FaultScan - Monitoring Body Wave Velocity Changes Across the San Jacinto Fault (2022-2025)

Daniel D. Hollis, Frank L. Vernon, Florent Brenguier, Yehuda Ben-Zion, Quentin Higueret, Aurelien Mordret, Coralie Aubert, & Yixiao Sheng

Published September 11, 2022, SCEC Contribution #12223, 2022 SCEC Annual Meeting Poster #032 (PDF)

University of Grenoble-Alpes, UC San Diego/IGPP and University of Southern California are collaborating on a three-year project to measure body wave velocity changes across the San Jacinto Fault. This project, named FaultScan, uses seismic noise data from a network of nodal seismometers (nodes) and the Southern California Seismic Network (SCSN) to monitor velocity changes at seismogenic depths. Preparatory field studies for this project started in 2018 and the main project, scheduled to start in 2020 but delayed due to the coronavirus pandemic, started in 2022. In April 2022, we deployed a 298-node array at the Piñon Flat Observatory (PFO) in the San Jacinto Mountains, about 17 miles south of Palm Springs. The PFO array will record continuously for three years until early 2025. The purpose of the project is to observe transient deformation within the vicinity of active faults and detect hidden fault movements. For the San Jacinto Fault monitoring, an excellent source of body wave energy comes from train traffic in the Coachella Valley to the east of PFO that provides ideal body wave energy and raypath geometry for measuring velocity perturbations at nearly seismogenic depths using the PFO array and SCSN stations.

European Union and other funding for the FaultScan project allowed for the purchase of 480 advanced 5 Hz, three-component nodes with 5-month recording life on battery power and 9 months with solar power. The additional 182 nodes remaining after the 298 nodes currently deployed at PFO are used to maintain the PFO array, and for short-duration projects or calibrating SCSN stations to do velocity monitoring of other faults. One of these SCSN station calibration projects was done in early 2022 at a SCSN station in the Ridgecrest, CA, area for a monitoring side-study of faults responsible for the 2019 Ridgecrest earthquakes. Future side-study projects under consideration include deployments in the Antelope Valley and Napa Valley.

We welcome potential collaborators and interested parties to participate in potential side-studies and PFO array maintenance.

Key Words
ambient noise, seismic velocity, tomography, San Jacinto Fault,

Citation
Hollis, D. D., Vernon, F. L., Brenguier, F., Ben-Zion, Y., Higueret, Q., Mordret, A., Aubert, C., & Sheng, Y. (2022, 09). FaultScan - Monitoring Body Wave Velocity Changes Across the San Jacinto Fault (2022-2025). Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology