Geology
Underpinning the area's land surface are unconsolidated clays, clay shales, and poorly-cemented sands extending to depths of several miles. The region's geology developed from stream deposits from the erosion of the Rocky Mountains. These sediments consist of a series of sands and clays deposited on decaying organic matter that, over time, was transformed into oil and natural gas. Beneath these tiers is a water-deposited layer of halite, a rock salt. The porous layers were compressed over time and forced upward. As it pushed upward, the salt dragged surrounding sediments into dome shapes, often trapping oil and gas that seeped from the surrounding porous sands.
The region is earthquake-free. While the neighboring city of Houston contains 86 mapped and historically active surface faults with an aggregate length of 149 miles (240 km), the clay below the surface precludes the buildup of friction that produces ground shaking in earthquakes. These faults move only very gradually in what is termed "fault creep".
Read more about this topic: Sugar Land, Texas, Geography and Climate