Abstract
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.