A surface depression caused by a collapse of soil or overlying formation above fractured or cavernous bedrock.
Sinkholes are depressions in the surface commonly found in in karst landscapes. Sinkholes often form where limestone or some other soluble rock is partially dissolved by groundwater, then collapses to form a depression. Sinkholes are often bowl shaped and can be a few to many hundreds of meters in diameter. Also known as dolines.
A depression in the Earth's surface caused by dissolving of underlying limestone, salt, or gypsum. Drainage is provided through underground channels that may be enlarged by the collapse of a cavern roof.