Land subsidence near Hanford and Corcoran, California, from Cryosat-2 altimetry and Sentinel-1A SAR imagery

Abstract This study demonstrates the effectiveness of the Cryosat-2 (C2) altimeter as a tool for land subsidence monitoring. The study area is near Hanford and Corcoran, California, where land subsidence can affect the stability and alignment of rail infrastructure, potentially leading to increased maintenance costs and safety concerns. We analyzed vertical land displacements from 2010 to 2018 using C2 altimeter data corrected for waveform contamination, as well as two years of Sentinel-1A (S1A) Interferometric Synthetic Aperture Radar (InSAR) imagery. Our findings show that subsidence rates from C2 data reach up to 27 cm/year, consistent with GPS-derived rates within a few cm/year. The Small Baseline Subset (SBAS) technique applied to S1A imagery yields significant subsidence, exceeding 18 cm/year in the southeast of Corcoran. Correlations between vertical displacements and environmental factors were examined using GRACE-derived equivalent water heights and rainfall data, revealing coefficients of 0.635 and 0.608, respectively, which indicate strong relationships between groundwater depletion and surface elevation changes. These results emphasize the complex interactions between subsidence, climatic factors, and groundwater management. Our study integrates distributed sensors such as altimetry, SAR imagery and GPS to monitor land subsidence, providing crucial information to mitigate subsidence risks and ensure the stability of vital infrastructure projects such as the California High-Speed Rail.