|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
DEPARTMENT OF EARTH SCIENCES AND INSTITUTE OF GEOPHYSICS AND PLANETARY PHYSICS, UNIVERSITY OF CALIFORNIA, RIVERSIDE
Abstract
The major, historically active San Jacinto and San Andreas fault systems pass through the San Bernardino Valley area of southern California. An array of six portable, high-gain seismographs was operated for five 2-week recording sessions during the summer of 1972 and winter and spring of 1973 in order to detail the microseismicity of the region. A crustal model for the Valley, modified after Gutenberg, was established using a 6-km reversed seismic refraction profile and a series of monitored quarry blasts. Fifty-five microearthquakes were used to establish a magnitude scale (1.5 to 3.3) based on coda lengths recorded by instruments peaked at 20 Hz. Forty-five hypocenters from the analysis of over 6,000 hr of low-noise records define two northeast trending lineations within the western portion of the Valley. A composite first-motion plot of 22 microearthquakes from these lineations indicates left-lateral strike-slip faulting. Fluctuations in microseismicity appear to reflect rapid changes in the stress patterns of southern California. Minor activity along the strike of the San Jacinto fault zone suggests a purely right-lateral strike-slip motion. Only minimal strain release was observed along the San Andreas fault zone.
Footnotes
* Present address: Seismological Laboratory, California Institute of Technology, Pasadena, California 91109.
Present address Institute for Geosciences, University of Texas at Dallas, P.O. Box 688, Richardson, Texas 75080.
This article has been cited by other articles:
|
|
 |
|
  R. W. Graves The Seismic Response of the San Bernardino Basin Region during the 2001 Big Bear Lake Earthquake Bulletin of the Seismological Society of America, February 1, 2008; 98(1): 241 - 252. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. Graves and D. J. Wald Observed and Simulated Ground Motions in the San Bernardino Basin Region for the Hector Mine, California, Earthquake Bulletin of the Seismological Society of America, February 1, 2004; 94(1): 131 - 146. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Delineation of Faulting and Basin Geometry along a Seismic Reflection Transect in Urbanized San Bernardino Valley, California Bulletin of the Seismological Society of America, August 1, 2002; 92(6): 2504 - 2520.
|
|
|
|
|
|
H. Magistrale, S. Day, R. W. Clayton, and R. Graves The SCEC Southern California Reference Three-Dimensional Seismic Velocity Model Version 2 Bulletin of the Seismological Society of America, December 1, 2000; 90(6B): S65 - S76. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Frankel Dense array recordings in the San Bernardino Valley of landers-big bear aftershocks: Basin surface waves, Moho reflections, and three-dimensional simulations Bulletin of the Seismological Society of America, June 1, 1994; 84(3): 613 - 624. [Abstract] [PDF]
|
|
|
|
|
|
A. FRANKEL Three-dimensional simulations of ground motions in the San Bernardino Valley, California, for hypothetical earthquakes on the San Andreas fault Bulletin of the Seismological Society of America, August 1, 1993; 83(4): 1020 - 1041. [Abstract] [PDF]
|
|
|
|
|
|
R. W. GRAVES and R. W. CLAYTON Modeling path effects in three-dimensional basin structures Bulletin of the Seismological Society of America, February 1, 1992; 82(1): 81 - 103. [Abstract] [PDF]
|
|
|
|
|
|
P. SPUDICH and D. P. MILLER Seismic site effects and the spatial interpolation of earthquake seismograms: Results using aftershocks of the 1986 North Palm Springs, California, earthquake Bulletin of the Seismological Society of America, December 1, 1990; 80(6A): 1504 - 1532. [Abstract] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
