Risk of Tsunami off Sumatra remains large, says new research

The risk of another large earthquake off the coast of Sumatra, the area struck by a 9.2 magnitude quake and tsunami in 2004 resulting in the death of 225,000 people, remains large, new research claims.

The report published in the journal Nature today claims that the subduction zone is "ripe" for yet another large seismic event, despite a series of quakes in 2007. "From what we saw we can say with some confidence that we're probably not done with large earthquakes in Sumatra," author Jean-Philippe Avouac, from the Tectonics, said.

On December 26th 2004, a huge earthquake occurred of the western coast of Sumatra, spawning a lethal tsunami throughout the Indian Ocean. The quake occurred in a subduction zone, where one tectonic plate dips under another, producing a new quake-prone region.

The researchers found despite large seismic activity in 2005 and 2007, the region there was still a considerable amount of stress built up in the subduction zone. "The 2007 quakes occurred in the right place at the right time," added Mr Avouac. "They were not a surprise. What was a surprise was that those earthquakes were way smaller than we expected."

"The quake north of this region, in 2005, ruptured completely," said fellow author, Ali Ozgun Konca, a Caltech scientist. "But the 2007 sequence of quakes was more complicated. The slippage of the plates was patchy, and it didn't release all the strain that had accumulated."

"It was what we call a partial rupture," added Mr Avouac. "There's still enough strain to create another major earthquake in that region. We may have to wait a long time, but there's no reason to think it's over." Source In The News