S51A-2662
Full source tensor inversions of San Jacinto fault zone earthquakes using 3D Green’s functions with the gCAP method
Friday, 18 December 2015
Poster Hall (Moscone South)
Zachary Ross, University of Southern California, Department of Earth Sciences, Los Angeles, CA, United States, Yehuda Ben-Zion, University of Southern California, Los Angeles, CA, United States, Lupei Zhu, Saint Louis University Main Campus, Earth & Atmospheric Sciences, Saint Louis, MO, United States and Robert W Graves, USGS California Water Science Center Menlo Park, Menlo Park, CA, United States
Abstract:
We perform a full source tensor inversion of several M > 4 earthquakes that occurred in the San Jacinto fault zone in southern California, with an emphasis on resolving signatures of volumetric source changes. A previous study on these events with Green’s functions based on a 1D velocity model identified statistically significant explosive isotropic components (Ross et al. 2015). Here we use the SCEC 3D Community Velocity Model to derive Green’s functions with source-receiver reciprocity and finite-difference calculations based on the code of Graves (1996). About 50 stations are used at epicentral distances of up to 55 km. The inversions are performed using the ‘generalized Cut and Paste’ method, which includes CLVD and isotropic components (Zhu and Ben-Zion 2013). The derived source tensors are compared to the results of the previous study based on the simplified 1D velocity model. The results are analyzed with bootstrap analysis to estimate uncertainties involved. Additional tests are performed using synthetic waveforms to study the effects of neglecting various features on the source inversions.
