Warning lights flash for next tsunami

PARIS, Monday (AFP) - Lightning does strike twice in the same place.

That is the warning of seismologists as they assess the risk of another Indian Ocean tsunami.

That may seem an exaggeration. Surely the gods of nature vented all their anger when they ripped open the Earth's crust last year and extinguished more than 200,000 lives?

Could it happen again?

Earthquake experts are usually loath to make predictions, but on this question they ditch their traditional reserve.

They say: Not only will a tsunami-generating quake happen again, it is likely to occur at almost the same place - and at any time.

"All the warning lights are flashing bright red," says Paul Tapponnier, a researcher at the Paris Institute for Planetary Physics (IPGP).

Earthquakes may seem random but the evidence shows that they come in clusters. One big temblor exerts stress on an adjoining part of the fault, bringing it that much closer to rupture.

Kerry Sieh of the California Institute of Technology's Tectonic Observatory notes that seven of the 10 giant earthquakes of the 20th century occurred between 1950 and 1965 - and five of these occurred around the northern Pacific margin.

What made the December 26 quake so powerful was that it was a type called a megathrust.