HR: 0800h
AN: T21B-0469    [Abstracts]
TI: Full-Waveform Earthquake Location and the Mechanics of Streaks on the Calaveras Fault
AU: * Rubinstein, J L
EM: justin@pangea.stanford.edu
AF: Stanford University, Department of Geophysics 397 Panama Mall, Stanford, CA 94305 United States
AU: Beroza, G C
EM: beroza@pangea.stanford.edu
AF: Stanford University, Department of Geophysics 397 Panama Mall, Stanford, CA 94305 United States
AB: Recent advances in earthquake location techniques and their application to large waveform datasets have uncovered a number of previously obscured seismic phenomena. These phenomena have the potential to provide new insight into the physics of faulting and earthquakes. Seismic streaks are one of these phenomena, and we have developed a new method of earthquake location to study them. Our technique is based upon standard array analysis methods, but applied in the reciprocal geometry to earthquake sources instead of the more typical receiver array analysis. Using array techniques allows us to use information contained throughout the entire waveform, unlike traditional location techniques that rely solely on measurements of the direct P and S arrivals. This allows us to determine centroid locations for earthquakes previously unlocated or poorly located by standard methods due to clipping or lack of data. It also has the potential to produce high-resolution earthquake locations for similar events even with relatively few stations. Here, we apply this method to medium magnitude earthquakes (M3.5-M5) near streaks on the Calaveras fault. We find that that these earthquakes initiate within the seismic streaks, and rupture into regions generally devoid of microseismicity. From this, we infer that seismic streaks represent a rheological boundary between creeping and locked sections of a fault.
UR: http://pangea.stanford.edu/~jrubinst/streaks.html
DE: 7200 SEISMOLOGY
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Tectonophysics [T]
MN: Fall Meeting 2005