COASTAL SUBSIDENCE ANALYSIS BETWEEN HOUSTON AND GALVESTON, TEXAS, USA

Observations of sea-level rises in the Houston-Galveston region, Texas, USA, have revealed a notable growth since the 1990s, which may be primarily attributed to land subsidence. This study aimed to estimate subsidence near the area by integrating state-of-the-art space geodetic techniques such as interferometric synthetic aperture radar (InSAR) and global navigation satellite systems (GNSS). Specifically, Sentinel-1 synthetic aperture radar (SAR) images captured between 2015 and 2022 were processed using two multi-temporal InSAR (MT-InSAR) methods, i.e., persistent scatter interferogram (PSI) and small baseline subset (SBAS). By combining InSAR results from both ascending and descending orbit acquisitions, land subsidence estimates were obtained. InSAR subsidence results were validated with favorable agreement between trend values derived from PSI/SBAS and GNSS measurements. For two of the high subsidence locations selected between Houston and Galveston, Texas, the extraction of large quantities of oil/gas, in close spatial proximity to coastal subsiding locations, is considered to be the main cause of observed land subsidence.