On decadal changes in fault behavior in Northern California

Danielle Lindsay, Taka'aki Taira, & Roland Bürgmann

Published September 8, 2024, SCEC Contribution #13910, 2024 SCEC Annual Meeting Poster #079

Understanding where creep occurs and how creep rates change through time is integral to determining seismic potential and constraining future earthquake scenarios. We utilize a repeating micro-earthquake catalog and surface creep rates from recent radar satellite-based measurements and terrestrial measurements to identify decadal-scale changes in fault behavior on Northern California faults. This project considers the Calaveras (CF), Hayward (HF), Rodgers Creek (RC), and Maacama (MF) faults in Northern California, with a focus on the lesser studied northern RC and MF segments. We ask: What is the multi-annual distribution of fault creep and locking along the CF-HF-RC-MF fault system? How does creep along these faults respond to moderate earthquakes? Does the MF display multi-annual variable creep rates on multiple strands? We evaluate evidence of long-term changes in surface creep rate by comparing early studies with new Interferometric Synthetic Aperture Radar (InSAR) results and continuing alignment array (AA) time series. As part of this project, we compute surface creep estimates from both Sentinel-1 and ALOS-2 InSAR time series for 2015 - 2024. We infer long-term changes in deeper creep rates from variability in the recurrence interval of characteristically repeating earthquakes (CREs). Integrating creep rate estimates from these geodetic and seismic observations, we examine the interaction between moderate earthquakes and creep rates, specifically the interactions between the 2007 and 2022 magnitude M~5 Alum Rock earthquakes on the CF and nearby CRE productivity.

Citation
Lindsay, D., Taira, T., & Bürgmann, R. (2024, 09). On decadal changes in fault behavior in Northern California . Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy