Ten Years of Seasonally Modulated Strain History in Southern California Inferred from cGPS Data

Alireza Bahadori, Jeonghyeop Kim, Meredith L. Kraner, & William E. Holt

Submitted August 15, 2017, SCEC Contribution #7823, 2017 SCEC Annual Meeting Poster #213

We quantify transient strain changes in southern California along with their statistical significance using cGPS data. We use PBO station data processed by NSF’s GAGE Facility at UNAVCO. We also analyzed cGPS data processed by the University of Nevada Reno’s (UNR) Geodetic Laboratory. The objective of our analysis is to quantify the transient strain changes associated with seasonal signals. Using the seasonally modulated strain change estimates, we determine the associated Coulomb stress changes on existing fault structures through time. A near-term goal is to investigate the links between seismicity rate changes and observed strain/stress changes on existing structures. An additional goal is to investigate the loading mechanisms for the seasonal strain changes, including hydrologic and thermoelastic sources. We have compiled the ten year seasonally modulated strain history in southern California into a continuous set of animations. Highlights in the ten year history are the large seasonal anomalies in the Los Angeles Basin region, and the wide spread strain changes associated with the postseismic signal following the El Mayor-Cucapah earthquake.

Key Words
Seasonal Strain, GPS, Transient, Coulomb Stress Changes

Citation
Bahadori, A., Kim, J., Kraner, M. L., & Holt, W. E. (2017, 08). Ten Years of Seasonally Modulated Strain History in Southern California Inferred from cGPS Data. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Stress and Deformation Over Time (SDOT)