Integrated Sentinel‐1 InSAR and GNSS Time‐Series Along the San Andreas Fault System

Xiaohua Xu, David T. Sandwell, Emilie Klein, & Yehuda Bock

Published November 18, 2021, SCEC Contribution #11839

Measuring crustal strain and seismic moment accumulation, is crucial for understanding the growth and distribution of seismic hazards along major fault systems. Here, we develop a methodology to integrate 4.5 years (2015–2019.5) of Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and continuous Global Navigation Satellite System (GNSS) time series to achieve 6 to 12-day sampling of surface displacements at ∼500 m spatial resolution over the entire San Andreas fault system. Numerous interesting deformation signals are identified with this product (video link: https://www.youtube.com/watch?v=SxNLQKmHWpY). We decompose the line-of-sight InSAR displacements into three dimensions by combining the deformation azimuth from a GNSS-derived interseismic fault model. We then construct strain rate maps using a smoothing interpolator with constraints from elasticity. The resulting deformation field reveals a wide array of crustal deformation processes including, on- and off-fault secular and transient tectonic deformation, creep rates on all the major faults, and vertical signals associated with hydrological processes. The strain rate maps show significant off-fault components that were not captured by GNSS-only models. These results are important in assessing the seismic hazard in the region.

Citation
Xu, X., Sandwell, D. T., Klein, E., & Bock, Y. (2021). Integrated Sentinel‐1 InSAR and GNSS Time‐Series Along the San Andreas Fault System. Journal of Geophysical Research: Solid Earth, 126(11). doi: 10.1029/2021JB022579. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JB022579

Related Projects & Working Groups
Community Geodetic Model, Tectonic Geodesy