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.
Mount Tondano in the province of North Sulawesi, Sulawesi, Indonesia, contains 20 bij 30 kilometer wide of Quarternary caldera. Pyroclastic cones, obsidian flows and geothermal areas are observed in the caldera area. The Lake Tondano lies in the east side of the caldera.