New Potential of InSAR for Geothermal Systems

Abstract

Monitoring crustal deformation using interferometric synthetic aperture radar (InSAR) has frequently been applied to geothermal systems but extensive use has been hampered by costly and intermittent data. New data streams from the current Sentinel-1 A/B and upcoming NISAR satellites should provide low-cost and easily accessible data with short repeat times. These new datasets, combined with open-source software designed to process time series of interferograms, will allow routine time series processing of InSAR data over geothermal regions in the Western U.S. and worldwide. This should enable observations of temporal change in deformation with sampling at less than one month intervals. Here we explore what signals might be resolvable, how they might be combined with other datasets, and what new information might be inferred about the geothermal systems. One example of open-source InSAR package is the GMTSAR package, which uses the Generic Mapping Tools (GMT) for back-end data analysis. It is maintained by a cross-institutional group of developers and includes the capability to process Sentinel 1 A/B data. Currently, the software is used by hundreds of scientists and engineers around the world. Yearly short courses for new users have been conducted and extensive documentation is available. We present examples of several geothermal areas examined with time series data and outline typical signals, provide examples of modeling, and address the likely resolution (spatial and temporal). Geothermal areas with little or no discernable signal are also presented to demonstrate current limits of the technique.