 550 ___ 550 15 ___ 15 Potential resources (ultimate recoverable resources): Oil ‘ Natural gas , Onshore Oifshore Total Onshore Offshore Total Cate or ____________ IV _-_ IV ' IV ___ IV g y Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing (200m >200m Producing Exploratory __ 21 5 ___ ___ ___ 21 5 Development __ 53 46 ___ ___ ___ 53 46 Producing wells as of 12/31/72: Onshore, 1,461; Offshore, ___; Total, 1,461. Olfshore concessions licensed as of 12/31/72: Not applicable. Ofl'shore exploration expenditures in 1972: Local UTSA, Companies of companies companies other countries Government Amount . _____________ T Percent ______________ { l\ot applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic -: of cubic bbl tons bbl tons feet meters Imports _______ 38 5.2 0 3.7 NA NA Exports _______ 0 0 0 1.6 0 O 11 12 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BAHAMAS Category: Archipelago. Margin: Area to 3,000-m depth, 75,000 sq Bordering water body: Atlantic Ocean. nautical miles (est). Area to 200 nau- Coastal length: 1,500 nautical miles (est). tical miles. 221,400 sq nautical miles. Shelf area to 200-m depth: 25,000 sq nau- Geology: Coastal onshore, sedimentary. tical miles (est). Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Olfshore Total Production in 1972 ____ 0 0 0 O 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 ' 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore Total Onshore Offshore Total Production in 1972 ____ 0 0 V 0 O 0 0 Cumulative production (through 1972) ____ O O 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 O O 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI VI VI VI VI VI Number of wells completed in 1972: Onshore Ofishore . Total Producing Number Producing <200m >200 111 Producing Exploratory __ 0 0 0 O 0 0 0 Development __ 0 0 0 0 O 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Nineteen concessions Within 200-m isobath licensed to five companies and one consortium. Ofl’shore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA 0 0 Percent ______________ 0 100 0 O Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42—gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 9.9 1.4 4.1 0 Negl N egl Exports _______ 1.7 .2 14.1 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 13 BAHRAIN Category: Shelf locked. Margin: Area to 3,000-m depth, 1,500 sq Bordering water body: Persian Gulf. nautical miles. Area to 200 nautical Coastal length: 68 nautical miles. miles, 1,500 sq nautical miles. Shelf area to 200-m depth: 1,500 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 25.5 0 25.5 3.5 0 3.5 Cumulative production (19334 2) _________ 532 0 532 73 0 73 Proved recoverable reserves (12/31/72) _ 514 0 514 70.4 0 70.4 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 64.9 0 64.9 1.8 O 1.8 Cumulative production (1933—72) _________ 350 O 350 9.8 0 9.8 Proved recoverable reserves (12/31/72) _ 840 O 840 23.8 0 23.8 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 1 ___ 0 1 0 Development _ _ 8 5 0 _ _ _ 0 8 5 Producing wells as of 12/31/72: Onshore, 221; Ofi'shore, 0; Total, 221. Offshore concessions licensed as of 12/31/72: Two concessions leased to one company. Offshore exploration expenditures in 1972: Local U.S. Companies of , _ companies companies other countries Gm e1 nment Amount _____________ 0 $5 million 0 0 Percent ______________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 60.3 8.2 1.6 0 NA NA Exports _______ .7 .1 77.2 . 0 0 0 14 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BANGLADESH Category: Open shelf. Margin: Area to 3,000-m depth, 20,800 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 310 nautical miles. miles, 22,400 sq nautical miles. Shelf area to 200-m depth: 16,000 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) _-_. 0 0 O 0 O O Proved recoverable reserves (12/31/72) _ NA NA NA NA NA NA Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 17 O 17 0.5 0 0.5 Cumulative production (1960—72) _________ >68.6 0 >68.6 >2 0 >2 Proved recoverable reserves (12/31/72) _ 9,250 0 9,250 262 0 262 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III III III Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O O 0 0 0 0 Development __ 0 0 0 0 O 0 0 Producing wells as of 12/31/72: Onshore, 6; Offshore, 0; Total, 6. Ofi’shore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 6.1 0.8 1 O 0 0 Exports _______ 0 O .2 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 15 BARBADOS Category: Open shelf. Margin: Area to 3,000—m depth, 2,300 sq Bordering water body: Atlantic Ocan. nautical miles. Area to 200 nautical Coastal length: 55 nautical miles. miles, 48,800 sq nautical miles. Shelf area to 200-m depth: 100 sq nautical Geology: Coastal onshore, sedimentary. miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ Negl 0 Negl Negl 0 Negl Cumulative production (through 197 2 ) _ _ _ _ Negl 0 Negl Negl 0 Negl Proved recoverable reserves (12/31/72) _ 1.0 0 1.0 0.1 0 0.1 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 0.1 0 0.1 Negl 0 Negl Cumulative production (through 197 2) ____ .5 0 .5 Negl 0 Negl Proved recoverable reserves (12/31/72) _ NA 0 NA NA 0 NA Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V IV V V [V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 O 0 0 0 0 Development _ 0 0 0 0 0 0 O Producing wells as of 12/31/72: Onshore, 5; Offshore, 0; Total, 5. Offshore concessions licensed as of 12/31/72: One concession that includes all onshore areas and offshore area to 200 meters is licensed to one U.S. company Ofi’shore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ O 0 0 0 Percent ______________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions 0f 42-gal : of metric of 42—gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0.9 0.1 1.3 0 O 0 Exports _______ 0 0 1.5 0 0 0 16 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BELGIUM Category: Shelf locked. Margin: Area to 3,000—m depth, 800 sq Bordering water body: North Sea. nautical miles. Area to 200 nautical Coastal length: 34 nautical miles. miles. 800 sq nautical miles. Shelf area to 200-m depth: 800 sq nautical Geology: Coastal onshore, sedimentary. miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ O 0 0 O 0 0 Cumulative production (through 1972) ___- 0 O 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) .____ o 0 0 0 0 o Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing (200m >200m Producing Exploratory __ 0 0 0 ___ 0 0 0 Development _ 0 O 0 ___ 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Oflshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: No information. Ofl'shore exploration expenditures in 1972: Local US. Companies of comDanies companies other countries Government Amount ____________ } N 0 information. Percent ______________ Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 260.8 35.7 0 6.1 293 8.3 Exports _______ 0 O O 13.2 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 17 BELIZE Category: Open shelf. Margin: Area to 3,000—m depth, 8,000 sq Bordering water body: Caribbean Sea. nautical miles. Area to 200 nautical Coastal length: 191 nautical miles. miles, 9,000 sq nautical miles. Shelf area to 200 meters: 2,800 sq nautical Geology: Onshore coastal, sedimentary. miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ____ O 0 0 0 O 0 Cumulative production (through 1972) _--_ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 ____ 0 7 0 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of Wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 5 0 0 O 0 5 0 Development __ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl’shore, 0; Total, 0. Ofl'shore concessions licensed as of 12/31/72: Five concessions leased to three companies. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 O 0.4 0 0 0 Exports _______ 0 O Neg] 0 O 0 18 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BHUTAN Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: Margin: None‘ Coastal length: None. Geology: Crystalline/sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ O ____ 0 0 ___- 0 Cumulative production (through 1972) ___- 0 ___- 0 O ___- 0 Proved recoverable reserves (12/31/72) _ 0 ____ 0 0 ___- 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ O ___- O 0 ___- 0 Cumulative production (through 1972) ___- 0 ___- 0 O ___- O Proved recoverable reserves (12/31/72) _ O ___- 0 0 __-_ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 ___- 0 0 ___- 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ ___ 0 0 Development _ 0 0 ___ ___ - ___ 0 0 Producing wells as of 12/31/72: Onshore, O; Offshore, ___; Total, 0. Ofi'shore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of Y companies COmDanies other countries Gm ernment Amount _____________ _ Percent } NOE appllcable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA NA 0 0 Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 19 BOLIVIA Shelf area to 200-m depth: None. Margin: None. Geology: Sedimentary/crystalline. Category: Landlocked. Bordering water body: None. Coastal length: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 16 ___- 16 1.9 ___- 1.9 Cumulative production (through 1972) ___- 144 __-_ 144 18 ___- 18 Proved recoverable reserves (12/31/72) _ 200 ____ 200 24 ____ 24 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 121 ___- 121 3.4 ____ 3.4 Cumulative production (through 1972) ___- 293.6 ___- 293.6 8.3 ___- 8.3 Proved recoverable reserves (12/31/72) _ 4,800 ___- 4,800 135.9 ___- 135.9 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Oflshore Total Category ____________ III ___- III II ___- II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing ___ ___ 8 2 ___ ___ 6 6 Exploratory __ 8. 2 ___ Development _ 6 6 ___ Producting wells as of 12/ 31/ 72: Onshore, 120; Offshore, ___; Total, 120. Offshore concessions licensed as of 12/31/72: Not applicable. ‘ Offshore exploration expenditures in 1972: Local U.S. Companies of Government companies companies other countries Amount ____-________‘ . Percent ______ } Not applicable. Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0.2 0 0 0 Exports _______ 10.9 1.4 O 0 35.5 1.0 20 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BOTSWANA Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___- 0 ' 0 ___- 0 Cumulative production (through 1972) ___- O ___- 0 0 _-__ O Proved recoverable reserves (12/31/72) _ 0 ___- 0 O ___- 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 __- 0 __-_ ’0 O ____ 0 Cumulative production (through 1972) ___- O ___- 0 O ___- 0 Proved recoverable reserves (12/31/72) _ 0 ___- O 0 ___- 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI ___- VI III ___- III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ ___ 0 0 Development _ 0 0 ___ ___ ___ O O Producing wells as of 12/31/72: Onshore, 0; Ofishore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US Companies of v , companies companies other countries Government Amount _____________ Y . Percent } l\0t applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA NA 0 0 Exports _______ 0 O 0 O l) 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 21 BRAZIL Category: Open shelf. Margin: Area to 3,000-m depth, 435,700 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 3,692 nautical miles. miles, 924,000 sq nautical miles. Shelf area to 200-m depth: 224,100 sq Geology: Coastal onshore, sedimentary/ nautical miles. crystalline, Offshore, sedimentary. Oil Millions of barrels Millions of metric tons . Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 57.6 3.5 61.1 7.9 0.5 8.4 Cumulative production (through 1972) ____ 660.6 5.5 666.1 90.3 .8 91.1 Proved recoverable reserves ( 12/31/72) _ 778.1 19.6 797.7 106.3 2.7 109 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 43.8 Negl 43.8 1.2 Negl 1.2 Cumulative production (through 1972) ____ 384.8 Negl 384.8 11.2 Negl 11.2 Proved recoverable reserves (12/31/72) _ 741.5 176.5 918.0 21 5 26 Potential resources (ultimate recoverable resources) : Oil Natural go 8 Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV II III II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing (200m >200m Producing Exploratory __ 52 10 28 0 3 80 13 Development __ 81 58 14 O 11 95 69 Producing wells as of 12/31/72: Onshore, 748; Offshore, 495; Total, 1,243. Offshore concessions licensed as of 12/31/72: No concessions licensed. Offshore exploration contracted by government— owned oil company. Offshore exploration expenditures in 197 2: Local US Companies of companies companies other countries Government Amount _____________ 0 0 0 <$1 million1 Percent ______________ 0 0 0 100 1Total expenditures, onshore and offshore were $1 million. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 171.1 23.4 7.9 0 0 0 Exports _______ 7.6 1.2 11.5 0 0 0 22 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BRUNEI Category: Open shelf. Margin: Area to 3,000-m depth, 5,300 sq Bordering water body: South China Sea. nautical miles. Area to 200 nautical Coastal length: 88 nautical miles. miles, 7,100 sq nautical miles. Shelf area to 200-m depth: 2,800 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ 21.8 45.2 67 3 6.2 9.2 Cumulative production (through 1972) _ _ __ > 809.2 190.8 > 1,000 > 110.8 26.1 > 136.9 Proved recoverable reserves (12/31/72) _ NA 2,413 >2,413 NA 330 >330 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Tgtal Onshore Offshore Total Production in 1972 _ _ _ NA NA NA NA NA NA Cumulative production (through 1972) _ _ _ _ NA NA NA NA NA NA Proved recoverable reserves (12 / 31 / 7 2) _ NA NA 15,000 NA NA 425 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV IV V IV Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200 1n >200m Producing Exploratory __ NA NA NA ”NA NA NA NA Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: Onshore, 233; Offshore, 198; Total, 431. Ofl'shore concessions licensed as of 12/31/72: No information. Offshore explorationexpenditures in 1972: Local US. Companies of . companies companies other countries Gm ernment Amount _____________ 0 NA NA 0 Percent _____________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 O Negl 0 NA NA Exports _______ ‘1 66.5 1 9.1 O 0 NA NA 1 Estimated. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 23 BULGARIA Category: Open shelf. Margin: Area to 3,000-m depth, 9,600 sq Bordering water body: Black Sea. nautical miles. Area to 200 nautical Coastal length: 134 nautical miles. miles, 9,600 sq nautical miles. Shelf area to ZOO-m depth: 3,600 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oflshore Total Production in 197 2 ___ 1.8 O 1.8 0.2 0 0.2 Cumulative production (1955—72) __________ >66 0 >66 >92 0 >92 Proved recoverable reserves (12/31/72) _ 278 0 278 38 0 38 Natural gas ‘ Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 14.9 0 14.9 0.4 O 0.4 ' Cumulative production (1965—7 2) __________ 93.9 0 93.9 2.4 0 2.4 Proved recoverable reserves (12/ 31 / 72) _ 1,000 0 1,000 28 0 28 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Oflshore Total Producing Number Producing <200m >200m Producing Exploratory _ _} Development _ No information. Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Ofi'shore concessions licensed as of 12/ 31/72: N 0 information. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 0 0 NA Percent ______________ O 0 0 100 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 60.4 8.2 NA 0 NA NA Exports _______ Negl Negl NA 0 NA NA 24 SUMMARY, 1972 OIL AND GAS STATISTICS, ONS HORE AND OFFSHORE AREAS, 151 COUNTRIES BURMA Category: Open shelf. tical miles. Area to 200 nautical miles, Bordering water body: Indian Ocean. 128,600 sq nautical miles. Coastal length: 1,230 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-111 depth: 22,900 sq nau- crystalline. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Ofishore Total Onshore Offshore Total Production in 1972 __ _ 7.5 0 7.5 1 0 1 Cumulative production (1889—1972) _______ 421.5 0 421.5 56 O 56 Proved recoverable reserves (12/ 31/7 2) _ 40 0 40 5.4 0 5.4 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ 4.2 0 4.2 0.1 0 0.1 Cumulative production (1889—1972) _______ 368.2 0 368.2 10.1 0 10.1 Proved recoverable . reserves (12/31/72) _ 100 0 100 2.8 O 2.8 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Oflshore Total Category ____________ III IV III III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 2 , O 3 0 0 5 0 Development _ 24 11 0 0 O 24 11 Producing wells as of 12/31/72: Onshore, 712; Offshore, 0; Total, 712. Ofl'shore concessions licensed as of 12/31/72: None. All exploration performed by government contract. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 0 0 NA Percent ______________ O 0 O 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 1.87 .2 .4 0 0 0 Exports _______ O 0 .4 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES BURUNDI Category: Landlocked. Bordering water body: None. Coastal length: None. Shelf area to 200-m depth: None. Margin: None. Geology: Crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 _-_- 0 0 ___- 0 Cumulative production (through 1972) ___- 0 ___- 0 0' ___- 0 Proved recoverable reserves (12/31/72) _ 0 _-__ O 0 ___- 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- 0 ___- Cumulative production (through 1972) ___- 0 ___- Proved recoverable reserves (12/31/72) _ 0 ___- o o ___- ;, 0 o 0 ____ 0 0 o ___- o Potential resources (ultimate recoverable resources) : Onshore Offshore Total Onshore Offshore Total Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 .---- 0 0 ___- 0 Number of wells completed in 1972 : Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ Development -_ 0 0 ___ Producing wells as of 12/31/72: Onshore, O; Ofi’shore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of companies COmpanies other countries Government Amount ___' __________ } Percent ______________ Not applicable. Imports and exports of oil, products, and natural/gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 Negl 0 0 Exports _______ O 0 O Negl 0 0 25 26 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES CAMEROON Category: Open shelf. Margin: Area to 3,000—m depth, 4,500 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 187 nautical miles. miles, 4,500 sq nautical miles. Shelf area to 200~m depth: 3,100 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 1 0 1 0 1 0 0 1 0 1 O lFirst discovery well SI; reserves not established. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ,__ 0 0 ’0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O O 0 0 Potential resources (ultimate recoverable resources) : Oil ’ Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V IV IV IV IV Number of wells completed in 1972: Onshore Olfshore Total Producing Number Producing <200m >200 1n Producing Exploratory __ 0 O 5 0 1 1 0 1 Development __ 0 0 0 0 0 0 O 1 s1. Producing wells as of 12/31/72: Onshore, 0; Ofishore, 0 1; Total, 0. I s1—1x Offshore concessions licensed as of 12/31/72: Eight concessions, none beyond 200 meters, licensed to one company and two consortia. Offshore exploration expenditures in 1972: codigfiiies cordiisnies oghgi'pcaoliirtiirles Government Amount _____________ 0 NA $70 million 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic :: of cubic bbl tons bbl tons feet meters Imports _______ 0 0 l 3.2 0 0 0 Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 27 CANADA Category: Open shelf. Margin: Area to 3,000-m depth, 1,240,000 Bordering water bodies: Arctic Ocean, At- sq nautical miles. Area to 200 nautical lantic Ocean, Pacific Ocean. miles, 1,370,000 sq nautical miles. Coastal length: 11,129 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200—m depth: 846,500 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 560.7 0 560.7 75.8 0 75.8 Cumulative production (1862—1972) _______ 5,761 0 5,761 776 0 776 Proved recoverable reserves (12/31/72) _ 10,200 1NA >10,200 1,378 1NA >1,378 1Some otfshore wells SI. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 2,913 0 2,913 82.5 0 82.5 Cumulative production (1862—1972) _______ 38,824 0 38,824 1,099 0 1,099 Proved recoverable reserves (12/31/72) _ 55,462 NA >55,462 1,570 NA >1,570 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ III III III II III II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing (200m >200m Producing Exploratory __ 1,710 528 16 0 4 1,726 532 Development _ 1,905 1,540 0 0 0 1,905 1,540 Producing wells as of 12/31/72: Onshore, 17,101; Offshore, 0; Total, 17,101. Offshore concessions licensed as of 12/31/72: Many offshore exploration permits granted, especially ofl‘ the east coast. Some concessions beyond 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 288.7 39 51.2 0 NA NA Exports _______ 348.4 47.7 34.1 0 NA NA 28 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES CENTRAL AFRICAN REPUBLIC Category: Landlocked. Shelf area to 200 m-depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Crystalline/ sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- 0 ___- O 0 ___- 0 Cumulative production ‘ ‘ (through 1972) ___- O ___- O 0 ____ 0 Proved recoverable reserves (12/31/72) _ 0 ____ 0 0 ___.. 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___- O O ___- 0 Cumulative production (through 1972) ___- 0 ___- 0 0 ____ 0 Proved recoverable reserves (12/31/72) _ 0 __-_ 0 0 ____ 0 Potential resources (ultimate recoverable resources) : Oil . Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V ___ V V ___ V D Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200 n1 Producing Exploratory __ 0 0 __ __ __ 0 0 Development __ 0 O __ __ __ 0 O Producing wells as of 12/31/72: Onshore, 0; Oflshore, __;Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Ofl'shore exploration expenditures in 1972: Local U.S. Compan' s f companies companies other coulritrties Government f$2532t_:::::::::::::} Not applicable- Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42—gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 Neg] 0 0 Exports _______ O 0 0 Negl O O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 29 CHAD Shelf area to 200-m depth: None. Margin: None. Geology: Sedimentary/crystalline. Category: Landlocked. Bordering water body: None. Coastal length: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___- O O ___- 0 Cumulative production (through 1972) ___- O ___- 0 O ____ 0 Proved recoverable reserves (12/31/72) _ 0 ___- 0 0 ____ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- 0 ___- 0 0 _ ___ 0 Cumulative production (through 1972) ___- 0 ___- 0 0 ___- 0 Proved recoverable reserves (12/31/72) _ 0 ___- 0 0 ____ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV ___ IV IV ___ IV Number of wells completed in 1972 : Onshore Offshore Total Producing Number Producing <200 m >200 III Producing Exploratory __ 0 0 __ _ _ __ 0 0 Development __ 0 0 __ __ _ _ 0 0 Producing wells as of 12/31/72 : Onshore, NA ; Offshore, _ _ _ ; Total, NA. Oflshore concessions licensed as of 12/31/72 : Not applicable. Offshore exploration expenditures in 1972 : Local U.S. 70mpanies of companies companies other countries Government $323£t_:::::::::::::} Not applicable- Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions, of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 < 1 0 O 0 Exports _______ 0 0 NA NA 0 0 30 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES CHILE Category: Open shelf. Margin: Area to 3,000-m depth, 167,900 Bordering water body: Pacific Ocean. sq nautical miles. Area to 200 nautical Coastal length: 2,882 nautical miles. miles, 667,300 sq nautical miles. Shelf area to 200-m depth: 80,000 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _.