Why is India’s only active volcano erupting again?
Barren Island, India's only active volcano in Andaman and Nicobar is erupting once again. The volcano, which has been dormant for more than 150 years, started erupting in 1991 and has shown considerable activity since then.
A team of scientists led by Abhay V Mudholkar, from CSIR-National Institute of Oceanography, Goa, reported that the volcano is active and spewing smoke and lava once again. On January 23, 2017, the scientific team on board CSIR-NIO's research ship RV Sindhu Sankalp were busy collecting sea floor samples in the Andaman Basin near the volcano when it suddenly started spewing ash.
Clouds of ash
The team moved about one mile from the volcano and began closely observing it. The volcano was erupting in small episodes lasting about 5 to 10 minutes. During the daytime, only ash clouds were observed.
Photo courtesy: National Institute of Oceanography
Spurts of blasts and smoke
However, after sundown, the team observed red lava fountains spewing from the crater into the atmosphere and hot lava flows streaming down the slopes of the volcano.
The volcano was revisited in the early hours of January 27, 2017 again during the second leg of the cruise led by B Nagender Nath. The team witnessed the continuation of spurts of blasts and smoke.
Photo courtesy: Wikimedia Commons
A volcanic arc
They sampled the sediments and water in the vicinity of the volcano and recovered coal-like black pyroclastic material representing proximal volcanic ejecta. Clouds were seen at the crater mouth where the smoke was bellowing out in the otherwise clear sky.
Scientists from CSIR-NIO have been surveying the Andaman Basin and they have identified many small submerged volcanoes in a linear chain called a volcanic arc. These volcanoes are formed due to the rising magma formed deep in the mantle due to the melting of the subducted Indian Ocean crust.
Photo courtesy: Andaman government website
Barren, devoid of vegetation
A few of these submarine volcanoes have been dredged for samples and pumice type of light volcanic rock have been recovered. The volcanic island is uninhabited and the northern part of the island is, as the name suggests, barren and devoid of vegetation. Private citizens of India can visit the volcanic island by chartered boats after obtaining the permission of the forest department in Port Blair.
Photo courtesy: NASA