Next killer tsunami is long overdue

Reuters

NEXT WAVE?: An Australian seismologist says an earthquake is long overdue at the northern end of the faultline that triggered the 2004 Boxing Day tsunami.

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A powerful earthquake on the same fault line that triggered the 2004 Boxing Day disaster could strike at any time in the Bay of Bengal, threatening tens of millions of people living on the coasts of Burma and Bangladesh with a devastating tsunami, a scientist has warned.
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The Boxing Day earthquake off Sumatra's coast measured at least 9.2 on the Richter scale and created a tsunami that killed more than 230,000 people around the Indian Ocean.

However, Phil Cummins, a seismologist with Geoscience Australia, says major earthquakes at the extreme northern end of the fault happen, on average, about once a century - and the next one could be long overdue.

The fault line marks where the Indian tectonic plate is being forced under the plate carrying the south-east Asian land mass. At the northern end, the collision of the plates is raising the Himalayan mountains.

Writing in the journal Nature, Dr Cummins says that while "there seems to be relatively little concern about" about what is happening beneath the Bay of Bengal, his research suggests there is "a high potential for giant earthquakes along the coast of Myanmar [Burma]" and "a large and vulnerable population is thereby exposed" to a significant hazard. The tectonic environment was similar to other areas that had experienced "megathrust earthquakes".

The last big quake struck the area on April 2, 1762. Dr Cummins's modelling suggests it may have been as powerful as 8.8. In 1841 the captain of a British ship surveyed the region, recording evidence that parts of the coast had been lifted by three to seven metres and residents once fished where there was now land.

Dr Cummins said yesterday land movement data suggested the region experienced a magnitude 9 quake on average every 500 years. However, smaller quakes could strike every century. "There is no question there will, some day, be a large quake ... if the next one is a magnitude 8, it is already overdue.

"The population is huge now. With more than 240 years passing since the last big quake, local residents may have lost the knowledge to seek higher ground on feeling the earth rumble."

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