__ 12.5 0 12.5 1.6 0 1.6 Cumulative production (through 1972) ____ 184.5 0 184.5 23.6 0 23.6 Proved recoverable reserves (12/31/72) _ 100.6 0 100.6 12.9 0 12.9 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 284.9 0 284.9 8.1 0 8.1 Cumulative production (through 1972) ____ 3,018 0 3,018 100.6 0 100.6 Proved recoverable reserves (12/31/72) _ 1,775 0 1,775 50 0 50 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV III III Number of wells completed in 1972: Onshore Olfshore Total Producing Number Producing <200m >200m Producing Exploratory __ 28 6 6 O 1 34 '7 Development __ 39 22 0 O 0 , 39 22 Producing wells as of 12/31/72: Onshore, 325; Offshore, 0; Total, 325. Offshore concessions licensed as of 12/31/72: All exploration is done by a government agency. Ofl'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 0 O $6.5 million Percent ______________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 26.7 3.7 0 Negl 0 0 Exports _______ 0 0 0 0.2 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 31 CHINA People’s Republic of China Category: Open shelf. Margin: Area to 3,00-m depth, 281,000 sq Bordering water bodies: South China Sea, nautical miles. Area to 200 nautical East China Sea. miles, 281,000 sq nautical miles. Coastal length: 3,492 nautical miles. Geology: Coastal onshore, crystalline/sedi- Shelf area to 200-111 depth: 230,100 sq mentary. Oii'shore, crystalline/sedimen- nautical miles. tary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 192 Negl 192 26 Negl 26 Cumulative production (through 1972) ______ <1,163 Negl 1,163 <159 Negl 159 Proved recoverable reserves (12/31/72) _ < 20,000 NA 20,000 <2,7 00 NA 2,7 00 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1 972 _ _ _ NA NA NA NA NA NA Cumulative production ( 1941—7 2) _________ NA NA NA NA NA NA Proved recoverable reserves (12/31/72)- NA NA 4,000 NA NA 133.3 Potential resources (ultimate recoverable resources): Oil Natural. gas Onshore Offshore ‘ Total Onshore Offshore Total Category ____________ III IV III II III II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA 0 NA ‘NA NA Development _ NA NA NA 0 NA NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: coxliigcaaiiies conliisnies ogfigpcaoriireifrigs Government Amount _____________ 0 O 0 NA Percent _____________ 0 O O 100 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA NA NA NA Exports _______ NA NA NA NA NA NA 32 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES CHINA—Continued Republic of China (Taiwan) Category: Open shelf. Margin: Area to 3,000—m depth, 39,900 sq Bordering water bodies: Pacific Ocean, nautical miles Area to 200 nautical South China Sea. miles, 114,400 sq nautical miles. Coastal length: 470 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-110 depth: 23,500 sq nau— Oflshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Olfshore Total Onshore Offshore Total Production in 1972 ___ 0.9 0 0.9 0.1 O 0.1 Cumulative production (1941—72) _________ 4.5 0 4.5 .6 O .6 Proved recoverable reserves (12/31/72) _ 18.7 0 18.7 2.5 0 2.5 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 34.7 0 34.7 0.1 0 0.1 Cumulative production (1941—72) _________ 255 0 255 6 0 6 Proved recoverable reserves (12/31/72) _ 500 0 500 14 0 14 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 6 1 O 0 0 6 1 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 51; Offshore, 0; Total, 51. Offshore concessions licensed as of 12/31/72: Eight concessions, seven companies holding leases for joint ventures with government owned company. Offshore exploration expenditures in 1972: ,. . 001734.33 coniiisnies oififipé’iififr‘i’is Government Amount _____________ 0 NA NA NA Percent ______________ 0 NA NA NA Imports and exports of oil. products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—ga1 = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 50.5 6.8 10.8 0 NA NA Exports _______ 0 0 9.7 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 33 COLOMBIA Category: Open shelf. Margin: Area to 3,000-m depth, 60,900 sq Bordering water bodies: Caribbean Sea, nautical miles. Area to 200 nautical Pacific Ocean. miles, 175,900 sq nauitcal miles. Coastal length: 1,022 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 19,800 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 71.7 0 71.7 10.2 0 10.2 Cumulative production (through 1972) ____ 1,722 0 1,722 244 O 244 Proved recoverable reserves (12/31/72) _ 1,590 0 1,590 227 0 227 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ____ 115.6 0 115.6 3.3 0 3.3 Cumulative production (through 1972) ____ 2,699 0 2,699 76 0 76 Proved recoverable reserves (12/31/72) _ 2,500 0 2,500 70 0 70 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Olfshore Total Category ____________ III IV III III III III Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 20 2 0 0 O 20 2 Development __ 36 30 0 0 0 36 30 Producing wells as of 12/31/72: Onshore, 2,026; Offshore, 0; Total, 2,026. Offshore concessions licensed as of 12/31/72: Four offshore concessions licensed; all Within 200-m depth. Ofi'shore exploration expenditures in 1972: Local US Companies of companies companies other countries Government Amount 1 ____________ 0 $360 $30 $190 Percent 1 ____________ 0 62 5 33 l Revised. Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0.5 0 0 0 Exports _______ 14.9 2.1 12.4 0 0 0 34 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREASY 151 COUNTRIES CONGO Category: Open shelf. Margin: Area to 3,000-m depth, 7,200 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 84 nautical miles. miles, 7,200 sq nautical miles. Shelf area to 200-m depth: 2,600 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 0.7 1.8 2.5 0.1 0.2 0.3 Cumulative production (through 1972) ____ 5.9 1.8 7.7 .8 .2 1.0 Proved recoverable reserves (12/31/72) _ <4,270 >730 5,000 <571 >98 669 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ NA NA 0.6 NA NA Negl Cumulative production (through 197 2) ____ NA NA 1.7 NA NA Negl Proved recoverable reserves (12/31/72) _ NA NA >5 NA NA Negl Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category _____________ IV V IV III V III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory .. 0 0 7 0 3 7 3 Development __ 0 0 36 0 35 36 35 Producing wells as of 12/31/72: Onshore, 1 8; Offshore, 12; Total, 1 20. 1 Estimated Ofl'shore concessions licensed as of 12/31/7 2: Four concessions, within 200 m, leased to two consortia. Offshore exploration expenditures in 197 2: Local US. Companies of , companies companies other countries Gox ernment Amount _____________ NA 0 NA NA Percent ______________ NA 0 NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : 0f metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 < 1 0 0 0 Exports _______ NA NA NA NA 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 35 COSTA RICA Category: Open shelf. Margin: Area to 3,000—m depth, 15,100 sq Bordering water bodies: Pacific Ocean, nautical miles. Area to 200 nautical Caribbean Sea. miles, 75,500 sq nautical miles. Coastal length: 446 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to ZOO-m depth: 4,600 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ____ 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 O 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O O 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- 0 O 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI V V VI IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 O 0 0 0 Development __ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofi'shore concessions licensed as of 12/31/72: Caribbean Sea: One concession licensed to one company. Pacific Ocean: No concession licensed. Offshore exploration expenditures in 197 2: Local US. Companies of . companies companies other countries GO‘ ernment Amount _____________ O 0 $250,000 0 Percent ______________ O 0 100 0 Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports and exports of oil, products, and natural gas in 1972: Imports _______ 2.7 0.4 0.5 0 0 0 Exports _______ 0 O O 0 0 0 Category : Archipelago. Bordering water body : Caribbean Sea. Coastal length: 1747 nautical miles. Shelf area to 200-m depth: 23,300 sq nau- tical miles. Atlantic Ocean, CUBA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES Margin: Area to 3,000-m depth, 68,900 sq nautical miles. Area to 200 nautical miles, 105,800 sq nautical miles. Geology : Coastal onshore, sedimentary / crystalline. Oifshore, sedimentary /crys- talline. 011 Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ - 1.2 0 1.2 0.2 O 0.2 Cumulative production (1968—7 2) _________ 13.2 0 13.2 6.6 0 6.6 Proved recoverable reserves (12/31/72) _ 9 0 9 1.3 0 1.3 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ NA 0 NA NA 0 NA Cumulative production (through 197 2) _____ NA 0 NA NA 0 NA Proved recoverable reserves (12/31/72) _ NA 0 NA NA 0 NA Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ V V V V IV V Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing NA NA NA 0 NA NA NA NA 0 NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: All exploration in the hands of state agency. Offshore exploration expenditures in 1972: NA NA NA Exploratory _ _ NA Development _ Local US. Companies of companies companies other countries Government Amount _____________ 0 0 NA NA Percent ______________ 0 0 NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 51.9 7.1 NA 0 NA NA Exports _______ NA NA NA 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 37 CYPRUS Category: Open shelf. Margin: Area to 3,000-m depth, 11,900 sq Bordering water body: Mediterranean nautical miles. Area to 200 nautical Sea. . miles. 29,000 sq national miles. Coastal length: 290 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200 m-depth: 1,900 sq nau- crystalline. Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197 2 __ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O O 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O 0 0 0 O 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofl’shore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of Y , companies companies other countries Gox e1 nment Amount _____________ 0 O 0 0 Percent _____________ O 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 4.9 0.8 1.9 O 0 0 Exports _______ 0 0 0 O 0 O 38 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES CZECHOSLOVAKIA Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions ofi barrels Millions of metric tons Onshore Offshore Total Onshore Ofishore Total Production in 1972 _ _ _ 1.4 _ _ _ 1.4 .2 _ _ _ .2 Cumulative production (1919—7 2) _________ 1 28.4 ___ 1 28.4 1 4.2 ___ 1 4.2 Proved recoverable reserves (12/31/72) _ 12 ___ 12 2 -__ 2 1 Estimated. Natural gas Billions of cubic feet Bililons of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 42.4 ___ 42.4 1.2 _ __ 1.2 Cumulative production (1919—72) _________ 550 ___ 550 15 -_._ 15 Proved recoverable reserves (12/31/72) _ 500 ___ 500 15 ___ 15 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV ___ IV IV ___ IV \ Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA ___ _-_ __- NA NA Development _ NA NA _ _ - _ _ _ _ _ _ NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Ofl'shore concessions licensed as of 12/31/72: Not applicable. Ofl'shore exploration expenditures in 1972: Local U .8. Companies of companies companies other countries Government Amount _____________ . __ Percent I Not applicable. Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + 01‘ metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 91.3 12.5 NA 0 Negl Negl Exports _______ 0 0 NA 0 Negl Negl SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 39 DAHOMEY Category: Open shelf. Margin: Area to 3,000-m depth, 2,600 sq Bordering water body : Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 65 nautical miles. miles. 7,900 sq nautical miles. Shelf area to 200—m depth: 500 square nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Product-ion in 1972 ___ 0 0 0 0 O 0 Cumulative production . (through 1972) ___- 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- o 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Potential resources (ultimate recoverable resources) : ' Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 1 O 0 0 O 1 0 Development _ O 0 0 0 0 0 O Producing wells as of 12/ 31/ 72: Onshore, 0; Offshore, 0; Total, 0. Ofi'shore concessions licensed as of 12/31/72: Five concessions, two extend beyond 200-m depth. Leased to one con- sortium and three companies. Offshore exploration expenditures in 1972: Local US. Companies of , companies companies other countries Government Amount _____________ a $1.5 millibn 0 0 Percent _____________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 0.3 0 0 Exports _______ 0 0 O 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES DENMARK Margin: Area to 3,000-m depth, 20,000 sq nautical miles. Area to 200 nautical miles, 20,000 sq nautical miles. Geology: Coastal onshore, sedimentary. Offshore, sedimentary. Category: Shelf locked. Bordering water body: North Sea. Coastal length: 686 nautical miles. Shelf area to 200-m depth: 20,000 sq nau- tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 1 0.6 1 0.6 0 Negl Negl Cumulative production (1967—72) __________ 0 .6 .6 0 Negl Negl Proved recoverable reserves (12/31/72) _ 0 250 250 0 34 34 1Fil'st production started in July, 1972. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 0 0 0 0 Cumulative production (1967—72) __________ 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 500 500 0 14 14 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200 m Producing Exploratory __ 0 0 0 _- O O 0 Development _ 0 0 2 __ 2 2 2 Producing wells as of 12/31/72: Onshore, 0; Offshore, 5; Total. 5. Offshore concessions licensed as of 12/31/72: One concession licensed. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ $17.6 million $70.4 million 0 0 Percent ______________ 20 80 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 71.2 9.8 0 12 NA NA Exports _______ .2 Negl O 2.4 NA NA SUMMARY, 1972‘ OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 41 DOMINICAN REPUBLIC Category: Open shelf. Margin: Area to 3,000-m depth, 28,900 sq Bordering water bodies: Caribbean Sea, nautical miles. Area to 200 nautical Atlantic Ocean. miles, 78,400 sq nautical miles. Coastal length: 325 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-111 depth: 5,300 sq nauti- Offshore, sedimentary. cal miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 O O O 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ 0 0 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72)’ _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Oflshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ 0 0 O O 0 0 0 Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession, less than 200 m deep, licensed. Offshore exploration expenditures in 1972: Local gs. Companies of , companies companies other countries Government Amount _____________ 0 0 0 0 Percent _____________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 104.3 0 0 0 Exports _______ O 0 0 0 0 0 42 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ECUADOR Category: Open shelf. Margin: Area to 3,000—m depth, 52,600 sq Bordering water body: Pacific Ocean. nautical miles. Area to 200 nautical Coastal length: 458 nautical miles. miles, 338,000 sq nautical miles. Shelf area to 200—m depth: 13,700 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 28.6 0 28.6 3.8 0 3.8 Cumulative production (1917—7 2) _________ 134.6 0 134.6 17.6. 0 17.6 Proved recoverable reserves (12/31/72) _ 5,750 0 5,750 758 0 758 Natural gas Billions of cubic feet Bililons of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 -1- 5.3 0 5.3 0.2 0 0.2 Cumulative production (1917—72) _________ 208 0 ' 208 6 0 6 Proved recoverable reserves (12/31/72) _ 6,000 0 6,000 170 0 170 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total» Onshore Offshore Total Category ____________ III IV III III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 19 6 1 0 0 2O 7 Development __ 30 30 ‘ O O 0 30 30 Producing wells as of 12/31/72: Onshore, 773; Offshore, 0; Total, 773. Offshore concessions licensed as of 12/31/72: Two concessions onshore and offshore; two concessions completely ofl'— shore. All concessions within 200-m depth. Two concessions licensed to consortium; two others leased to single company. Ofi'shore exploration expenditures in 1972: Local US Companies of , . companies companies other countries Gox ernment Amount _____________ 0 $1.6 million 0 0 Percent _______________ 0 100 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic :: of cubic bbl tons bbl tons feet meters Imports _______ 8.5 1.2 3 0 0 0 Exports _______ 24.9 3.3 .5 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 4-3 EGYPT Category: Open shelf. Margin: Area to 3,000-m depth, 28,900 sq Bordering water bodies: Red Sea, Mediter- nautical miles. Area to 200 nautical ranean Sea. miles, 50,600 sq nautical miles. Coastal length: 1,307 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 10,900 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ NA >584 79 NA >84 11.4 Cumulative production (1911—72) _________ NA >530.4 1,015 NA >764 146.4 Proved recoverable reserves (12/31/72) _ NA NA 3,800 NA NA 550.7 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oflshore Total Onshore Offshore Total Production in 1972 _ _ _ NA NA 160.8 NA NA 4.6 Cumulative production (1911—72) _________ NA NA 459 NA NA 131 Proved recoverable reserves (12/31/72) _ NA NA 7,500 NA NA 213 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ IV III III II III II Number of wells completed in 1972: Onshore Olfshore Total Producing Number Producing <200m >200m Producing Exploratory __ 21 3 0 0 0 21 3 Development __ 32 27 0 0 O 32 27 Producing wells as of 12/31/72: Onshore, <166; Offshore, >54; Total, 220. Offshore concessions licensed as of 12/31/72: Mediterranean Sea: Two concessions leased to two companies. Red Sea: One concession leased to one company. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent _______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42—gal + of. metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 9.5 1.4 0 0.8 0 0 Exports _______ 36.2 5.2 0 .4 O O 44 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES EL SALVADOR Category: Open shelf. Margin: Area to 3,000-m depth, 12,300 sq Bordering water body: Pacific Ocean. nautical miles. Area to 200 nautical Coastal length: 164 nautical miles. miles. 26,800 sq nautical miles. Shelf area to 200-In depth: 5,200 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ O 0 0 0 0 O Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 O O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ O V V O V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 O 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of 7 companies companies other countries Gox ernment Amount _____________ 0 0 0 0 Percent _____________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 2.9 0.4 Negl Negl 0 0 Exports _______ 0 0 Negl Negl 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 45 EQUATORIAL GUINEA Margin: Area to 3,000—m depth, 14,800 sq nautical miles. Area to 200 nautical miles, 82,600 sq nautical miles. Geology: Coastal onshore, sedimentary. Offshore, sedimentary. Category: Open shelf. Bordering water body : Atlantic Ocean. Coastal length: 184 nautical miles. Shelf area to 200-m depth: 3,600 sq nau- tical miles. Oil Millions of "barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 O 0 Cumulative production (through 1972) ___- 0 O 0 O 0 O Proved recoverable , reserves (12/31/72) _ O 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 O 0 O O 0 Cumulative production (through 1972) ___- 0 O 0 O 0 O Proved recoverable reserves (12/31/72) _ 0 O 0 O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Olfshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Ofl'shore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 O O 0 O 0 Development __ 0 O O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Ten concessions, one licensed. Offshore exploration expenditures in 1972: Local U.S. Companies of _ companies companies other countries GOV ernment Amount _____________ 0 0 O 0 Percent ______________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA NA NA NA Exports _______ NA NA NA NA NA NA 46 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ETHIOPIA Category: Open shelf. Margin: Area to 3,000-m depth, 22,100 sq Bordering water body: Red Sea. nautical miles. Area to 200 nautical Coastal length: 546 nautical miles. miles, 22,100 sq nautical miles. Shelf area to 200-m depth: 13,900 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Ofishore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Ofishore Total Category ________-__'_ V V V III IV III Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 3 1 0 0 0 3 1 Development _ 0 O ’ O 0 0 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Ofl'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ O O 0 0 Percent _____________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 4.6 0.6 0.5 0 0 0 Exports _______ 0 0 .6 O O O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 47 FIJI Category: Archipelago. sq nautical miles. Area to 200 nautical Bordering water body: Pacific Ocean. miles, 330,900 sq nautical miles. Coastal length: >650 nautical miles. Geology: Coastal onshore, crystalline/sedi~ Shelf area to 200-m depth: >4,500 sq nau- mentary. Offshore, sedimentary/crystal- tical miles. line. Margin: Area to 3,000-m depth, <80,000 Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oflt'shore Total Production in 1972 ___ 0 O O 0 0 0 Cumulative production (through 1972) -_-- 0 O O O O 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 O O 0 Cumulative production (through 1972) _-_._ O 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O 0 O 0 0 0 Development __ 0 0 O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Oflshore concessions licensed as of 12/31/72: Five concessions licensed, some beyond. 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ O 0 NA 0 Percent ______________ 0 O 100 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42—gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 2.8 O O 0 Exports _______ O 0 0 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES FINLAND Category: Shelf locked. Margin: Area to 3,000-m depth, 28,600 sq Bordering water body: Baltic Sea. nautical miles. Area to 200 nautical Coastal length: 735 nautical miles. miles. 28,600 sq nautical miles. Shelf area to 200-m depth: 28,600 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 __ _ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ O V V 0 V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 ___ 0 0 0 Development _ O 0 0 _ _ _ 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of . companies companies other countries Gm ernment Amount _____________ 0 0 0 0 Percent _____________ O O O O Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 66.7 9.1 0.8 4.6 0 0 Exports _______ 0 O .9 Negl 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 49 FRANCE Category: Open shelf. Margin: Area to 3,000-m depth, 75,800 sq Bordering water bodies: Atlantic Ocean, nautical miles. Area to 200 nautical Mediterranean Sea. miles, 99,500 sq nautical miles. Coastal length: 1,373 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 43,100 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. talline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 16.8 0 16.8 2.3 0 2.3 Cumulative production (1918—72) ______ _-__ 315 0 315 4:3 0 43 Proved recoverable reserves (12/31/72) _ 94.2 0 94.2 13 0 13 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 __- 385.8 0 385.8 10.9 0 10.9 Cumulative production (1960—72) __________ 3,708 0 3,708 105 0 105 Proved recoverable reserves (12/31/72) _ 6.600 0 6,600 187 0 187 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 10 0 1 0 0 11 0 Development _ 15 13 0 0 0 15 13 Producing wells as of 12/31/72: Onshore, 340; Offshore, 0; Total, 340. Offshore concessions licensed as of 12/31/72: No concessions licensed at end of year. Four exploration licenses in effect. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount ______________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 862.9 118.2 0 9 252.2 7.2 Exports _______ 0 O 0 16.1 0 0 50 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GABON Category: Open shelf. Margin: Area to 3,000-m depth, 40,900 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 399 nautical miles. miles, 62,300 sq nautical miles. Shelf area to 200-m: 13,400 sq nautical Geology: Coastal onshore, sedimentary. miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 -_ _ 25.8 19.9 45.7 3.6 2.7 6.3 Cumulative production (1958—7 2) _________ 216 67 283 29.6 9.7 39.3 Proved recoverable reserves (12/31/72) _ 275.3 652 927.3 38 90 128 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ NA NA 31.8 NA NA 0.9 Cumulative production ( 1957—7 2) _________ NA NA 168 NA NA 5 Proved recoverable reserves (12/31/72) _ NA NA 6,532 NA NA 181 ‘ Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Olfshore Total Onshore Offshore Total Category ____________ IV IV III III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory- __ 1 0 16 0 6 17 6 Development __ NA NA NA NA NA 19 18 Producing wells as of 12/31/72: Onshore, 140; Offshore, 31; Total, 171. Ofi'shore concessions licensed as of 12/31/72: Ten concessions and 2 exploration permits licensed to 15 companies; some extend into waters deeper than 200 m. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 O Neg] 0 0 0 Exports _______ 38.9 5.4 1.3 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, 0N SHORE AND OFFSHORE AREAS, 151 COUNTRIES GAMBIA Category. Open shelf. Margin: Area to 3,000-m depth, 3,300 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 38 nautical miles. miles. 5,700 sq nautical miles. Shelf area to 200-m depth: 1,700 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ .. 0 0 0 0 0 0 Cumulative production (through 1972) _ _ _ _ 0 0 O 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0’ 0 0 Cumulative production (through 1972) ____ 0 O 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Oflshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 O O 0 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One offshore concession, within 200-m depth, leased to US. company. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Governmpfl Amount _____________ 0 0 0 0 Percent ______________ 0 O 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA NA 0 0 Exports _______ 0 O 0 0 0 0 51 52 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GERMAN DEMOCRATIC REPUBLIC Category: Shelf locked. tical miles. Bordering water body: Baltic Sea. Margin: Area to 3,000-m depth, 2,800 sq Coastal length: 191 nautical miles. nautical miles. Area to 200 nautical Shelf area to 200-m depth: 2,800 sq nau- miles, 2,800 sq nautical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1.8 O 1.2 0.2 0 0.2 Cumulative production (through 1972) ___- NA 0 NA NA 0 NA Proved recoverable reserves (12/31/72) _ 11 0 11 1.5 0 1.5 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 I.-- 190 0 190 5.4 0 5.4 Cumulative production (through 1972) ___- NA 0 NA NA 0 NA Proved recoverable reserves (12/31/72) _ 500 0 500 14.2 0 14.2 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV II IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200 m >200 1n Producing Exploratory _ _ NA NA NA _ _ _ _ NA NA NA Development _ _ NA NA NA , _ _ _ NA NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, 0; Total, NA. Offshore concessions licensed as of 12/31/72: N 0 information. Ofi'shore exploration expenditures in 1972: Local US. Companies of . companies companies other countries Gm ernment Amount _____________ 0 0 0 NA ’ Percent ______________ O 0 O 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 108.4 14.8 0 0 NA NA Exports _______ 0 0 0 1.4 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GERMANY, FEDERAL REPUBLIC OF Category: Shelf locked. Margin: Area to 3,000-m depth, 11,900 sq Bordering water bodies: North Sea, Baltic nautical miles. Area to 200 nautical Sea. miles, 11,900 sq nautical miles. Coastal length: 308 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 11,900 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 51.3 0 51.3 7.1 0 7.1 Cumulative production (1880-197 2) _______ 994 0 994 138 0 138 Proved recoverable reserves (12/ 31 / 7 2) _ 545 O 545 76 0 76 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 624.8 0 624.8 17.7 0 17 .7 Cumulative production (196042) _________ 2,477 0 2,477 70 0 7O Proved recoverable reserves (12/31/72) _ 12.400 0 12,400 351 O 351 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III IV III Number of wells completed in 1972: Onshore Oflfshore Total Producing Number Producing <200m >200m Producing Exploratory __ 26 7 0 0 O 26 7 Development __ 22 19 0 0 0 22 19 Producing wells as of 12/31/72: Onshore, 3,318; Offshore, 0; Total, 3,318. Ofl'shore'concessions licensed as of 12/31/72: Thirty-three concessions licensed; all Within 200-m isobath. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of ‘cubic : of cubic bbl tons bbl tons feet meters Imports _______ 749 102.6 0 37.8 501.3 14.2 Exports _______ 56 7.7 0 7.8 3.5 .1 53 54 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GHANA Category: Open shelf. Margin: Area to 3,000—m depth, 20,100 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 285 nautical miles. miles. 63,600 sq nautical miles. Shelf area to 200—m depth: 6,100 sq nau- Geology: Coastal onshore, sedimentary/ tical miles. crystalline. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 O 0 Cumulative production (through 1972) ___- 0 o 0 o 0 0 Proved recoverable reserves (12/31/72) _ 0 1 7.5 1 7.5 0 1 1 1 1 1 s1. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 O O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 NA NA 0 NA NA Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Oflshore Total Onshore Offshore Total Category ____________ V IV IV IV IV IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 1 O 1 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Fourteen concessions; four outside 200-m isobath, one partly outside 200-m isobath. Licensed to nine companies or consortia. Offshore exploration expenditures in 1972: Local US. Companies of , . companies companies other countries (’0‘ ernment Amount _____________ NA $3.5 million NA 0 Percent _____________ NA NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 376.5 51.6 5 Negl 0 0 Exports _______ .1 Negl 2 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GREECE Category: Open shelf. Margin: Area to 3,000-m depth, 82,100 sq Bordering water body: Mediterranean nautical miles. Area to 200 nautical Sea. miles, 147,300 sq nautical miles. Coastal length: 1,645 nuatical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 7,200 sq nau- crystalline. Ofishore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 0 0 Cumulative production (through 1972) ___- O 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ O O 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 ___- 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory .._ 0 0 2 0 11 2 11 Development __ 0 0 0 O O 0 0 1 s1. Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Four concessions, onshore and offshore, leased to three groups. Three concessions offshore, leased to three groups. Ofi'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 $3 million 0 0 Percent ______________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 51.1 7.0 O 2.3 0 0 Exports _______ 0 0 O .4 0 0 55’ 56 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GUATEMALA Margin: Area to 3,000-m depth, 8,200 sq nautical miles. Area to 200 nautical miles, 28,900 sq nautical miles. Geology: Coastal onshore, sedimentary. Oflshore, sedimentary. Category: Open shelf. Bordering water bodies: Pacific Ocean, Caribbean Sea. Coastal length: 178 nautical miles. Shelf area to 200-m depth: 3,600 sq nau- tical miles. Oil Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Oifshore Total Production in 1972 ___- 0 0 O 0 O 0 Cumulative production (through 1972) ___- 0 0 O 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 O 0 O 0 Cumulative production (through 1972) __-_ 0 0 0 O O 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ IV V IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O O 1 0 0 1 Development __ 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Caribbean Sea: One concession, Within 200-m isobath, leased by one com— pany. Pacific Ocean: Four concessions, some extending beyond 200-m depth. Three concessions leased to one company and the other to a consortium. Offshore exploration expenditures in 1972: 0 0 Local US. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 7.1 0.2 0 0 Exports _______ 0 0 0 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 57 GUINEA Category: Open shelf. Margin: Area to 3,000-m depth, 15,300 sq Bordering Water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 190 nautical miles. miles, 20,700 sq nautical miles. Shelf area to 200-m depth: 11,200 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 O O 0 0 0 Cumulative production (through 1972) ____ 0 O O 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 O 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ O O 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 0 0 0 Percent _____________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA NA 0 0 Exports _______ 0 0 NA NA 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES GUYANA Category: Open shelf. Margin: Area to 3,000-m depth, 28,300 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 232 nautical miles. miles, 38,000 sq nautical miles. Shelf area to 200-m depth: 14,600 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 0 O O O O 0 Cumulative production (through 1972) ____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) -_-_ O 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV IV V IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory -_ 0 0 0 0 O 0 0 Development _ 0 O 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Six concessions licensed by four companies. N o concessions beyond 200-m isobath. Offshore exploration expenditures in 1972: Local US. Companies of companies , companies other countries Government Amount _____________ 0 0 $1 million 0 Percent ______________ 0 0 100 0 Imports and exports of oil, products, and natural gas in 1972: , Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 3.8 0 0 0 Exports _______ 0 0 O 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 59 HAITI Category: Open shelf. Margin: Area to 3,000-m depth, 16,000 sq Bordering water bodies: Caribbean Sea, nautical miles. Area to 200 nautical Atlantic Ocean. miles, 46,800 sq nautical miles. Coastal length: 584 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 3,100 sq nau- Ofishore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 __- 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O O 0 O 0 Cumulative production (through 1972) ___._ 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ O 0 0 0 O O Potential res0urces (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development __ 0 O 0 0 O 0, 0 Producing wells as of 12/31/72: Onshore, O; Ofl'shore, 0; Total, 0. Oifshore concessions licensed as of 12/31/72: One concession granted to one company includes most of onshore area and offshore area within and beyond 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 0 O 0 Percent ______________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ O 0 0.9 0 0 0 Exports _______ O 0 0 0 O O 60 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE,AND OFFSHORE AREAS, 151 COUNTRIES HONDURAS Category: Open shelf. Margin: Area to 3,000—m depth, 43,900 sq Bordering water body: Carribbean Sea. nautical miles. Area to 200 nautical Coastal length: 374 nautical miles. miles, 58,600 sq nautical miles. Shelf area to 200-m depth: 15,600 sq nau— Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total On shore Offshore Total Production in 1972 ___ O 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 O 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Oifshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 3 0 0 3 0 Development _ O 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Ofl’shore concessions licensed as of 12/31/72: Twenty concessions leased by eight companies or consortia. Ofl’shore exploration expenditures in 1972: Local U.S. Companies of . companies companies other countries GO‘ ernment Amount _____________ NA NA NA 0 Percent ______________ NA NA NA 0 Imports and eiports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 4.5 0.6 0.5 0 NA NA Exports _______ N egl Neg] 1.5 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 61 HUNGARY Shelf area to 200-m depth: None. Margin: None. Geology: Sedimentary. Category: Landlocked. Bordering water body: None. Coastal length: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 15.2 ___- 15.2 2 ___- 2 Cumulative production (1937—72) __________ 28.3 ___- 283 37 -___ 37 Proved recoverable reserves (12/31/72) _ 210 ___- 210 27.6 ___- 27.6 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ 144 ___ 144 4 ___ 4 Cumulative production (1937—72) __________ 975 _-_ 975 28 ___ 28 Proved recoverable reserves (12/31/72) _ 4.200 ___ 4,200 119 ___ 119 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV ___ IV IV ___ IV Number of wells completed in 1972 : Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory "} No information. Development _ Producing wells as of 12/ 31/ 7 2: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Not applicable. Ofishore exploration expenditures in 197 2: Local US. Companies of companies companies other countries Government Amount _____________ . Percent } Not applicable. Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 40.2 5.5 NA 0 NA NA Exports _______ NA NA NA 0 NA NA 62 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ICELAND Category: Open shelf. Margin: Area to 3,000-m depth, 252,000 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 1,080 nautical miles. miles, 252,800 sq nautical miles. Shelf area to 200-m depth: 39,000 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 9 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 0 0 0 O 0 Number of wells completed in 1972: Onshore Oflfshore Total Producing Number Producing <200m >200m Producing Exploratory -_ 0 0 0 0 0 0 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, O; Ofl’shore, 0; Total, 0. Ofi'shore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _______________ 0 O O 0 Percent ______________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ O 0 0 4.1 NA NA Exports _______ 0 0 O 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 63 INDIA Category: Open shelf. nautical miles. Area to 200 nautical Bordering water body: Indian Ocean. miles, 587,600 sq nautical miles. Coastal length: 2,759 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 131,800 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. talline. Margin: Area to 3,000-m depth, 339,700 sq Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ 57 0 57 7.7 0 7 .7 Cumulative roduction (1889—1972 ________ 433 0 433 59 0 59 Proved recoverable reserves (12/ 31 / 7 2) _ 834 0 834 112 O 112 Natural gas Billions of cubic feet Billions of cubic meters - Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 56.3 0 56.3 1.6 0 1.6 Cumulative production (1960—7 2) _________ 393 O 393 12 O 12 Proved recoverable reserves (12/31/72) _ 1,500 0 1,500 42 0 42 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III -' III III III III Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 62 NA 0 0 O 62 NA Development _ 10 10 O 0 0 10 10 Producing wells as of 12/31/72: Onshore, 1,190; Offshore, 0; Total, 1,190. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of . companies companies other countries uovernment Amount _____________ 0 0 0 $3 million Percent ______________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42—gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 90.2 12.4 24.2 0 0 0 _ Exports _______ 0 0 1.1 0 0 0 64 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES INDONESIA Category: Archipelago. Margin: Area to 3,000-m depth, 1,229,800 Bordering water bodies: Pacific Ocean, In- sq nautical miles. Area to 200 nautical dian Ocean, South China Sea. miles, 1,577,300 sq nautical miles. Coastal length: 19,784 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 809,600 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 374 21 395 51 3.2 54.1 Cumulative production (1893—1972) _______ 5,043 24 5,067 686 3.2 690.1 Proved recoverable reserves (12/31/72) _ 10,300 400 10,700 1,410 55 1,465 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ 137.4 Negl 137.4 3.9 N egl 3.9 Cumulative production (1893497 2) _______ 3,960 N egl 3,960 112 Negl 112 Proved recoverable reserves (12/31/72) _ NA NA 5,500 NA NA 156 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III III II III II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA 1 NA 137 32 Development _ NA NA NA NA NA 416 365 Producing wells as of 12/31/72: Onshore, 2,404; Offshore, 23; Total, 2,427. Ofi'shore concessions licensed as of 12/31/72: Ninety-one companies or groups hold concessions. Some concessions deeper than 200-m, and one is as deep as 6,000 ft. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent _____________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0.9 0.1 10.9 0 NA NA Exports _______ 299 31.2 46.4 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 65 IRAN Category: Open shelf. Margin: Area to 3,000-m depth, 45,400 sq Bordering water bodies: Persian Gulf, nautical miles. Area to 200 nautical Indian Ocean. miles, 45,400 sq nautical miles. Coastal length: 990 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 31,200 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1,580 258 1,838 214.4 35 249.4 Cumulative production (1913—72) _________ NA NA 15,809 NA NA 2,145 Proved recoverable reserves (12/31/72) _ 60,000 5,000 65,000 8,141 678 8,819 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ NA NA 1,470 NA NA 42.4 Cumulative production (1913—72) _________ NA NA 12,335 NA NA 350 Proved recoverable reserves (12/ 31 / 7 2) - NA NA 200,000 NA NA 5,700 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ II III II II II II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 10 2 8 0 4 18 6 Development _ 35 33 6 0 6 40 39 Producing wells as of 12/31/72: Onshore, 224; Offshore, 89; Total, 313. Offshore concessions licensed as of 12/31/72: Seven joint venture agreements with government. No areas beyond 200-m depth. Offshore exploration expenditures in 1972: Local i US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 0 0 0 Exports _______ 1,843 250 108.9 0 289.4 8.2 66 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES IRAQ Category, Shelf locked. Margin: Area to 3,000—m depth, 200 sq Bordering water body: Persian Gulf. nautical miles. Area to 200 nautical Coastal length: 10 nautical miles. miles, 200 sq nautical miles. Shelf area to 200-m depth: 200 sq nautical Geology: Coastal onshore, sedimentary. miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972,--- 529 O 529 71.2 0 17.2 Cumulative production (1927—72) __________ 8,658 0 8,658 1,164 0 1,164 Proved recoverable reserves (12/31/72) _ 33,000 0 33,000 4,400 0 4,400 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ - 3.4 0 3.4 Negl 0 Negl Cumulative production (1927—72)L __________ NA 0 NA NA 0 NA Proved recoverable reserves (12/31/72) - 20,000 0 20,000 566.6 0 566.6 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Ofi'shore Total Category ____________ III IV III III IV III Number of wells completed in 1972: Onshore Offshore _ Total Producing Number Producing (200m >200m Producing Exploratory "} N 0 information. Development Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount -------------- 0 0 0 NA Percent ______________ 0 0 0 NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports ------- 0 0 Negl 0 NA NA Exports _______ 523.6 70.5 497 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 67 IRELAND Category: Open shelf. Margin: Area to 3,000—m depth, 84,100 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 663 nautical miles. miles, 110,900 sq nautical miles. Shelf area to 200-m depth: 36,700 sq Geology: Coastal onshore, sedimentary. nautical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O O 0 0 0 0 Cumulative production ' (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 NA NA 0 NA NA Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V IV IV I'II Number of wells completed in 1972: Onshore Oflshore Total Produ’cing Number Producing <200m >200m Producing Exploratory __ 0 O 3 0 1 1 3 1 1 Development _ 0 0 0 0 0 0 0 1 s1. Producing wells as of 12/31/72: Onshore, 0; Ofi'shore, 0; Total, 0. Ofl’shore concessions licensed as of 12/31/72: No concessions granted; 52 exploratory licenses granted. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount ______________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 17.2 2.4 18.3 0 NA NA Export/s _______ 0 O 3.8 0 0 0 68 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ISRAEL Category: Open shelf. Margin: Area to 3,000—m depth, 5,700 sq Bordering water body: Mediterranean Sea. nautical miles. Area .to 200 nautical Coastal length: 124 nautical miles. miles, 6,800 sq nautical miles. Shelf area to 200-m depth: 1,300 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1 43.9 0 1 43.9 6 0 6 Cumulative production (1958—71) _________ 170 o 170 24 0 24 Proved recoverable reserves (12/31/72) _ 9.0 0 9.0 1.2 0 1.2 1 Includes estimated Sinai production. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 4.4 0 4.4 0.1 0 0.1 Cumulative production (1958—71) _________ 45 0 45 1 0 1 Proved recoverable reserves (12/31/72) _ 50 0 50 1.5 0 1.5 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Ofi’shore Total Producing Number Producing (200m >200m Producing Exploratory __ 4 0 O 0 O 4 0 Development __ 0 0 0 O 0 0 0 Producing wells as of 12/31/72: Onshore, 27; Offshore, 10; Total, 37. Ofl'shore concessions licensed as of 12/31/72: Nine offshore exploration licenses in efl'ect. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ } . . . . Percent ______________ No Significant expenditures in 1972. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 40.5 5.5 3 0 NA NA Exports _______ 38.4 5.2 5.9 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 69 ITALY Category: Open shelf. Margin: Area to 3,000-m depth. 160,000 sq Bordering water body: Mediterranean Sea. nautical miles. Area to 200 nautical Coastal length: 2,451 nautical miles. miles, 161,000 sq nautical miles. Shelf area to 200-m depth: 42,000 sq nau- Geology: Coastal onshore, sedimentary/ tical miles. crystalline. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 7 .3 0.7 8 1.2 Negl 1.2 Cumulative production (1860—1970) _______ 122 63 185 18 9 27 Proved recoverable reserves (12/31/72) _ NA NA 320 NA NA 32 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 261.2 240 501 7.4 6.8 14.2 Cumulative production (1865—1972) _______ 5,281 377 5,713 150 8.8 159 Proved recoverable reserves (12/31/72) - NA NA 6,000 NA NA 169.9 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV III II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 28 5 15 0 NA 43 5 Development __ 30 23 4 0 NA 34 23 Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Ten exploration concessions; none beyond 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products. and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 867.2 118.8 19.3 0 49.4 1.4 Exports _______ 0 0 3.8 0 NA NA 70 SUMMARY, 1972 OIL AND GAS STATISTICS, ONS HORE AND OFFSHORE AREAS, 151 COUNTRIES IVORY COAST Category: Open shelf. Margin: Area to 3,000-m depth, 15,700 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 274 nautical miles. miles, 30,500 sq nautical miles. Shelf area to 200-m depth: 3,000 sq nau- Geology: Coastal onshore, sedimentary/ tical miles. crystalline. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ____ 0 0 0 0 O 0 Cumulative production (through 1972) ____ O 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 O Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ____ O 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 2 0 0 2 0 Development __ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofi'shore, 0; Total, 0. One exploration license covering the entire coastal area and the continen- tal shelf granted in 1970 to a consortium of three companies. Offshore depth locally greater than 200 meters. Ofl'shore exploration expenditures in 197 2: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 $6 million 0 0 Percent ______________ O 100 0 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 7.8 0.1 0.3 0 0 0 Exports _______ 0 0 2.4 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 71 JAMAICA Category: Open shelf. Margin: Area to 3,000-m depth, 59,000 sq Bordering water body: Caribbean Sea. nautical miles. Area to 200 nautical Coastal length: 280 nautical miles. miles, 86 800 sq nautical miles. Shelf area to 200—m depth: 11,700 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ____ O 0 0 0 0 0 Cumulative production (through 1972) ____ O 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) _ _ _ _ 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 1 O 0 0 O 1 0 Development __ 0 0 0 O O 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Six exploration licenses in effect. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal :: of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 11.3 1.5 35.9 0.8 0 0 Exports _______ O 0 .9 Negl 0 0 72 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES JAPAN Category: Archipelago. Margin: Area to 3,000-m depth, 440,900 sq Bordering water bodies: Pacific Ocean, nautical miles. Area to 200 nautical Sea of Japan, East China Sea. miles, 1,126,000 sq nautical miles. Coastal length: 4,842 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200—m depth: 140,100 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 4.8 0.4 5.2 0.6 0.1 0.7 Cumulative production (1874—1971) _______ 158 9.4 167 22 1 23 Proved recoverable reserves (12/31/72) _ 8 15 23 1 2 3 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 - _ _ NA NA 87.4 NA NA 2.5 Cumulative production (1874—1971) _______ <935 NA 935 <27 NA 27 Proved recoverable reserves (12/31/72) _ <400 NA 400 <11 NA 11 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 5 O 5 0 O 10 1 Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: Onshore, 2,601; Offshore, 133; Total, 2,734. Offshore concessions licensed as of 12/31/72: Nineteen concessions, some beyond 200—m depth licensed. Offshore exploration expenditures in 1972: Local U. S. Companies of companies companies other countries Government ‘Anlount _____________ (1) (1) (1) (1) Percent ______________ NA NA NA NA 1Total of $28.2 million expended in Japanese fiscal year 1972 (April ’72—March ’73). Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 1,499 203.8 280.8 0 0 0 Exports _______ 7,601 55.9 8.1 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES JORDAN Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 O ___ 0 Cumulative production (through 1972) ___- O ___ 0 0 ___ O Proved recoverable reserves (12/31/72) _ O ___ O 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O __c O 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ O 0 ___ O Proved recoverable reserves (12/31/72) _ O ___ 0 0 __- 0 Potential resources (ultimate recoverable resources) : Oil Natural ga s Onshore Offshore Total Onshore Offshore Total Category ____________ IV __- IV IV ___ IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ ___ 0 0 Development _ 0 0 ___ ___ ___ 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of V companies companies other countries Government Amount _____________ _ Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 4.4 0.6 Negl Negl 0 0 Exports _______ 0 0 O 0 0 0 73 74 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES KENYA Category: Open shelf. Margin: Area to 3,000-m depth, 21,600 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 247 nautical miles. miles, 34,400 sq nautical miles. Shelf area to 200-m depth: 4,200 sq nau— Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- O 0 O 0 0 0 Cumulative production (through 1972) _-.._ O 0 0 0 O O Proved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore Total Onshore Offshore ’l‘otal Production in 1972 ___ 0 0 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 O O Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV III V III Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 O O 0 0 Development __ 0 0 O 0 0 O O Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Two concessions licensed, one inside 200-m depth and other extends be- yond 200-m depth. Offshore exploration expenditures in 1972: cogg‘aehlies comtiisnies ogggi‘iiildtsrgs Government Amount _____________ 0 O 0 0 Percent ______________ O 0 0 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 18.2 2.5 11.9 0 0 0 Exports _, ______ 0 0 N egl Negl 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 75 KHMER REPUBLIC Category: Shelf locked. Margin: Area to 3,000-m depth, 16,200 sq Bordering water body: South China Sea. nautical miles. Area to 200 nautical Coastal length: 210 nautical miles. miles, 16,200 sq nautical miles. Shelf area to ZOO-m depth: 16,200 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ O 0 0 0 0 0 Cumulative production (through 1972) ____ 0 O 0 O 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 H. 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 o 0 o o o Proved recoverable reserves (12/31/72) _ 0 0 0 0 O O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Oflshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O 1 O 0 1 0 Development _- 0 0 O 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Two concessions, Within 200-m depth, licensed by one company and one consortium. Offshore exploration expenditures in 1972: Local US. Companies of ‘ companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 0 0 Exports _______ 0 0 NA 0 0 0 76 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES KOREA, DEMOCRATIC PEOPLE’S REPUBLIC OF Category: Open shelf. Margin: Area to 3,000—m depth, 20,400 sq Bordering water body: Sea of Japan, East nautical miles. Area to 200 nautical China Sea. miles, 37,800 sq nautical miles. Coastal length: 578 nautical miles. Geology: Coastal onshore, crystalline. Off— Shelf area to ZOO-m depth: 13,200 sq nau- shore, crystalline/sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 o 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 O Natural gas Billions of cubic feet Bililons of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 IV IV 0 IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA NA NA NA NA Development __ 0 0 O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: Local US. Companies of , companies companies other countries Government Amount _____________ 0 0 0 NA Percent ______________ 0 O 0 NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions m of 42-ga1 : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA 0 0 0 Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 77 KOREA, REPUBLIC OF Margin: Area to 3,000-1n depth, 93,300 sq nautical miles. Area to 200 nautical miles, 101,600 sq nautical miles. Geology: Coastal onshore, crystalline. Off- shore, crystalline/sedimentary. Category: Open shelf. Bordering water bodies: Sea of Japan, East China Sea. Coastal length: 712 nautical miles. Shelf area to 200-m depth: 71,300 sq nau- tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oflshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 O 0 0 O Proved recoverable reserves (12/ 31 / 72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ____ O 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 III III 0 III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ 0 O 0 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: _Seven concessions licensed; 2 extend beyond 200—m depth. Offshore exploration expenditures in 1972: Local U.S. Companies of , companies companies other countries Gm ernment Amount _____________ 0 $4 million $3.4 million $0.6 million Percent ______________ 0 50 42 8 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 92.6 12.7 1.4 0 NA NA Exports _______ 4 .5 8 0 NA NA 78 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, '151 COUNTRIES KUWAIT [Includes one-half of Kuwait—Saudi Arabia Neutral Zone] Category: Shelf locked. Margin: Area to 3,000-m depth, 4,100 sq Bordering water body: Persian Gulf. nautical miles. Area to 200 nautical Coastal length: 135 nautical miles. miles, 4,100 sq nautical miles. Shelf area to 200-m depth: 4,100 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Ofishore Total Onshore Offshore1 Total Production in 1972 ___ 1,126.3 75 1,201.3 155.5 11 166.5 Cumulative production (1946—71) _________ «4,902 >505 15,407 <2,052 >70 2,122 Proved recoverable reserves (12/31/72) _ NA NA 77,041 NA NA 10,750 1Oifshore protection and reserves from Neutral Zone. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 608 37.2 645.2 17.2 1 18.2 Cumulative production (1946—71) _________ 11,048 252 11,300 313 7 320 Proved recoverable reserves (12/31/72) _ NA NA 42,000 NA NA 1,190 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ II III II III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O 0 ___ 0 l2 0 Development _ 0 0 0 ___ 0 0 0 1Two wells reported as drilled but locality NA. Producing wells as of 12/31/72: Onshore, NA; Ofl’shore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Three concessions licensed. Offshore exploration expenditures in 1972: corIiJilp‘laaxiies confiignies oghlg‘pgoliifiirgis Government Amount _____________ 0 NA 0 0 Percent ______________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Naturalgas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 28.8 3.9 Neg] 0 0 0 Exports _______ 1 994.8 1 138.2 2 113.2 0 900 25.4 1Kawalt only; does not include any of 193.9 million bbls (28.4 metric tons) exported from Neutral Zone. “Kawait only; does not include any of 19.3 million bbls exported from Neutral Zone. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 79 LAOS Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. 011 Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 __- 0 O __.. 0 Cumulative production (through 1972) ____ O ___ O O -_- 0 Proved recoverable reserves (12/31/72) _ 0 _-_ O 0 _-_ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ O _ - - 0 O - _ _ 0 Cumulative production (through 1972) ____ O _-- 0 O ..-_ 0 Proved recoverable reserves (12/31/72) _ 0 ___ O 0 ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Ofishore Total Category ____________ IV -__ IV IV ___ IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA _-- _.._ _-_ NA NA Development __ NA NA ___ ___ ___ NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, ___; Total, NA. Oflshore concessions licensed as of 12/31/72: Not applicable. Ofi'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ _ Percent 1 Not appllcable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—ga1 : of metric of 42—ga1 + of metric of cubic :: of cubic bbl tons bbl tons feet meters Imports _______ O 0 1,284 0 NA NA Exports _______ 0 0 0 0 NA NA a:- SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES LEBANON Category: Open shelf, Margin: Area to 3,000-m depth, 4,600 sq Bordering water body: Mediterranean Sea. nautical miles. Area to 200 nautical Coastal length: 105 nautical miles. miles, 6,600 squ nautical miles. Shelf area to 200-m depth: 1,300 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Oflshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 0 0 O 0 O 0 Cumulative production (through 1972) ____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 O 0 0 Cumulative production (through 1972) ____ O 0 0 O O O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ 0 O 0 0 0 0 O Producing wells as of 12/31/72: Onshore, 0; Oflshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Five exploration permits in effect, all include areas, beyond 200—m depth. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 O 0 0 Percent ______________ 0 O O 0 Imports and exports of oil7 products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42~ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 1 15.9 1 2.2 1.6 0 NA NA Exports _______ 0 O Negl 0 NA NA 1 Estimated. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 81 LESOTHO Shelf area to 200-m depth: None. Margin: None. Geology: Sedimentary/crystalline. Category: Landlocked. Bordering water body: None. Coastal length: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O ___ O O ___ 0 Cumulative production (through 1972) ___- O ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 -__ O O ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore Total Onshore Offshore Total Production in 1972 _-_ O ___ O O -__ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI _ _ _ VI VI _ _ _ VI Number of wells completed in 1972 : Onshore Offshore Total Producing Number Producing <200 m >200 m Producing Exploratory __ 0 0 ___ __- ___ 0 0 Development _ _ 0 O _ _ _ _ _ _ _ _ _ O O Producing wells as of 12/31/72: Onshore, O; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. companies of v companies companies other Countries GOV ernment Amount _____________ _ Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ O 0 NA 0 NA NA Exports _______ 0 0 0 0 NA NA 82 SUMMARY, 1972 OIL AND GAS STATISTICS, ONS HORE AND OFFSHORE AREAS, 151 COUNTRIES LIBERIA Category: Open shelf. Margin: Area to 3,000—m depth, 19,600 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 290 nautical miles. miles, 67,000 sq nautical miles. Shelf area to 200—m depth: 5,700 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Olfshore Total Onshore Oifshore Total Production in 1972 ___ O 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 o Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 O 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 O O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 V V 0 V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 O 0 0 0 Development __ 0 0 0 0 O O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Two concessions leased to a consortium of two companies. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 NA 0 0 Percent ______________ 0 NA 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 3.3 0.5 0.3 0 0 0 Exports ________ 0 O Negl 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 83 LIBYAN ARAB REPUBLIC Category: Open shelf. Margin: Area to 3,000—m depth, 60,100 sq Bordering water body: Mediterranean Sea. nautical miles. Area to .200 nautical Coastal length: 910 nautical miles. miles, 98,600 sq nautical miles. . Shelf area to 200-m depth: 24,400 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 819.6 0 819.6 107.8 0 107.8 Cumulative production (through 1972) _____ 7,314.6 0 7,314.6 961 0 961 Proved recoverable reserves (12/31/72) _ 30,400 NA >30,400 4,000 NA >4,000 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197‘) ___ 496 0 496 123 0 123 Cumulative production (through 1972) _____ 4,360 0 4,360 14 0 14 Proved recoverable reserves (12/ 31 / 7 2) _ 27,500 NA > 27,500 779 NA > 779 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ II II II II II II Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 34 1 0 O 0 34 1 Development __ 43 NA 0 0 0 43 NA Producing wells as of 12/31/72: Onshore, 1,010; Offshore, 0; Total, 1,010. Offshore concessions licensed as of 12/31/72: Thirteen concessions leased by nine companies or consortia. Balance of offshore area available for participation agreements with government owned oil company. Some areas extend beyond 200-m depth. Offshore exploration expenditures in 1972: corlligcaariies coniliisnies (Eggpcadiifiirtiis Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 5.4 0 0 0 Exports _______ 810.3 111 .1 0 NA NA 84 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES LICHTENSTEIN Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) _____ O ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) _____ 0 ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) ._ O ___ O 0 ___ O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 _ _ _ 0 0 _ _ _ 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 __ _ _ _ _ _ __ O 0 Development __ 0 0 __ _ _ _ _ _ Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of G 7 companies companies other countries overnment Amount _____________ . Percent _____ } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42»ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 N A 0 NA NA Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 85 LUXEMBOURG Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 0 __- 0 0 -__ 0 Cumulative production (through 1972) ___- 0 ___ 0 O ___ 0 Proved recoverable _ reserves (12/31/72) _ 0 _-_ O 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ 0 ___ 0 0 _ _- 0 Cumulative production (through 1972) ___- 0 ___ 0 O ___ 0 Proved recoverable reserves (12/31/72) _ O ___ 0 0 ___ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ O __- 0 0 ___ 0 Number of wells completed in 1972: Onshore Ofl’shore Total Producing Number Producing <200m >200m Producing Exploratory _ _ 0 O _ __ ___ _ _ _ O 0 Development _ 0 0 - _ _ _ _ - _ _ - O O Producing wells as of 12/31/72: Onshore, 0; Offshore, _-._; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ _ Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 O 1.6 .3 Negl Exports _______ 0 0 0 0 O 0 86 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES MALAGASY REPUBLIC Category: Open shelf. tical miles. Bordering water body: Indian Ocean. Margin: Area to 3,000-m depth, 131,300 sq Coastal length: 2,155 nautical miles. nautical miles. Area to 200 nautical Shelf area to 200-m depth: 52,600 sq nau- miles, 376,800 sq nautical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 __- 0 0 O O O 0 Cumulative production (through 1972) _____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O O 0 Natural gas Billions of cubic feet Billions of cubic meters . Onshore Oifshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 O 0 0 Cumulative production (through 1 972) _____ 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 1 0 0 0 0 1 0 Development __ 0 O O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofl’shore concessions licensed as of 12/31/72: Fifteen concessions licensed to 15 companies or consortia. Offshore exploration expenditures in 1972: Local US. Companies of . , companies companies other countries Government Amount _____________ 0 $430 thousand $990 thousand 0 Percent ______________ 0 30 7O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 4.6 0.6 0 0 O 0 Exports _______ 0 O O .3 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 87 MALAWI Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Crystalline/sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ 0 ___ O O ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ O Proved recoverable reserves (12/31/72) _ 0 ___ 0 O ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 -__ O Proved recoverable reserves (12/31/72) _ 0 ___ O 0 ___ O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 ___ 0 0 ___ 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 .. _ _ _ __ ___ 0 0 Development _ 0 0 _ __ -__ __ _ 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ . Percent ______________ } Not apphcable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 0 0 Exports _______ O O 0 O O O 88 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES MALAYSIA Category: Open shelf. Margin: Area to 3,000-m depth, 125,600 sq Bordering water bodies: South China Sea, nautical miles. Area to 200 nautical Indian Ocean. miles, 138,700 sq nautical miles. Coastal length: 1,853 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 108,900 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. talline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ 0 33.6 33.6 0 4.4 4.4 Cumulative production (through 1972) ___- 4 69.2 73.2 .6 8.9 9.5 Proved recoverable reserves (12/31/72) _ NA NA 1,500 NA NA 205 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 0 0 Cumulative production (through 1972) ___- 0 O O O 0 O Proved recoverable reserves (12/31/72) _ NA NA 10,000 NA NA 284 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Oifshore Total Onshore Offshore Total Category ____________ III III III III III III ' Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA 0 NA NA NA Development _ NA NA NA 0 NA NA NA Producing wells as of 12/31/72: Onshore, 88; Offshore, 45; Total, 133. Offshore concessions licensed as of 12/31/72: Licenses granted to 7 companies covering a total of 175,905 square anile?l (small part of that onshore). All offshore licenses within 200-m ept . Offshore exploration expenditures in 1972: Local US Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent _____________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 43 5.6 10.4 0 O 0 Exports _______ 30.9 4 18 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 89 MALDIVES Category: Archipelago. Margin: Area to 3,000—m depth, >4,000 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautlcal Coastal length: Not available. miles, 279,700 sq nautical miles. Shelf area to 200-m depth: 3,000 (?) sq Geology: Onshore coastal, sedimentary. nautical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ __ O O 0 O O 0 Cumulative production (through 1972) _____ O O O O 0 O Proved recoverable reserves (12/31/72) _ 0 O O O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) _____ O O 0 0 O O Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI VI VI VI VI VI Number of wells completed in 1972: Onshore Offshore Total. Producing Number Producing (200m >200m Producing Exploratory __ O 0 0 0 0 0 0 Development __ 0 O O 0 0 0 0 Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession leased to a consortium. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ O 0 0 0 Percent ______________ 0 O 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42—ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 NA 0 0 0 Exports _______ 0 O 0 0 0 O 90 SUMMARY, 1972, OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES MALI Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 O ___ 0 Cumulative production (through 1972) ___- O ___ 0 O ___ 0 Proved recoverable reserves (12/31/72) _ O ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ O O ___ O Proved recoverable reserves (12/31/72) _ O ___ 0 0 __- 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV ___ IV IV ___ IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 ___- ___ ___ 0 0 Development _ O 0 -__ ___ ___ 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. C ' f companies companies otlfileli'pciriireifries Government $323§€_:::::::::::l Not applicable- Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal : of metric of 42-gal +‘ of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 NA NA Exports _______ 0 0 NA 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 91 MALTA Category: Open shelf. Margin: Area to 3,000—m depth, 17,300 sq Bordering water body: Mediterranean Sea. nautical miles. Area to 200 nautical Coastal length: 50 nautical miles. miles, 19,300 sq nautical miles. Shelf area to 200-m depth: 3,800 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O O O 0 Cumulative production (through 1972) _____ O 0 0 0 O O Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore. Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O 0 O 0 Cumulative production (through 1972) _____ 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ O 0 0 O O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI IV IV VI IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O O 3 0 O 3 0 Development __ 0 0 O O O 0 O Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Three concessions licensed to three companies or consortia. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA NA Percent ______________ 0 NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O O 1.4 Negl 0 0 Exports _______ 0 0 NA 0 0 0 92 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES MAURITANIA Category: Open shelf. Margin: Area to 3,000-m depth, 26,300 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 360 nautical miles. miles, 45,000 sq nautical miles. Shelf area to 200m depth: 12,900 sq nau- Geology. Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 O 0 Cumulative production (through 1972) _____ 0 O 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 0 O 0 O O 0 Cumulative production (through 1972) ______ 0 O O 0 0 0 Proved recoverable reserves (12/31/72) _ O O 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 O 2 O 0 2 0 Development __ 0 0 O O 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Four concessions, one mostly onshore, three licensed to two companies and one consortium. Offshore exploration expenditures in 1972: Local US Companies of , companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : 0f metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 NA 0 0 0 Exports _______ O O 0 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 93 MAURITIUS Category: Open shelf. Margin: Area to 3,000-m depth, 149,200 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 87 nautical miles. miles, 345,000 sq nautical miles. Shelf area to 200-m depth: 26,700 sq nau- Geology: Coastal onshbre, crystalline. Off- tical miles. shore, crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofi'shore Total Production in 1972 ___ 0 0 O 0 O 0 Cumulative production (through 1972) _____ O 0 O 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofi'shore Total Onshore Offshore Total Production in 197 2 ___ 0 0 0 O 0 0 Cumulative production (through 1972) _____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Cate o ____________ 0 0 0 0 O 0 g ry Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 0 0 0 0 Development __ 0 0 0 O O 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession licensed to one company. Offshore exploration expenditures in 1972: Local U.S. Companies of G rn t companies companies other countries ove men Amount _____________ 0 NA 0 0 Percent ______________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 0 0 Exports _______ 0 0 NA 0 0 0 94 SUMMARY, 1972 OIL AND GAS STATISTICS, ON SHORE AND OFFSHORE AREAS, 151 COUNTRIES MEXICO Category: Open shelf. Margin: Area to 3,000—m depth, 343,000 sq Bordering water bodies: Pacific Ocean, nautical miles. Area to 200 nautical Gulf of Mexico, Caribbean Sea. miles, 831,500 sq nautical miles. Coastal length: 4,848 nautical miles. Geology; Coastal onshore, sedimentary/ Shelf area to 200-m depth: 128,900 sq nau- crystalline. Ofl’shore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 159.2 25.8 185 22.4 3.6 26 Cumulative production (1901—72) __________ 4,856 103.8 4,960 683.4 14.6 698 Proved recoverable reserves (12/31/72) _ NA >1,934 5,388 NA >272.4 758.8 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ NA NA 6,602 NA NA 18.7 Cumulative production , (1901—72) __________ NA NA 9,220 NA NA 261 Proved recoverable reserves (12/31/72) _ NA NA 11,500 NA NA 326 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore OlTshore Total Onshore Ofit‘shore Total Category ____________ III II II II III II Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <2001n >200m Producing Exploratory __ £140 26 E3 0 3 143 29 Development _ NA NA NA 0 NA 143 197 Producing wells as of 12/31/72: Onshore, 3,640; Offshore, 50; Total, 3,690. Offshore concessions licensed as of 12/31/72: None. State ownership and control of petroleum industry. All govern- ment exploration is Within 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ O O 0 NA Percent ______________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 11.2 1.5 15 0 NA NA Exports _______ 0 0 7.7 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 95 MONGOLIA Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary—crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 _-_ O 0 _ __ 0 Cumulative production (through 1972) ___- 0 __- 0 O __- 0 Proved recoverable reserves (12/31/72) _ O ___ 0 O ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total- Production in 1972 - _ .. 0 _ .. _ 0 O _ _ _ 0 Cumulative production (through 1972) ___- O ___ 0 O ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 O ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Oflfshore Total Onshore Offshore Total Category ____________ IV ___ IV III ___ III Number of wells completed in 1972: Onshore Otfshore Total Producing Number Producing <200m >200m Producing Exploratory __ Development _} No informatlon, Producing wells as of 12/31/72: Onshore, 1,461; Offshore, ___; Total, 1,461. Offshore concessions "licensed as of 12/31/72: No information. Ofl'shore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount ------------- } No information. Percent _____________ Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 70.8 9.7 0 28.3 53 1.5 Exports 5- _____ 0 O 0 1.7 0 0 96 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES MOROCCO Category: Open shelf. Margin: Area to 3,000-m depth, 42,100 sq Bordering water bodies: Atlantic Ocean, nautical miles. Area to 200 nautical Mediterranean Sea. miles, 81,000 sq nautical miles. Coastal length: 895 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 18,100 sq nau- Offshore, sedimentary. tical miles. 011 Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 0.2 O 0.2 N egl 0 Negl Cumulative production (through 1972) _-__ 15 0 15 2 0 2 Proved recoverable reserves (12/31/72) _ 1.2 0 1.2 .2 O .2 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore_ Total Onshore Ofifshore Total Production in 1972 __- 2.2 0 2.2 N egl O Negl Cumulative production (through 1972) __-- 10.2 0 10.2 .3 0 .3 Proved recoverable reserves (12/31/72) _ 17 0 17 .4 0 .4 Potential resources (ultimate recoverable resources): 011 Natural gas Onshore Oifshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore . Total Producing Number Producing <200m >200m Producing Exploratory __ 5 0 2 O 0 7 0 Development _ O 0 O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 37; Offshore, 0; Total, 37. Offshore concessions licensed as of 12/31/72: Ten concessions; 1 wholly beyond 200—m depth, parts of other 9 locally beyond 200-m depth. Concessions licensed to one company (four leases) and two consortia. Offshore exploration expenditures in 1972: coggiaaiiies conijpsnies octgldi-pcaoliilfiircigs Government Amount _____________ 0 N egl $3.6 million $4 million Percent _____________ 0 >1 9O 9 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 13.1 1.7 0.3 0 O 0 Exports _______ O 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 97 MOZAMBIQUE Category: Open shalf. Margin: Area to 3,000—m depth, 77,900 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 1,352 nautical miles. miles, 163,900 sq nautical miles. Shelf area to 200-m depth: 30,400 sq nau- Geology. Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 0 0 O 0 Cumulative production (through 1972) _____ 0 O 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oflshore Total Production in 1 972 _ _ _ 0 0 0 O O 0 Cumulative production (through 1972) _____ O O 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory -_ O 0 1 0 O 1 0 Development __ 0 0 0 0 0 O O Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession, within 200-m depth, leased to one company. Offshore exploration expenditures in 1972: coxIngcaaiiies contiiiSilies (Egg-pggfiirgfes Government Amount _____________ 0 $1.1 million 1 $2.2 million 1 0 Percent ______________ O 33 67 O 1 Consortium drilled one well and relinquished lease before year’s end. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 5.7 0.8 1.2 0 0 0 Exports _______ O 0 2.9 O O 0 98 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES NAURU Category: Archipelago. Margin: Area to 3,000—m depth, 200 sq Bordering water body: Pacific Ocean. nautical miles. Area to 200 nautical Coastal length: 10 nautical miles. miles, 125,700 sq nautical miles. Shelf area to 200-m depth: 100( ?) sq nau- Geology: Coastal onshore, sedimentary. tical miles. Oflshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 0 0 O 0 0 0 Cumulative production (through 1972) ___- 0 O 0 0 O 0 roved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O O O O O 0 Cumulative production (through 1972) ___- O 0 0 0 O O Proved recoverable reserves (12/31/72) _ O O 0 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Olfshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ O 0 O 0 0 O 0 Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of , . companies companies other countries (’0‘ ernment Amount _____________ O 0 0 0 Percent _____________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports """" } No information. Exports __ ______ SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES Category: Landlocked. Bordering water body: None. Coastal length: None. 99‘ NEPAL Shelf area to 200—m depth: None. Margin: None. Geology : Sedimentary /crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O ___ 0 0 ___ 0 Cumulative production (through 1972) ____ 0 ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 __- 0 0 ___ O Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Tgtal Onshore Offshore Total Production in 1972 ___ O ___ 0 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 O ___ O Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V ___ V V ___ V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <20() m >200 111 Producing Exploratory __ 0 0 ___ ___ ___ 0 0 Development _ 0 O _ _ _ _ _ _ _ _ _ 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofishore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 197 2 : L 1 us. 0 ‘ f comgcaanies companies otggi'pcaoliireiircies Government fiéflfié‘rtt :::::::::::::} Not applicable Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42—gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 NA NA Exports _______ 0 O O 0 NA NA 100 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES NETHERLANDS Category: Shelf locked. Margin: Area to 3,000-m depth, 24,700 sq Bordering water body: North Sea. nautical miles. Area to 200 nautical Coastal length: 198 nautical miles. miles, 24,700 sq nautical miles. Shelf area to 200-m depth: 24,700 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oflfshore Total Production in 197 2 ___ 10.9 0 10.9 1.6 O 1.6 Cumulative production (1933—72) ......... 271 0 271 39 0 39 Proved recoverable reserves (12/31/72) _ 269 0 269 39 O 39 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 2,043 N egl 2,043 57.9 Negl 57 .9 Cumulative production (1955—72) _________ 6,889 Negl 6,889 195 Negl 195 Proved recoverable reserves (12/31/72) _ 88,000 NA 88,000 2,493 NA 2,493 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV III II III II Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 12 3 11 0 5 23 8 Development _ 61 6O 7 0 5 68 65 Producing wells as of 12/31/72: Onshore, NA; Ofl'shore, 0; Total, NA. Offshore concessions licensed as of 12/31/72: Eleven areas assigned to companies ”or groups, for drilling or as con- cessions. All Within 200-m depth; only 2 areas do not include onshore areas. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ NA NA NA 0 Percent _____________ NA NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports ....... 668.7 91.6 63.4 0 O 0 Exports _______ 86.4 11.8 27 5.4 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 101 NEW ZEALAND Category: Open shelf. Margin: Area to 3,000-m depth, 571,100 sq Bordering water body: Pacific Ocean. nautical miles. Area to 200 nautical Coastal length: 2,770 nautical miles. miles, 1,409,500 sq nautical miles. Shelf area to 200-m depth: 70,800 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil 1 Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 1.1 O 1.1 0.1 0 0.1 Cumulative production (1933—72) _________ 5.5 O 5.5 .3 O .3 Proved recoverable reserves (12/31/72) _ NA NA 250 NA NA 31.3 1 Condensate. Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 14.6 0 14.6 0.4 0 0.4 Cumulative production (1955—72) _________ >29 1 0 >29 >.s 1 0 .8 Proved recoverable reserves (12/31/72) _ NA NA >6,000 NA NA >6,000 1 s1. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V IV III III Number of wells completed in 1972: Onshore Oflshore Total Producing Number Producing <200m >200m Producing Exploratory __ 11 O 0 0 0 11 0 Development _ O 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 4; Offshore, 0; Total, 4. Offshore concessions licensed as of 12/31/72: Part of 211 concessions leased in territorial seas. Twenty-nine conces- sion leased on continental shelf; 7 extend into waters deeper than 200-m, and locally as deep as 1,000-m. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 25.9 3.2 2.5 0 O 0 Exports _______ 0 0 2.6 0 NA NA 102 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES NICARAGUA Category: Open shelf. Margin: Area to 3,000-m depth, 37,400 sq Bordering water bodies: Caribbean Sea, nautical miles. Area to 200 nautical Pacific Ocean. miles, 46,600 sq nautical miles. Coastal length: 445 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 21,200 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 O 0 0 0 O Proved recoverable reserves (12/31/72) _ O 0 O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___- 0 0 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 O Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore , Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 O 0 0 0 0 Development __ 0 0 0 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Caribbean Sea: Eleven concessions leased by four companies. Parts of two concessions extend beyond 200-m depth. Pacific Ocean: Ten concessions leased by one company. Parts of four con— cessions extend beyond 200—m depth. Offshore exploration expenditures in 1972: corIriopgéiilies coriiiisnies ogfigipcibliildfrgs Government Amount _____________ 0 NA 0 0 Percent ______________ 0 100 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 3.6 0.5 5.4 0 0 0 Exports _______ O O O .7 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 103 NIGER Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 _ _ _ O 0 _ _ _ 0 Cumulative production (through 1972) _____ 0 ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ O 0 ___ 0 Cumulative production (through 1972) _____ 0 ___ O O ___ O Proved recoverable reserves (12/31/72) _ 0 ___ O 0 ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Oflshore Total Category ____________ IV _-_ IV IV ___ IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ ___ 0 0 Development __ 0 0 ___ ___ ___ O O Producing wells as of 12/31/72: Onshore, O; Ofi’shore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ . \ Percent ______________ } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : 0f metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 0 0 Exports _______ 0 0 0 0 0 0 104 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES NIGERIA Category: Open shelf. Margin: Area to 3,000-m depth, 37,700 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 415 nautical miles. miles, 61,500 sq nautical miles. Shelf area to ZOO—m depth: 13,500 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 482.5 182.7 665.3 65.1 24.7 89.8 Cumulative production (through 1972) ___- 1,798 563.8 2,362 243 76 31878 Proved recoverable reserves (12/31/72) _ 9,200 3,400 12,600 1,243 459 1,702 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 438.7 165.9 604.6 12.4 4.7 17.1 Cumulative production (through 1972) ___- 1 1,338 1 566 1,907 1 38 1 16 54 Proved recoverable reserves (12/31/72) _ 1 30,000 1 10,000 40,000 1 840 1280 1,120 1Estimated. Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III III III III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing (200m >200m Producing Exploratory __ 40 19 21 0 7 61 26 Development _ 167 NA 30 0 NA 197 170 Producing wells as of 12/31/72: Onshore, 425; Offshore, 185; Total, 610. Offshore concessions licensed as of 12/31/72: Total of 32 concessions; none beyond 200-m depth. Eleven partly onshore. Six licensed by four companies and five li- censed by one consortium. Twenty-one completely offshore. Fourteen licensed by seven different companies and seven licensed by two consortia. Offshore exploration expenditures in 1972: cozlnggeiiies conflisnies 0312312111663; Government Amount _____________ 0 NA NA 0 Percent _____________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ O 0 0.8 O 0 0 Exports _______ 648.3 87.5 0.9 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 105 NORWAY Category: Open shelf. Margin: Area to 3,000-m depth, 463,700 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 1,650 nautical miles. miles, 590,500 sq nautical miles. Shelf area to 200—m depth; 30,000 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, crystalline/sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 0 12.1 12.1 0 1.6 1.6 Cumulative production (197 1—7 2) _________ O 14 14 0 1.9 1.9 Proved recoverable reserves (12/31/72) _ 0 7,000 7,000 0 960 960 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofi'shore Total Onshore Offshore Total Production in 1972 ___ 0 18,659 18,659 0 528,6 528.6 Cumulative production (In 1972) _________ 0 18,659 18,659 0 528.6 528.6 Proved recoverable ’ reserves (12/31/72) _ 0 50,000 50,000 0 1,420 1,420 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 III III 0 III III Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 14 0 6 l4 6 Development _ 0 0 2 0 2 2 2 Producing wells as of 12/ 31/72: Onshore, 0; Offshore, 4; Total, 4. Offshore concessions licensed as of 12/31/72: Thirty-five concessions licensed; none beyond 200—m depth. Offshore exploration expenditures in 1972: cogggfiiies coniiisnies ogfigi'pcsifiigfriés Government Amount _____________ (I) (1) (.) NA Percent _____________ NA NA NA NA lEstimated $38.7 million total; no breakdown available. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal = of metric of 42-gal + of metric of cubic = of cubE bbl tons bbl tons feet meters Imports _______ 48.5 6.5 0 4.3 0 0 Exports _______ 11.9 1.6 0 2.2 o 0 106 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES OMAN Category: Open shelf. Margin: Area to 3,000— depth, 44,500 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 1,005 nautical miles. miles, 163,800 sq nautical miles. Shelf area to 200-m depth: 17,800 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 102.8 0 102.8 14.1 0 14.1 Cunmlatlve production (1967—7 2) _________ 560 0 560 76 0 76 Proved recoverable reserves (12/31/72) _ NA NA 5,000 NA NA 684.9 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 54.7 0 54.7 1.5 0 1.5 Cumulative production ( 1967—7 2) _________ 397.5 0 397.5 12.7 0 12.7 Proved recoverable reserves (12/31/72) _ NA NA 1,895 NA NA 53.7 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ III IV III III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 9 5 0 O O 9 5 Development _ 35 35 0 O « 0 35 35 Producing wells as of 12/31/72: Onshore, 109; Offshore, 0; Total, 109. Offshore concessions licensed as of 12/31/72: One concession extending beyond 200—m isobath, leased to one consortium. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA 0 NA 0 Percent ______________ NA , 0 NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports ______ ._ 0 0 1 3 0 O 0 Exports _______ 102.3 14 0 O 0 0 1 Esttmated. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES PAKISTAN Category: Open shelf. Bordering water body: Indian Ocean. Coastal length: 440 nautical miles. Shelf area to 200—m depth: 17,000 sq nau- tical miles. Margin: Area to 3,000—m depth, 61,400 sq nautical miles. Area to 200 nautical miles, 92,900 sq nautical miles. Geology: Coastal onshore, sedimentary. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 _ _ _ 3.4 0 3.4 0.5 0 0.5 Cumulative production (1947—72) _________ 76 0 76 11 0 11 Proved recoverable reserves (12/31/72) _ 35 0 35 5 0 5 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 124.5 0 124.5 3.5 O 3.5 Cumulative production (1955—72) _________ 1,246 0 1,246 36 0 36 Proved recoverable reserves (12/31/72) _ 19,500 0 19,500 550 O 550 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III IV III III IV III Number of wells completed in 1972: Onshore Offshore Total Producing 107 Number Producing <200m >200m Producing Exploratory __ 5 2 1 0 0 6 2 Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: Onshore, 23; Offshore, 0; Total, 23. Offshore concessions licensed as of 12/31/72: One concession licensed to consortium of two companies. Offshore exploration expenditures in 197 2: Local U.S. Companies of companies companies other countries Government Amount _____________ NA $2 million $2 million NA Percent _____________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 25.6 3.5 4.7 0 0 0 Exports _______ O O 4.2 0 0 0 108 SUMMARY, 1972 OIL AND GAS STATISTICS, ON S HORE AND OFFSHORE AREAS, 151 COUNTRIES PANAMA Category: Open shelf. Margin: Area to 3,000—m depth, 40,300 sq. Bordering water bodies: Pacific Ocean, nautical miles. Area to 200 nautical Caribbean Sea. miles, 89,400 sq nautical miles. Coastal length: 979 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200-m depth: 16,700 sq nau- crystalline. Olfshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ____ 0 O O 0 0 0 Cumulative production (through 197 2‘) ____ 0 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Olfshore Total Production in 1972 ____ O O 0 0 0 0 Cumulative production (through 1972) ____ O 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O O 0 O O 0 0 Development __ O 0 O 0 0 O 0 Producing wells as of 12/31/72: Onshore, O; Oflshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Caribbean Sea: No concessions licensed. Pacific Ocean: Eight areas, part of two beyond 200-m depth, leased to three companies or groups. Ofl'shore exploration expenditures in 1972: Local US. 30mpanies of , companies companies other countries Gm ernment Amount _____________ NA NA NA NA Percent ______________ NA NA NA N A Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 28.3 3.9 0.3 0 0 0 Exports _______ O 0 4 0 0 O SUMMARY, 1972 OIL AND GAS STATISTICS, ONS HORE AND OFFSHORE AREAS, 151 COUNTRIES 109 PARAGUAY Category: Landlocked. Shelf area to 200-m depth: None. Bordering Water body: None. Margin: None. . Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ____ 0 O ____ 0 Cumulative production (through 1972) ____ O -___ O O ____ O Proved recoverable reserves (12/31/72) _ 0 _-__ 0 O _-__ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 0 ____ 0 0 ____ 0 Cumulative production (through 1972) ____ 0 ____ 0 O ___- 0 Proved recoverable reserves (12/31/72) _ 0 ___- 0 0 ___- 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ IV ___ IV 1V _ __ IV Number of wells completed in 1972: Onshore Offshore ‘ Total Producing Number Producing <200m >200 m Producing Exploratory __ 5 0 -_ __ __ 5 0 Development __ 0 O __ __ __ O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Ofishore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Lo 1 Us C ' f compgiies companies otfigi'pgriidfries Government f$EE§§_::::::::::} Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal : of metric of 42-gal + of metric of cubic : V of cubic bbl tons bbl tons feet meters Imports _______ 1 0.1 0 Negl 0 0 Exports _______ O 0 0 0 0 0 110 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES PERU Category: Open shelf. Margin: Area to 3,000—m depth, 48,900 sq Bordering water body: Pacific Ocean. nautical miles. Area to 200 nautical Coastal length: 1,258 nautical miles. miles, 229,400 sq nautical miles. Shelf area to 200—m depth: 24,100 sq nau- Geology: Coastal onshore, crystalline/ tical miles. sedimentary. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 13.5 10.1 23.6 1.8 1.3 3.1 Cumulative production (through 1972) ___- 808.5 59.1 867.6 107.8 7.3 115.1 Proved recoverable reserves (12/31/72) _ NA NA 500 NA NA 66.6 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore Total Onshore Offshore Total Production in 1972 ___ 41.2 23.2 64.4 1.2 0.7 1.9 Cumulative production (through 1972) ___- 1,585. 116. 1,701. 44.2 3.7 47.9 Proved recoverable reserves (12/31/72) _ NA NA 500 NA NA 67 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III IV III III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 22 12 3 0 2 25 14 Development _ 67 55 25 O 22 92 77 Producing wells as of 12/31/72: Onshore, 2,139; Offshore, 237; Total, 2,376. Offshore concessions licensed as of 12/31/72: One concession licensed. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 $185 million 0 0 Percent _____________ 0 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 11.9 1.6 2.5 0 0 0 Exports _______ 1 .1 .9 O 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 111 PHILIPPINES Margin: Area to 3,000-m depth, 65,000 (est) sq nautical miles. Area to 200 nau- tical miles, 551,400 sq nautical miles. Geology: Coastal onshore, crystalline/sedi- mentary. Offshore, sedimentary. Category: Archipelago. Bordering water bodies: Pacific Ocean, South China Sea. Coastal length: 6,997 nautical miles. Shelf area to 200-m depth: 52,000 sq nau- tical miles. 011 Millions of barrels Millions of metric tons Onshore Oflshore Total Onshore Offshore Total Production in 1972 ___ O O 0 0 0 0 Cumulative production (through 1972) _____ 0 0 0 O 0 O Proved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 0 0 Cumulative production (through 1972) _____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV III IV III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 9 0 0 0 0 9 0 Development __ 0 0 0 0 0 0 O Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: More than 1,000 concessions licensed by 50 companies or consortia. Offshore exploration expenditures in 1972: Local ES. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 67.6 9.2 1.2 0 NA NA Exports _______ O 0 3.5 0 NA NA 112 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES POLAND Category: Shelf locked. Margin: Area to 3,000-m depth, 8,300 sq Bordering water body: Baltic Sea. nautical miles. Area to 200 nautical Coastal length: 241 nautical miles. miles, 8,300 sq nautical miles. Shelf area to 200-m depth: 8,300 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 2,6 0 2.6 .3 0 .3 Cumulative production (1874—1972) _______ 324.6 0 324.6 43 0 43 Proved recoverable reserves (12/31/72) _ 60 0 60 8 O 8 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 200 0 200 5.7 0 5.7 Cumulative production (1874—1972) _______ 1 1,773 0 1 1,773 1 51 0 1 51 Proved recoverable reserves (12/31/72) _ 5,000 0 5,000 140 0 140 lEstimated. Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Oifshore Total Onshore Ofishore Total Category ____________ IV V IV IV V IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200 m >200m Producing Exploratory __ NA NA ___‘ ___ ___ NA NA Development _ NA NA ___ -__ __- NA NA Producing wells as of 12/31/72: Onshore, O; Offshore, ___; Total, 0. Ofl'shore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount } N ’ ------------- ‘ot a licable. Percent _____________ pp Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Mil-lions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 0 0 Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 113 PORTUGAL Category: Open shelf. Margin: Area to 3,000—m depth, 44,800 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 743 nautical miles. miles, 517,400 sq nautical miles. Shelf area to 200m depth: 11,400 sq nau- Geology: Coastal onshore, sedimentary/ tical miles. crystalline. Oifshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O O 0 0 0 0 Cumulative production (through 1972) _____ 0 O O 0 O O Proved recoverable reserves (12/31/72) _ 0 O 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 0 0 0 0 Cumulative production (through 1972) _____ 0 O 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development __ 0 0 0 O 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/ 31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of G 0 rn t companies companies other countries ve men Amount _____________ 0 0 0 0 Percent ______________ O 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 32.2 4.3 7.6 O 0 0 Exports _______ 0 0 3.7 0 0 0 114 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES PORTUGUESE GUINEA Category: Open shelf. Margin: Area to 3,000-n1 depth, 30,800 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 215 nautical miles. miles, 43,900 sq nautical miles. Shelf area to 200-m depth: 13,500 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 O 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 O O 0 0 Development _ 0 0 O 0 0 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession within 200 meters. Offshore exploration expenditures in 1972: Local U.S. Companies of Y companies companies other countries Gm ernnlent Amount _____________ 0 NA 0 0 Percent _____________ O 100 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA NA 0 0 Exports _______ 0 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 115 QATAR Category: Shelf locked. Margin: Area to 3,000—m depth, 7,000 sq Bordering water body: Persian Gulf. nautical miles. Area to 200 nautical Coastal length: 204 nautical miles. miles, 7,000 sq nautical miles. Shelf area to 200—m depth: 7,000 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 88.8 87.7 176.5 11.5 11.4 22.9 Cumulative production (1949—72) _________ 782 288 1,070 172 57 229 Proved recoverable reserves (12/31/72) _ NA NA 1,700 NA NA 909 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 44.3 44.4 88.7 1.2 1.3 2.5 Cumulative production (1949—7 2) _________ 737 244 982 21 6 28 Proved recoverable reserves (12/31/72) _ NA NA 8,000 NA NA 266.6 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III III III III III Number of wells completed in 1972: Onshore Offshore . Total Producing Number Producing <200m >200m Producing Exploratory _ _ 0 0 5 - _ _ 2 5 2 Development _ 4 NA 0 _ _ - 0 4 NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Two concessions licensed in water depth less than 200-m. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA 0 NA 0 Percent ______________ NA 0 NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0.8 0 NA NA Exports _______ 175.8 22.8 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ROMANIA Category: Open shelf. Margin: Area to 3,000-m depth, 9,300 sq Bordering water body: Black Sea. nautical miles. Area to 200 nautical Coastal length: 113 nautical miles. miles, 9,300 sq nautical miles. Shelf area to 200-m depth: 7,100 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Olfshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 105 0 105 14.2 0 14.2 Cumulative production (1857—1972) _______ 3,037 0 3,037 407 0 407 Proved recoverable reserves (12/31/72) _ NA NA 1,480 NA NA 41.9 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1,169 0 1,169 33.1 0 33.1 Cumulative production (1857—1972) _______ 8,553 0 8,553 240 0 240 Proved recoverable reserves (12/31/72) _ NA NA 10,000 NA NA 283.3 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Oflshore Total Category ____________ IV IV IV III IV III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory _ _ NA NA NA NA NA NA NA Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: Local US. Companies of . companies companies other countries Government Amount _____________ 0 0 0 NA Percent ______________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 21.9 2.9 NA 0 NA NA Exports _______ 0 0 NA 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 117 RWANDA Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology. Crystalline. Oil Millions of barrels Millions of metric tons Onshore Olfshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 ___ 0 __- 0 O ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 O ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ O __ _ 0 O -_ _ 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 ___ O 0 0 Development _ 0 0 0 _-_ 0 O 0 Producing wells as of 12/31/72: Onshore, O; Offshore, __-; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of Government companies companies other countries Amount _____________ . Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 O Negl 0 0 Exports _______ O 0 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SAN MARINO Category: Landlocked. Shelf area to 200—m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) _____ 0 ___ O 0 ___ O Proved recoverable reserves (12/31/72) _ O ___ O 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 ___ 0 O _ -_ 0 Cumulative production (through 1972) _____ 0 ___ O O ___ O Proved recoverable reserves (12/31/72) _ 0 ___ 0 O ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 _ _ _ O O _ _ _ 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory _ _ O 0 _ _ _ ___ _ - _ 0 0 Development _- 0 0 _ __ _ __ ___ 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ . Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 N A NA Exports _______ 0 0 O 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHOR; l) OFFSHORE AREAS, 151 COUNTRIES 119 SAUDI ARABIA [Includes one-half Kuwait-Saudi Arabia Neutral Zone] Category: Open shelf. Margin: Area to 3,000-m depth, 54,600 sq Bordering water bodies: Red Sea, Persian nautical miles. Area to 200 nautical Gulf. miles, 54,900 sq nautical miles. Coastal length: 1,336 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 22,700 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1,595 757 2,352 216 103 319 Cumulative production (1936—72) _________ 13,292 3,985 17,277 1,810 543 2,353 Proved recoverable reserves (12/31/72) _ 83,905 57,338 141,248 11,500 7,879 19,373 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 416 727 1,143 11.7 20.6 32.3 Cumulative production (1936—72) _________ 9,189 3,148 12,337 260 90 349 Proved recoverable reserves (12/31/72) _ NA NA 54,400 NA NA 1,541 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ II II II II II II Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA ___ NA NA NA Development _ NA NA NA ___ NA NA NA Producing wells as of 12/31/72: Onshore, 395; Offshore, 203; Total, 598. Offshore concessions licensed as of 12/31/72: Persian Gulf: Three concessions leased to two consortia. Red Sea: Four concessions leased to two companies. N o concession beyond 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 O O Negl 0 0 Exports _______ 1 1,904.6 1 260.9 2 125.9 0 NA NA 1Saudi Arabia only; does not include any of 193.9 million bbls (28.4 metric tons) exported from Neutral Zone. 2Saudi Arabia only; does not include any of 19.3 million bbls exported from Neutral Zone. 120 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSH RE AND OFFSHORE AREAS, 151 COUNTRIES SENEGAL Category: Open shelf. Margin: Area to 3,000-m depth, 23,700 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 241 nautical miles. miles, 60,000 sq nautical miles. Shelf area to 200-m depth: 9,200 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ 0 0 0 O O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O O 0 0 0 Cumulative production (through 1972) __-_ 0 O 0 0 O O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore OiTshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 1 O O 1 0 Development _ 0 0 0 O 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Three concessions, two completely offshore, leased to one company and one group. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 4.4 0.6 0 N egl Negl Negl Exports _______ 0 O 0 .2 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SIERRA LEONE Category: Open shelf. Bordering water body: Atlantic Ocean. Coastal length: 219 nautical miles. Shelf area to 200-m depth: 7,700 sq nau- tical miles. Margin: Area to 3,000-m depth, 14,700 sq Area to 200 nautical nautical miles. miles, 45,400 sq nautical miles. Geology: Coastal onshore, crystalline/sedi- mentary. Offshore, sedimentary. 121 Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ____ O 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 O O 0 0 Cumulative production (through 1972) _-__ 0 0 O O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 0 0 0 0 Development _ 0 0 0 O 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Three concessions; one extends beyond 200-m depth. Leased to three companies or groups. Offshore exploration expenditures in 1972: Local US Companies of , companies companies other countries Gm ernment Amount _____________ 0 NA NA 0 Percent _____________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 2.1 0.3 0.2 0 NA NA Exports _______ 0 0 O 0 NA NA 122 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SINGAPORE Category: Shelf locked. Margin: Area to 3,000~m depth, 100 sq Bordering water body: South China Sea. nautical miles. Area to 200 nautical Coastal length: 28 nautical miles. miles, 100 sq nautical miles. Shelf area to 200-m depth: 100 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofl’shore Total Production in 197 2 ___ O 0 0 0 0 0 Cumulative production (through 1972) ___- O O O 0 O 0 Proved recoverable reserves (12/31/72) _ 0 O O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 197 2 _l_ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 V V 0 V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory -_ 0 0 O ___ 0 0 0 Development _ 0 0 0 __- 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 197 2: Local US. Companies of companies companies other countries Government Amount _____________ O 0 0 0 Percent _____________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 144.7 19.8 50.2 0 O 0 Exports _______ .4 Negl 122.1 0 0 0 SUMMARY. 1972 OIL AND GAS STATISTICS. ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 123 SOMALIA Category: Open shelf. Margin: Area to 3,000-m depth, 106,200 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 1,596 nautical miles. miles, 228,300 sq nautical miles. Shelf area to 200-m depth: 17,700 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Ofishore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ O 0 O O 0 0 Cumulative production (through 1972) ___- O O 0 O 0 0 Proved recoverable reserves (12/31/72) _ O 0 O 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Tgtal Onshore Offshore Total Production in 1972 ___ 0 0 0 O O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O O O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV V V V Number of wells completed in 197 2: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory _- 1 O O 0 0 1 0 Development _ O 0 0 0 O 0 O Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: One concession leased. Offshore exploration expenditures in 197 2: Local US. Companies of companies companies other countries Government Amount _____________ O 0 NA 0 Percent _____________ 0 O 100 O Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0.5 0 NA NA Exports _______ 0 O O O 0 0 124 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SOUTH AFRICA Category: Open shelf. Margin: Area to 3,000-m depth, 183,700 sq Bordering water bodies: Indian Ocean, nautical miles. Area to 200 nautical Atlantic Ocean. miles, 296,500 sq nautical miles. Coastal length: 1,462 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to ZOO-m depth: 41,800 sq nau- crystalline. Olfshore, crystalline/sedi- tical miles. mentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ O 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 O 0 O 0 Proved recoverable reserves (12/31/72) _ NA NA NA NA NA NA Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 O 0 Cumulative production (through 1972) _-__ 0 0 0 0 0 0 Proved recoverable reserves ( 12/ 31/ 72) _ NA NA NA NA NA NA Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI V V III IV III Number of wells completed in 1972: Onshore Oflshore Total Producing Number Producing <200m >200m Producing Exploratory __ 9 0 1 0 O 10 0 Development _ O 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Ofi'shore concessions licensed as of 12/31/72: State oil company holds prospecting rights for all ofl'shore areas. Ten areas leased to seven companies or groups. ‘Some blocks beyond 200-m isobath are subleased. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 90.8 12.4 30.4 0 NA NA Exports _______ 0 O 24.6 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 125 SOUTHWEST AFRICA (NAMIBA) Category: Open shelf. nautical miles. Area to 200 nautical Bordering water body: Atlantic Ocean. miles, 145,900 sq nautical miles. Coastal length: 748 nautical miles. Geology: Coastal onshore, crystalline/sedi- Shelf area to ZOO-m depth: 19,000 sq nau- mentary. Offshore, sedimentary/crystal- tical miles. line. Margin: Area to 3,000-m depth, 72,700 sq Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ O 0 O 0 0 0 Cumulative production (through 1972) _____ 0 O 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) _____ 0 0 o o 0 0 Proved recoverable reserves (12/31/72) _ O 0 O 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Ofishore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 O 0 0 0 Development __ O O O O 0 0 0 Producing wells as of 12/31/72: Onshore, O; Offshore, 0; Total, 0. Ofishore concessions licensed as of 12/31/72: Thirteen concessions licensed to three companies and two consortia. One concession both less than and greater than 200-m deep. Six concessions greater than 200—m deep and as deep as 3,000-m. Offshore exploration expenditures in 1972: Local US. Companies of G rn nt companies companies other countries ove me Amount _____________ NA NA NA 0 Percent ______________ NA NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42~ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 NA 0 NA NA Exports _______ 0 0 O 0 O O 126 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SPAIN Category: Open shelf. Margin: Area to 3,000—m depth, 158,200 sq Bordering water bodies: Atlantic Acean, nautical miles. Area to 200 nautical Mediterranean Sea. miles, 355,600 sq nautical miles. Coastal length: 2,038 nautical miles. Geology: Coastal onshore, sedimentary/ Shelf area to 200—m depth: 49,700 sq nau- crystalline. Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore1 Offshore Total Onshore Offshorel Total Production in 1972 ___ 1 0 1 0.1 0 0.1 Cumulative production (1966—72) _________ 7 0 7 1 0 1 Proved recoverable reserves (12/31/72) _ 300 NA >300 41.7 NA >41.7 1 SI. Natural gas Billions of cubic feet Billions of cubic meters Onshore Oifshore 1 Total Onshore Offshore 1 Total Production in 1972 ___ 0.1 0 0.1 Negl 0 Negl Cumulative production ( 1969—72) _________ .4 0 .4 Negl O Negl Proved recoverable reserves (12/31/72) _ NA NA 500 NA NA 15 1 SI. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV V IV Number of wells completed in 1972: Onshore Ofl’shore Total Producing Number Producing <200m >200m Producing Exploratory __ 4 0 3 0 0 7 0 Development _ 3 3 3 0 3 6 6 Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Ei ht concessions within 200-m isobath. ix completely offshore leased by two companies and four consortia. Two offshore and onshore licensed by two companies. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA 0 Percent ______________ NA NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 271.6 37.2 17.4 0 52.2 1.5 Exports _______ 0 O 37 .2 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 127 SRI LANKA Category: Open shelf. Margin: Area to 3,000-m depth, 26,9001sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 650 nautical miles. miles, 150,900 sq nautical miles. Shelf area to 200-m depth: 7,800 sq nau- Geology. Coastal onshore, crystalline/sedi- tical miles. mentary. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 O 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ O V V 0 V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 O 0 0 0 0 Development _ 0 0 0 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofl'shore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of . companies companies other countries Gm ernment Amount _____________ 0 0 0 NA Percent _____________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 13.5 1.9 0.4 0 NA NA Exports _______ 0 0 1.7 0 NA NA 128 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SUDAN Category: Open shelf. Margin: Area to 3,000-m depth, 26,500 sq Bordering water body: Red Sea. nautical miles. Area to 200 nautical Coastal length: 386 nautical miles. miles, 26,700 sq nautical miles. Shelf area to 200- depth: 6,500 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Olfshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in .1972 ___ 0 0 0 O 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 O O 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Olfshore Total Onshore Offshore Total Category _____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 o 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of , companies companies other countries Gox ernment Amount _____________ 0 0 0 0 Percent _____________ 0 0 O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 7.9 1 0 5.6 0 0 Exports _______ 0 0 O 1.3 0 0 SUMMARY, 1972 OIL AN D GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 129 SWAZILAND Category: Landlocked. Bordering water body: None. Coastal length: None. Shelf area to 200—m depth: None. Margin: None. ‘ Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 197 2 ___ 0 -__ 0 O ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 O ___ O Proved recoverable reserves (12/31/72) _ 0 ___ 0 O ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ O _ _ _ O O _ _ _ 0 Cumulative production (through 1972) ___- 0 -__ 0 O ___ O Proved recoverable reserves (12/31/72) _ 0 _-_ 0 0 ___ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI _ _ _ VI VI _ _ _ VI Number of wells completed in 1972 : Onshore Offshore Total Producing Number Producing <200 111 >200 111 Producing Exploratory __ 0 0 ___ ___ ___ O 0 Development _ O 0 ___ ___ ___ 0 0 Producing wells as of 12/ 31/ 7 2 : Onshore, 0; Offshore, ___ ; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 197 2 : Lo al US. 0 r ‘e f compglnies companies othreii‘pgolhlnirges Government $$2§§€ :::::::::::::} Not applicable- Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 NA 0 0 0 Exports _______ 0 0 NA 0 0 0 130 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SWEDEN Category: Shelf locked. Margin: Area to 3,000—m depth. 45,300 sq Bordering water body: Baltic Sea. nautical miles. Area to 200 nautical Coastal lenght: 1,359 nautical miles. miles, 45,300 sq nautical miles. Shelf area to 200-m depth: 45,300 sq nau- Geology: Coastal onshore, crystalline. Off- tical miles. shore, crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 O 0 0 Cumulative production (through 1972) ___- 0 0 0 O O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oifshorc Total Production in 1972 _ _ _ 0 O 0 0 O 0 Cumulative production (through 1972) ___- 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 O 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI V V VI V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200 m >200m Producing Exploratory __ 20 0 0 O 0 20 0 Development _ 0 0 0 0 O 0 0 Producing wells as of 12/31/72: Onshore, 0; Ofl'shore, 0; Total, 0. Ofl'shore concessions licensed as of 12/31/72: Exclusive concession granted in 1967 for 8 years to joint venture (50 percent Swedish government and 50 percent private Swedish com- panics). Ofl'shore exploration expenditures in 1972: Local US Companies of , ‘ companies companies other countries Gm einment Amount- _____________ $242 thousand 0 0 $242 thousand Percent _____________ 50 0 0 50 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 81.8 11.2 0 18.9 0 0 Exports _______ O 0 O 1.8 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 131 SWITZERLAND Shelf area to 200-m depth: None. Margin: None. Geology: Sedimentary/crystalline. Category: Landlocked. Bordering water body : None. Coastal length: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total , Onshore Offshore Total Production in 1972 __- 0 ___ O 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oflshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ O 0 ___ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ O Proved recoverable reserves (12/31/72) _ 0 ___ O O ___ 0 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V ___ V V ___ V Number of wells completed in 1972 : Onshore. Offshore Total Producing Number Producing <200 m >200 m Producing Exploratory -_ 1 0 ___ ___ ___ 1 0 Development _ 0 O _ _ _ _ _ _ _ - _ O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of G or rnment companies companies other countries e Amount _____________ . Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 39.1 5.4 0 8.3 10.6 0.3 Exports _______ 0 0 0 0 Negl Negl 132 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES SYRIAN ARAB REPUBLIC Category: Landlocked. Shelf area to 200-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Sedimentary/crystalline. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 43.5 ___ 43.5 6.3 ___ 6.3 Cumulative production (through H?) _____ NA ___ NA NA ___ NA Proved recoverable reserves (12/31/72) _ 7,250 ___ 7,250 1,044 -__ 1,044 Natural gas Billions of cubic feet Bililons of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 197‘) _ _ _ NA _ _ _ NA NA _ __ NA Cumulative production (through H?) _____ NA ___ NA NA ___ NA Proved recoverable reserves (12/31/72) _ 700 ___ 700 19.8 -__ 19.8 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV - _ _ IV IV _ _ _ IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory "} No information. Development __ Producing wells as of 12/31/72: Onshore, 120; Offshore, -__; Total, 120. Offshore concessions licensed as of 12/31/72: Not applicable. Ofl'shore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ . Percent No applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 45.2 6.5 0.8 0 NA NA Exports _______ 29.1 4.2 .1 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 133 TANZANIA Category: Open shelf. Margin: Area to 3,000-m depth, 41,600 sq Bordering water body: Indian Ocean. nautical miles. Area to 200 nautical Coastal length: 669 nautical miles. miles, 65,100 sq nautical miles. Shelf area to 200-m depth: 12,000 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 O O O 0 0 Cumulative production (through 1972) ___- O 0 0 0 O 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O O 0 0 0 0 Cumulative production (through 1972) ___- 0 0 0 0 0 o Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 O 0 0 Development _ 0 0 0 0 0 O O Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofl'shore concessions licensed as of 12/31/72: None. Ofl'shore exploration expenditures in 1972: Local US Companies of companies companies other countries Government Amount _____________ 0 O 0 0 Percent ______________ 0 O O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—ga1 = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 6 0.9 5.1 0 0 0 Exports _______ 0 0 5.5 0 O 0 134 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES THAILAND Category: Open shelf. Margin: Area to 3,000-m depth, 94,700 sq Bordering water bodies: South China Sea, nautical miles. Area to 200 nautical Indian Ocean. miles, 94,700 sq nautical miles. Coastal length: 1,299 nautical miles. Geology: Coastal onshore, crystalline/sedi- Shelf area to 200-m depth: 75,100 sq nau- bentary. Offshore, sedimentary/crystal- tical miles. line. 011 Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ Negl 0 Negl Negl 0 Negl Cumulative production (1960—7 2) _________ 0.6 0 0.6 0.1 O 0.1 Proved recoverable reserves (12/31/72) _ .5 0 .5 .1 0 .1 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 O 0 Cumulative production ( 197 1—7 2 ) _________ Negl 0 Negl N egl 0 Negl Proved recoverable reserves (12/31/72) _ Negl 0 Neg] Negl 0 Negl Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: V Onshore Ofl’shore Total Producing Number Producing (200m >200m Producing Exploratory __ 2 O 3 0 0 5 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 25; Offshore, 0; Total, 25. Offshore concessions licensed as of 12/31/72: Total of 23 concessions; none beyond 200-m depth. Gulf of Siam: Nineteen concessions held by five groups and two com- panics. Andaman Sea: Four concessions held by three companies. Ofl'shore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 $11.8 million $2.3 million 0 Percent ______________ 0 83 17 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 1 49.6 1 6.8 5.5 0 0 0 Exports _______ 0 0 3.2 0 0 0 1 Estimated. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 135 TOGO Category: Open Shelf. Margin: Area to 3,000-m depth, 300 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 26 nautical miles. miles, 300 sq natuical miles. Shelf area to 200-m depth: 300 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 O 0 0 0 Cumulative. production (through 1972) ___- 0 O O O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oflshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ___- 0 0 O 0 O O Proved recoverable reserves (12/31/72) _ 0 0 O 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 2 0 0 2 0 Development _ 0 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: TWO concessions leased to one company and one group. One concession extends beyond 200-m depth. Offshore exploration expenditures in 1972: Local US. Companies of Y companies companies other countries Gm ernment Amount _____________ O 0 NA 0 Percent _____________ 0 O 100 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O O O 0.1 0 0 Exports _______ 0 0 0 0 0 0 136 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES TONGA Category: Archipelago. Margin: Area to 3,000-n1 depth, 12,000 (?) Bordering water body: Pacific Ocean. sq nautical miles. Area to 200 nautical Coastal length: Not available. miles, 173,800 sq nautical miles. Shelf area to 200—m depth: 4,200 (?) sq Geology: Coastal onshore, crystalline. Off- nautical miles. shore, crystalline/sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ____ O 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ O 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) ____ 0 0 0 0 0 O Proved recoverable reserves (12/31/72) _ O 0 0 O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 O O 0 0 Development _ 0 0 0 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 197 2: Local US. Companies of 7 companies companies other countries Gm ernment Amount _____________ 0 0 0 0 Percent _____________ O O O 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports """"" } No information. Exports _______ SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 137 TRINIDAD AND TOBAGO Category: Open shelf. Margin: Area to 3,000-m depth, 17,300 sq Bordering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 254 nautical miles. miles. 22,400 sq nautical miles. Shelf area to 200-m depth: 8,500 sq nauti- Geology: Coastal onshore. sedimentary. cal miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 41.5 9.7 51.2 6 1.3 7.3 Cumulative production (1908—72) __________ 1,054.5 290.7 1,345.2 151 41.3 192.3 Proved recoverable reserves (12/31/72) _ 275 1,300 1,575 39.4 1,862.2 225.6 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 69.9 34.4 104.3 2 0.9 2.9 Cumulative production (1960—72) __________ 1,011 504 1,515 29 14 43 Proved recoverable reserves (12/31/72) _ 900 4,000 4,900 25.8 113 138.8 Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 6 2 17 0 3 23 5 Development _ 133 125 40 0 35 173 60 Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, 2,932. Ofi'shore concessions licensed as of 12/31/72: Thirty-one concessions licensed to five companies and seven consortia. Parts of some concess1ons extend beyond 200 m. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet. meters Imports _______ 106.6 14.6 0.3 0 O 0 Exports _______ 14.4 1.9 127 O O O 138 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES TUNISIA Category: Open shelf. Margin: Area to 3,000—m depth, 25,000 sq Bordering water body: Mediterranean Sea. nautical miles. Area to 200 nautical Coastal length: 555 nautical miles. miles, 25,000 sq nautical miles. Shelf area to 200-m depth: 14,800 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Oifshore Total Onshore Offshorel Total Production in 1972 ___ 31.6 0 31.6 4.1 0 4.1 Cumulative production (1966—72) _________ 173 0 173 22 0 22 Proved recoverable reserves (12/31/72) _ NA NA 1,000 NA NA 130 1 Ofishore reserves established but production not started. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1 60 0 1 6O 1 1.7 O 1 1.7 Cumulative production (1949—72) _________ 61 0 61 1.7 0 1.7 Proved recoverable reserves (12/31/72) _ 1,505 NA >1,505 43 NA >43 ‘54.7 billion cubic feet (est.) flared. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Oifshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ 9 1 3 0 1 12 2 Development _ 5 5 1 O 0 6 5 Producing wells as of 12/31/72: Onshore, 49; Offshore, 0; Total, 49. Offshore concessions licensed as of 12/31/72: Twelve concessions licensed ’by nine companies or consortia. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent ______________ NA NA ' NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42—ga1 : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 7.0 0.9 3.0 0 O 0 Exports _______ 28.5 3.7 1.2 0 NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES TURKEY Margin: Area to 3,000-m depth, 69,000 sq nautical miles. Area to 200 nautical miles, 69,000 sq nautical miles. Category: Open shelf. Bordering water bodies: Mediterranean Sea, Black Sea. Coastal length: 1,921 nautical miles. Geology: Coastal onshoer, sedimentary/ Shelf area to 200-m depth: 14,700 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. talilne. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 24.2 0 24.2 3.4 O 3.4 Cumulative production (1948—7 2) _________ 198 O 198 27 O 27 Proved recoverable reserves (12/31/72) _ 550 0 550 77.5 0 77.5 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ NA 0 NA NA 0 NA Cumulative production (1948—72) _________ 1 >79 0 1 >79 1 >2 0 1 >2 Proved recoverable reserves (12/31/72) _ 170 0 170 5 0 5 lEstimated. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 25 4 O 0 0 25 4 Development _ 24 12 0 0 0 24 12 Producing wells as of 12/31/72: Onshore, 292; Offshore, 0; Total, 292. Offshore concessions licensed as of 12/31/72: Fifty offshore licenses in effect. Offshore exploration expenditures in 1972: Local US Companies of companies companies other countries Government Amount _____________ NA NA NA 0 Percent _____________ NA NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions of 42-gal : of metric Millions Millions of 42-ga1 + of metric Billions Billions of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 55 7.5 1.6 0 NA NA Exports _______ 0 O 6.9 0 NA NA 139 140 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES UGANDA Category: Landlocked. Shelf area to ZOO-m depth: None. Bordering water body: None. Margin: None. Coastal length: None. Geology: Crystalline. Oil Millions of barrels Millions of metric tons Onshore Ofishore Total Onshore Offshore Total Production in 1972 ___ O ___ 0 0 _ __ 0 Cumulative production (through 1972) ___- 0 ___ 0 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ O 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O ___ 0 O u- 0 Cumulative production (through 1972) ___- 0 ___ 0 O ___ O Proved recoverable reserves (12/31/72) _ O ___ O O ___ 0 Potential resources (ultimate recoverable resources); Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 s _ _ 0 0 _ __ 0 Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing (200m >200m Producing Exploratory __ 0 0 ___ ___ ___ O 0 Development _ O O ___ __ _ _ __ 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Ofl’shore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of V COmpanies companies other countries Gm ernment Amount _____________ Y _ Percent } l\ot applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ O 0 3.4 0 NA NA Exports _______ 0 O Negl 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 141 UNION OF SOVIET SOCIALIST REBUBLICS Category: Open shelf. tical miles. Bordering water bodies: Arctic Ocean, Pa- Margin: Area to 3,000-m depth, 735,900 sq cific Ocean, Baltic Sea, Black Sea, Sea nautical miles. Area to 200 nautical of Japan. miles, 1,309,500 sq nautical miles. Coastal length: 23,098 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 364,300 sq nau- Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 __- 2,895.9 0 2,895.9 394 0 394 Cumulative production (1863—1972) _______ 1 37,183 1 0 37,183 1 5,059 1 0 5,059 Proved recoverable reserves (12/31/72) _ 75,000 NA >75,000 10,273 NA >10,273 lPrevious oflshore production added to onshore production. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 __- 7 ,912 0 7,912 224 0 224 Cumulative production (1863—1972) _______ 1 69,886 1 0 69,886 1 1,979 1 0 1,97 9 Proved recoverable reserves (12/31/72) _ <706,000 NA 706,000 <20,000 NA 20,000 1Previous ofishore production added to onshore production. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Oifshore Total Category ____________ II II II II II I Number of wells completed in 1972: Onshore Oifshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA NA NA NA NA Development _ NA NA NA NA NA NA NA Producing wells as of 12/31/72: 'Onsh‘ore, 1 60,000; Offshore, NA; Total, 1 60,000. 1 Estimated. Offshore concessions licensed as of 12/31/72: No information. Oflshore exploration expenditures in 1972: Local US Companies of companies companies other countries Government Amount _____________ 0 0 0 NA Percent ______________ 0 0 0 100 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 56.9 7.8 0 1.3 NA NA Exports _______ 560 76.2 30.8 0 NA NA 142 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES UNITED ARAB EMIRATES Category: Shelf locked. Margin: Area to 3,000-m depth, 17,300 sq Bordering water body: Persian Gulf. nautical miles. Area to 200 nautical Coastal length: 420 nautical miles. miles, 17,300 sq nautical miles. Shelf area to ZOO—m depth: 17,300 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ ‘ 259.6 173.3 432.9 34.6 23.1 57.7 Cumulative production (1962—72) _________ 1 1,178 1 796 1,974 1 157 1 105 262 Proved recoverable reserves (12/31/72) _ NA NA 20,209 NA NA 2,695 l Estimated. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ NA NA NA NA NA NA Cumulative production (1962—72) _________ 1 >859 >446 >1,325 1 >25 >13 >38 Proved recoverable reserves (12/31/72) _ NA NA 11,800 NA NA 33.2 1Estimated. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ III III III III III III Number of wells completed in 1972: Onshore Ofishore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA NA NA 6 NA Development _ NA NA NA ___ NA 58 NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Offshore concessions licensed as of 12/31/72: Ten concessions leased to seven consortia and one company. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA NA Percent ______________ 0 NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 .9 0 NA NA Exports _______ 439 58.5 0 0 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 143 UNITED KINGDOM Category: Open shelf. Margin: Area to 3,000-m depth, 281,800 sq Bordering water bodies: Atlantic Ocean, nautical miles. Area to 200 nautical North Sea. miles, 274,800 sq nautical miles. Coastal length: 2,790 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 143,500 sq nau- Offshore, sedimentary. tical miles. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 0.6 0 0.6 Negl O Negl Cumulative production (1919—72) _________ 19 0 19 3 0 3 Proved recoverable reserves (12/31/72) _ NA 1 5,000 >5,000 NA 1 694 >694 1 Offshore production SI. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofiz'shore Total Production in 1972 ___ 3.6 919.8 923.4 0.1 26 26.1 Cumulative production (1954—72) _________ >9.6 >2,238 <2,248 >.3 >633 <63.6 Proved recoverable reserves (12/31/72) _ NA 45,000 >45,000 NA 1,275 >1,275 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ V III III V III III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 9 1 25 O 12 34 13 Development _ 0 0 46 0 38 46 38 Producing wells as of 12/31/72: Onshore, 59; Offshore, 140; Total, 199. Offshore concessions licensed as of 12/31/72: Two hundred thirteen production licenses, 3 wholly beyond 200—m depth, and parts of others partially beyond 200-m depth. Offshore exploration expenditures in 197 2: Local US. Companies of companies companies other countries Government Amount _____________ NA NA NA NA Percent _____________ NA NA NA NA Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal = of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 786.2 107.7 145.3 0 30.5 0.9 Exports _______ 25.9 3.6 116.9 0 0 0 144 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES UNITED STATES OF AMERICA Category: Open shelf. tical miles. Bordering water bodies: Pacific Ocean, Margin: Area to 3,000-In depth, 862,600 sq Gulf of Mexico, Atlantic Ocean, Arctic nautical miles. Area to 200 nautical Ocean. , miles, 2,222,000 sq nautical miles. Coastal length: 11,650 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 545,400 sq nau- Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 2,982.7 472.3 3,455 403.1 63.8 466.9 Cumulative production (1859—1971) _______ 1104,210 5,046 1 109,256 1 14,049 1 681 1 14,730 Proved recoverable reserves (12/31/72) _ 130,398 17,665 38,062 14,107 1 1,035, 5,143 1 Estimated. Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Olfshore Total Production in 1972 ___ 20,654 3,325 23,979 585 94.2 679.3 Cumulative production (1859—1971) _______ 1 415,342 1 23,931 1 439,273 1 11,761 1 678 1 12,439 Proved recoverable reserves (12/31/72) _ NA NA 266,085 NA NA 7,537.8 1 Estimated. Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ II II II I I I Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 7,279 1,271 260, 0 14 7,539 1,285 Development _ 19,047 14,502 705 0 447 19,752 14,949 Producing wells as of 12/31/72: Onshore, NA; Ofi'shore, NA; Total, 503,505. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: US. Companies of companies other countries Government Amount _____________ NA NA 0 Percent ______________ NA NA 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 811.1 111.1 924.2 0 1,019 28.9 Exports _______ .2 Negl 81.2 0 78.8 2.2 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 145 UPPER VOLTA Category: Landlocked. Margin: None. Bordering Water body: None. Geology: Crystalline/sedimentary. Coastal length: None. Coastal and offshore placers: None. Shelf area to 200—m depth: None. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 ___ O O ___ 0 Cumulative production (through 1972) ___- 0 ___ O 0 ___ 0 Proved recoverable reserves (12/31/72) _ 0 ___ O 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Oifshore Total Production in 1972 __ _ 0 _ __ 0 0 __ - 0 Cumulative production (through 1972) ___- 0 ___ O 0 -__ 0 Proved recoverable reserves (12/31/72) _ O __- 0 0 ___ O Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ O ___ 0 0 __- 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ _ _ _ 0 0 Development _ 0 O _ _ _ _ _ _ _ __ 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Offshore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other Countries Government Amount _____________ ' Percent } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal' : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 Negl 0 0 0 Exports _______ 0 O O O 0 0 146 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES URUGUAY Category: Open shelf. nautical miles. Area to 200 nautical Bordering water body: Atlantic Ocean. miles, 34,800 sq nautical miles. Coastal length: 305 nautical miles. Geology: Coastal onshore, sedinientary/ Shelf area to 200—m depth: 16,500 sq nau- crystalline. Offshore, sedimentary/crys- tical miles. stalline. Margin: Area to 3,000-m depth, 39,600 sq Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 O 0 0 0 0 Cumulative production (through 1972) _~__ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 0 0 O O 0 0 Cumulative production (through 1972) __-_ 0 O 0 O 0 O Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 O Potential resources (ultimate recoverable resources) : Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V V IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 O 0 0 Development _ O 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of companies companies other countries Government Amount _____________ 0 0 O 0 Percent _____________ O O 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42 gal = of metric of 42-ga1 + of metric of cubic : of cubic . bbl tons bbl tons feet meters Imports _______ 11.3 1.5 2 0 0 0 Exports _______ 0 0 0 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 147 VENEZUELA Category: Open shelf. Margin: Area to 3,000-m depth, 69,700 sq Bordering water bodies: Caribbean Sea, nautical miles. Area to 200 nautical Atlantic Ocean. miles, 106,100 sq nautical miles. Coastal length: 1,081 nautical miles. Geology: Coastal onshore, sedimentary. Shelf area to 200-m depth: 25,700 sq nau- Offshore, sedimentary. tical miles. 011 Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ 1,178 0 1,178 168.3 0 168.3 Cumulative production (1909—71) _________ 28,808 0 28,808 4,112 0 4,112 Proved recoverable reserves(12/31/72) _ <13,800 NA 13,800 <1,971 NA 1,971 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 1,667 0 1,667 47.2 0 47.2 Cumulative production (1909—71) _________ 27,504 0 27,504 779.2 0 7 7 9.2 Proved recoverable reserves (12/31/72) _ < 36,000 NA 36,000 <1,020 NA 1,020 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Ofishore Total Onshore Offshore Total Category ____________ III III II II II II Number of wells completed in 1972: Onshore Olfshore Total Producing Number Producing <200m >200m Producing Exploratory __ 62 31 2 0 O 64 31 Development _ 1 307 300 0 0 O 1 307 300 lDoes not include 131 wells suspended in previous years and completed in 1972. Producing wells as of 12/31/72: Onshore, 11,299; Offshore, 0; Total, 11,299. Offshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local U.S. Companies of companies companies other countries Government Amount _____________ 0 NA NA NA Percent ______________ 0 NA NA NA Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 0 O 0 Exports _______ 780.4 111.5 352.2 0 Negl Negl SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES VIET-NAM, DEMOCRATIC REPUBLIC OF Margin: Area to 3,000-m depth, 22,200 sq Category: Shelf locked. Bordering water body: South China Sea. Coastal length: 382 nautical miles. Shelf area to 200-m depth: 22,200 sq nau- tical miles. nautical miles. Area to 200 nautical miles, 22,200 sq nautical miles. Geology : Coastal onshore, sedimentary. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 O O O 0 Cumulative production (through 1972) ___- 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore OlTshore Total Production in 1972 ___ O O O 0 0 0 Cumulative production (through 1972) ___- 0 0 0 O 0 O Proved recoverable reserves (12/31/72) _ O 0 0 O 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category _____________ V V V V V V Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 ___ O 0 0 Development _ 0 0 O ___ 0 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: None. Ofi'shore exploration expenditures in 1972: Local U.S. Companies of V , companies companies other countries Gm e1 nment Amount _____________ O 0 0 0 Percent _____________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ NA NA NA NA NA NA Exports _______ NA NA NA NA NA NA SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 149 VIET-N AM, REPUBLIC OF Category: Open shelf. nautical miles. Area to 200 nautical Bordering water body: South China Sea. miles, 188,400 sq nautical miles. Coastal length: 865 nautical miles. Geology: Coastal onshore, crystalline/sedi- Shelf area to 200-m depth: 95,600 sq nau- mentary. Offshore. crystalline/sedimen- tical miles. tary. Margin: Area to 3,000-m depth, 151,400 sq Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 -__ 0 0 0 0 O 0 Cumulative production (through 1972) ____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 O 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _ _ _ 0 0 0 0 0 0 Cumulative production (through 1972) ..___ 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV IV IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development _ O O 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Oflshore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of G . t companies companies other countries 0‘ emmen ’ Amount _____________ 0 0 0 0 Percent _____________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 0 1.8 0 0 Exports _______ 0 0 O 0 0 0 150 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES WESTERN SAMOA Category: Archipelago. Margin: Area to 3,000-m depth, 2,500 ( ?) Bordering water body: Pacific Ocean. sq nautical miles. Area to 200 nautical Coastal length: 190 nautical miles. miles, 188,400 sq nautical miles. Shelf area to 200-m miles: 1,200 ('3) sq Geology: Coastal onshore, crystalline. Off- nautical miles. shore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 0 0 O 0 Cumulative production (through 1972) _____ 0 0 0 O 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Ofishore Total Production in 1972 ___ 0 O 0 0 0 0 Cumulative production (through 1972) _____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 O O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ Iv IV IV IV IV Iv Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory -_ 0 0 O 0 0 0 0 Development __ 0 0 0 0 O O 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Ofl'shore concessions licensed as of 12/31/72: None. Offshore exploration expenditures in 1972: Local US. Companies of ‘1 - companies companies other countries Government Amount _____________ 0 0 0 0 Percent ______________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 197 2: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Exports """" } No information. Imports _______ SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 151 YEMEN ARAB REPUBLIC (SAN’A) Category: Open shelf. Margin: Area to 3,000-m depth, 9,900 Sq Bordering water body: Red Sea. nautical miles. Area to 200 nautical Coastal length: 244 nautical miles. miles, 9,900 sq nautical miles. Shelf area to 200-m depth: 7 ,200 sq nauti- Geology: Coastal onshore, sedimentary. cal miles. Oifshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oflshore Total Production in 1972 _ _- O 0 0 0 0 0 Cumulative production (through 1972) _____ 0 0 O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 _-_ 0 0 0 0 0 0 Cumulative production (through 1972) _____ 0 0 0 0 0 0 Proved recoverable reserves (12/31/72) ,_ 0 0 O 0 O 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ VI IV VI VI IV VI Number of wells completed in 1972: Onshore Ofi'shore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 0 0 0 0 0 Development __ O 0 0 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0. Offshore concessions licensed as of 12/31/72: Two concessions licensed. Offshore exploration expenditures in 1972: Local U.S. Companies of Governm nt companies companies other countries 9 Amount _____________ 0 NA NA 0 ' Percent ______________ 0 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports _______ 0 0 1.0 0 NA NA Exports _______ 0 0 O 0 0 0 152 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES YEMEN, PEOPLE’S REPUBLIC OF (ADEN) Category: Open shelf. Margin: Area to 3,000-m depth, 90,100 sq Bordering water body: Arabian Sea. nautical miles. Area to 200 nautical Coastal length: 654 nautical miles. miles, 160,500 sq nautical miles. Shelf area to 200m depth: 15,100 sq nau- Geology: Coastal onshore, sedimentary, tical miles. offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Offshore Total Onshore Oifshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) _____ 0 O O 0 0 0 Proved recoverable reserves (12/31/72) _ 0 0 0 0 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Offshore Total Onshore Offshore Total Production in 1972 ___ O 0 O 0 0 0 Cumulative production (through 1972) _____ 0 0 O 0 0 O Proved recoverable reserves (12/31/72) _ 0 0 O 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ V IV IV V IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ O 0 0 0 0 0 0 Development __ 0 O O 0 0 0 0 Producing wells as of 12/31/72: Onshore, 0; Offshore, 0; Total, 0.. Offshore concessions licensed as of 12/31/72: No information. Offshore exploration expenditures in 1972: Local U.S. Companies of ‘1 9 companies companies other countries (’0‘ ernment Amount _____________ 0 O O 0 Percent ______________ O 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42~ga1 : of metric of 42ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 26.5 3.6 1.8 0 N A NA Exports _______ 0 0 0 0 O 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 153 YUGOSLAVIA Category: Shelf locked. Margin: Area to 3,000- m depth, 15,300 sq Bordering water body: Adriatic Sea. nautical miles. Area to 200 nautical Coastal length: 426 nautical miles. miles, 15,300 sq nautical miles. Shelf area to 200—m depth: 10,700 sq nau- Geology: Coastal onshore, sedimentary. tical miles. Offshore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Ofishore Total Onshore Offshore Total Production in 1972 _-_ 23.7 0 23.7 3.2 O 3.2 Cumulative production (through 1972) ___- 228.7 0 2,287 31.2 0 31.2 Proved recoverable reserves (12/31/72) _ 356 0 356 48 0 48 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofishore Total Onshore Offshore Total Production in 1972 __- 43.8 0 43.8 1.2 0 1.2 Cumulative production («through 1972) ___- 1,844 0 1,844 51 O 51 Proved recoverable reserves (12/31/72) _ 1,700 0 1,700 48.2 0 48.2 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ IV V IV IV IV IV Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ NA NA 4 ___ 0 E4 NA Development _ NA NA NA ___ NA NA NA Producing wells as of 12/31/72: Onshore, NA; Offshore, NA; Total, NA. Ofl'shore concessions licensed as of 12/31/72: State oil agency has signed oint-venture agreement with 2 American companies for exploration in waters less than 200—m deep. Offshore exploration expenditures in 197 2: Local U.S. Companies of companies companies other countries Government Amount _____________ NA 0 0 NA Percent _____________ NA 0 0 0 Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-gal : of metric of 42-ga1 + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 31.3 4.3 7.8 0 NA NA Exports _______ 0 .7 1.5 0 NA NA 154 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES ZAIRE Category: Open shelf. Margin: Area to 3,000-m depth, 300 sq Bodrering water body: Atlantic Ocean. nautical miles. Area to 200 nautical Coastal length: 22 nautical miles. miles, 300 sq nautical miles. Shelf area to 200—m depth: 300 sq nautical Geology: Coastal onshore, sedimentary. miles. Ofishore, sedimentary. Oil Millions of barrels Millions of metric tons Onshore Ofishore Total Onshore Oflshore Total Production in 197 2 ___ 0 0 0 0 0 0 Cumulative production (through 1972) _____ 0 0 0 O 0 O Proved recoverable reserves (12/31/72) _ 0 0 O O 0 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Oflfshore Total Onshore Offshore Total Production in 1972 ___ 0 0 0 0 0 0 Cumulative production (through 1972) _____ 0 O O 0 0 0 Proved recoverable reserves (12/31/72) - 0 0 0 0 0 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Otfshore Total Category ____________ V V V III V III Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing (200m >200m Producing Exploratory __ 5 1 1 0 1 6 2 Development __ 0 0 0 0 0 O 0 Producing wells as of 12/31/72: Onshore, 0; Ofl’shore, 10; Total, 10. 1 Offshore wells capable of production SI. Offshore concessions licensed as of 12/31/72: One concession licensed to a group of companies. Offshore exploration expenditures in 1972: Local U.S. Companies of , companies companies other countries Gm ernment Amount _____________ 0 NA NA 0 Percent ______________ 0 NA NA 0 1 Oil'sbore wells capable of production SI. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 : of metric of 42-gal + of metric of cubic : of cubic bbl tons bbl tons feet meters Imports ; ______ 5.3 0.7 1.1 0 NA NA Exports _______ 0 O .8 O 0 0 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES 155 ZAMBIA Shelf area to 200-m depth: None. Margin: None. Geology: Crystalline/sedimentary. Category: Landlocked. Bordering water body : None. Coastal length: None. Oil Millions of metric tons Onshore Offshore Total Millions of barrels Onshore Oflt'shore Total Production in 1972 ___ 0 ___ 0 0 ___ 0 Cumulative production (through 1972) _____ 0 _-_ O 0 ___ O Proved recoverable reserves (12/31/72) _ 0 ___ 0 0 ___ 0 Natural gas Billions of cubic feet Billions of cubic meters Onshore Ofl’shore Total Onshore Offshore Total Product-ion in 1972 _ _ _ 0 _ _ _ 0 O _ _ _ 0 Cumulative production (through 1972) _____ 0 ___ O O ___ 0 Proved recoverable reserves (12/31/72) ._ 0 ___ 0 O ___ 0 Potential resources (ultimate recoverable resources): Oil Natural gas Onshore Offshore Total Onshore Offshore Total Category ____________ 0 --_ 0 0 ___ 0 Number of wells completed in 1972: Onshore Offshore Total Producing Number Producing <200m >200m Producing Exploratory __ 0 0 ___ ___ ___ O 0 Development __ 0 0 ___ ___ __- 0 O Producing wells as of 12/31/72: Onshore, 0; Offshore, ___; Total, 0. Ofi'shore concessions licensed as of 12/31/72: Not applicable. Offshore exploration expenditures in 197 2: Local US. Companies of Gov rn t companies companies other countries 9 men Amount _____________ . Percent ______________ } Not applicable. Imports and exports of oil, products, and natural gas in 1972: Crude oil Petroleum products Natural gas Millions Millions Millions Millions Billions Billions of 42-ga1 = of metric of 42-gal + of metric of cubic = of cubic bbl tons bbl tons feet meters Imports _______ 0 0 3.8 0 NA NA Exports 1 ______ 0 O O 0 0 0 156 SUMMARY TABLES TABLE 1.—Ooastal and shelf characteristics, by continents, of countries bordered by oceans or inland seas SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES TABLE 1.—Ooastal and shelf characteristics, by continents, of countries bordered by oceans or inland seas—Continued Margin Margin Marg‘in ar2egoto Margin aaréegoto area 0 area to Continent and Shelf area 3,000-m nautical Continent and Shelf area 3,000-m nautical country C1333? 0212:9103!) degab maize country $011531 {0 23107111 depth m(iles ‘ ' \ en ( ep sq sq sq (nautical nautical nautical nautical (nautical nautical nautical nautical miles) miles) miles) miles) miles) miles) miles) miles) Afrkzlligeria 596 4 000 13 600 40 000 Europe and Asm : éngola __________ 806 191500 65900 1471000 Uns‘g‘clgfigmet C3333: 13; 31183 $338 3,1333 Republics _______ 23,098 364,300 735,900 1,309,500 Dahomey 65 ’500 2:600 7:900 Egypt ____________ 1,307 10,900 28,900 50,600 Europe : Equatorial Guinea _ 184 3,600 14,000 82,600 Albania 155 1,600 3,600 3,600 Ethiopia __________ 546 13,900 22,100 22,100 Belgium - 34 800 800 800 Gabon ____________ 399 13,400 40,900 62,300 Bulgaria _ _ 134 3,600 9,600 9,600 Gambia ___________ 3 1,700 3,300 5,700 Denmark 686 20,000 20,000 20,000 Ghana ____________ 285 6,100 20,100 63,600 Finland 735 28,600 28,600 28,600 Guinea ___________ 190 11,200 15,300 20,700 France ___________ 1,373 42,100 75,800 99,500 Ivory Coast _______ 274 3,000 15,700 30,500 German Democratic Kenya ____________ 247 4,200 21,600 34,400 Republic ________ 191 2,800 2,800 2,800 Liberia ___________ 290 5,700 19,600 67,000 Germany, Federal Libya ____________ 910 24,400 60,100 98,600 Republic of _____ 808 11,900 11,900 11,900 Malagasy Republlc 2,155 52,600 131,300 376,800 Greece _______ 1,645 7,200 82,100 147,300 Mauritania __-_ 360 12,900 26,300 5,000 Iceland _ 1,080 39,000 252,000 252,800 Mauritius _ 87 26,700 149,200 345,000 Ireland _ 663 36,700 84,100 110,900 Morocco 895 18,10 42,100 81,100 Italy __ 2,451 42,000 160,000 161,000 Mozambique __ 1,352 30,400 77,900 163,900 Malta ___- - 50 3,800 17,300 19,300 Nigeria ___________ 415 13,500 37,700 61,500 Netherlands 198 24,700 24,700 24,700 Portuguese Guinea - 215 13,500 30,800 43,900 1,650 30,000 463,700 590,500 Senegal ___________ 241 9,200 23,700 60,000 241 8,300 .300 8,300 Sierra Leone ______ 219 7,700 14,700 45,400 743 11,400 44,800 517,400 Somalia __________ 1,596 17,700 106,200 228,300 113 7,100 9,300 9,30 South Arica _______ 1,462 41,800 183.700 296,500 2,038 49,700 158,200 305,600 Southwest Africa __ 748 19,000 72,700 145,900 1,359 45,300 45,300 45,300 Sudan ____________ 387 6.500 26,500 26,700 United Kingdom ___ 2,790 143,500 281,800 274,800 Tanzania __________ 632 12,3080 41,633 65,;38 Yugoslavia ________ 426 10,700 15,300 15,300 533 14’383 25388 25’388 Total __________ 19,063 570,800 1,800,000 2,709,300 17,812 424,800 1,345,400 2,755,400 New, America, Bahamas (U.K.) 1,500 25,000 75,000 221,400 A513 ' Barbados 55 100 2 300 48 800 Bahrain __________ 68 1,500 1,500 1,500 Belize ______ 191 2 800 8,000 9,00 Bangladesn 310 16:000 20800 22,400 Canadian“ 11 129 846500 1 240000 1 370000 Brunei ——————————— 88 2.800 5.300 7,100 Costa. Rica : ’446 460 ' 15’100 ' 75:500 ggfma ——————————— 1,231 66,900 111,300 148,600 Cuba _____________ 1,747 23,300 68,900 105,800 nil’eople’s Republic Dlomsinlicala Republic- 2%? 51280) 22,838 20,830) E a va or ______ , , , R of l()Illilinaf ___- 3,492 230,100 281,100 281,100 Guatemala ________ 178 3,600 8,200 218,900 eCplii c 0 aiti _______ ___- 584 3,100 16,000 46,800 470 23,500 39,900 114,400 fi‘fil‘gfims - $3 3983 $338 $3,333 29" 1'9“ ”’9‘” 29'000 Mexicoa ' 4 848 128900 343000 831500 2359 1311300 339,700 587,600 Nicara u9—__ — ’445 21200 37400 46600 19,784 809,600 1,229,800 1,577,300 Pan mi ‘ 979 16,700 40’300 89,400 990 31,200 45,400 45,400 Uniiled Stat—e—s """" ’ ’ ’ 1&2 1 ggg 5 $33 6 £00 of America ______ 11,650 545,400 826,600 2,222,000 4,842 140,100 440,900 1,126:000 Ilihmer SEDUblicti-_— 210 16,200 16,200 16,200 Total ___________ 34,895 1,659,000 2,824,900 5,346,300 orea, 01110018. C People’s Republic 2 0 South America . 0f ------------- 578 13' 00 20,400 3730 Argentina ‘_ __ 2,120 232,200 484.100 339,500 Korea. Republic of- 712 71,300 93,300 101,600 Kuwait ___________ 135 4 100 4’100 4,100 Brazil _ __ 3,692 224,100 435.700 924,000 Lebanon __ __ 105 1:300 4,600 6,600 Chile ___ __ 2,882 80,000 167,900 661,300 Malaysia _ _- 1,853 108,900 25,600 138,700 Colombia — —— 1,022 19,800 60,900 173,900 Maldives __ __ 7 3,000”) >4,000 279,700 Ecuador -_ __ 458 13,700 52,600 333,000 Oman -___ __ 1,005 7,800 44,500 163,800 Guyana —— 2,332 14,600 28300 353,000 Pakistan __ 430 327,080 61,300 3%,988 Tiihlidad'aI—la _______ 1,258 24,100 48,900 2-0,400 _ _ , . ,0 V, 0 5 ,4 _ 3395p??? _____ __ 6 303 07,00?) 67,030 7,000 , Tobago _________ 204 8,500 17,300 22,400 Saudi Arabia _____ 1,336 22,700 54,600 54,900 Lrusuay —————— 305 16500 39,600 34,300 Singapore 28 100 100 100 Venezuela 1,081 20,700 69,700 106,100 _- '0 , 2 ,90 1 0,900 .. Csl‘lbiaillillildki_ 1,299 75,23?) 92,703 34,700 Total ___________ 13,304 659,200 1,400,000 2,875,400 Turkey __________ 1,921 14,700 69,000 69,000 United Arab Oceania ; Emirates ——————— 420 17,300 17300 17,300 Australia _________ 15,091 661,600 1,445,400 2,049,300 “37293181137: Fi'i _________ >650 >4,500 «0,033 230233 Y Republic of _____ 382 22,200 22,200 22,200 figazealand - 275,70 73333”) 53307,”)1’173’800 Republic bof _____ 865 95,600 151,400 188,400 Nauru """" '10 jog”) ’200 1 5: 00 Yemen ra """""""" '2 Republic (San’a)- 244 7,200 9,900 9,900 Western Samoa ___ 190 1,200( .) 2,500(?) 188,400 Yemen, People’s REDUbHC 0f Total __________ 18,711 742,400 2,111,200 4,271,600 (Aden) _________ 654 15,100 90,100 160,500 > Total ___________ 54.496 2,046,500 3,515,800: 6.011.800 121—country total- 1811379 604671000 13.738.200 251279-300 157 SUMMARY, 1972 OIL AND GAS STATISTICS, ONSHORE AND OFFSHORE AREAS, 151 COUNTRIES II A. A. A. A. A. A. A. A. A. .. A. A. A. A. ...A .A. III .A. _. I H A. 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L 2502. cued-HO 0.3.22.0 2.59.2. anon-HO 4 IL 239,—. anon-HO 20.22.22 2.5.2.50 can user—2.30 .5238. £32.. 3...: we :3: :mm .8. 3...... .o 3.8. =m as... a...“ no 35:52 .8. use. «a 33:3 882.. 3...... no 3.3:... .3. 3...: «a 3.3:... .3338: . 8?.qu 029.058.. 2.05.2 cogs—3.: 3.3.5.50 33533.2 «52 82.5.2 2122.032 vaunflnoolawfisea? 23:822. 68.. 63.5.9. 2.25.3 {$2932.95 25 23.3.3216. H.252. SUMMARY, 1972 OIL AND GAS STATISTICS, ONSrHORE AND OFFSHORE AREAS, 151 COUNTRIES REFERENCES Albers, J. P., Carter, M. D., Clark, A. L., Coury, A. B., and Schweinforth, S. P., 1973, Summary petroleum and selected mineral statistics for 120 countries, including offshore areas: U.S. Geol. Survey Prof. Paper 817, 149 p. American Association of Petroleum Geologists, 1973a, Foreign developments 1972: Am. Assoc. Petroleum Geologists Bull. v. 57, no. 10. 1973b, North American Developments, 1972: Am. Assoc. Petroleum Geologists Bull. v. 57, no. 8. Hendricks, T. A., 1965, Resources of oil, gas, and natural-gas liquids in the United States and the world: U.S. Geol. Survey Circ. 522, 20 p. McCaslin, J. 0. [ed.], 1973, International petroleum encyclo- pedia: Petroleum Publishing 00., Tulsa, Okla. McKelvey, V. E., and Wang, F. F. H., 1970, World subsea min- eral resources: U.S. Geol. Survey Misc. Geol. Inv. Map 1—632, 4 sheets, 17-page text. 163 Petroleum Press Bureau, 1973, Petroleum Press Service, vol. 40, nos. 1—12: Petroleum Press Foundation, London. US. Bureau of Mines, 1974, International Petroleum annual, 1972: Div. Fossil Fuels, Bur. Mines, Washington, DC. US. Department of State, 1969a, Sovereignty of the sea: US. Dept. State Geog. Bull, 3, 33 p. 1969b, Status of the world’s nations: US. Dept. State Geog. Bull. 2, 20 p. 1971, Boundaries of separate seabed areas of contrast- ing topographic gradients: US. Dept. State, Office of the Geographer, Map. 1972, Theoretical areal allocations of seabed to coastal states, based on certain U. N. Seabeads Committee pro- posals: U. S. Dept. State Bur. of Intelligence and Research, Internat. Boundary Study, Sec. A, Limits in the seas, no. 46, 35 p. World Oil, 1973. International outlook issue: World Oil, v. 177, no. 3, p. 63—171. * u.s. GOVERNMENT PRINTING OFFICE: 1974—- 543—555/1 36 .. swag—3m