Kenneth S. Johnson

TL;DR: Sinkhole identification, investigation, prediction, and mitigation using field surveys and geomorphological mapping combined with accounts from local people and historical sources is studied in this paper, where detailed sinkhole maps can be constructed from sequential historical maps, recent topographical maps, and digital elevation models (DEMs) complemented with building-damage surveying, remote sensing, and high-resolution geodetic surveys.

Abstract: Evaporites, including gypsum (or anhydrite) and salt, are the most soluble of common rocks; they are dissolved readily to form the same type of karst features that typically are found in limestones and dolomites, and their dissolution can locally result in major subsidence structures. The four basic requirements for evaporite dissolution to occur are: (1) a deposit of gypsum or salt; (2) water, unsaturated with CaSO4 or NaCl; (3) an outlet for escape of dissolving water; and (4) energy to cause water to flow through the system. Evaporites are present in 32 of the 48 contiguous states of the United States, and they underlie about 35–40% of the land area. Karst is known at least locally (and sometimes quite extensively) in almost all areas underlain by evaporites, and some of these karst features involve significant subsidence. The most widespread and pronounced examples of both gypsum and salt karst and subsidence are in the Permian basin of the southwestern United States, but many other areas also are significant. Human activities have caused some evaporite–subsidence development, primarily in salt deposits. Boreholes may enable (either intentionally or inadvertently) unsaturated water to flow through or against salt deposits, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures above the cavity can cause land subsidence or catastrophic collapse.

TL;DR: The most widespread and pronounced examples of both gypsum and salt karst are in the Permian basin of the southwestern United States, but many other areas are also significant as discussed by the authors.

TL;DR: In many parts of the Permian Basin of the southwestern U.S.A. as mentioned in this paper, salt dissolution produces a self-perpetuating cycle: dissolution causes cavern development, followed by collapse and subsidence of overlying rock; then the resulting disrupted rock has a greater vertical permeability that allows increased water percolation and additional salt dissolution.