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Procedures for Estimating Earthquake Ground Motions

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Procedures for Estimating Earthquake Ground Motions PROCEDURES FOR ESTIMATING EARTHQUAKE GROUND MOTIONS High-altitude view of the San Francisco Bay region showing surface traces of the Hayward and Calaveras faults. The Hayward fault was the source of two large earthquakes in 1836 and 1868 that caused surface rupture along as much as 64 km of its trace. The Calaveras fault, with a length of approximately 160 km, is one of the largest in northern California. The San Andreas fault passes offshore near Mussel Rock (arrow at bottom of photograph). Fault systems such as these must be critically studied when evaluating the seismic hazards and risk in an urban area. Procedures for Estimating Earthquake Ground Motions By WALTER W. HAYS GEOLOGICAL SURVEY PROFESSIONAL PAPER 1114 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Hays, Walter W. Procedures for estimating earthquake ground motions. (Geological Survey professional paper ; 1114) Bibliography: p. 69-77. Supt.ofDocs.no.: 119.16:1114 1. Earthquakes-United States. 2. Seismology United States. 3. Earthquake resistant design. I. Title. II. Series: United States. Geological Survey. Professional paper ; 1114. QE539.H39 363.3'495 79-607183 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 Stock Number 024-001-03276-7 CONTENTS Page Page Glossary ____________________________VII Define the characteristics of ground shaking—Continued Abstract ______________________________ 1 Spectra _______________________________ 34 Introduction______________________________ 2 Knowledge gained from nuclear explosion ground- Determine seismicity ______________________ 3 motion studies________-_ —— ————— ———— 37 Sources of information _____________________ 5 Intensity ___________________ ———— — —— ——— 41 Summary of United States earthquake history _______ 5 Probabilistic estimates of peak ground acceleration ___ 42 Identify seismotectonic features._________________ 9 Effective peak ground acceleration ____—————————— 43 Summary of United States earthquakes ___________ 12 Define design response spectra for site —__ —————— _______ 43 Western United States ___________________ 12 Summary of procedures for siting of nuclear powerplants __ 44 Eastern United States ___________________ 17 Site-independent response spectra__—————— ———— _ 46 Determine regional seismic attenuation _ _______ _____ 19 Site-dependent response spectra __—————— —— —— _ 51 Define the characteristics of ground shaking expected at the site 21 Design time histories _____——— ——— __ —— ———— 54 The seismogram___________________________ 23 Determine local ground response _ __ __ _—————————— 56 Types of information derived from the seismogram _____ 25 Summary of Uniform Building Code procedures __________ 63 Peak ground acceleration.___________________ 28 Define uncertainties of the ground-motion design values ———_ 66 Peak ground velocity and displacement ___________ 31 Seismic design trends for the future___________---——— 68 Duration ______________________________ 33 References cited —____ ——— —————— ———— —--————— 69 ILLUSTRATIONS Page FRONTISPIECE. High-altitude view of the San Francisco Bay region showing surface traces of the Hayward and Calaveras faults. FIGURE 1. Flow diagram illustrating steps in estimating ground motions for design of earthquake-resistant structures —— 4 2-5. Maps showing: 2. Location of past destructive earthquakes in the United States____________________________ 6 3. Areas of the conterminous United States where regional seismicity studies have been made—— ——— __— 7 4. Seismic source zones within the conterminous United States ____________ ——————— —— ----— 8 5. Principal faults in the vicinity of Fremont, Calif ____________— — ——— __ ———— -_ — ——— ——— 11 6. Chart for correlating fault rupture length and earthquake magnitude _______————__ —————— -- —— ——— 12 7-15. Maps showing: 7. Major tectonic features along the Pacific-North American plate boundary in Alaska —— — ——— ———— 12 8. Epicenters of earthquakes in Alaska between 1962 and 1969 __________— ——————— ——— ———— 13 9. Major faults in southern Alaska _____________———————— —————— _ ——— ——— ——— --— 14 10. Major faults in California and Nevada and locations of past surface ruptures___________ — ———— —— 15 11. Wasatch fault zone.