Mapping deformation processes using InSAR PS+DS timeseries estimation in Northern California, U.S

Several major faults in Northern California, including the Hayward, northern Calaveras, Rodgers Creek, Maacama, and Green Valley-Concord Faults, traverse densely vegetated and non-urban regions. Current differential synthetic aperture radar interferometry (DInSAR) timeseries approaches, such as small-baseline subset (SBAS) and persistent scatterers interferometry (PSI), face limitations in these areas, resulting in substantial data gaps that affect surface fault creep estimation. In this study, we investigate the use of InSAR PS+DS (persistent scatterers + distributed scatterers) timeseries approach to map surface creep-related deformation across the major fault systems in northern California. The PS+DS approach involves statistical analysis of all possible interferometric pairs, minimizing loss of information and maximizing spatial density of estimates. We obtained surface velocity estimates in northern California over a 200 km by 200 km extent and having 100 m spatial resolution using the PS+DS approach, which agree well with GNSS (global navigation satellite system) velocities, with root mean square error (RMSE) of $\sim$3 mm/yr and $\sim$2 mm/yr for descending and ascending tracks, respectively. We observe surface creep ranging from 4-8 mm/yr along the 75 km extent of the Hayward Fault. We detect surface creep across the northern Rodgers Creek and Concord Faults, at rates of 1-2 mm/yr. We also are able to quantify vertical motion attributed to geothermal activities in The Geysers and hydrological effects in the Santa Clara Valley in northern California.