'No fresh evidence to indicate Bay of Bengal tsunami'

KOLKATA: The Geological Survey of India has allayed fears of a tsunami hitting the Bay of Bengal soon - though the findings of an Australian geologist suggest that a giant undersea earthquake could inundate India, Bangladesh and Myanmar.

"We are not bothered about the findings. There is no fresh evidence to indicate that a tsunami will hit the Bay of Bengal soon. While one can never predict when an earthquake will occur, what Australian geologist Phil Cummins has written in Nature magazine has been known to us for long," Geological Survey of India (GSI) director Sujit Dasgupta told.

"The findings were recorded by the Geological Survey of India in 1881 after the great earthquake in 1762. In fact, anyone can go through our archive and read about it."

The study by Cummins - a senior seismologist of Geo Science Australia - suggests that a crustal fracture over a 900-km area from the northern Andaman trench to the northern tip of Bay of Bengal is capable of triggering tsunamigenic earthquakes, leading to the loss of millions of lives.     

"There is nothing new in the findings. We have carried out mapping of the entire area, known as the great tectonic zone, which extends over a 10-degree latitude from the mouth of the Brahmaputra river up to 16 km in the Bay of Bengal," Dasgupta said.

"This stretch, also known as the Andaman trench, passes through the Bay of Bengal and is buried under deep sediments of soil. But the thickness of sediments does not always indicate that the magnitude of the earthquake will be large as has been reported in the magazine," he added.

Dasgupta, however, conceded that the GSI does not have the wherewithal to carry out deep sea surveys.

"We do not have the equipment to carry out surveys very deep under the sea to predict the possibility of earthquakes," he said but added that it was unlikely that they were missing out any new development.

The GSI director said the Australian geologist had only mentioned a 900-km fracture in earth's crust beneath the Bay of Bengal, but actually the total area was 1,300 km after the 2004 earthquake.

"Another 1,300 km area in the Andaman trench has developed a rupture, our recent findings indicate," Dasgupta said.

Cummins had combined geo-physical data relating to a northern extension of the fracture in the Sumatra-Andaman earthquake of 1762 and the tsunami of 2004 with 18th century British archives to argue that a seismologic zone lies underneath the Bay of Bengal.

The GSI director, however, denied that the new findings would prompt it to carry out further studies in the Bay of Bengal region.

"We do not need to carry out any more research based on the findings of the Australian geologist as they are just hypothesis collated from several data, including ours," he said. 

The Asian tsunami in December 2004 left 10,000 people dead in India.