* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> General news -> Barren Island
Post Info TOPIC: Barren Island
Blobrana


L

Posts: 131433
Date:
Barren Island volcano
Permalink  
 

India's Only Live Volcano Active Again After 150 Years

India's only live volcano in the Andaman and Nicobar Islands which had started showing activity in the year 1991 after being dormant for over 150 years has once again started spewing ash, the researchers at Goa based National Institute of Oceanography (NIO) said on Friday. "The only live volcano in the Andaman and Nicobar islands is erupting once again. The Barren Island volcano, located 140-km north-east of Port Blair, dormant for more than 150 years started erupting in 1991 and has since then shown intermittent activity," CSIR-NIO said in a statement.
Read more



__________________
Blobrana


L

Posts: 131433
Date:
RE: Barren Island
Permalink  
 

Barren Island volcano is 1.8 million years old

India's only active volcano in the Barren Island in the Andaman Sea is at least 1.8 million years old, a new study has said.
Scientists at the IIT-Bombay and Physical Research Laboratory (PRL), Ahmedabad used the Argon dating technique to find out the age of the two ash layers older than 42,000 years and generated by this volcano.
Read more



__________________
Blobrana


L

Posts: 131433
Date:
Barren Island volcano
Permalink  
 

Title: A minimum age for the active Barren Island volcano, Andaman Sea
Authors: Jyotiranjan S. Ray, Kanchan Pande and Neeraj Awasthi

Barren Island of Andaman Sea is the only active volcano in the Indian subcontinent. While the volcano has erupted sporadically many times over the last ~70 ka, it is not known when it formed and breached the sea surface. To provide estimates for the timing of these events, we dated two tephra (ash) layers older than 42 ka and generated by this volcanism in a previously studied marine sediment core collected ~32 km southeast of the island using the newly established modern 40Ar-39Ar facility in India. The 40Ar-39Ar plateau ages of plagioclase separates from successive tephra layers at 310 and 375 cm are 1.8 ± 0.4 (2sigma) Ma and 1.5 ± 1.8 (2 sigma) Ma respectively. We interpret the more robust age of 1.8 Ma as the time of crystallisation of plagioclase grains. As this age is very much older than the depositional age of the tephra layer (~61 ka), we infer that it represents the age of older rocks present in the plumbing system of the volcano that were blown out with later pyroclastic eruptions and therefore, sets a strict younger limit to the time of formation of the volcano.

Read more (PDF)



__________________
Blobrana


L

Posts: 131433
Date:
RE: Barren Island
Permalink  
 

The Barren Island Volcano erupted on April 5, 2006, sending a plume of volcanic ash and steam toward the northeast over the Andaman Sea. The Aqua satellite took this picture the same day. This image shows Barren Island at Aqua’s full 250-meter resolution.


Position: 12°17'31.00"N 93°52'29.80"E
In this image, the volcanic plume dissipates as it moves northeast, away from the island. The white dots southwest of the volcano are clouds.

Just 3 kilometres wide with a 2-kilometer wide caldera, Barren Island is the summit of a volcano that rises about 2,250 meters from the sea floor, poking 354 meters above the water line. About 135 kilometres northeast of Port Blair in the Andaman Islands, the volcanic island is uninhabited. It is the only historically active volcano in the north-south volcanic arc between Sumatra and Myanmar (Burma). Mid-March 2006 news reports assured India’s citizens that the volcano’s activity in early 2006 was no cause for alarm as seismologists surmised that it did not indicate an increased risk of earthquakes.

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Indian geologists will study molten rock samples from a volcano on a tiny island in the Bay of Bengal to find out if last week's eruption could be traced to December's earthquake and tsunami.
Since Saturday, the volcano on an uninhabited island located 135 km east of Port Blair, in the tsunami-hit Andaman and Nicobar archipelago has been spewing smoke, dust and lava gas up to 90 ft in the air.
Indian authorities said there was no immediate threat to the environment and marine life.



A team of scientists from the state-run Geological Survey of India (GSI) is leaving this week for Barren Island to collect lava samples.
"Volcanoes and earthquakes happen independent of each other, but there is scope for studying the link in this case," - M.K. Mukhopadhyay, a GSI deputy director-general.
Another senior GSI scientist said the Dec. 26 earthquake and tsunami caused "re-adjustment of lithospheric plates" that might have disturbed lava pockets and caused the volcanic eruptions.
"There is no thumb rule that earthquakes cause volcanoes or vice-versa. But we can study whether the crustal re-adjustment caused by the tsunami disturbed the earth's crust".

The Andaman and Nicobar islands are situated on an undersea fault that continues to Indonesia to the south. The island chain has experienced hundreds of aftershocks following the powerful undersea earthquake that caused the Dec. 26 tsunami.
Officials say more than 430 people were killed and at least 3,000 are still missing after the tsunami slammed into the archipelago. But voluntary groups say the death toll could be much higher.



This photography from the Space Shuttle shows an eruption plume from Barren Island, a stratovolcano in the Indian Ocean. The view is to the northwest. There have been at least five moderate sized explosive eruptions at Barren Island since 1787. The eruption in 1991 lasted six months and caused some damage. The last eruption began in 1994.
The photo was taken on March 10, 1995 from an altitude of 183 nautical miles.




__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> General news -> Barren Island


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard