SCEC Award Number 18208 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Time dependent crustal deformation and seismicity in California constrained by geodetic and earthquake data
Investigator(s)
Name Organization
Zheng-Kang Shen University of California, Los Angeles Yuehua Zeng United States Geological Survey
Other Participants
SCEC Priorities 1a, 1e, 2a SCEC Groups Geodesy, SDOT, WGCEP
Report Due Date 03/15/2019 Date Report Submitted 03/27/2019
Project Abstract
 This project is to recover an important dataset of Electronic Distance Measurement (EDM) observed from the 1970s to early 1990s in California, and use the data to deduce deformation rates across major faults such as the San Andreas. The result is compared with deformation rates derived using GPS data observed from the 1990s to 2010s, to decipher the rate changes over the past 4 decades. We deduced fault-parallel deformation rates across the San Andreas fault using improved constraints on the EDM data. Our preliminary result shows that the EDM derived deformation rates are ~2 mm/yr and ~5 mm/yr slower than GPS across the Carrizo and Mojave sections of the San Andreas, respectively. The project is still ongoing since more reliable result covering major faults in California requires more comprehensive analysis of the EDM data.
Intellectual Merit The EDM derived deformation rates can be compared with deformation rates derived using GPS data observed from the 1990s to 2010s, to decipher the rate changes over the past 4 decades. The dataset and the rate change result can be useful to address science questions posted in SCEC5 RFP, such as: “how are faults loaded across temporal and spatial scales?”, and “what is the role of off fault inelastic deformation on strain accumulation, dynamic rupture, and radiated seismic energy?”
Broader Impacts knowledge acquired from this project can be transformative for future studies on fault zone structure, crustal rheology, stress/strain evolution, and earthquake hazard assessment in California.
Exemplary Figure Figure 4. Fault-parallel velocity profiles across the Carrizo, Mojave, and Coachella sections of the San Andreas fault. The blue and red squares denote the EDM and GPS components respectively, and the error bars on the EDM data points represent 1-sigma uncertainty.