This project will support rapid geologic, geodetic and seismological field investigations associated with the Searles Valley earthquake sequence in the Eastern California Shear Zone, which included a magnitude (M) 6.4 earthquake on July 4, 2019, and a subsequent M 7.1 event on July 5. The immediate field response is essential because the seismic and geodetic signals decay rapidly with time and geological evidence becomes obscure quickly. Rapid field studies should provide a wealth of data to facilitate understanding of the earthquake rupture properties and fault damage zones, 3D crustal structures around the ruptures, post seismic transients of geodetic fields, and effects of the events on the subsurface and human structures. This study should help clarify earthquake processes and structures in the highly active and complex Eastern California Shear Zone, which hosted three M > 7 events in the last three decades, and contribute significantly to improved understanding of the tectonic deformation and seismic hazard in Southern California. The field studies and recorded data will provide valuable experience for students and early career scientists, and produce excellent material for education and outreach activities.
This study will include obtaining differential lidar and optical image surveys, campaign Global Positioning System measurements, seismic deployments of across-fault linear and 2D arrays, and mapping effects of the ground motion on infrastructure. The obtained multi-disciplinary observations will enable researchers to address numerous outstanding questions about earthquake ruptures, spatio-temporal seismicity patterns, fault zone and crustal structures, intensity of ground shaking and postseismic deformation.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.