Abstract

The Hueco Bolson, or basin, of Trans-Pecos Texas was formed by extensional faulting that began in the Tertiary and continues to the present. The Quaternary faults were investigated as part of a study of an area in the southeastern Hueco Bolson that is being considered as a potential site for a Texas repository for low- level radioactive wastes. Studies of past faulting events are important as indicators of the potential for future earthquakes and are important to the design of the proposed facility.

The major Quaternary fault closest to the site is the Campo Grande fault. There have been about five episodes of major displacement since the middle Pleistocene on at least one strand of the fault. Vertical offsets during single faulting events have been about 3 to 6.5 ft (1.0 to 2.0 m). Another major fault of the southeastern Hueco Bolson is the Amargosa fault that is present on the southwest edge of the basin in Chihuahua, Mexico. The Amargosa fault possibly has had Holocene movement.