HR: 15:25h
AN: S13E-08    [Abstracts]
TI: Another Look at the Source of the 1906 San Francisco Earthquake
AU: * Song, S
EM: seisgoo@pangea.stanford.edu
AF: Stanford University, 397 Panama Mall, Stanford, CA 94305 United States
AU: Beroza, G C
EM: beroza@pangea.stanford.edu
AF: Stanford University, 397 Panama Mall, Stanford, CA 94305 United States
AU: Segall, P
EM: segall@pangea.stanford.edu
AF: Stanford University, 397 Panama Mall, Stanford, CA 94305 United States
AB: We have taken another look at the source model of the 1906 San Francisco earthquake. Our study is motivated by the large and unresolved discrepancy between geodetic and seismic models of that event. The seismic model [Wald et al., 1993] of the earthquake has rupture that is only about two thirds of the total rupture length as determined geodetically [Thatcher et al., 1997]. Observations of recent large, continental strike-slip earthquakes [e.g., Bouchon and Vallee, 2003] suggests that rupture during these earthquakes may have exceeded the local shear wave velocity. It is reasonable to expect that the source behavior of the 1906 earthquake would be similar to these recent large strike-slip earthquakes, which motivates us to consider the possibility that the rupture velocity in the 1906 earthquake was supershear. Moreover, theoretical models of in-plane rupture suggest that supershear rupture might be expected to occur in this geometry. Our preliminary results suggest that supershear rupture does help to resolve the discrepancy between the seismic and geodetic models of the 1906 earthquake. We are revisiting the analysis of both the geodetic and seismic observations to test this hypothesis.
DE: 7230 Seismicity and seismotectonics
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics and mechanics
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting