Seismic Intensities of Earthquakes of Conterminous United States Their Prediction and InterpretationJL Seismic Intensities of Earthquakes of Conterminous United States Their Prediction and Interpretation By J. F. EVERNDEN, W. M. KOHLER, and G. D. CLOW GEOLOGICAL SURVEY PROFESSIONAL PAPER 1223 Description of a model for computing intensity patterns for earthquakes. Demonstration and explanation of systematic variations of attenuation and earthquake parameters throughout the conterminous United States UNITED STATES GOVERNMENT PRINTING OFFICE, WASH INGTON: 1981 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Doyle G. Frederick, Acting Director Library of Congress catalog-card No. 81-600089 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Page Abstract ___________________________ ___ 1 Examples of observed predicted intensities Con. Introduction __ ____________________ 1 Seattle earthquake of April 13, 1949 ____________ 23 Rossi-Forel intensities versus Modified Mercalli intensities __ 2 Lompoc earthquake of November 4, 1927 __________ 27 Presently available models for predicting seismic intensities __ 3 Earthquakes of Eastern United States _ _______ _ 36 California ___________________________ 3 Fault length versus moment, magnitude, and energy release Conterminous United States _______________ 4 versus k region._______________________ 36 Examples of observed versus predicted intensities____ ___ 7 Crustal calibration as function of region __ _ _________ 42 Santa Barbara earthquake of June 29, 1925 _ ___ ___ 7 Length of break versus moment versus k value throughout the Monterey Bay earthquake of October 22, 1926 ______ 7 United States and suggested interpretation _______ 43 San Jose earthquake of July 1, 1911 _______________ 10 Maps of predicted intensity patterns _______________ 47 Fort Tejon earthquake of January 9, 1857 ________ _ 12 Estimate of dollar loss for individual potential earthquakes __ 48 Long Beach earthquake of March 10, 1933 ________ 13 Mathematical details of model for predicting intensities _ __ _ 51 Bryson earthquake of November 21, 1952 __________ 15 Details of Rossi-Forel and Modified Mercalli intensity scales __ 54 Kern County earthquake of July 21, 1952 _________ 19 References cited ____ ________ -_________- 55 ILLUSTRATIONS [Plates are in pocket] PLATE 1. Maps showing ground-condition units digitized on Vfc-minute by Vfe-minute grid and predicted Rossi-Forel intensities for the 1857 Fort Tejon earthquake, southern California. 2-5. Maps of conterminous United States showing: 2. Ground-condition units and attenuation factors digitized on 25-km by 25-km grid. 3. Predicted Rossi-Forel intensities on saturated alluvium and on digitized ground-condition units for the 1906 San Francisco, California, 1755 Cape Ann, Massachusetts, and potential Wasatch fault, Utah, earthquakes. 4. Predicted Rossi-Forel intensities on saturated alluvium and on digitized ground-condition units for the 1886 Charleston, South Carolina, and 1872 Owens Valley, California, earthquakes. 5. Predicted Rossi-Forel intensities on saturated alluvium and on digitized ground-condition units for the 1811 New Madrid, Missouri, 1949 Seattle, Washington, and 1857 Fort Tejon, California, earthquakes. Page FIGURE 1. Map showing area of California for which geology has been digitized on a Vfc-minute by Vfe-minute grid __ 3 2. Graph showing intensity.data of Oroville earthquake ______________________ 6 3-21. Maps showing: 3. Reported and predicted R/F intensity values for Santa Barbara, Calif., earthquake, 1925 __ __ 7 4. Predicted R/F intensity values on saturated alluvium and on ground-condition units digitized on 6-minute by 6-minute grid, Santa Barbara earthquake, 1925 ____________ __ 8 5. Predicted R/F intensity values on ground-condition units digitized on Mi-minute by Vis-minute grid, Santa Barbara earthquake, 1925 _____________________________________________ _____ 9 6. Location of main shock, aftershocks, and isoseismals, Monterey Bay earthquake, 1926 10 7. Predicted R/F intensities for saturated alluvium and ground-condition units digitized on 6-minute by 6-minute grid, Monterey Bay earthquake, 1926 __________________ - --- 11 8. Predicted M/M and R/F intensities for the 1933 Long Beach, Calif., earthquake ___________________ 15 9. Predicted M/M intensities for saturated alluvium and for 6-minute by 6-minute ground-condition units, Bryson, Calif., earthquake __________________________ __ 19 10. Observed and predicted M/M intensities for Kern County earthquake, 1952, for all of California 21 III IV CONTENTS Page FIGURE 11. Comparison of observed and predicted M/M intensities for region of k=lV2, Kern County, Calif., earthquake, 1952 22 12. Predicted M/M intensities for Kern County earthquake, 1952, for range of ground conditions and focal depths __ 23 13. Predicted R/F and M/M intensities for Kern County earthquake, 1952 __________________________ 24 14. Predicted M/M intensities for Seattle, Wash, earthquake, 1949, for saturated alluvium conditions and different fault lengths _________________________________________________________ 26 15. Predicted M/M intensities for Seattle earthquake, 1949, ground conditions from 25-km by 25-km grid ______ 26 16. Predicted and observed R/F intensities for Lompoc, Calif, earthquake, 1927, for two hypothetical fault breaks through epicenter located by Byerly__________________________________________ 27 17. Predicted and observed R/F intensities for Lompoc earthquake, 1927, for two hypothetical fault breaks through epicenter located by Hanks ___ ___________ _ ______ _ _____ - _______ _________ - 28 18. Predicted and observed R/F intensities for Lompoc earthquake, 1927, for hypothetical fault with orientation and length suggested by Hanks _____________________ _____________________________ 29 19. Predicted and observed R/F intensities for Lompoc earthquake, 1927, based on hypothetical fault placed so as to yield isoseismals in agreement with observed intensities __________________________ 29 20. Predicted and observed R/F intensities for Lompoc earthquake, 1927, for various lengths of Hosgri fault and various ground conditions ____________________________________________________ 30 21. Fault models used in calculations of site-intensity values for Lompoc earthquake, 1927 ____________ 31 22-24. Graphs showing: 22. Lengths of fault break as a function of seismic moment and area within intensity VI contours for k= 1% and k= 1% 39 23. Length of fault break as a function of seismic moment for all k regions of conterminous United States___ ___ 44 24. Area within intensity VI contour as a function of seismic moment for all k regions of conterminous United States 45 25. Map of California showing fault breaks used in models for estimating replacement value of damaged wood-frame construction _________________________________________________________ 46 TABLES TABLE 1. Correlation of geologic and ground-condition units in California ________________________ 3 2. Correlation of ground-condition units of California and assigned relative intensity values ___________ 3 3. Correlation of geologic and ground-condition units, conterminous United States _____________________ 5 4. Correlation of ground-condition units and assigned relative intensity values, conterminous United States ___ 5 5. Observed and predicted intensities, Santa Barbara earthquake ___________________________ 8 6. Observed and predicted R/F intensity values, Monterey Bay earthquake_________ 10 7. Observed and predicted R/F intensities, San Jose earthquake ___________ -___ _ 12 8. Observed and predicted R/F intensities, Fort Tejon earthquake _______________________________- 12 9. Observed and predicted M/M intensities, Long Beach earthquake _______ ________________ 14 10. Calculated parameters for the Long Beach earthquake _____________________________________ 16 11. Observed and predicted M/M intensities, Bryson earthquake _____________________ 17 12. Calculated parameters for the Bryson earthquake _________________ _________-_____ 17 13. Calculated parameters for the Bryson earthquake _________________________ ____________ 18 14. Observed and predicted M/M intensities, Seattle earthquake _________________ 25 15. Predicted and observed intensity values at specific sites, Lompoc earthquake of November 4, 1927___ _ _ _ 30 16. Average predicted intensities for saturated alluvium and Mi-minute by %-minute ground-condition units, Lompoc earthquake ________________________________________________________ 31 17. Calculated parameters for the Lompoc earthquake using midpoint of Byerly's (1930) "observed" intensity bands, k = 1.75 __________________________________________________________________ 32 18. Calculated parameters for the Lompoc earthquake using modified "observed" intensities, k = 1.75 _____ 33 19. Calculated parameters for the Lompoc earthquake using midpoint of Byerly's (1930) "observed" intensity bands, k = 1.675 _____________________________________________________________________________________________ 34 20. Calculated parameters for the Lompoc earthquake using modified "observed" intensities, k = 1.675 35 21. Observed and estimated parameters for selected earthquakes in the Eastern United States _____________ 37 22. 2L, "E0", and "M" values for selected earthquakes in the United States ___ _ _______ _______ 37 23. Observed and calculated parameters of earthquakes in regions of k = 1% and k = I1/., California and Idaho _ 38 24. Observed and calculated