Russian Journal of Earth Sciences
Vol. 5, No. 1, February 2003
Seismic regime of Southern California in relation
to the crustal rigidity variations
V. I. Lykov and A. O. Mostryukov
Abstract
The Landers (southern California) destructive ( M = 7.3) earthquake of June 28, 1992 had epicentral coordinates of
(34.2oN, 116.44oW) and was a major seismic event of the period
from 1985 through 2002. It was examined in many
papers, mostly published in a special issue of Bulletin of Seismological Society
of America (BSSA) of June 1994
(vol. 84, no. 3). The majority of the works were devoted to phenomena related
to the earthquake itself and its effects.
The present paper presents the results derived from the analysis of rigidity variations
at the preparation stage
of the main shock. This analysis was based on a method developed by the authors for
the monitoring of rigidity
variations in the seismically active layer of the crust. The method reduces to the
possibility of discriminating
between the brittle and viscous failure modes using
P wave first arrival patterns.