HR: 14:25h
AN: S52H-04    [PDF]
TI: Spectral Element Moment Tensor Inversions for Earthquakes in Southern California
AU: * Liu, Q
EM: lqy@gps.caltech.edu
AF: Seismological Laboratory California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Komatitsch, D
EM: komatitsch@yahoo.com
AF: Seismological Laboratory California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Tromp, J
EM: jtromp@gps.caltech.edu
AF: Seismological Laboratory California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AB: We have developed and implemented a Centroid Moment-Tensor (CMT) inversion procedure to determine source parameters for southern California earthquakes. The method is based upon spectral-element simulations of regional seismic wave propagation in a recently developed three-dimensional southern California model. Sensitivity to source parameters is determined by numerically calculating the Fr\'{e}chet derivatives required for the CMT inversion. We use a combination of waveform and waveform-envelope misfit criteria, and facilitate pure double-couple or zero-trace moment-tensor inversions. The technique is applied to six recent southern California earthquakes: the September~9, 2001, $M_w = 4.2$ Hollywood event, the October~31, 2001, $M_w=4.9$ Anza event, the September~3, 2002, $M_w = 4.2$ Yorba Linda event, the February~22, 2003, $M_w = 5.2$ Big Bear event and $M_w = 4.5$ Big Bear aftershock, and the July~15, 2003, $M_w =3.8$ Lucerne Valley event. Using more than half of the available three-component data at periods of 6~seconds and longer, the focal mechanisms, locations, and magnitudes we obtain are in good agreement with estimates based upon classical body-wave, surface-wave, and first-motion inversions.
DE: 1734 Seismology
SC: Seismology [S]
MN: 2003 Fall Meeting