The Edwards Formation, on the downthrown side of Mt. Bonnell fault in the Austin, Texas, area (Hays and Travis Counties), is part of the northeastern extension of the Edwards Underground Reservoir, the primary source of water in numerous counties along the Balcones Fault Zone.

Gas reservoirs that water out under moderate to strong water drives are normally abandoned when the expenses associated with salt-water disposal make continued operations uneconomical.

This report summarizes results of the East Texas Waste Isolation (ETWI) program from January 1, 1978, to March 30, 1983. Having an extensive data base, the study comprised 33 different lines of research by 67 scientists and research assistants.

Characterization of 500 of the largest Texas oil reservoirs permits grouping into plays of similar geology and common engineering and production attributes.

Several microearthquake recording stations were operated as a network in the East Texas Basin beginning in June 1981. At least six certain and two probable earthquakes as well as hundreds of events of undetermined origin were recorded through August 1982.

Permian strata in the Texas Panhandle exhibit a variety of deformation styles that are attributed to tectonic stresses as well as to collapse caused by evaporite dissolution. At Caprock Canyons State Park, deformation structures above salt dissolution zones include veins, faults, and folds.

Oversize color geologic map that depicts the surface geology of Dallam County and parts of Sherman, Moore, and Hartley Counties, Texas. The 6-page booklet indicates geologic formations, abbreviations, and ages.

Sand dunes at Monahans Sandhills State Park display a variety of dune forms that develop under a unique trimodal wind regime. Large expanses of unvegetated sand form akle dunes having reversing slip faces.