Sinkholes are closed depressions generated by karstification that occur naturally on the surface of the ground.
Sinkholes are usually circular or subcircular, and range in size from one to several hundred meters in diameter and up to several tens of meters in depth. The inclination of the slopes varies from vertical to gentle. Sinkholes can appear on karst rocks (mainly carbonates and evaporites), non-karst rocks and also on detrital sediments.
Collapses caused by human activity are sometimes categorized as sinkholes, as well as depressions where streams sink underground. The term sinkhole, equivalent to doline, is more common among engineers and researchers in North America (Ford and Williams, 2007) but is becoming more frequent in European literature.
- Waltham, T., Bell, F., and Culshaw, M., 2005. Sinkholes and Subsidence. Karst and Cavernous Rocks in Engineering and Construction. Berlin: Springer. 382 pp.Google Scholar
- Williams, P., 2003. Dolines. In Gunn, J. (ed.), Encyclopedia of Caves and Karst Science. New York and London: Taylor & Francis, pp. 304–310.Google Scholar