The Illinois State Geological Survey (ISGS) now provides up-to-date downloadable data about sinkholes for the entire state of Illinois. This replaces the previous ISGS GIS dataset of statewide sinkhole areas, which was published in 1997.
“Sinkholes are a real hazard and we owe it to Illinoisans to ensure that the best and most up-to-date information is available so that informed planning and economic development decisions can be made,” said Dick Berg, ISGS director and Illinois State Geologist.
When ISGS published its high-resolution digital elevation data for all 102 Illinois counties in 2019, ISGS geologists Sam Panno and Donald Luman, both now retired, realized they could use the more accurate data to update the statewide inventory of cover-collapse sinkholes, which develop when carbonate bedrock is eroded, creating a cavity, and the covering material collapses under its own weight.
The geologists used several additional GIS databases to help them interpret the lidar shaded relief imagery and distinguish sinkholes from other depressions, including the statewide 1:500,000-scale bedrock geology map layer that defines generalized areas of underlying carbonate bedrock, digitized point locations of known mine sites in Illinois from the U.S. Geological Survey Mineral Resource Data System, and ISGS maps of active and abandoned coal mines.
The updated sinkhole inventory includes two GIS datasets: Illinois Sinkhole Points (n=21,799) and Illinois Sinkhole Areas (n=138).