Mt. TAMBORA " The Largest Volcanic Eruption in Recorded History "

Geographical setting and Geological historySumbawa IslandSumbawa Island is composed of Early Miocene volcanics, Middle Miocene (20-15 Ma) reef limestones and sandstones (Takada et al., 2000), Pliocenevolcanoes (5-3 Ma), Early Pleistocene volcanoes (1.7-1.1 Ma) and coral reeflitmes ones, and Middle Pleistocene to Holocene volcanoes (B barier te al.,1983). Tambora volcano, which is younger than 200 ka, overlies coral reeflimestone on its western foot, and cover an older volcano, here called KawindaToi volcano (410 ka) on the northern foot (Takada et al., 2000).Lesser Sunda IslandsThe Global Volcanism Program database for Lesser Sunda Islands currently contains 29 Holocene volcanoes,sorted besorted b lowe in in geographical geograph(volcanoolcan nu n mber) uorderLesser Sunda Islands are located on the eastern sector of the Sunda arc. More than 100 Quaternary volcanoes have developed along the Sunda arc.IndonesiaThe Global Volcanism Program database for Volcanoes of Indonesia currently contains 146 Holocene volcanoes and 4 Pleistocene volcanoes with thermal activityThese are caused by the northward subduction of the Australian plate beneath the Eurasian plate (Hamilton, 1979). Just to the east, however, thetectonics is complicated by a change in the nature of the subducting plate from oceanic to continental. The thickness of the crust from Java to Baliislands is estimated to be about 20 km (Silver et al., 1983).Benioff zone beneath Tambora, SumbawaTambora lies 340 km north of the Java Trench systemyand 180–190 kmabove the upper surface of the active north-dipping subduction zone.oCircles show location of earthquakes below TamboraMantle tomographySumbawa subduction zoneRed : slow seismic velocityBlue: fast seismic velocitySubduction slab beneathTambora to ˃ 1000 kmSigurdsson H. “Lost kingdom of Tambora”. Graduate School of Oceanography, University of Rhode Island