TC no. 116:/ ;":ARY THE RESOURCES AGENCY OF CALIFORNIA partment of Wa ter Resources BULLETIN No. 116-1 n CRUSTAL STRAIN AND FAULT MOVEMENT INVESTIGATION Progress Report MAY 1963 HUGO FISHER EDMUND G. BROWN WILLIAM E. WARNE Administrator Governor Director The Resources Agency of California State of California Department of Water Resources ACTIVE FAULTS 1 2 3 SAN ANDREAS NACIMIENTO HAYWARD - CALAVERAS II 12 13 MILL CREEK- MISSION CREEK IMPERIAL SAN JACINTO 4 SANTA YNEZ 14 A6UA CALIENTE 5 6 BIG PINE GARLOCK 15 16 ELSINORE INGLEWOOD 7 WHITE WOLF 17 SAN CLEMENTE 8 SIERRA 18 MANIX 9 HELENDALE 19 FORT SAGE NEWBERRY 20 MOHAWK VALLE Active Earthquake Faults in California state ot Calitornia THE RESOURCES AGENCY Of CALIFORNIA Department of Wa ter Resources BULLETIN No. 116-1 CRUSTAL STRAIN AND FAULT MOVEMENT INVESTIGATION Progress Report MAY 1963 HUGO FISHER EDMUND G. BROWN WILLIAM E. WARNE Administrator Governor Director The Resources Agency of California State of California Department of Water Resources LIBRARY u*i».raii;iTY OF CALlFOHAiA TABLE OF CONTENTS Page LETTER OP TRANSMITTAL v ORGANIZATION vl ACKNOWLEDGMENT vil INTRODUCTION 1 CALIFORNIA EARTHQUAKES — A SPORADIC PROBLEM 3 REVIEW OP EARTHQUAKE INVESTIGATIONS IN CALIFORNIA 9 United States Coast and Geodetic Survey 12 California Institute of Technology 12 University of California at Berkeley 13 Stanford Research Institute 13 Other Universities and Public Agencies 13 Earthquake Engineering Research Institute 14 DEPARTMENT CRUSTAL STRAIN AND FAULT MOVEMENT INVESTIGATION . . 15 Scope and Objectives of Investigation 15 Program Accomplishments to Date l8 Fault and Earthquake Epicenter Map l8 Earthquake Hazard Evaluations 19 Electronic Data Processing 19 Technical Reports 20 Geodlmeter Survey 20 Trlangulatlon Survey 21 Federal-State Cooperative Subsidence Leveling Program 22 Future Program 22 Applied Seismology Studies 23 -111- Geodetic Studies 30 Engineering Geology Studies 32 DEPARTMENT EARTHQUAKE ENGINEERING INVESTIGATIONS 35 Illustration No , Frontispiece 1 2 ILLUSTRATIONS Active Earthquake Faults in California San Andreas Fault, San Bernardino County San Andreas Fault, San Luis Obispo County Page Plate No. PLATES (Plates bound at end of bulletin) 1 Crustal Strain and Fault Movement Investigation Geodetic Program -iv- pn GOIDEERG 'jputy Director lUD C. PRICE iDireclor Policy I' GARDNER EDMUND G BROWN GOVERNOR Of CALIFORNIA HUGO FISHER ADMINISTRATOR RESOURCES AGENCY ADDRESS REPLY TO P. O. Box 388 Socramenlo 2, Colif. THE RESOURCES AGENCY OF CALIFORNIA DEPARTMENT OF WATER RESOURCES 1120 N STREET, SACRAMENTO February 27, I963 The Honorable Edmund G. Brown, Governor, and Members of the Legislature of the State of California Gentlemen: I have the honor to transmit herewith Bulletin No. II6-I, "Crustal Strain and Fault Movement Investigation — Progress Report." This Investigation was initiated by the department in 1959 under funds budgeted for the California Water Development Program. Plans are under way to implement additional Investigations into earthquake problems and their solution based on recommendations of our Consult- ing Board for Earthquake Analysis. The major objectives of the department's earthquake engin- eering investigations are: (l) to Investigate, evaluate, and report on all phenomena of earthquakes, faults, and crustal movements which may affect engineering planning, design, construction, operation, and safety of hydraulic structures; and (2) to develop earthquake, crus- tal movement, and aseismic design factors and criteria to improve or replace the empirical factors in current use for the engineering design of hydraulic structures in California, Bulletin No. II6-I has been prepared primarily as a brief report to the Legislature on the objectives, accomplishments, and proposed future program of the Crustal Strain and Fault Movement Investigation -- which may appropriately be referred to as the earth- quake hazard studies of the department. This report also briefly refers to the objectives of the programs now being formulated for the department's other earthquake engineering investigations. This report will provide background for a series of earthquake data and earthquake engineering reports which will be issued by the department as progress is made in these investigations. Sincerely yours. Director i STATE OP CALIFORNIA THE RESOURCES AGENCY OP CALIFORNIA DEPARTMENT OP WATER RESOURCES EDMUND G. BROWN, Governor HUGO PISHER, Administrator, The Resources Agency of California WILLIAM E. WARNE, Director, Department of Water Resources ALFRED R, GOLZE ' , Chief Engineer DIVISION OP RESOURCES PLANNING William L. Berry Division Engineer Raymond C. Rlchter Geology Staff Specialist The investigation leading to this report was conducted under the direction of Meyer Kramsky* Chief, Statewide Investigations Branch and Carleton E. Plumb Chief, Planning Investigations Section by David M. Hill Senior Engineering Geologist William M, Gibson Associate Engineer, Water Resources Laurence B, James Chief Geologist and Coordinator of Department's Seismic Investigations *Albert J. Dolclnl was Chief of the Statewide Investigations Branch until July 1, I962. -vl- ACKNOWLEDGMENT Valuable assistance^ data, and consultation by federal, state, and private agencies and Individuals have materially assisted the department in its studies of seismic problems in California. In particular, the continued cooperation and assistance of the following individuals and agencies are acknowledged: Professors Hugo Benioff, Charles Richter, George Housner, and Clarence Allen, California In- stitute of Technology] Professors Perry Byerly and Donald Tocher, University of California at Berkeley; Dr. Pierre St. Amand, China Lake Naval Ordnance Test Station; the United States Coast and Geo- detic Surveyj the United States Geological Survey; and the California State Division of Mines and Geology. Additional guidance in formulating departmental earthquake engineering investigations and in developing rational factors for earthquake-resistant design of hydraulic structures will be provided by the recently constituted Consulting Board for Earthquake Analysis. Dr. Hugo Benioff, Seismologist, California Institute of Technology, specializing in seismic phenomena and instrumentation, is chairman of the board. Members of the board include: Dr. George W. Housner, a Structural Engineer, California Institute of Technology, specializing in engineering seismology and earthquake-resistant design; Dr. Harry B. Seed, Soils Mechanics, University of California at Berkeley, special- izing in soil mechanics and model studies in connection with earth dams; Mr. Nate D. Whitman, Jr., Consulting Engineer, specializing in design of hydraulic structures; and Dr. James L, Sherard, Consulting Engineer, specializing in the design of embankment dams. -vii- f INTRODUCTION Bulletin