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 several years of cold of volcanic winter, and Mount Tambora for the most violent eruption in recorded history in 1815. Indonesia's Mount Sinabung has recently erupted, two days after it sprang back into life after over 400 years of inactivity.
Volcanoes in Indonesia are a part of the Pacific Ring of Fire. There are about 150 known volcanic sources. Most are in what is called the Sunda Arch (Sumatra and Java). The remaining volcanoes are those of Halmahera, including its surrounding volcanic islands, and the volcanoes of Sulawesi and the Sangihe Islands. The latter group is in one volcanic arc together with the Philippine volcanoes.
The most active Indonesian volcanoes are Kelut and Merapi on Java island which have been responsible for thousands of deaths in the region. Since AD 1000, Kelut has erupted more than 30 times. While Merapi has erupted more than 80 times.
The first eruption of Mount Sinabung — which caught many scientists off guard since the volcano is not as closely monitored as other volcanoes — over the last August weekend was followed by a second, more powerful blast on August 30th that spewed soot and debris more than a mile into the air, leaving the region on high hazard alert.
Mount Sinabung last erupted in 1600 and government vulcanologists acknowledged they had made no efforts before the mountain started rumbling last week to sample gases or look out for rising magma or other signs of seismic activity.
The Indonesian government was reported to have evacuated around 17,500 people from the region on and around the volcano. The government issued the highest-level warning for the area, which was expected to remain in force for around a week, since scientists were unfamiliar with the characteristics of the volcano, due to it having been dormant for so long.
Indonesia is prone to earthquakes, volcanic eruptions, and the occasional tsunami. It can well be considered a very dangerous place to live despite its beauty due to these tectonic caused effects. Yet geothermal power in Indonesia is an increasingly significant source of renewable energy. As a result of its volcanic geology, Indonesia has about 40% of the world's potential geothermal resources. To live well one may have to live dangerously.