The lake is a crater lake, a basin formed on an old volcanic cone that was later filled with water. It was erroneously reported as a circular rift lake, as this area is not a rift zone but a volcanic area evident by the presence of nearby volcanic peaks like Musuan Peak ( to the E), Mount Kalatungan ( to the NW), Mount Dagumbaan ( to the SW), Mount Kidongin ( to the SW), and the volcanic field east of Pangantucan, Bukidnon ( to the west). Another small volcanic cone is located just southwest of Lake Apo.