The wide caldera is part of an two older filled calderas (Acigöl-Nevsehir & Icik) and is of Pleistocene age. The caldera contains some lava domes (75.000-15.000 years old), maars and craters. Some scoria layers were dated to 11.000-4300 years ago and a tephra-layer covers archaeological sites of prehistoric age, 2300-1850 BC. Future eruptions are possible.