The Barren Island volcano, near Andaman Islands, which rejuvenated its activity three years ago continues to be active and the series of eight earthquakes in the Andaman Sea in the last two days indicates the possibility of undersea volcanic activity.

'During the last 15 days, the volcano activity in the island has increased. Fire glow over the central cone can be seen at the night from a distance of 10 km,' according to Indian Coast Guard sources.

Barren Island volcano was reactivated following killer Sumatra earthquake of December 26, 2004 which created tsunami, killing lakhs (a unit in the Indian numbering system equal to one hundred thousand) of people in various Asian countries, including India and Indonesia.

'Barren Island volcano located at 135 km northeast of Port Blair is the northern most point of Indonesian volcanic chain and is very active,' Dr D Chandrasekharam, Volcanologist of IIT Mumbai said, confirming it.

It appears that this volcanic activity must have triggered a series of eight earthquakes since evening of June 27 in southwest of Port Blair, magnitude varying from 4.8 to 6.6 on Richter scale occurring in the same junction which was earlier considered aseismic (not an earthquake zone), Chandra Sekharam, Head, Centre of Studies in Resources Engineering, said.

The series of earthquake originated in a junction between two underwater ridges. These ridges extends along the 90 E longitude and is called the 90 E ridge and the other is the Andaman ridge that extends as a curvilinear (arched) trench towards Sumatra.

Therefore, the volcanologist does not rule out undersea (submarine) volcanic activity in this region.

The 90 E ridge is known as the 'aseismic' ridge since there was no seismic activity recorded over this ridge for several decades. The current location of the earthquakes' epicenters at the junction of the above two ridges makes these current earthquakes very interesting for further investigation, Chandrasekharam said.

'Whether these events are forerunners of a major future event has to be investigated,' he said while replying a query on the predictions of any major earthquake or volcanic activity in the region.

The US Geological Survey (USGS) seismic analysis showed that all the earthquakes are generated due to thrust fault along the major 'subduction' plate located parallel to Andaman Island along its western margin.

'The effect of these eight tremors must have been seen over the Andaman Islands but accessibility to a large part of the island is restricted and hence what we observe in and out Port Blair is not what is actually happening over the entire Islands,' Chandrasekharam said.

According to sources, people in Port Blair are sleeping outside their homes braving the rains, fearing major calamity.

Barren Island volcano has a central pyroclastic cone that has been the source of historical eruptions reported in 1787, 1789, 1795, 1803, possibly 1852, 1991 and 1995.