Mount Merapi, Gunung Merapi, is an active stratovolcano located on the border between the province of Central Java and the Special Region of Yogyakarta, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. It is located approximately 28 kilometres north of Yogyakarta city which has a population of 2.4 million, and thousands of people live on the flanks of the volcano, with villages as high as 1,700 metres above sea level.
Smoke can often be seen emerging from the mountaintop, and several eruptions have caused fatalities. A pyroclastic flow from a large explosion killed 27 people on 22 November 1994, mostly in the town of Muntilan, west of the volcano. Another large eruption occurred in 2006, shortly before the Yogyakarta earthquake. In light of the hazards that Merapi poses to populated areas, it has been designated as one of the Decade Volcanoes.
On 20 October 2010, the Indonesian government raised the alert for Mount Merapi to its highest level and warned villagers in threatened areas to move to safer ground. People living within the range of a 20 km zone were told to evacuate.