Report on Barren Island (India) — 29 December-4 January 2005

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 December-4 January 2005
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2004. Report on Barren Island (India). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 29 December-4 January 2005. Smithsonian Institution and US Geological Survey.

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Barren Island

India

12.278°N, 93.858°E; summit elev. 354 m

All times are local (unless otherwise noted)


Reports of increased volcanic activity at Barren Island and Narcondam volcanoes during the week of 2 January were found to be false. Professor Chandrasekharam from the Indian Institute of Technology reported that as of 4 January no unusual volcanic activity was occurring at these volcanic islands. Newspaper reports of active "mud volcanoes" in the Andaman Islands caused a great deal of concern and confusion.

Backgrounds. 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-trending volcanic arc extending between Sumatra and Burma (Myanmar). The 354-m-high island is the emergent summit of a volcano that rises from a depth of about 2,250 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 W, was created during a major explosive eruption in the late Pleistocene that produced pyroclastic-flow and -surge deposits. The morphology of a fresh pyroclastic cone that was constructed in the center of the caldera has varied during the course of historical eruptions. Lava flows fill much of the caldera floor and have reached the sea along the western coast during eruptions in the 19th century and more recently in 1991 and 1995.

Narcondum volcano, an island possession of India in the Andaman Sea, is part of a volcanic arc that continues northward from Sumatra to Burma (Myanmar). The small 3 x 4 km wide conical island, located about 130 km E of North Andaman Island, rises to 710 m, but its base lies an additional 1,000 m beneath the sea. The island is densely vegetated, bounded by cliffs on the southern side, and capped by three peaks. No evidence of historical volcanism is present, although the summit region is less densely vegetated and volcanism at the andesitic volcano is considered to have continued into the Holocene. The island's name means "pit of hell," although the name could have been mistakenly transferred from the historically active Barren Island volcano, 140 km to the SSW.

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-trending volcanic arc extending between Sumatra and Burma (Myanmar). The 354-m-high island 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.

Source: Professor Chandrasekharam from the Indian Institute of Technology