SCEC Award Number 15036 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Basin Response to Virtual Earthquakes on the San Jacinto Fault and the Itoigawa-Shizuoka Fault
Name Organization
Marine Denolle University of California, San Diego Frank Vernon University of California, San Diego
Other Participants
SCEC Priorities 6b SCEC Groups Seismology, GMP
Report Due Date 03/15/2016 Date Report Submitted 03/03/2016
Project Abstract
Our project aims to construct Virtual M7 earthquakes on the San Jacinto Fault (SJF) and the Itoigawa-Shizuoka Tectonic Line (ISTL) and predict ground motion in the greater Los Angeles and Tokyo metropolitan areas using high-quality, multi-year stacks ambient seismic field Green’s functions. We have computed 3-year stacks in Japan of all 9 component of the Green tensor between virtual sources on the Itoigawa-Shizuoka Tectonic Line (ISTL) and all receivers in the Tokyo Metropolitan area. We are currently pre-processing the California data set for years 2010-2014.
The cross-correlations functions in Japan are unusual in that several modes of Love and Rayleigh waves are visible in the frequencies of interest. The virtual earthquake approach was developed based on the assumption that only surface-wave fundamental modes were present. We need to isolate all modes, decouple Rayleigh from Love waves on all 9 components of the Green’s function and isolate the fundamental and higher overtones of surface waves. We use well established kinematic simulator to construct realistic earthquake source scenario and will be able to investigate effects of source directivity onto strong ground motion in Kanto and Los Angeles sedimentary basins.
Intellectual Merit The richness of the ambient seismic field Green’s function obtained from extensive stacking of ambient seismic noise cross-correlation functions has shown the dominance of the surface-wave higher modes in wave propagation in sedimentary basins. We are evolving the virtual earthquake approach to account for higher modes and ray bending. We use a realistic kinematic earthquake simulator to generate a suite of scenario sources that will enable statistical analysis of strong ground motion.
Broader Impacts This research has involved strong collaborations with other postdoctoral fellows, currently creates new research for undergraduate students (senior thesis) and collaboration between three U.S. institutions and one Japanese institution. It has been presented at national conferences (AGU), part of the results is submitted for peer reviewing, two other publications are in preparation.
Exemplary Figure Raw ambient seismic field Green’s function between stations SSGH and all MeSO-net stations for the ZZ, RR, and TT components. constant seismic wavespeed move-outs are shown and interpreted based on our finding in Boué et. al (2015, 2016).