________________________________—-- ————— — ——— ——— 17 12. Major tectonic features and historic earthquake activity in the Mississippi Valley area __ — ——— _——— 18 13. Historic seismicity in South Carolina area______—__ — ———— __ ——— __ ——— ——— — ——— ———— 19 14. Isoseismal contours for 1971 San Fernando, Calif., earthquake ______ — ——— ——— — ______———— 20 15. Isoseismal contours for 1906 San Francisco and 1811 New Madrid earthquakes _ ———— — ——— ————— 21 16-20. Graphs showing: 16. Empirical intensity attenuation curves proposed for the southern Appalachian seismic zone and the central Mississippi Valley _______________________--_____-———————— —— _____ 22 17. Average value of maximum acceleration in relation to distance from fault for earthquakes of various magnitudes, Western United States _____________________— —— ——————— __ ——— ——— 22 18. Schnabel and Seed acceleration-attenuation curves modified for use in the Eastern United States ———— 23 19. Acceleration-attenuation relations derived from worldwide earthquakes and the San Fernando earth­ quake, 1971 ______________________________________________________ 24 20. Frequency-dependent attenuation of horizontal ground motions, southern Nevada and Colorado __ ——— — 26 21. Schematic diagram of elements that affect ground motion _________________________________ 26 22. Accelerogram of the 1940 Imperial Valley, Calif, earthquake recorded at El Centre, Calif_______________ 27 V VI CONTENTS Page FIGURE 23. S. 16° E. accelerogram recorded at Pacoima Dam and the velocity and displacement seismograms derived from it; 1971 San Fernando, Calif., earthquake _________________________________________ 28 24. Graphic illustration of determination of Richter magnitude--_________________————————————— 28 25. Graph showing range of horizontal peak acceleration as a function of distance and magnitude for rock sites in the Western United States ____________________________________________________ 31 26. Graph showing relation between peak horizontal ground velocity and distance from source of energy release for magnitude 6.5 earthquakes-__________________________———____ ———— - —————— — 34 27. Bracketed duration values for the S. 16° E. accelerogram recorded at Pacoima Dam from the 1971 San Fer­ nando earthquake and graph showing bracketed duration as a function of magnitude and fault rupture length ______________________________________________________________ 35 28. Graph of integral definition of duration of shaking for a site on rock and a site underlain by alluvium — ————— 36 29. Graph of Fourier amplitude spectrum derived from the accelerogram recorded at El Centre from the 1940 Im­ perial Valley, Calif, earthquake —_____________________________ — _______————- 36 30-35. Schematic illustrations of: 30. Far-field displacement spectrum and some of the information about the source that can be derived from it—_____________________________________________________________________—_ 37 31. Narrow-band-pass filtering involved in deriving a response spectrum _——__ ——————————— ————— 38 32. Response spectra derived from the 1940 Imperial Valley, Calif, earthquake accelerogram ————————— 39 33. Time-dependent response envelope derived from the 1940 Imperial Valley, Calif, earthquake accelerogram 39 34. Source effects on the spectral composition of ground motion________———————————————————— 39 35. Transmission path effects on the spectral composition of ground motion, 1971 San Fernando earthquake-- 39 36. Map showing Nevada Test Site and vicinity ______________________________________———— 40 37-41. Graphs showing: 37. Response spectra for 1940 Imperial Valley, Calif, earthquake and Cannikin nuclear explosion— —— ——— 40 38. Response spectra for two sites equidistant from energy source but on different travel paths _________ 40 39. Variability of ground motion recorded at two sites in Tonopah, Nev _________ _____ ____ ___ 40 40. Intensity and acceleration relations _________________________________________ 41 41. Mean values and standard-deviation error bars of peak ground acceleration, peak ground velocity, and peak ground displacement as a function of Modified Mercalli intensity, Western United States ——— 42 42. Map showing levels of peak horizontal ground acceleration expected at the 90-percent probability level at rock sites in the United States within a 50-year period _______________________________ 43 43. Acceleration, velocity, and displacement seismograms from the 1966 Parkfield, Calif., earthquake recorded at station Cholame-Shannon No. 2 __________________________________—————____——— 44 44-56. Graphs showing: 44. Variation in ground-motion response spectra and peak ground acceleration values for the same value of Modified Mercalli intensity, San Fernando, Calif, earthquake _________________—___ 47 45. Site-independent velocity and acceleration response spectra _______________________———— 47 46. Schematic illustration of technique for developing site-independent response spectra ————_____——— 49 47. "Standard" site-independent horizontal response spectra _________________———————_————_ 50 48. Site-independent
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