By Tan Ee Lyn

HONG KONG, Sept 6 (Reuters) - Powerful earthquakes could rock the Bay of Bengal, triggering tsunamis that would inundate Myanmar, Bangladesh and possibly India, an Australian geologist has warned.

It was known that the risk of another large quake off Indonesia's central Sumatra was high, but a large subduction zone in the Bay of Bengal along the coasts of Myanmar and Bangladesh appeared to have been forgotten, Phil Cummins of Geoscience Australia wrote in a letter in the latest issue of the journal Nature.

A subduction zone is an area where two tectonic plates meet and move towards one another, with one sliding underneath the other creating volcanoes and earthquakes.

At issue are the Indian and Sunda plates on the eastern side of the Bay of Bengal, which could trigger quakes and tsunamis.

"Yes, it may have some effect on the eastern Indian coast," Cummins said in a telephone interview from Canberra.

Using historical documents and computer modelling, Cummins warned that a million people might die from such a catastrophe.

"Up to a million lives could be lost, based on the fact that 60 million people live within 10 metres of the sea level in the Ganges delta, 6 million people live in Chittagong directly above the rupture area and 10 million each in Dhaka and Calcutta, which are some distance from the quake but have a number of not particularly resilient structures that could result in a lot of deaths," Cummins said.

Cummins also took into account a huge quake in 1762.

"It ruptured from central Myanmar coast to Chittagong, a distance of 500 km (310 miles) or so, a very large earthquake ... and also a tsunami," he said.

He said it was not possible to predict when a quake might strike.

"By measuring the rate at which stresses are accumulating on the fault, we don't think that that would reach the pre-1762 level for another 200 years," he said.

"But those estimates don't do all that great a job in predicting when quakes may happen. It could happen tomorrow."

Cummins called for more research to verify his hypothesis.

Geoscience is a government unit that provides scientific information and advice to the Australian government and public.

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