Strong SH-to-Love Wave Scattering off the Southern California Continental Borderland

Zhongwen Zhan, Chunquan Yu, Egill Hauksson, & Elizabeth S. Cochran

Published August 15, 2017, SCEC Contribution #7714, 2017 SCEC Annual Meeting Poster #036

Seismic scattering is commonly observed and results from wave propagation in heterogeneous medium. Yet, deterministic characterization of scatterers associated with lateral heterogeneities remains challenging. In this study, we analyze broadband waveforms recorded by the Southern California Seismic Network (SCSN) and observe strongly scattered Love waves following the arrival of teleseismic SH wave. These scattered Love waves travel approximately in the same (azimuthal) direction as the incident SH wave but at an apparent velocity of ~3.6 km/s as compared to the ~11 km/s for the SH wave. Back-projection suggests that this strong scattering is associated with pronounced bathymetric relief in the Southern California Continental Borderland, in particular the Patton Escarpment and possibly the borderland basins. Finite-difference simulations using a simplified 2-D bathymetric and crustal model are able to predict the arrival times and amplitudes of major scatterers. The modeling suggests a relatively low shear wave velocity in the Continental Borderland.

Key Words
Seismic scattering, Body-to-surface wave conversion, Heterogeneity, California Continental Borderland

Zhan, Z., Yu, C., Hauksson, E., & Cochran, E. S. (2017, 08). Strong SH-to-Love Wave Scattering off the Southern California Continental Borderland. Poster Presentation at 2017 SCEC Annual Meeting.

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