HR: 0830h
AN: NG41C-0066    [PDF]
TI: An Observational Test of the Stress Recovery Model for Seismicity Preceding Landers.
AU: * Levin, S Z
EM: shoshanl@earth.usc.edu
AF: University of Southern California, Department of Earth Sciences, Los Angeles, CA 90089-0740 United States
AU: Sammis, C G
EM: sammis@earth.usc.edu
AF: University of Southern California, Department of Earth Sciences, Los Angeles, CA 90089-0740 United States
AU: Bowman, D D
EM: dbowman@fullerton.edu
AF: Cal-State Fullerton, Department of Geological Sciences, Fullerton, CA 92834-6850 United States
AB: We test the Bowman and King [GRL, 2001] "stress recovery" model by examining the pattern of strain released by small events prior to the 1992 Landers earthquake. The stress recovery (SR) model was developed to explain observations of accelerating seismicity preceding large earthquakes. The model proposes that the accelerating seismicity sequences result from tectonic loading that erodes the stress shadow from a prior event and increases elastic strain across the locked portion of the main fault. We test the prediction of the SR model that the pattern of strain released by the precursory seismicity should correlate with the strain building across the locked portion of the main fault. Our results show correlation of the seismicity-based strain field with the pre-Landers model strain field, and weak anti-correlation with the post-Landers model strain field. The correlation and anti-correlation are optimized when an approximately N-S compressive stress of 8 to 20 bars is added to the model.
DE: 7230 Seismicity and seismotectonics
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting