Smithsonian Institution
Global Volcanism Network Bulletin v. 20, no. 4, April 1995

Barren Island (India)  Ash plumes from three vents; fire
      fountaining and lava flows

Barren Island
Andaman Islands, India
12.29N, 93.88E; summit elev. 305 m

The Geological Survey of India (GSI) made an aerial survey on 2
March and a land survey on 8 March 1995 to monitor the ongoing
eruption that was first noticed on 20 December 1994 (Bulletin v.
20, no 2). Surveys in late January revealed mainly Strombolian
emissions from two vents near the S crater wall (figure 5; vents A
and B). Lava flows had reached the sea by the end of January.
The GSI Photogeology and Remote Sensing Division analyzed seven
Landsat Thematic Mapper IRS images of Barren Island from November
1994 through February 1995. No signs of eruption were seen on 6
November or 8 December, but conspicuous activity was present on 29
December 1994. Vigorous activity was noted on 9 January. An image
from 20 January showed decreasing emissions, but on 25 January the
eruption was increasing again. Billowing smoke could be seen
through gaps in the cloud cover on 11 February. The lava surface
temperature was estimated to be well above 1,000 deg C on 9 and 25
January, based on preliminary analysis of a few thermally radiant
pixels.
On 2 March aerial observers noted thick columns of dark to
yellowish gray gas followed by white fumes gushing vigorously from
the two vents active in late January. The gas column was rising ~1
km, and the eruption was confined to the S side of the summit
crater. Denser air containing volcanic aerosols was encountered ~90
km WSW of the volcano at an altitude of ~2,100 m. Very dense air
was noticed ~35 km W, and a very thick gas and smoke cloud was
encountered ~15 km W at a height of ~1,500 m.
On 8 March the eruption was largely characterized by
phreatomagmatic explosions. In addition to the two previously
mentioned vents, the pre-existing conduit in the center of the 1991
crater (figure 5; vent C) was vigorously active. Huge billowing
dark emissions from all three summit vents were followed by thick
jets of white fumes at intervals of 30-60 seconds, with deep
thundering explosions. The combined eruption column rose ~1.5 km
before being blown SW by the wind into a horizontal plume. Space
Shuttle astronauts observed this plume blowing generally W on 9 and
14 March (Bulletin v. 20, no. 2).
A fourth vent had also opened at the S foot of the existing
volcanic cone by 8 March (figure 5; vent D). It had constructed a
small spatter cone from which thick lava was pouring out and a fire
fountain was rising ~30 m. Ground temperature ~100-300 m from the
foot of the cone was 62-83 deg C. Hot lava was cascading into the
sea along the NW shore, ~200 m S of the landing site, causing the
seawater to boil profusely. The lava front thickness had increased
from ~6 m on 24 January to ~10 m on 8 March. Ejecta ranged in size
up to 10 x 18 x 25 cm. Extensive ashfalls covered the S and W parts
of the island, and ash was seen falling as far as 10 km S of the
island. Marine life has not been seriously affected; fish were
observed ~500 m from shore. Birds were also seen flying over the N
part of the island.
Reference: Haldar, D., Laskar, T., Bandyopadhyay, P.C., Sarkar,
N.K., and Biswas, J.K., 1992, Volcanic eruption of the Barren
Island volcano, Andaman Sea: Journal of the Geological Society of
India, v. 39, p. 411-419.
Information Contacts: Director General, Geological Survey of India,
27 Jawaharlal Nehru Road, Calcutta 700016, India; Deputy Director
General, Geological Survey of India, Ops: WSA Eastern Region, 4
Chowringhee Lane, Calcutta 700016, India.

Figure 5. Geologic sketch map of Barren Island showing lava flows
and distribution of volcanic products from the 1995 and 1991
eruptions. Modified from Haldar and others (1992); courtesy of the
Geological Survey of India.