HR: 0830h
AN: T51D-0196    [PDF]
TI: A System for Evaluating Earthquake Driven Stress Changes in the Los Angeles Region.
AU: * Powers, P M
EM: pmpowers@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Avenue South Science Hall, Rm. 117, Los Angeles, CA 90089-0740 United States
AU: Sammis, C
EM: sammis@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Avenue South Science Hall, Rm. 117, Los Angeles, CA 90089-0740 United States
AU: Jordan, T
EM: tjordan@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Avenue South Science Hall, Rm. 117, Los Angeles, CA 90089-0740 United States
AU: Okaya, D
EM: okaya@usc.edu
AF: University of Southern California, Dept. of Earth Sciences 3651 Trousdale Avenue South Science Hall, Rm. 117, Los Angeles, CA 90089-0740 United States
AB: Studies of Coulomb stress changes associated with large earthquakes (greater than M6.0) demonstrate that aftershocks commonly fall within zones of increased stress and that seismic hazard from additional large events increases within these zones. We are developing a system that will automate stress change calculations and integrate the results with ever-changing assessments of seismic risk in the Los Angeles region. One problem that arises in stress analysis is that it is difficult to determine stress changes on regional faults following earthquakes as fault geometries are often poorly constrained. For this reason, we integrate calculations of stress changes associated with 'scenario' earthquakes with the SCEC Community Fault Model (CFMA). By determining the stress change on each triangular patch of a fault, a clear picture of triggered earthquake hazard emerges. Here, we model ruptures on the San Andreas Fault and examine the resultant Coulomb stress change on the Sierra Madre Fault. A second motivation for the system is the desire to view the time-evolution of the regional stress field as it is altered by the numerous small (less than Mw5.0) earthquakes that occur in and around Los Angeles. Our system is also designed to access, query, and filter earthquake focal-mechanism catalogs and do summations of resultant stress changes.
DE: 8020 Mechanics
DE: 8123 Dynamics, seismotectonics
DE: 8164 Stresses--crust and lithosphere
SC: Tectonophysics [T]
MN: 2003 Fall Meeting