Land subsidence in Houston, Texas, measured by radar interferometry and constrained by extensometers

Abstract

We present results from a radar interferometry study over the Houston‐Galveston, Texas Gulf Coast region. From the nearly 60 potential interferograms considered, an atmospheric artifact assessment is performed and a tractable set of interferograms selected for detailed processing and error analysis. The subsequent interferogram time series spanning 1996–1998 is constrained by coincident extensometer data with root‐mean‐square error less than 2.5 mm. The interferogram time series confirms that historic subsidence in east Houston has stopped. Consistent with current groundwater use patterns, broad‐scale subsidence bowls are observed in west and northwest Houston, where maximum subsidence rates are in excess of 2 and 4 cm yr−1, respectively. Linear interferogram phase signatures associated with approximately 1 cm of differential subsidence across faults, including the Long Point fault in northwest Houston, are observed. Near the Seabrook extensometer, a hereto‐unidentified subsidence bowl with a maximum subsidence rate in excess of 3 cm yr−1 is revealed. This study demonstrates that when used in conjunction with a set of traditional geodetic measurements, radar interferometry can measure the spatial and temporal evolution of urban land subsidence within even the most challenging of environments.