HR: 1340h
AN: T13A-1342    [Abstracts]
TI: Combined Teleseismic and Local Earthquake Tomography of the SAFOD Drill Site
AU: * Krajewski, J
EM: krajej@rpi.edu
AF: Rensselaer Polytechnic Institute, Dept Earth and Enivronmental Sciences 110 Eighth Street, Troy, NY 12180 United States
AU: Roecker, S
EM: roecks@rpi.edu
AF: Rensselaer Polytechnic Institute, Dept Earth and Enivronmental Sciences 110 Eighth Street, Troy, NY 12180 United States
AU: Thurber, C
EM: thurber@geology.wisc.edu
AF: University of Wisconsin-Madison, Dept Geology and Geophysics 1215 W Dayton St, Madison, WI 53706 United States
AB: Using data from the PASO array in Parkfield, California, we derived an image of P wavespeeds and Vp/Vs ratios in the crust and upper mantle beneath the region of the SAFOD drill site though a combined teleseismic and local arrival time inversion. Relative teleseismic arrival times are determined using a waveform correlation technique similar to that described by VanDecar and Crosson (1990). In all, our teleseismic data set consists of about 14,000 arrivals from 320 events, which we combine with about 60,000 P and S arrival times from 636 local earthquakes and 103 shots. The broader ray coverage afforded by the teleseismic arrivals allows us to resolve structure below the upper 8-10 km sampled by local events to depths of about 30 km, and the combination of data sets reduces the potential for streaking of the strongest heterogeneities near the upper parts of the fault zone to deeper depths. Nevertheless, we find that inversions using teleseismic arrivals alone are capable of resolving the first order features apparent in the local earthquake tomography results of Thurber et al. (2004) and Roecker et al (2004).
DE: 8180 Tomography
DE: 8015 Local crustal structure
DE: 8110 Continental tectonics--general (0905)
DE: 7200 SEISMOLOGY
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting