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Scientists work out formula to forecast tsunami

Washington, April 1 -- Now tsunamis won't be able to catch you unaware, thanks to a mathematics formula worked out by scientists that will give advance warnings and an idea of their destructive might.

The research, led by Newcastle University maths professor Robin Johnson, was prompted by the 2004 post-Christmas tsunami that devastated coastal communities in Indonesia, Sri Lanka, India and Thailand.

In this instance, an earthquake in the ocean depths triggered a long surface wave which resulted in six massive wave fronts, one after the other.

Of these waves it was the third and largest one that caused the most devastation, hitting the beaches with terrifying speed. Reaching a height of 20 metres or 65 feet, it hefted a train from its tracks as it travelled along the Sri Lankan coastline, killing almost 1,000 people.

Johnson and his colleague Adrian Constantin, professor at the University of Vienna, Austria, felt that if we could understand more about how these long waves behave we could predict where they might hit and how devastating they might be.

"What we found was that the number and height of the tsunami waves hitting the shoreline depends critically on the shape of the initial surface wave in deep water," explained Johnson.

"From this it is possible to work out whether a 'trough' or a 'peak' is the leading wave. In the case of a trough then the familiar sight of the tide suddenly going out is the precursor to an approaching tsunami.

"If a peak is the leading wave, there is no warning except a fast-approaching wall of water. Potentially this could provide vital information for areas facing an impending disaster," said Johnson, according to a Newcastle release.

Their research was published in the Science Direct: Fluid Dynamics Research, and this paper has just been named the journal's best paper of the year.

copyright 2009 by IANS.

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