Global Volcanism Program

Volcanoes of the World

Volcanoes of Indonesia and the Andaman Islands

	Sumatra, Andaman Islands, and Krakatau
	Java
	Lesser Sunda Islands and Banda Sea
	Sulawesi, Sangihe Islands, Halmahera, and Borneo

Regional Volcanology Highlights from Simkin and Siebert, 1994.

Indonesia consists of more than 13,000 islands, spread over an area approximating that of the conterminous United States. Its 182 million population is 77% of the US's, but it has only one-fifth of the land area.

Although Chinese records show a Krakatau eruption in the 3rd century AD, and some 17 additional historical eruptions are reported from Kelut as well as Krakatau through the 15th century, uncertainty surrounds many of them. The first eruptions documented by Europeans were not until 1512 (Sangeang Api and Gunungapi Wetar), about the time Portugal gained control of the Mollucan clove trade. The Dutch East India Company controlled the islands from 1602 through 1780, followed by the Dutch government. Britain took temporary control of the islands in the early 19th century, but the Dutch returned and unrest marked much of the century. The disastrous Krakatau eruption of 1883 was followed by several devastating eruptions on other islands and in 1921 a Volcano Survey was established by the government, leading to much improved volcano monitoring and reporting. The islands were occupied by Japan from early 1942, and WW-II was followed by a 4-year war of independence, with sovereignty gained at the end of 1949. The Volcanological Survey of Indonesia now operates a network of volcano observatories.

The great sweep of the Sunda Arc, over 3,000 km from NW Sumatra to the Banda Sea, results from the subduction of Indian Ocean crust beneath the Asian Plate. This arc includes 76% of the region's volcanoes, but those on either end are tectonically more complex. To the NNW, the basaltic volcanism of the Andaman Islands results from short spreading centers, and to the east the Banda Arc reflects Pacific Ocean crust subducted westward. North of this arc, tectonic complexity increases, with converging plate fragments forming multiple subduction zones, mainly oriented N-S, that in turn produce the Sulawesi-Sangihe volcanoes on the west and Halmahera on the east of the collision zone.

Indonesia leads the world in many volcano statistics. It has the largest number of historically active volcanoes (76), its total of 1171 dated eruptions is only narrowly exceeded by Japan's 1274, and these two regions have combined to produce 1/3 of the known explosive eruptions. Indonesia has suffered the highest numbers of eruptions producing fatalities, damage to arable land, mudflows, tsunamis, domes, and pyroclastic flows (104, 186, 84, 13, 76, and 96, respectively). In the first five of these, Indonesia also leads other regions in the global proportion of eruptions with each characteristic.

Four-fifths of Indonesian volcanoes with dated eruptions have erupted in this century, and history shows the danger of volcanoes that have not erupted in recent centuries. Relatively few stratigraphic studies of older volcanic deposits have been completed in Indonesia, and only 0.5% of known Indonesian eruptions have been dated by other than historical techniques, emphasizing the need for more study of the prehistoric record in this region.

Indonesia was the subject of the first CAVW in 1951; authored in Holland by Meir Neumann van Padang, who had grown up in Indonesia and worked there as a geologist. He went on to spearhead the CAVW series; authoring or co-authoring six catalogs and overseeing publication of 21 before retiring, at the age of 73, in 1967.