Indonesia consists of more than 17.000 islands, of these about 6.000 which are permanently inhabited. About 80 percent of the archipelago is water. The country stretches across some 5.150 km from Sumatra in the west to Papua in the east, almost one eighth of the Earth’s circumference. The distance from north to south is about 1.931 km. Indonesia lies at the junction of the Asian and the Australian continental plates, which is the reason for the high volcanic activity in this region.