Deformation in the Basin & Range Province and Rio Grande Rift using InSAR Time Series

High heat flow in the Basin and Range Province and Rio Grande Rift has been attributed to partial melting in the crust and upper mantle as a result of ongoing extension (e.g. Lachenbruch 1978). We would then expect to observe surface deformation in areas with actively moving magmatic fluids. The distribution of these magmatic fluids has implications for the rheology of the crust and upper mantle. For this study, we use InSAR to locate deformation due to magmatic sources as well as localized hydrologic deformation. While our focus is magmatic deformation, hydrologic signals are important for correcting geodetic data used to monitor tectonic activity. InSAR is a suitable technique for a large study in the Basin and Range and Rio Grande Rift since SAR acquisitions are both numerous and temporally extensive in these regions. We use ERS-1, ERS-2, and ENVISAT SAR images from 1992-2010 to create time series' with interferograms up to 1800km long from both ascending and descending satellite tracks. Each time series has an average of 100 interferograms reducing the atmospheric noise that masks small deformation signals in single interferograms. The time series' results are validated using overlapping tracks and are further compared to signals identified in previous geophysical studies (e.g. Reilinger and Brown 1980, Massonnet et al 1997, Finnegan and Pritchard 2009). We present results for several areas of deformation in the Basin & Range Province and Rio Grande Rift. An agricultural area near Roswell, NM exhibits seasonal uplift and subsidence of ±3.5cm/yr between 1992 and 1999. Results indicate subsidence on the order of 1cm/yr and uplift of 2cm/yr at the Raft River power plant, ID that is likely related to the start of geothermal fluid production and injection. Just north of the Raft River plant, we detect what appears to be rapid agricultural subsidence in an area extending for 50km. We discuss subsidence of ~2cm/yr in Escalante Valley, UT that is comparable to deformation observed in an earlier InSAR study on subsidence caused by ground-water withdrawal (Forster, 2006).