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 Mahawu is located immediately east from Lokon-Empung volcano in North Sulawesi, Indonesia. The volcano is capped with 180 m wide and 140 m deep crater with two pyroclastic cones in the northern flanks. A small explosive eruption was recorded in 1789. In 1994, fumaroles, mudpots and small geysers activities were observed along the greenish shore of a crater lake.