There is “a high potential for giant earthquakes along the coast of Myanmar” that could trigger large tsunamis with catastrophic consequences for the densely populated regions of Bangladesh and along the Ganges-Brahmaputra delta where millions of people live, a research by an Australian seismologist, being published in the coming issue of Nature, has said. (Source: The Hindu)
Potential for quakes along Myanmar coast
N. Gopal Raj , September 7, 2007, The Hindu
THIRUVANANTHAPURAM: There is “a high potential for giant earthquakes along the coast of Myanmar” that could trigger large tsunamis with catastrophic consequences for the densely populated regions of Bangladesh and along the Ganges-Brahmaputra delta where millions of people live, a research by an Australian seismologist, being published in the coming issue of Nature, has said.
Although it could be another 200 years before sufficient stress is built up to trigger an earthquake on the scale of the one in 1762 along the Arakan coast of Myanmar with an estimated magnitude of 8.8, the research indicated that “the northern tip of the Bay of Bengal should be on our radar for earthquake and tsunami risk,” according to Phil Cummins, senior seismologist at Geoscience Australia.
Previous interpretations of the tectonics along the Arakan coast suggested that even if the tectonic plates bearing India and south-east Asia were being pushed together, such powerful earthquakes were unlikely, said Dr. Cummins during a press briefing. But recent GPS measurements, though sparse, showed that the tectonic plates were being deformed near the Myanmar coast in a way that was consistent with the sort of offshore “locked thrust” fault that could generate tsunamis.
In 1762, the rupture along both southern and northern extremes of the Arakan coast, a length of well over 500 km, would have resulted in a very large earthquake. Though there were no clear accounts that anything more than a local tsunami along the Myanmar coast had resulted, “this is the type of earthquake that could generate a large tsunami that could impact the densely populated Ganges delta.”
Such an earthquake could cause much damage in Chittagong and perhaps significant damage even in Dhaka and Kolkata. At a guess, it seemed likely that may be over a million lives could be at risk, he said.
As the potential for large earthquakes and tsunamis existed in the northern Bay of Bengal, more geological studies were needed to establish how such events could be and how often they occurred, added Dr. Cummins in an e-mail.
The fault near Myanmar had not generated an earthquake for hundreds of years, according to C.P. Rajendran of the Centre for Earth Science Studies here.
He has studied earthquakes and tsunamis that have affected India in the past.
“In a classical way of looking at these things, you would expect an earthquake where there is such a seismic gap,” he told The Hindu.
However, Dr. Rajendran believes that there was not enough evidence at present to indicate that the Indian and south-east Asian plates were meshed in a locked thrust fault, which could suddenly give away.
“We don’t have the kind of the data to say whether the fault near Myanmar is going to break or not. We should look for evidence of palaeo-earthquakes and tsunamis along the Myanmar coast, Bangladesh and northern Andaman,” he said.
The country’s National Early Warning System for Tsunami & Storm Surges is nearing completion.
“We are now ready” in terms of being able to assess the location of an earthquake and its characteristics, detecting whether a tsunami is heading towards India and issuing an alert on that basis, according to Shailesh Nayak, director of the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad.
A round-the-clock early warning centre is already operating at the INCOIS, which receives data in real-time from a network of seismic stations, coastal tide gauges as well as bottom pressure recorders.
The bottom pressure recorders, which are installed on the ocean floor, are able to pick up a tsunami as it passes by and relay that information to moored ocean buoys on the surface which then transmit the data to the control centre.
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