GEOTHERMAL AND SEISMIC ACTIVITY IMPACTS ON GROUND DEFORMATION AT THE COSO GEOTHERMAL SITE, CALIFORNIA

The Coso geothermal site is one of the most seismically active regions in eastern California. It resides within the Eastern California Shear Zone (ECSZ) that accommodates plate movements between the North American plate and the Pacific plate. The continual right-shearing with the induced geothermal processes contribute to the high seismicity and fluctuations of surface motion at the Coso geothermal site. Spatio-temporal analysis of the Earth's deformation rates and patterns at Coso can be utilized to understand the interaction between the vigorous geothermal process and, the recent seismic activity to assess potential hazards. Geodetic Global Positioning System (GPS) and Synthetic Aperture Radar Interferometry (InSAR) measurements, as well as USGS seismic records between 1992 and 2015 are used in this investigation. Multi-sensor, multi-temporal InSAR data acquired during 1992-2015 by ERS-1, ERS-2, ENVISAT and Sentinel-1 satellites are analyzed using the two-pass interferometric approach to characterize the rates and patterns of crustal motions during the period of observation. Ultimately, simultaneous inversion of GPS and InSAR measurements is conducted to address volumetric changes of the geothermal reservoir in space and time and to infer the deformation source parameters. This work is still in progress and preliminary results will be presented at the GSA national meeting of 2015.