The geography of Indonesia is dominated by volcanoes that are formed due to subduction zones between the Eurasian plate and the Indo-Australian plate. Some of the volcanoes are notable for their eruptions, for instance, Krakatau for its global effects in 1883, Lake Toba for its supervolcanic eruption estimated to have occurred 74,000 Before Present which was responsible for six years of volcanic winter, and Mount Tambora for the most violent eruption in recorded history in 1815.
Perbakti is an eroded stratovolcano at the west of Mount Salak in West Java, Indonesia. The summit is elongated in a northwest-southwest direction, in which Gunung Endut volcano rises above a saddle of Perbakti. Two 2 km wide of depressions on the northern and the sourthern side has formed two rivers, the Kaluwung Herang and Pamatutan rivers. Fumaroles, mud pots and hot springs are located on the south and the southeast flanks.