Land-surface subsidence has been mapped in the Houston-Galveston area and is known to have occurred in other areas within the Texas coastal region. Most of the subsidence has been caused by both the withdrawal of ground water and by the production of oil, gas, and associated ground water.
Land-surface subsidence was determined by comparing adjusted elevations of bench marks for various periods of releveling and by comparing topographic maps of the same areas for different years. In general, most of the Texas coastal region has subsided less than 0.5 foot (0.15 meter). The largest amount of subsidence measured in the region is in the Pasadena-Houston Ship Channel area, where the land surface subsided between 8.5 and 9.0 feet (2.6 and 2.7 meters) during 1906-73. The cause of the subsidence in this area was ground-water withdrawals. Local subsidence caused by sulfur mining in the Moss Bluff Salt Dome area has been reported to exceed 15 feet (4.6 meters).
In Jefferson County, the Spindletop Dome area subsided approximately 5 feet (1.5 meters) during 1925-77, and the Port Acres area subsided about 3 feet (0.9 meter) during 1959-77, mainly from the withdrawal of oil or gas and associated ground water. Local subsidence caused by sulfur mining in the Spindletop Dome area has been estimated to exceed 10 feet (3.0 meters).
In southeastern Jackson County and northwestern Matagorda County, the land surface subsided more than 1.5 feet (0.46 meter) during 1943-73 as a result of ground-water withdrawals. Withdrawals of oil, gas, and associated ground water caused more than 5 feet (1.5 meters) of subsidence during 1942-75 in the western part of Corpus Christi in Nueces County.