No. II6-I has been prepared as a brief report to the Legislature on the objectives, present accomplishments, and pro- posed program of the department's Crustal Strain and Fault Movement Investigation in the Division of Resources Planning. This activity is a part of the department's overall program of earthquake investi- gations. Specialized technical model and earthquake design studies, which are conducted by the Division of Design and Construction and ' the Supervision of Dam Safety Office, are only briefly mentioned herein. The data collected by the Crustal Strain Unit are utilized by the Division of Design and Construction in their program for developing earthquake design criteria for the State Water Facilities. These data are also of value to the Supervision of Dam Safety Office, the Division of Operations, and the planning activities of the department. This bulletin is the first of a series of reports which will present the results of the various technical earthquake and crustal movement studies being conducted in the Division of Resources Planning. The first basic data report in the series will be Bulletin No. 116-2, "Earthquake Epicenters and Faults in California," The Crustal Strain and Fault Movement Investigation was Initiated by the department in January 1959. Funds for the Crustal Strain Program are provided in the I962-63 budget, page 679, line 8. CALIFORNIA EARTHQUAKES -- A SPORADIC PROBLEM The California Water Plan envisions a system of reservoirs, aqueducts, pumping plants, and. other hydraulic facilities throughout the State. The potential threat to these structures posed by earth- quakes and crustal movements is an important factor in the location, design, construction, and operation of the various facilities of such an extensive project. Inasmuch as precautionary aseismic design measures entail additional expense, any appraisal of earthquake risk must also include consideration of the purpose, type, and useful life of the structure concerned, and the seriousness of the loss or the danger to life should structural failure occur. The Department of Water Resources has undertaken the Crustal Strain and Fault Movement and other earthquake engineering Investigations herein described, to provide objective evaluations of the potential hazards related to our sporadic earthquakes, and to provide rational criteria for the design of hydrauic structures to obviate or minimize any adverse effects from future earthquakes. Evaluation of earthquake activity indicates that California is located in the second most highly seismic area in the United States, the first being Alaska. The great majority of reported earthquakes in California are associated with major fault systems concentrated in the Coast Ranges in Central and Northern California, in the Transverse and Peninsular Ranges in Southern California, and in the Sierra Nevada. Locations of some of the known active faults are shown diagrammatically on the Frontispiece and in Illustrations 1 and 2. -3- Illustration 1 shows an aerial view southeastward along the San Andreas fault north of San Bernardino near the proposed Devil's Canyon Powerplant No. 2. The earthquake of January 9, I857, which was comparable In strength to the famous I906 San Francisco earthquake, accompanied rupture and displacement of the ground along the fault line In the area shown In the picture. The rupture ex- tended northwesterly from San Bernardino about I50 miles or more, following the trace of the fault through Antelope Valley, the moun tains south of the San Joaquin Valley, and Carrlzo Plain. Illustration 2 shows an aerial view of the San Andreas fault near Carrlzo Plain, which Is located about 18 miles west and northwest of Taft and is about I50 miles northwest of the area shown in Illustration 1. The abrupt offsets of stream channels at the fault line provide evidence of recent lateral fault movement. The photo is typical of an area that will be crossed by the California Aqueduct, Effects of earthquakes which may damage hydraulic struc- tures include: shaking of foundations, surface rupture, earth lurches, slumps, raudflows, landslides, avalanches, seiches, and seismic sea waves. Any one or a combination of these effects, if not properly considered in design, could seriously Impair the use- fulness of hydraulic structures. Crustal strain in the form of tilting of the land surface occurs along some faults, and could alter the hydraulic gradient of a canal or place a critical pumping plant facility out of alignment without an actual earthquake. Never theless, experience has shown that with proper evaluation of these Illustration 1. San Andreas Fault , San Bernardino County (looking boutheast). The San Andreas fault (indicated by arrows) forms the boundary between the San Bernardino mountains on the left and the alluvlum-f llled valley on the right. -5- ■^^. *-vN^*c3:-* -> '; Illustration 2. San Andreas Fault , San Luis Obispo County (looking east across fault) . The California Aqueduct will cross the San Andreas fault in areas similar to the road crossing shown in the center of the photograph. The fault is indicated by arrows. factors Incorporated In design of hydraulic structures, these poten- tial problems can be minimized. Although California Is an area of high seismic activity, a preliminary review of available data on hydraulic structures In California Indicates that relatively few structures have been dam- aged by earthquakes during the past 70 years. During this period, l4 earthquakes caused some damage to 10 dams, 3 small water supply reservoirs, 1 sewage treatment plant, 1 pumping plant, and 1 power- plant. For example. In 19'^0 the All-Amerlcan Canal was displaced 14 feet 10 Inches by movement along the Imperial fault Just prior to Initial use. Repairs were Immediately Implemented, and the canal was then placed In operation. During the I906 San Andreas earth- quake, displacements of 5 to 8 feet were measured In fills and out- let tunnels of three earthflll dams In the Crystal Springs area south of San Francisco where they were cut by the San Andreas fault. It should be noted that these dams did not fall. Shaking of the foundation and materials In Sheffield Dam (earthflll) in Santa Barbara County during the 1925 earthquake caused failure of the structure. The dam was rebuilt during the same year. Reports of earthquake damage to hydraulic and other engin- eering structures may be unintentionally misleading as to the extent of the damage, because emphasis may be placed on the instances of damage rather than on the number of structures which survive earth- quakes unscathed. However, the past record of hydraulic structures damaged by earthquakes is a reminder that damaging earthquakes have occurred repeatedly in the past and can be expected to recur in the -7- future. Therefore, planning, design, construction, and operation