HOUSTON, TEXAS GEOMORPHOLOGY: INVESTIGATING SURFACES ABOVE SALT DOMES USING GIS AND REMOTE SENSING TECHNIQUES

The Gulf Coast is a major source of oil and gas for the United States. In Texas an oil field over a salt dome known as Spindletop started the Texas Oil Boom. Salt domes are great traps because they are mostly impermeable and create an upward structure for oil and gas to accumulate. Several salt domes have been documented in and around the Houston area such as Pierce Junction, Mykawa, and Webster to just name a few. The diapirism of the salt domes can be attributed to regional extension and sedimentation. Monitoring the topographical changes directly above salt domes can give insight to subsurface movements of the salt. Geographic Information System (GIS) and remote sensing techniques are used to quantify surface movements of the salt domes the Houston area. Data collected by Light Detection and Ranging (LiDAR) and Global Positioning System (GPS) allow detection of surface changes on a centimeter to millimeter scale. Preliminary statistical analysis of Digital Elevation Models (DEM) over a span of 12 years (1996, 2001, and 2008) showed increased surface changes over some salt dome locations. GPS studies from Engelkemeir (2008) and the Harris-Galveston Subsidence District (HGSD) show most of Houston is subsiding. Areas that are not subsiding or rising are mostly over known salt dome locations. Gravity surveys will be conducted over these areas to ensure that it is salt under these areas. Areas over salt domes should have a significantly different reading compared to areas without a salt dome. Quantitatively tracking surface movements of salt domes can be an easier and cheaper alternative to subsurface monitoring. Variations or abnormal movements may signify regional tectonic activity.