Crawford Sink, near Russell, Kansas by Ron Schott

Crawford Sink is an anthropogenic sinkhole that sits beside Interstate 70 just west of Russell, Kansas. One of the oil wells in this field had a failed casing that allowed water to seep into soluble salt layers deep underground. Over time the salt dissolved and a cavity opened. Eventually the overlying layers began to collapse into this cavern. The depression at the surface is now occupied by a small pond located just south of the eastbound lanes of the interstate highway. The highway is sinking with the surrounding land surface. Already the Kansas Department of Transportation (KDOT) has had to resurface and re-level the highway twice and remove the overpass that used to cross the highway at the left side of this image. Although the leaking well has been remediated, subsidence continues at almost one foot per year. Fort Hays State University Geosciences Department faculty and students are involved in monitoring ongoing subsidence with the support of KDOT.