High Resolution Imaging of the San Andreas Fault System in Baja California Using Triple-Difference Tomography

Date: 4/24/2019

Time: 06:00 PM

Room: Fifth Avenue

Understanding transform plate boundary processes and the associated seismic hazard for society requires knowledge of the geometry and material properties along major faults comprising these boundaries. While high-resolution structural properties of the San Andreas Fault System (SAFS) in Southern California have been obtained through various geoscientific studies, corresponding information for the SAFS in northern Baja California is less clear. Deriving high-resolution velocity models for the southern portion of the SAFS in Baja California is important for understating properties and processes of the plate boundary. Toward this goal, we image the seismogenic crust in the area at high-resolution using arrival time tomography that incorporates both station-pair and event-pair double differences (triple-difference tomography). The study uses arrival time data of local earthquakes and stations from the Seismological Network of CICESE (Centro de Investigación Científica y de Estudios Superiores de Ensenada, Baja California, México) and southern stations of the Southern California Seismic Network. The addition of station-pair data allows for better absolute event locations and higher model resolution near the surface. In total, ~120,000 P-wave and ~75,000 S-wave arrivals recorded by >150 stations from >10,000 events (from 2007-2018) are incorporated in the tomographic inversion. Initial tomographic results with interpretations on the geometries and material properties of major faults in northern Baja California will be presented at the meeting.

Presenting Author: Pieter-Ewald Share

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