Geologic
sketch map of Barren Island.
By D. Haldar, T. Laskar, and J.K. Biswas. GSI.
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Barren Island in the Indian Ocean 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 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 a long, long time ago, that produced pyroclastic-flow and -surge
deposits.
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.
August 23rd, 2010
Occasional ash plumes and frequent thermal alerts ongoing into 2010
During January to mid-September 2009, Barren Island produced occasional
ash plumes and stimulated almost
daily thermal alerts . Additional ash plumes were reported on 1 November
2009, then again on 3-4, 11,
and 23 January 2010.
As per today, the volcano is in eruption or eruption may
occur at any time.
http://getaway2india.wordpress.com/2009/10/07/andaman-and-nicobar-islands-%E2%80%93-indias-archipelago/
Tuesday, May 31st, 2005
An Indian coast guard ship sighted a thick plume of smoke on Saturday,
May 28th, as it
came close to Barren Island and authorities said they were monitoring
the situation and had
informed the state-run Geological Survey of India. There is smoke intermittently
coming out
from its crater and flames or lava have also been
also sighted.
Monday, January 3rd, 2005
The lava from the volcano on the uninhabited Barren Islands will flow
into the sea, and there
is no cause for alarm. Residents of Diglipur, a village on an island
near the Barrens, reported
seeing smoke and fumes rising from the volcano after the earthquake
and tsunami waves.
The Geological Survey of India have said that the eruption was minimal.
A mud volcano in the Baratang Islands in Andaman also erupted after
the earthquake,
again according to GSI. The authorities have moved the villagers on
the island away from
the volcano.
Saturday, January 1st, 2005
According to "The Indian
Express" a survey aircraft from the National Remote Sensing
Agency arrived at Andaman and Nicobar Islands today. It
will carry out a detailed aerial
survey and submit a report to the administration.
Its only after this that the actual
condition of the volcano could be accurately assessed.
Residents from Diglipur, close to Barren Island, are said to have sighted
some plumes of
smoke, it was learnt from official sources.
Incidentally, yesterday, authorities had confirmed that
the volcano at Bara Tang, also an uninhabited island,
had started belching out mud to a height of 3 m above its mouth.
Friday, December 31st, 2004
Confusing news have been coming the last two days about the volcanic
activity in the
Andaman Islands. The first report said that a mud-volcano
had erupted. As other reports later told that lava had been spewing
our from the volcano, the confusion was complete, as lava doesn't come
out from mud-volcanoes.
One
report goes like this: "A mud volcano at the inhabited Baratang
Island in Middle
Andaman has erupted. Mud keeps
bubbling in the volcano, but on December 28, the
eruption was up to three metres and there was considerable heat.
The mud volcano was located on
one side of the Baratang Island, which was about 100 km
from Port Blair. People live on
the other side, but there is no cause for concern.
The
Geological Survey of India said barring some aftershocks, it has not
found any major
activity in the Andaman and Nicobar region, including eruption from
any of its dormant
volcanoes."
The next report looked like
this:
"INDIA's last active volcano, in the Andaman and Nicobar islands,
has erupted in the
aftermath of the earthquake that set off tsunamis killing thousands
of people, official sources
said today. People have been evacuated from Barren Island since the
eruption began on
Tuesday night and there are no reports of injury. Lava was flowing out
of the rim of the crater.
The volcano, known as Barren 1, is located 135km north-east of the capital
Port Blair
and last erupted in 1996. It runs about 150 fathoms under the sea and
usually gives off smoke.
The risk is minimised because it is surrounded by the sea so if at all
there is a lava flow it will
roll off into the sea." (Is this a sub-marine volcano?)
Finally, a third report says:
"Lava is spewing from a crater on India's Andaman islands. People
have been evacuated
from the area around the crater near Baratang town on Middle Strait
island, about 100
kilometres (60 miles) from the capital Port Blair. There were no reports
of injury.
It began on Tuesday night. Flames and lava are shooting up three metres
high. (?)
The population was cleared from a half kilometre range as a precaution
... and they put up
barricades." Some 2,000 people live at Baratang.
The Geological Survey of India describes the Baratang crater as a mud
volcano covering an
area of about 1,200 square metres (1,440 yards), which has been increasing
in size from a
minor fissure.
Official sources earlier mistakenly sited the volcano on Barren Island,
site of a crater traditionally known as the only active volcano in India."
So what has really happened, is absolutely NOT clear from our side yet.
More news to follow.
Latest news always on top. Below is older history.
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May 1991
Reports of strong emissions of "thick smoke" on 30 April prompted
a visit to the island on
16 May by geologists from the GSI. Lava poured continuously from a subsidiary
vent on the
NE face of the central volcanic cone, travelling N into a valley, then
W along the course of the
1803 lava flow. An area of ~800 x 200 m had been covered by fresh lava,
with an average
thickness of 5-6 m. Explosions at the vent occurred at intervals of
several seconds, ejecting
bombs, lapilli, and ash to heights >50 m.
August 1991.
Lava production continued from the subsidiary vent on the NE face of
the volcanic cone,
80 m below the main crater, during a visit on 26 June. Incandescent
material was ejected in a
pulsating fountain, to [80] m height, more intensely than during the
previous visit on 16 May.
Satellite monitoring had indicated a temperature of 1,100°C around
the vent on 6 May.
A dark plume rose 300-400 m from the crater of a large spatter cone
that had formed at the
eruptive vent. The main crater remained quiet. The lava flow observed
in May had bifurcated,
with one branch extending along the NW and W valleys, and a new branch
extending S.
By 26 June, lava had reached the sea at the boat landing near the NW
corner of the island
(~1.2 km from the vent); during the 16 May fieldwork, the lava front
was still 200 m from
shore. Vigorous boiling and thick jets of steam were observed for 100
m along the shore.
Studies of water near the shore indicated a considerable decrease in
pH, and visibilit
y dropped to <10 cm (Srinivas, 1991). Nearby coral was destroyed.
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