Report on Barren Island (India) — 25 January-31 January 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 January-31 January 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Barren Island (India). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 January-31 January 2006. Smithsonian Institution and US Geological Survey.
12.278°N, 93.858°E; summit elev. 354 m
All times are local (unless otherwise noted)
During 12-13 January, a team from the Geological Survey of India visited Barren Island. They reported that dense clusters of incandescent tephra of various sizes were ejected from the crater. In addition to the eruption from the main crater, the scientists saw incandescence on the N flank of the volcanic cone and thin layers of incandescent material on the W slope. In comparison to activity during the early stages of the eruption in May-June 2005, activity had diminished considerably. The Darwin VAAC reported that ash plumes emitted from Barren Island during 26-27 January rose to ~3 km (10,000 ft) a.s.l.
Geologic Background. Barren Island, a possession of India in the Andaman Sea about 135 km NE of Port Blair in the Andaman Islands, is the only historically active volcano along the N-S volcanic arc extending between Sumatra and Burma (Myanmar). It is the emergent summit of a volcano that rises from a depth of about 2250 m. The small, uninhabited 3-km-wide island contains a roughly 2-km-wide caldera with walls 250-350 m high. The caldera, which is open to the sea on the west, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. Historical eruptions have changed the morphology of the pyroclastic cone in the center of the caldera, and lava flows that fill much of the caldera floor have reached the sea along the western coast.