oi the State Water Facilities must take into account all phases and ramifications of earthquake phenomena to minimize the potential damage from future earthquakes and to assure the safety of the facilities. -8« REVIEW OP EARTHQUAKE INVESTIGATIONS IN CALIFORNIA Even though the historical record of California earthquakes extends back to 1769, It was not until I887 that systematic compila- tion and publication of earthquake descriptions were Inaugurated. This valuable program was undertaken by the University of California. The first seismographs In California were Installed during the late 1880 's and early l890's at the following San Francisco Bay area locations: Lick Observatory on Mt. Hamilton] University of Califor- nia (Berkeley) j Chabot Observatory (Oakland); Mills Seminary (Oak- land); and University of the Pacific (San Jose). Lick Observatory began Its active work In I888 and was the early leader In collecting reports of earthquakes on the Pacific Coast. Following the destructive San Andreas earthquake and fire which devastated San Francisco In I906, a State Earthquake Investi- gation Commission was formed to study all aspects of the earthquake and the resultant damage. Funds for operation of the commission and publication of Its findings were provided by the Carnegie Institu- tion of Washington, D, C, Soon after the earthquake, the United States Coast and Geodetic Survey remeasured Its trlangulatlon net In the area to determine the width of the zone affected by crustal movement. After publication of the report of the Earthquake Investi- gation Commission, public "earthquake psychology" developed which opposed discussion or investigation of earthquakes, because it was "bad for business." In the midst of this opposition, a group of -9- San Francisco Bay area geologists and others organized the Selsmo- loglcal Society of America. Bulletins of that society have been Issued quarterly since 19II. Funds to support earthquake Investiga- tions in California came from outside the State during those lean years -- largely from the Carnegie Institution of Washington. In 1921 the Carnegie Institution of Washington established a program for earthquake recording and research, with headquarters in Pasadena The torsion seismometer was developed for this work by J. A. Anderson and H, 0, Wood, By the summer of 1927, four seismograph stations had been installed in Southern California, The damaging offshore submarine earthquake which struck Santa Barbara in 1925 reawakened public Interest in earthquake inveS' tlgations. As a result, new equipment was installed at the Universi of California at Berkeley and at Lick Observatory. New stations wer established at Stanford University and in San Francisco. In I925, the United States Coast and Geodetic Survey began publishing descrip tive notes of earthquakes which had formerly been published by the United States Weather Bureau and Lick Observatory. Most of the earl earthquake Investigations followed the lines of "pure science" because of lack of public interest and funds for applied research. In 1930, Stanford University and the United States Coast and Geodetic Survey designed and built a large shaking table for model studies. Even though the studies were useful in measuring the effects of earthquakes on structures, the work was hampered by lack of adequate funds, and subsequently was discontinued. About the same time, the United States Coast and Geodetic Survey began making -10- periodic geodetic measurements along and across the San Andreas fault at a few critical localities with a view to accurately determining the rate and direction of earth movements. Surveys across the fault from Monterey to Pacheco Pass were made In 1930 and continued In 1932 In the area from San Luis Obispo to Lost Hills, and from San Fernando to Bakersfleld. Other projects followed In subsequent years and are being repeated at 10-year Intervals, supported by federal funds. In 1932, the United States Coast and Geodetic Survey de- signed and put Into operation a program for the Instrumental record- ing of strong-motion earthquakes. Prior to that time, no appreciable Instrumental data had been obtainable near earthquake epicenters because the Initial shock always put sensitive seismographs out of order. This Important development enabled the recording of earth- quake data near the epicenters. The strong-motion seismographs have been placed In strategic locations like "mousetraps" to lie In wait for a strong shock. Unlike other sensitive Instruments, these strong- motion Instruments are triggered Into operation by the Initial shock. There are approximately 80 strong-motion seismographs located In the State of California, centered largely In the metropolitan areas. The California Institute of Technology has administered a selsmologlcal program for Southern California since 1937- The Uni- versity of California at Berkeley administers a similar selsmologlcal program for Northern California. The United States Coast and Geo- detic Survey has a separate statewide program. There Is a free and Informal exchange of data between the organizations that Includes copies of all seismograph records. As of 1956, the California 11- Institute of Technology had l6 stations In operation, the Universits of California had 11 stations, and the United States Coast and Geo- detic Survey had one teleselsmlc station and about 80 strong-motion stations. The universities are currently adding to their networks, Activities of various organizations engaged in seismologic investigations may be generally summarized as follows: United States Coast and Geodetic Survey 1. Collection and publication of descriptive Information on earthquakes. 2. Compilation of earthquake history. 3. Preparation and distribution of intensity maps of strong earthquakes. 4. Operation of a network of strong-motion instruments located primarily in metropolitan areas and at the sites of United States Bureau of Reclamation dams. 5. Detennlnation of the natural frequency of vibration of buildings and other structures. 6. Location of epicenters of the larger earthquakes. 7. Precise measurements across earthquake faults by means of trlangulatlon, traverse, leveling, and astronomic azimuths, 8. Cooperation with universities and other agencies in earthquake engineering investigations. California Institute of Technology 1. Operation of a seismological laboratory. 2. Collection and publication of instrumental data on earthquakes in Southern California. -12- 3. Compilation and study of earthquake history. 4. Operation of a network of seismographs. 5. Research In all problems related to earthquakes. University of California at Berkeley 1, Operation of a selsmologlcal laboratory. 2, Collection and publication of Instrumental data on earthquakes In Northern California. 3, Compilation and study of earthquake history, 4, Operation of a network of seismographs. 5, Research In all problems relating to earthquakes. Stanford Research Institute Instrumental recording of small shocks, determination of epicenters, and other research activities. Other Universities and Public Agencies Activities by universities comprise essentially the operation of a few seismographs and cooperation in epicenter and intensity determinations. In addition, the California Department of Public Works, Division of Architecture, in connection with its administration of the Field Act, has spent approximately $200,000 in research on framed structures, and currently budgets as much as $50,000 annually for this purpose. Other countries, notably Japan, have contributed greatly to earthquake engineering research as ap- plied to framed structures. -13- Earthquake Engineering Research Institute The United States Coast and Geodetic Survey, In 19^7, es- tablished an Advisory Committee on Engineering Seismology to assist the survey In Its selsmologlcal program. In 19^9^ the committee was Incorporated with the title "Earthquake Engineering Research Insti- tute." Its major purpose Is to function as an Independent Institu- tion to promote continuing research In engineering seismology that would lead to greater understanding of destructive earthquakes and to Improvement In safety, and In the economical design, construction^ and location of structures of all types to resist forces Induced by earth motion. Activities of the Institute center largely on sponsoring and/or promoting research and development by the Institute and others, mainly In the field of framed structures, to which a consld erable amount of research and study has been devoted. To date, little emphasis by 'KERl has been placed on earthquake problems re- lating to dams, canals, and other hydraulic structures. .14- DEPARTMENT CRUST AL STRAIN AND FAULT MOVEMENT INVESTIGATION To achieve the most economic location and design of the various proposed State Water Facilities commensurate with safety and with an uninterrupted water supply, the Department of Water Resources has undertaken an Investigation Into the nature and extent of the potential problems which relate to earthquakes and crustal movements In California, The various technical studies Involved In the depart- ment's overall program of earthquake engineering Investigations have been grouped Into two functional categories. The Crustal Strain and Fault Movement Investigation comprises the first group of studies. These largely Involve geology, seismology, and geodesy, and are aimed toward obtaining knowledge of the seismic effects to be expected at specific sites or within specified areas. The second group of stud- ies Is more closely associated with structural and soils engineering and is Intended to develop procedures for aselsmlc design and opera- tion of hydraulic structures and for the Investigation of safety of dams. Studies In the second group are within the responsibilities of the Division of Design and Construction and the Supervision of Dam Safety Office. The Crustal Strain and Fault Movement Investigation was Initiated by the department In January 1959* following Its endorse- ment by Dr. Hugo Benloff, the department's chief selsmologlcal consultant. Scope and Objectives of Investigation The earthquake data and earthquake hazard studies Included In the Crustal Strain and Fault Movement Investigation In the Division -15- of Resources Planning have the following objectives: 1. To Investigate, evaluate, and report on all phenomen of earthquakes, faults, and crustal movements which may affect en^ gineering planning, design, construction, safety, and operation of hydraulic facilities built by the department. 2. To develop rational seismic and crustal movement fac tors which may be utilized in engineering design, based on frequer and intensity of earthquakes, foundation conditions, probable crus displacement, and associated considerations at each site as relate to structural type and seriousness of loss, should structural dama occur. Intrinsic in the overall objectives are the following specific objectives: 1. To determine the rate, constancy, and magnitude of ground movements (accumulating crustal strain) near sites proposed for hydraulic structures. 2. To locate active faults which may produce destructiv earthquakes or along which the ground surface may rupture as the result of accumulated crustal strain. 3. To estimate the destructive potential of the probabl earthquake forces which should be anticipated at the site of each structure constructed on or near active faults and on foundations which vary in strength and stability. 4. To estimate the amount and direction of displacement across active faults which may occur either abruptly or gradually and which may sever or otherwise damage tunnels, conduits, or othe -16- hydraulic structures, or Impede the movement of water by altering the hydraulic gradient. 5. To locate areas of active tectonic uplift or subsidence and to estimate the rate at which the resultant crustal tilting will alter the hydraulic gradient of canals and thus change their capacity. 6. To develop and/or acquire and operate special instru- ments and equipment of various types, which will implement the fore- going. Such instruments are necessary in order to: (a) detect and measure horizontal and vertical movements of the earth's crust j (b) detect and record the crustal vibrations which may precede earth- quakes and/or surface rupture j (c) measure and record the effects of earthquakes on foundation materials at sites proposed for State Water Facilities; and (d) measure and record the effects of earthquakes on existing and proposed hydraulic structures. 7. To collect and compile basic data pertaining to earth- quakes. Including epicentral locations, magnitude, ground vibration frequencies, and earthquake effects on ground surface and on manmade structures. 8. To prepare programs for electronic data machine proc- essing, analysis, and plotting of data which will facilitate the evaluation of earthquake and crustal movement factors. 9. To develop rational ground motion factors and criteria which may be utilized in developing earthquake-resistant design of 'hydraulic structures. 10. To investigate the characteristics of, and potential foi^ earthquake-generated seiches in reservoirs and aqueducts. -17- Program Accomplishments to Date The following are the principal activities and accompllsl: ments to date of the department's Crustal Strain and Fault Movement Investigation: Fault and Earthquake Epicenter Map . A fault and earthqu epicenter map of the entire State, the first of Its kind, has been prepared and will be published shortly In Bulletin No. 116-2. Epl centers of all earthquakes of Rlchter Magnitude 4 and above, which have occurred In California and adjacent areas since 1932, are plot ted on the map. The map graphically represents the relative sels- mlclty of the various regions of the State during the past 30 years and will greatly assist engineers, particularly those who design hy? draullc structures and other types of engineering structures. In appraising the earthquake hazard at various locations. Over 2,000 epicenters are plotted on the map, which shows groupings of eplcen^ ters In certain areas. Indicating potentially dangerous seismic activity. The same map shows the most complete delineation ever pub llshed of faults throughout the State. The location of over 3,000 faults Is shown. The mapped faults represent a compilation of the latest available geologic mapping, published and unpublished, by th Department of Water Resources, the California State Division of Min^ and Geology, the United States Geological Survey, by other state an federal agencies, and by other organizations and Individuals. The information on fault locations on this map will be invaluable in planning the location of hydraulic and other structures. -18- The combination fault and epicenter map Is expected to serve as a primary reference for applied seismology throughout the State. Earthquake Hazard Evaluations . Preliminary evaluations of earthquake hazards at many of the sites of proposed hydraulic struc- tures have been completed or are under way. Such studies include: compilation of the earthquake history of the area, plotting of earth- quake epicenters In the vicinity, analysis of the magnitude and In- tensity of each earthquake, and evaluation of site foundation for stability and susceptibility to shaking. Earthquake frequency. In- tensity, and acceleration factors are estimated for each site to provide design engineers with a basis for aselsmlc design of hydrau- lic structures. These studies also Include consideration of some of the side effects of earthquakes which can cause damage, such as sur- face rupture, slumps, landslides, earth or mud flows, seismic sea waves, and waves generated within reservoir areas. Electronic Data Processing , A new method of tabulating earthquake data has been developed which utilizes electronic data processing equipment. The latitude and longitude, date, time, ac- curacy of epicenter plot, and magnitude of earthquakes occurring from 1932 through i960 have been placed on IBM cards. A tabulation of the earthquake data is Included in Bulletin No. 116-2. Until now such data were not available for the entire State in the files of a single agency, but were scattered in the files of various agencies which have collected and analyzed them for specific areas and purposes. It is now possible to obtain and reproduce the •19- earthquake record of any area accurately and rapidly. Utilization of the data processing machines will permit machine plotting of epi' centers on maps and enable the compilation and plotting of accumula^ tive earthquake energy release for any desired area. Technical Reports . An annotated bibliography on engineer' ing seismology as applied to hydraulic structures and on earthquake damage to hydraulic structures is being prepared. Selected technical reports are summarized in sufficient detail to provide essential dat| as well as descriptions of instrumentation and procedures. In addi-t tion to providing the results of the investigations and research coni ducted by other agencies, such a bibliography will provide a basis for determining which lines of investigation should be pursued fur- ther to satisfy the department's requirements in connection with the, planning, design, and operation of hydraulic structures. Geodlmeter Survey . Through the use of a geodimeter which may be generally described as the most precise distance-measuring device available, 65 lines crossing nine faults between San Prancisc and Indio have been established. The locations of these lines are shown on Plate 1, titled "Crustal Strain and Fault Movement Investi gation Geodetic Program." The purpose of these geodetic studies is to measure horizontal movements of the earth's crust due to strain build-up or fault slippage near the location of present and proposed hydraulic structures, to delimit areas or zones thus affected, and to detect strain build-up that may be released by large earthquake- producing fault displacements. The geodimeter lines are remeasured to determine the rate, direction, and constancy of differential horl zontal movements of the crust on opposite sides of the fault. -20- Emphasis has been on measurements across the San Andreas fault; most of the other faults crossed are related parallel faults. Most of the geodlmeter lines have been surveyed three times, representing approxi- mately 2,600 miles of surveying over a period of three years. It should be pointed out that the data accumulated during this brief period are Insufficient to warrant positive conclusions. However, a preliminary evaluation of measurements across the San Andreas fault suggests right lateral movement (the west side moving northward rela- tive to the east side) between Holllster and Slmmler. The few re- peat measurements available between Slmmler and the Intersection of the San Andreas and Qarlock faults suggest left lateral movement. South of the Garlock fault. It has not been possible to establish a consistent pattern of movement. Repetition of the measurements will, of course, be continued to confirm or revise these preliminary evalu- ations, and to establish more definite directions, amounts, and, pos- sibly, variations of magnitude In the movements. Trlangulatlon Survey . Through the cooperation of the United States Coast and Geodetic Survey, an extremely precise trl- angulatlon network has been established covering the area of the San Andreas, Garlock, White Wolf, and other faults which converge near the extreme southern end of the San Joaquin Valley. The trlangula- tlon network Is shown on Plate 1. Repetition of the trlangulatlon will be accomplished after the geodlmeter measurements, previously described. Indicate that sufficient ground movement has taken place to warrant the re survey. -21- Federal-State Cooperative Subsidence Leveling Program !