An eruption on Mount Dukono on Halmahera Island, Indonesia, on Saturday 5 October 2013 produced a 1.8 km high ash column according to the Darwin Volcanic Ash Advisory Center. This follows an eruption on Thursday 3 October which produced a 2.1 km high ash column that drifted about 50 km to the northwest before dissipating. The volcano has been in a state of more-or-less constant eruption since 1933; it did enter a quiet period in June this year, but eruptions resumed at the end of August and appear set to continue.
An ash column from an eruption on Mount Dukono. Antara News.
The Halmahera Islands arc a volcanic arc; formed where one tectonic plate is being subducted beneath another, with the underlying plate being melted by the heat of the Earth's interior, and lighter minerals bubbling up through the overlying plate to form volcanoes. However the Halmahera Islands are unusual in that they lie on a double subduction zone. The underlying plate, a northeaster extension of the Molucca Plate, is being overridden form the Philippine Plate from the east and the Eurasian Plate from the west. The Halmahera volcanoes are located where the Philippine Plate is overriding the Molucca Plate; to the west the Sangihe Islands lie where the Molucca Plate is being overridden by the Eurasian Plate.
The approximate location of Mount Dukono. Google Maps.
See also Eruptions on Mount Dukono, Eruption on Gamalama and Volcanic activity in the Halmahera Islands.
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