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Historic coal mine subsidence incident in Boulder County, Colorado, March 2003. Photo credit: T.C. Wait for the CGS.

Ground Subsidence

Subsidence is the sinking or settling of the ground surface. It can occur by a number of processes. Ground subsidence may result from the settlement of native low density soils, or the caving in of natural or man-made underground voids. Subsidence may occur gradually over many years as sags or depressions form on the ground surface. More infrequent, subsidence may occur abruptly as dangerous ground openings that could swallow any part of a structure that happen to lie at that location, or leave a dangerous steep-sided hole. In Colorado, the types of subsidence of greatest concern are settlement related to collapsing soils, sinkholes in karst areas, and the ground subsidence over abandoned mine workings.

Legal definition

H.B. 1041, 106-7-103(10): Ground subsidence means a process characterized by downward displacement of surface material caused by natural phenomena such as removal of underground fluids, natural consolidation, or dissolution of underground minerals, or by man-made phenomena such as underground mining.

Evaporite Karst Subsidence

[ED: Originally written by Jonathan White, Senior Engineering Geologist (emeritus staff) for a 2001 volume of…

Case Study: Colorado Mountain College, Spring Valley

In early February of 2003, a 24-foot-wide (7.5 m) sinkhole spontaneously opened on a soccer field at the Colorado Mountain…

Mine Subsidence Hazards in Colorado

This video, produced by the CGS in 2011, examines the significant geo-hazards related to the long history of underground coal…

Collapsible Soils

By Jonathan White, Senior Engineering Geologist, Emeritus At the end of the 19th and beginning of…

Case Study: Lykins Formation

Small but significant areas of Colorado are underlain by bedrock that is composed of evaporative…

Case Study: Roaring Fork sinkhole

[ED: This report from January 17, 2005 was written by Jon White, (Senior Engineering Geologist, Emeritus). Lightly edited for dated…