SANE provided additional information . . . from passing ships and aircraft, and occasional visits. The eruption's start date remained uncertain, but the first reported activity consisted of gusts of hot air from the N end of the crater on 28 March, and "smoke" observed from a Coast Guard aircraft on 6 April. By 1 May, intensified activity and bigger plumes were seen from ships, and pilots observed numerous dead fish near the island on 9 May. When a GSI team reached Barren Island on 16 May, lava had covered an 800 x 200 m area, and by their next visit on 26 June (16:5 & 8) lava had reached the sea. Continued lava production was reported through July, and accompanying pulsating columns of incandescent tephra were ejected to roughly 60 m height twice in five minutes during observations from Navy aircraft on 30 July. Little information was available on August and September activity.

The eruption was continuing on 24 October, but the 1991 cone collapsed shortly thereafter and only small amounts of "smoke" were intermittently observed during the first week in November.

Geological Summary. 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.

Information Contacts: S. Acharya, SANE; D. Shackelford, Fullerton, CA.