SCEC Award Number 25123 View PDF
Proposal Category Individual Research Project (Single Investigator / Institution)
Proposal Title Temporal and spatial creep variability: Detecting decadal changes in fault behavior in Northern California
Investigator(s)
Name Organization
Roland Bürgmann University of California, Berkeley Taka'aki Taira University of California, Berkeley Danielle Lindsay University of California, Berkeley
SCEC Milestones A1-3, A3-5, D1-1 SCEC Groups Geodesy, SDOT
Report Due Date 03/15/2026 Date Report Submitted 05/07/2026
Project Abstract
 Earthquake potential along faults is not constant through time, but rather a time-dependent process whereby changes in strain accumulation over short (e.g., slow slip events) and long (e.g., viscous relaxation) time scales affect hazard assessment. Understanding where fault creep occurs and how creep rates change through time is integral to determining seismic potential and constraining future earthquake scenarios. 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 utilize an updated 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. Specifically, surface creep rates will be extracted from Interferometric Synthetic Aperture Radar (InSAR) and alignment array (AA) time series, while deeper creep rates are inferred based on 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, surface creep rates and nearby CRE productivity.
Intellectual Merit This project advances understanding of spatiotemporal fault creep variability on the understudied Rodgers Creek–Maacama fault zone in northern California, directly contributing to SCEC objectives on geodetic fault slip rates (A3-5) and time-dependent seismic hazard (D1-1). By integrating ALOS-2 and Sentinel-1 InSAR, alignment arrays, and a new characteristic repeating earthquake catalog, we document a previously unreported decade-long creep suppression following a 2002 slow-slip event, seasonal modulation of surface creep. Results are submitted for peer review in Seismica and archived publicly.
Broader Impacts This project supported the training of a PhD candidate (Danielle Lindsay) in space geodesy and seismic hazard research. Results are fully open-access: InSAR time series, velocity products, and the CRE catalog are archived on Zenodo with DOIs; code is publicly available on GitHub.
Project Participants Roland Bürgmann (PI, UC Berkeley) provided scientific oversight and mentorship. Danielle Lindsay (PhD candidate, UC Berkeley) led InSAR processing, alignment array analysis, and manuscript preparation. Taka'aki Taira (UC Berkeley/BSL) produced the characteristic repeating earthquake catalog. Austin Elliott (formally USGS) provided guidance on alignment array datasets. The project utilized USGS alignment array data maintained by Frank McFarland and colleagues, and ALOS-2 data provided through JAXA-NASA data sharing research agreements.
Exemplary Figure Figure 2. Spatial Distribution of Creep. (left) Maacama and (right) Rodgers Creek faults. Maps of (a,b) CREs and background seismicity, (c,d) line-of-sight (LOS) velocity field. (e,f) Surface creep estimates from ALOS-2, Sentinel-1, and alignment arrays. (g,h) Along fault cross-sections with background seismicity, CRE’s and depth of 90% and 95% of seismicity.

Lindsay, D., Taira, T., & Bürgmann, R. (submitted). Temporal and Spatial Creep Variability: Detecting Decadal Changes in Fault Behavior in Northern California.
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