| The cooperative leveling program for the measurement of deep subsidence has been sponsored by the department for a number ci years to obtain precise data on changes In elevation of the land s{\ face In several areas of the State. The current program Is dlrecte; I toward obtaining such data In those areas of the San Joaquin Vallejj and the Sacramento-San Joaquin Delta which are critical to the desj and operation of the presently authorized State Water Facilities. The program Is administered by the Crustal Strain Unit In the Dlvls of Resources Planning, Funds for the cooperative program are pro- vided In the 1962-63 budget on page 678^ line 40. The principal cause of deep subsidence In the San Joaquir: Valley Is attributed to withdrawal of ground water. Vertical tec- tonic movement also Is thought to be a contributing factor In land j subsidence In some areas such as at the south end of the San Joaqulj Valley near the base of Wheeler Ridge. In either case, the potent adverse effect on aqueduct gradients locally will be the same as t. discussed under tectonic movement as measured by tlltmeters. It Is critical for the department to know the varying rates of land sub- sidence along the aqueduct route so that allowances for this factor may be made during design and construction of the facilities to mln mlze the adjustments which may become necessary after the facllltle are placed In operation. Future Program The department's seismic Investigations, as recommended b the Consulting Board for Earthquake Analysis, Include continuation -22- of the foregoing activities of the Crustal Strain and Fault Movement Program and Implementation of additional studies employing Instru- mentation and engineering models. The solution to earthquake engin- eering problems requires an Integrated program of studies in the following fields: applied seismology, geodesy, engineering geology, and aselsmic engineering design. These studies comprise the major phases of the department's future investigational programs. As mentioned earlier, all of the department's present and proposed studies have been grouped into two functional categories. Studies which fall in the first category and which have been assigned to the Crustal Strain and Fault Movement Investigation in the Division of Resources Planning are discussed under the following headings: Applied Seismology Studies, Geodetic Studies, and Engineering Geology Studies. Studies which have been assigned to the second category and which are the responsibility of the Division of Design and Construc- tion and the Supervision of Dam Safety Office, are presented in the next chapter under the heading. Departmental Earthquake Engineering Studies. Applied Seismology Studies . Studies of the phenomena associated with earthquakes, and the behavior of foundation materials and hydraulic structures during earthquakes, comprise the keystone in establishing aselsmic design criteria. The following seismological studies are part of the future program in the Crustal Strain Investigation: 1. Seismological field studies involving various types of seismic instrumentation will be a major effort of the dopartment ' s -23- program in securing Information on ground, motion characteristics. The following field instrumentation program is under way or in the final planning stages: a. Installation and operation of a series of strong-motion seismograph assemblies includ- ing accelerometers and. displacement meters, and supporting seismoscopes. These instru- ments will be established in critical areas throughout the State and maintained for an approximate 10-year period or longer. In the event of a large earthquake, these in- struments will provide valuable design data which cannot be secured from the sensitive instruments. In most major earthquakes , sensitive instruments are commonly rendered inoperative. b. Installation and operation of portable high- sensitivity seismographs for use in deter- mining the ground spectral amplification factor for critical sites and for determin- ing the spectral response characteristics of selected existing dams. Two high- sensitivity seismographs will be acquired and used at individual structure sites. Where such sites are underlain by alluvium or by slightly to moderately compacted -24- sediments, one seismograph will be located on the proposed site, and a second Instru- ment will be located on rock in the near vicinity of the site. Frequency curves for design use can be compiled by digitiz- ing records from the two seismographs. Maintenance of these instruments at a pro- posed site during several smaller earth- quakes will provide adequate data for design, thus allowing seismographs to be moved to other structure sites. Installation and operation of a fused- quartz strain extensometer at the recently acquired site in Antelope Valley, Los Angeles County, about l4 miles southeast of Gorman. This instrument will provide a record of the accumulation of strain in bedrock in the wedge-shaped crustal block between the San Andreas and Garlock faults. Earthquakes and surface rupture are the predicted effects which will occur when the accumulating strain is suddenly re- leased. It will also record the transient strains induced in bedrock during the passage of earthquake waves. Installation and operation of tripartite tiltmeters to determine the direction and -25- rate of tilt along the alignment of aque- duct routes and at other critical locations such as pumping plant sites. Tlltmeters will be located in tectonlcally active areas, and measurements repeated at periodic inter- vals, in order to evaluate the extent and the magnitude of the problem. Installation and operation of permanent seismograph stations associated with State Water Facilities* A class A seismograph station is presently under construction at Oroville Dam, Butte County. This station will provide a continuous record of earth- quake activity in the Oroville and adjacent areas with respect to the dam and appurte- nant structures. Data from this station ivill be useful in establishing seismic design criteria for projects contemplated under the State Water Resources Development System. Installation and operation of the recently acquired variable reluctance transducer seis- mograph on the San Andreas fault or in an area of the State, such as the North Coastal area, where seismograph records are insuf- ficient or are not available. A sensitive seismograph station at such a site (l) will -26- monitor some of the local "rock noises" or microtremors generated by nearby active faults which may be the precursor of a major earthquake, (2) will assist in deter- mining epicentral locations of all earth- quakes in the area, and (3) will furnish data on ground motion characteristics at the site. 2. Selsmological office studies will be undertaken as needed in order to evaluate seismic hazards at proposed structure sites. Studies undertaken may include, but not necessarily be limited to, the following: a. Continuing collection and processing of basic data on earthquakes. Including their effects on ground surface and on manmade structures, and programming the earthquake data for machine analysis. Coordination with universities and the Coast and Geo- detic Survey will be continued to obtain all available seismological data pertinent to the program, b. Development of special types of earthquake data maps in the future at critical struc- ture sites or areas. The preparation of these special maps depicting magnitude, intensity, and acceleration, and the analy- sis of their correlation and interrelationship -27- with the phenomena and. expression of strain energy release, are steps in the development of rational factors for earthquake-resistant engineering design of State Water Facilities, Some of the special maps which might be compiled Include: (1) Maps depicting eplcentral locations of earthquakes below Rlchter Magni- tude 4, These small earthquakes are the result of minor adjustments in the earth's crust. Such earth- quakes release a small, but appre- ciable, portion of the elastic strain energy which accumulates in the earth's crust as the result of crustal movements. Thses smal^l earthquakes also reflect adjust- ments in the crust which are the consequence of the rapid release of accumulated strain energy dur- ing major earthquakes. The pat- tern which develops by plotting the epicenters of small earth- quakes may provide a clue to the mechanism involved in the strain build-up which results in major earthquakes . -28- (2) Earthquake intensity maps depleting areas In which earthquake damage has been reported or which have been subjected to moderate to Intense shaking. Such a map may be useful In developing rapld^ qualitative appraisals of the earthquake hazards at sites of proposed facilities of the State Water Resources Develop- ment System. (3) Maps depleting cumulative earthquake energy release. The map would show graphically whether strain energy Is being released by numerous minor earthquakes along some faults or segments of faults or by only a few major earthquakes along other faults or fault segments. Thus, the rela- tive seismic activity of a proposed site could be compared with adjacent areas. This map will assist In plan- ning the location and design of hy- draulic structures by providing a numerical basis for appraising the earthquake hazard In any area In terms of the rate at which earth- quake energy Is released. -29- 3. The Consulting Board for Earthquake Analysis has recc mended that the department undertake a study of long-period standlr waves (seiches) which may be generated In reservoirs as a result of earthquake activity. The department's studies will encompass anal^ sis and evaluation of existing seismograph records and the design. Installation, and operation of special Instrumentation to measure seiches In reservoirs throughout the State. Correlation of the rec ords from the seiche recorders with records from long-period seismc graphs will enable the department to determine the probability of seiche development In each reservoir and whether the seiches genera by a strong earthquake may be In any way destructive. These studle may be a joint effort of the Divisions of Resources Planning and Design and Construction. Geodetic Studies . The measurement of vertical and hori- zontal movements of the earth's crust, using geodetic instruments a techniques, is another essential phase of the department's program for investigating and evaluating the problem of accumulating crusta strain. The following studies and activities will be continued a^ part of the geodetic phase of the Crustal Strain Investigation: 1. The department's program of geodlmeter measurements will be repeated along the San Andreas fault. These measurements are being improved by the adaptation of new techniques for obtalninj midline atmospheric measurements. It is planned to extend the department's program of geodlmeter measurements to other areas of the State where water development facilities are close to other active faults. These measurements will assist In distinguishing -30- active from Inactive faults and will show the various rates at which parts of the earth's crust are undergoing horizontal movements. 2. Coordination of state and federal earthquake engineer- ing survey programs will be continued. Inasmuch as the United States Coast and Geodetic Survey has been given primary responsibility for long-term earthquake triangulatlon surveys by acu of Congress, coor- dination is necessary to eliminate overlapping and duplication and to lend more specific direction to the federally financed geodetic pro- grams. Federal programs Include fault zone triangulatlon and astro- nomic azimuths for the measurement of horizontal crustal movements, and precise leveling to detect vertical movements. 3. The cooperative ultrapreclse triangulatlon project of the department and the United States Coast and Geodetic Survey for measurement of horizontal movements in the area of junction and near approach of the San Andreas, Garlock, and White Wolf faults will be repeated when the department's geodlmeter measurements indicate suf- ficient crustal movement to warrant the repetition. 4. The Federal-State Cooperative Leveling Program for Subsidence, administered by the department. Is another area of coop- ration with the United States Coast and Geodetic Survey. This pro- gram provides basic data on subsidence for planning and design sngineers in the department, and for other Interested agencies. This ooperative program will be continued. 5. The proposed Federal-State Cooperative Selsmologlc and leodetic Programs for Earthquake Engineering, with the United States oast and Geodetic Survey, will provide complete analysis and inter- pretation of already completed field work of special geodetic repeat -31- observations in California fault zones, analyses of existing strong- motion seismograph records of California earthquakes, and additional special geodetic repeat observations and analyses in fault zones in the vicinity of proposed State Water Pacillties, The survey will continue to operate and maintain the seismograph stations that have been made part of the cooperative program, and will supply personnel and services to install, operate, maintain, and interpret records of several of the seismographic Instruments and stations recommended by the Consulting Board for Earthquake Analysis. This cooperative pro- gram does not duplicate the department's Crustal Strain Program, but is an essential complement thereto. Engineering Geology Studies . Geologic studies are an es- sential phase of any thorough study of the hazards of earthquakes an crustal movements to manmade structures. Engineering geologists hav a public responsibility to ensure that engineers, architects, proper owners, and public officials are properly informed with respect to | earthquake hazards, without being too reassuring or needlessly alarni Ing. A clear idea must be formed of the long-term nature of earth- quake risk, as well as its relation to the location of faults and to the character of the ground or foundation. The following activities and studies are included in the geologic phase of the Crustal Strain- Investigation: 1, Detailed seismic microregionalization maps may be developed for specific sites and/or critical areas. This will entail compilation of the following types of data: a. Detailed information on potential activity of faults with particular emphasis on those ij -32- 1 faults which may affect existing and proposed hydraulic structures, b. Characteristics of foundation rocks and materials relative to seismic stability. These data and seismic microregionalization maps are im- portant in any earthquake engineering study, and will be most useful in appraising the earthquake and crustal movement hazards at sites of proposed facilities of the State Water Resources Development System. 2. Geologic interpretation will be provided for the strain build-up detected by the geodetic and geophysical measurements being made in other phases of the investigation. 3. Geologic field studies will Include reconnaissance of possible sites for future geodlmeter or other geodetic stations, or for future installations of geophysical instrumentation such as seismographs, quartz-strain extensometers, recording tlltmeters, accelerograph, and related types of instrumentation recommended by the department's Consulting Board for Earthquake Analysis. 4. Sites chosen for water development facilities through- out the State will be inspected as part of the department's earth- quake hazard evaluation studies, and a geologic evaluation of the earthquake and/or crustal movement hazards will be made at such sites. •33- DEPARTMENT EARTHQUAKE ENGINEERING INVESTIGATIONS The primary function of the earthquake engineering studies to be conducted by the Division of Design and Construction and the Supervision of Dam Safety Office will be the development of procedure: and criteria for aselsmlc design of features of the California Water Resources Development System and for Investigation of dams under Jurisdiction of the department's Supervision of Dam Safety Office from the seismic standpoint. These studies will utilize the afore- mentioned earthquake hazard studies to obtain an appreciation of the earthquake hazards which should be anticipated In any given area. The Division of Design and Construction has completed a proof test of the Orovllle embankment design. This seismic model study was one of several essential engineering studies which have been completed In connection with the design of Orovllle Dam. This : proof test of the embankment design was conducted on the shaking table of the Engineering Materials Laboratory on the Berkeley campus . of the University of California, IJie report on this seismic model , study will soon be completed In Its report of November 19, 1962, the Consulting Board ! for Earthquake Analysis recommended that the department undertake the following earthquake engineering Investigations In addition to the basic studies previously discussed: "l. Experimental investigations of the strength and deformation characteristics of soils under simu- lated earthquake loading conditions for the purpose of determining the appropriate soil properties for use in analyses of earthquake response character- istics. Studies should include: -35- " (a) Investigations of the strength and de- formation characteristics of soils under combined static and pulsating loads. " (b) Investigations of volume changes and strength characteristics of saturated granular materials under combined shear and vibratory loading conditions and also under high confining pressure con- ditions associated with large dams with the object of determining the pore pres- sures likely to develop in embankments composed of saturated granular materials during earthquakes. These studies should be supplemented by investigations of volume changes induced in dry granular materials by typical earthquake ground motions with the object of throwing some light on the extent of subsidence of such soils as a result of earthquakes, "2. Investigation of methods for predicting the danger of liquefaction of soils both in the laboratory and in the field. This investigation is closely related to that suggested in 1 (b) above. " 3. Investigation of the stability and deformation of model dams during simulated earthquake motions induced by a shaking table. Such studies would serve two purposes. " (a) As an interim procedure, tests on models of proposed prototypes would provide a guide to the probable effect of earth- quakes on these structures. However, this would only be possible for certain types of embankments. " (b) The results would provide data for de- termining the applicability of analyses and measured soil characteristics for predicting the response of embankments and dams to known ground motions. With- out such tests it is difficult to see how analytical procedures can ever be checked under controlled conditions. "4. Investigation of the stability against surface sliding of banks of granular materials subjected to earthquake ground motions, for the purpose of checking the appli- cability of available analyses for computing the ac- celeration at which sliding is likely to occur and -36- for determining the extent of sliding and flattening of slopes resulting from a given ground motion. "5= Investigations of the dynamic behavior of dams by the methods of analytical mechanics. Analyses of the elastic response of dams and embankments have been developed, but studies of elastic-plastic response are required to determine the stresses and displace- ments resulting from known earthquake ground motions. It is the inelastic displacements which are of pri- mary Importance in stability analyses. "6. Investigations of the dynamic behavior of existing dams by means of field tests using a shaking machine. The results of such studies can be Interpreted to evaluate the dynamic shear modulus of the soil com- prising the dam and can thus be used to check the validity of laboratory methods for determining the dynamic shear modulus of the soils in advance of construction. " The Crustal Strain and Fault Movement Investigation and the Dther earthquake engineering Investigations herein briefly described, lave been undertaken by the Department of Water Resources to provide Dbjectlve evaluations of possible hazards at hydraulic structure sites as related to the potential effects of California's sporadic arthquakes and to develop rational criteria for aseismic design of structures at those sites to obviate or minimize the adverse effects of future earthquakes. Utilization of the data on earthquake hazards and the criteria for aseismic design will contribute to the competent design of safe and economical hydraulic structures in all areas of the State. -37- /f ^ CRUSTAL STRAIN AND FAULT MOVEMENT INVESTIGATION GEODETIC PROGRAM 1959-1962 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW RENEWED BOOKS ARE SUBJECT TO IMMEDIATE RECALL RET. tifcB 1 1) 19B5 VIAR 9 107R '1 REC'D LIBRARY, UNIVERSITY OF CALIFORNIA, DAVIS Book Slip-50m-8,'63(D9954s4)4: ,,„, iiiili. .^^,. 3 1175 02037 7514 PHYSICAL SCIENCES LIBRARY TC^24 cz A2 ho n 6 I UNIVERSITY OF CAUf ORWIA DAVIS 306035