10.7914/SN/YA_2020
Frank Vernon
University of California San Diego
Pieter-Ewald Share
Oregon State University
Yehuda Ben-Zion
University of Southern California
Yuri Fialko
University of California, San Diego
Amir Allam
University of Utah
Southern San Andreas Fault Zone
International Federation of Digital Seismograph Networks
2020
Seismic Network
2020/2020
2800000 MB
SEED data
The San Andreas Fault (SAF) in California is a mature plate boundary fault capable of great (magnitude 8 or greater) earthquakes. The southern section of the SAF has not produced a major event in historic times (over the last 300 years), and is currently believed to pose the largest seismic risk in California (Weldon et al., 2005; Field et al., 2014). While much progress was made toward understanding seismic potential of the Southern San Andreas Fault (SSAF) and the likely socio-economic impacts of a large future earthquake on the SSAF, several important questions remain. Over the last decade several lines of evidence emerged suggesting that the 80 km-long Coachella Valley- Bombay Beach segment of the SSAF may not be vertical and may have a substantial dip to the East, similar to a well-recognized SSAF dip in the San Gorgonio bend further to the North. We propose to test this hypothesis by imaging a low-rigidity damage zone and/or a bi-material interface associated with the SSAF in the upper crust. This will be accomplished by deploying a dense seismic array spanning the SSAF in the Mecca Hills area. Data from the deployed seismic array and regional seismic networks will be used to generate high-resolution tomographic images of the fault zone throughout the seismogenic layer. Seismic data will be combined with high-resolution geodetic observations to place robust constraints on the subsurface geometry and mechanical properties of the bi-material interface and/or damage zone associated with the SSAF.
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