HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by BOLT, B. A. Search for Related Content GeoRef GeoRef Citation

San Fernando rupture mechanism and the Pacoima strong-motion record

SEISMOGRAPHIC STATION DEPARTMENT OF GEOLOGY AND GEOPHYSICS UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA

Abstract

The extent of fault rupture in the main San Fernando earthquake of February 9, 1971 is well determined. This paper explains the time history of the unique Pacoima accelerogram in terms of the rupture mechanism and elastic wave theory. The Pacoima strong-motion record was obtained on the crystalline rocks of the San Gabriel Range which were thrust southward.

The three recorded components are resolved along the strike, dip and normal to the fault plane. Filtered accelerograms are given for 0.5, 0.75, 1.0, 1.5, 2, 4, and 10 Hz. These time histories are very different. The first half of the records (with the longer spectral components) show clearly P and S onsets from the focus, and the fault dislocation passing with average rupture velocity 3.0 km/sec under Pacoima. The latter part of the record consists predominantly of 1.5 to 10 Hz waves which cease 9 to 10 sec after P. These waves are the superposition of high-frequency waves (mainly S) which propagated with little attenuation through the crystalline crustal rocks. As the rupture progressed, waves were produced in a random manner as bursts of high-frequency energy near the rupture front.

This article has been cited by other articles:

				An Observation of Rupture Pulses of the 20 September 1999 Chi-Chi, Taiwan, Earthquake from Near-Field Seismograms Bulletin of the Seismological Society of America, October 1, 2004; 91(5): 1247 - 1254.

				A. S. PAPAGEORGIOU and K. AKI A specific barrier model for the quantitative description of inhomogeneous faulting and the prediction of strong ground motion. Part II. Applications of the model Bulletin of the Seismological Society of America, August 1, 1983; 73(4): 953 - 978. [Abstract] [PDF]

				M. BOUCHON A dynamic source model for the San Fernando earthquake Bulletin of the Seismological Society of America, December 1, 1978; 68(6): 1555 - 1576. [Abstract] [PDF]

				R. DOBRY, I. M. IDRISS, and E. NG Duration characteristics of horizontal components of strong-motion earthquake records Bulletin of the Seismological Society of America, October 1, 1978; 68(5): 1487 - 1520. [Abstract] [PDF]

				J. SHOJA-TAHERI and B. A. BOLT A generalized strong-motion accelerogram based on spectral maximization from two horizontal components Bulletin of the Seismological Society of America, June 1, 1977; 67(3): 863 - 876. [Abstract] [PDF]

				A. NIAZY An exact solution for a finite, two-dimensional moving dislocation in an elastic half-space with application to the San Fernando earthquake of 1971 Bulletin of the Seismological Society of America, December 1, 1975; 65(6): 1797 - 1826. [Abstract] [PDF]

				J. P. FLETCHER and J. G. ANDERSON First strong-motion records from a central or eastern United States earthquake Bulletin of the Seismological Society of America, October 1, 1974; 64(5): 1455 - 1465. [Abstract] [PDF]

				J. ANDERSON A dislocation model for the Parkfield earthquake Bulletin of the Seismological Society of America, June 1, 1974; 64(3-1): 671 - 686. [Abstract] [PDF]

				D. M. BOORE The effect of simple topography on seismic waves: Implications for the accelerations recorded at Pacoima Dam, San Fernando Valley, California Bulletin of the Seismological Society of America, October 1, 1973; 63(5): 1603 - 1609. [Abstract] [PDF]