The evaporitic layers in the molasse deposits of the northeastern Carpathian forelands have been mined for potassium salt mainly in the 1970s and 1980s. Collapse of mining-induced cavities is the most likely cause for the rapid formation of a sinkhole in 2017, 300 m in diameter and 50 m deep. The ground in this area is unstable, with a dynamic system of evolving cracks and frequent small landslides.