Sunday, 7 June 2015

Eruption on Barren Island.

The Darwin Volcanic Ash Advisory Center issued a warning to aviation after an ash column was spotted over Barren Island, an active volcano in the Andaman Islands, by the Japan Meteorological Agency's MTSAT-2 satellite on Saturday 6 June 2015. The ash column rose about 3 km above the volcano and drifted about 35 km to the east. Observations in infra-red also spotted a hotspot on the island, which may indicate hot lava on or close to the surface.

MSAT infra-red image of East Asia. Barren Island is on the left of the image, west of the northern Malay Peninsula and to the south of Myanmar. Japan Meteorological Agency.

Barren Island is an uninhabited volcanic island belonging officially to India's Andaman Islands (making it India's only active volcano), though it is about 100 km to the east of the main Andaman Island group and about 450 km west of the coast of southern Myanmar. The island is about 3 km in diameter and rises 354 m above sea level. It is the only active volcano in the region, though it forms part of a group with a number of dormant volcanoes including Narcondam Island and Alcock and Sewell seamounts.

The approximate location of Barren Island. Google Maps.

The volcanoes sit on the Burma (or Burmese) Plate, a small tectonic plate underlying the Andaman Islands, part of the eastern Indian Ocean and the western part of Sumatra. To the west of the Andaman Islands this plate is being subducted beneath the Indian Plate, but to the east the situation is more complex. The Burma Plate is being pushed northward relative to the Eurasia and the Sunda Plate (which underlies eastern Sumatra, Java, southern Southeast Asia, most of Borneo and the western Philippines) by the northward movement of the Indian Plate, but there is an area of seafloor spreading beneath the Andaman Sea (separating the Andaman Islands from Southeast Asia), which in turn causes stresses within the Burma Plate, leading to a zone of faulting upon which the volcanic islands and seamounts are situated.

(Left) The movement of the Burma and surrounding plates. Sheth et al. (2011). (Right) Tectonic stresses within and around the Burma Plate. Renjith (2013).

See also...

Barren Island is an uninhabited volcanic island belonging officially to India's Andaman Islands (making it India's only active volcano), though it is about 100 km to the east of the main Andaman Island group and about 450 km west of the coast of southern Myanmar. The island is about 3 km in diameter and rises 354 m above sea level. It is the only active volcano in the region...

NASA's MODIS (Moderate Resolution Imaging Spectroradiometer) system, mounted on the Terra (EOS AM) and Aqua (EOS PM) satellites, detected a hotspot developing over the Baren Island Volcano in the Andaman Islands over the period 10-16 October...


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