Plain Language Summary
Seismic hazard models rely on accurate measurements of small interseismic motion over large space on the Earth’s crust. Traditional geodetic models based on Global Navigation Satellite System (GNSS) data cannot resolve small scale deforming patterns, mainly due to expensive and limited station deployment. Interferometric Synthetic Aperture Radar (InSAR) has become the emerging tool for mapping the surface deformation, with its advantages of low-cost and full-coverage. Yet InSAR measurement, compared to GNSS, comes with larger bias from the atmospheric noise, especially over length scales greater than 80 km. Here we combined the two methods to resolve fine spatial scales and achieve high accuracy.  Our results are presented as deformation time-series over the entire San Andreas fault system. From these deformation time series we have estimated fault creep rates and strain accumulation. One important finding is that there is significant off-fault strain, though we suspect they are mainly due to hydrological processes. These results will advance our knowledge of the earthquake cycle, strain/moment accumulation, and the associated seismic hazards.