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Strong SH ‐to‐Love Wave Scattering off the Southern California Continental Borderland
Author(s) -
Yu Chunquan,
Zhan Zhongwen,
Hauksson Egill,
Cochran Elizabeth S.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl075213
Subject(s) - geology , seismology , escarpment , bathymetry , scattering , continental shelf , amplitude , azimuth , seismogram , waveform , microseism , geophysics , geodesy , oceanography , physics , geomorphology , optics , quantum mechanics , voltage
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 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 at a dominant period of ~10 s 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. 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.