Indonesia is at the same time one of the most populous (5th in the world after PR China, India, USSR, USA), and one of the most volcanic, areas in the world, lying as it does at the intersection of three major plates. (The Geological background has been covered by Dr. Barber's contribution).
Volcanological Office at Jalan Cendana 15-Yogyakarta initially was a Branch office of Volcanology Service.
Mt. Merapi is the most active volcano in Indonesia. The period of dormaney is 1 to 5 years. Because of the short period of dormaney and the densily populated slopes. Mt. Merapi belonge to the most dangerous volcanoes in Indonesia.
Mt. Merapi is one of the most active volcanoes in Indonesia, geologically is situated on the intersection of two faults of regional importance, namely the transverse fault which separates East Java from Central Java, and a longitudinal fault through Java which forms the boundary between the western Kendeng Ridge and the Ngawi sub Zone North of Simo.