Subsidence in Houston Observed by Satellite Radar Instruments

Subsidence can be caused by a diverse set of human activities and natural processes, including mining of coal, withdrawal of ground water, petroleum, and melting of permafrost. More than 80 percent of the identified subsidence in the Nation results from underground water pumping. The increasing development of urban area and need of water resources threaten to exacerbate existing land subsidence problems and initiate new ones (Galloway et al., 1999). Local collapse may damage buildings, roads, and utilities, and either impair or totally destroy them, leading to expensive repairs. The Nation Research Council estimated that annual costs in the United States from flooding and structural damage caused by land subsidence exceeded $125 million (National Research Council, 1991). Thus, it becomes vital to monitor the land subsidence in high spatial and temporal resolutions to be able to assess its impacts on civil infrastructure. In this study, we focus on mapping land deformation over the Houston area that has been caused by the withdrawal of groundwater, oil and gas using an innovative satellite radar imaging technique.