HR: 0800h
AN: S21A-0235    [Abstracts]
TI: 3D structure effects on local and near-regional seismic wave propagation in the San Francisco Bay Area
AU: * Kim, A
EM: ahyi@seismo.berkeley.edu
AF: University of California, Berkeley, 289 McCone Hall Department of Earth and Planetary Science, Berkeley, CA 94720, United States
AU: Dreger, D
EM: dreger@seismo.berkeley.edu
AF: University of California, Berkeley, 289 McCone Hall Department of Earth and Planetary Science, Berkeley, CA 94720, United States
AU: Larsen, S
EM: larsen8@llnl.gov
AF: Lawrence Livermore National Laboratory, Box 808, L-103, Livermore, CA 94551, United States
AB: In this study we performed 3D waveform modeling of 10 small to moderate events (Mw 4.1-5.0) in the San Francisco Bay Area using the USGS SF06 3D velocity model (Brocher et al., 2005; Jachens et al., 2005). In the simulations we assumed the source parameters reported in the Berkeley Seismological Laboratory (BSL) Moment Tensor Catalog. Broadband seismic data from the Berkeley Digital Seismic Network (BDSN), and strong motion data from the USGS and the California Geologic Survey California strong motion arrays were used in the analysis. We analyzed and modeled the data in three frequency bands, namely 0.03-0.15 Hz, 0.1-0.25 Hz, and 0.1-0.5Hz. Preliminary waveform modeling shows that the USGS SF06 model predicts many important features of observed seismograms including bodywave arrival times, and peak ground velocity. On the other hand, as reported by Rodgers et al. (2007), the model produces late arriving surface waves. While peak ground velocity is generally well modeled there are paths that have significant amplitude mismatches and also poor waveform fit to sedimentary basin generated surface waves. We are identifying which paths need additional waveform modeling in order to further calibrate the 3D structure. We will present the bodywave and surface wave arrival time, and peak ground velocity correlations as well as forward modeling results for the problematic paths. References Brocher, T. M., (2005). Emprical relations between elastic wave speeds and density in the Earthfs crust, Bull. Seism. Soc. Am., 95 No. 6, 2081-2092. Jachens, R., R. Simpson, R. Graymer, C. Wentworth, T. Brocher (2006). Three-dimensional geologic map of northern and central California: A basic model for supporting ground motion simulation and other predictive modeling, 2006 SSA meeting abstract, Seism. Res. Lett., 77, No.2, p 270. Rodgers, A., A. Petersson, S. Nilsson, B Sjogreen, K. McCandless (2007). Broadband waveform modeling of moderate earthquakes in the San Francisco Bay Area and preliminary assessment of the USGS 3D seismic velocity model, submitted Bull. Seism. Soc. Am.
UR: http://seismo.berkeley.edu/~ahyi/
DE: 7203 Body waves
DE: 7205 Continental crust (1219)
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7290 Computational seismology
SC: Seismology [S]
MN: 2007 Fall Meeting