Monday 29 April 2024

Eruption on Mount Ibu, Halmahera Island, Indonesia.

The Regional Disaster Mitigation Agency for West Halmahera District has reported an eruption on Mount Ibu, a 1325 m stratovolcano on the northwest coast of Halmahera Island, Indonesia, on Sunday 28 April  2024 (a stratovolcano is a cone-shaped volcano made up of layers of ash and lava, although Mount Ibu has a truncated shape, having lost its upper part in an explosion at some point in the past). The eruption started at 0.37 am local time, and lasted approximately three minutes and 26 seconds, producing a column of dark ash which rose 3.5 km above the summit of the volcano and drifted to the west. The Regional Disaster Mitigation Agency has asked people not to go within 2 km of the volcano for the time being, and has issued dust masks to residents of 16 villages in the area. Sam Ratulangi International Airport, about 100 km from the volcano in the city of Manado, is closed to flights temporarily.

An ash column over Mount Ibu at 0.44 am local time on Sunday 28 April 2024. Abdul Fatah/Antara News Agency.

The Halmahera Island chain is a volcanic arc formed where the Halmahera Plate, a northeaster extension of the Molucca Sea Plate is being subducted beneath Philippine Plate from the east and the Eurasian Plate from the west, 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. The Halmahera volcanoes are located where the Philippine Plate is overriding the Molucca Sea Plate; to the west the Sangihe Islands lie where the Molucca Sea Plate is being overridden by the Eurasian Plate.

Diagrammatic representation of the subduction zones beneath Halmahera (middle), plus the Philippines (top) and Sulawesi (bottom), with the Eurasian Plate to the left, the Molucca Sea Plate in the middle, and the Philippine Plate to the right.  Hall & Wilson (2000).

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