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Integrated Sentinel-1 InSAR and GNSS time-series along the San Andreas fault system
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  • Xiaohua Xu,
  • David T. Sandwell,
  • Emilie Klein,
  • Yehuda Bock
Xiaohua Xu
University of California, San Diego

Corresponding Author:xix016@ucsd.edu

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David T. Sandwell
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Emilie Klein
2Laboratoire de géologie - CNRS UMR 8538, Ecole normale supérieure - PSL University, Paris, France 

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Yehuda Bock
Scripps Institution of Oceanography
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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 (SAFS). 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.
Nov 2021Published in Journal of Geophysical Research: Solid Earth volume 126 issue 11. 10.1029/2021JB022579