SCEC Award Number 16074 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title High-resolution seismic imaging of the very shallow crust
Name Organization
Yehuda Ben-Zion University of Southern California
Other Participants The following USC students will be involved:
Hongrui Qiu
Lei Qin
Xin Liu

The funding will be used to support mainly Hongrui
SCEC Priorities 4b, 6a, 6c SCEC Groups CCSP, GMP, Seismology
Report Due Date 03/15/2017 Date Report Submitted 03/25/2017
Project Abstract
We performed detailed imaging of seismic velocities, attenuation and anisotropy in the shallow crust within and around the San Jacinto Fault Zone (SJFZ) using data recorded by dense linear and rectangular fault zone arrays. The studies are associated with a newly developed technique using focal spots of surface waves associated with the zero lag amplitudes of noise cross-correlations computed between different stations. The results reveal very low seismic velocities and attenuation coefficients in the top few hundred m of the crust, along with clear variations of properties across the fault and a shallow trapping structure adjacent to a mapped surface trace of the Clark fault in the trifurcation area. We also analyzed random errors in cross-correlations of ambient seismic noise in the frequency domain and estimate confidence interval of stacked cross-spectrum of finite amount of data at different frequencies The technique is applied to constrain values and uncertainties of amplitude and phase velocity of stacked noise cross-spectrum at different frequencies, using data from southern California at both regional scale and dense linear array across the SJFZ. Finally, we developed and implemented a new technique for estimating deviations from a fully diffuse random noise field by analyzing cross-frequency correlations in stations of the regional southern California network.