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Tsunami 'will strike again'
24/12/2006 08:15 - (SA)
Padang, Indonesia - Two years ago, a monster earthquake off western Indonesia spawned a tsunami that killed or left missing some 230 000 people in Asia and horrified the world.
Now, scientists say the same fault that hatched the quake is due to rupture again - and this town stands to take the full force of the waves.
Researchers expect the quake to hit within 30 years and predict a large swathe of Sumatra island's densely populated coastline just south of the area devastated in 2004 will be washed away.
"All this area in red will disappear," said Padang Mayor Fauzi Bahar, pointing at a satellite map on his office wall showing the likely reach of the waves into the town.
He and other officials have started mapping out evacuation routes and educating the public on the threat.
But even with the preparations, authorities fear up to 60 000 people could die in the low-lying town of 900 000, unable to outrun the oncoming waves even if they are warned or flee as soon as the ground stops shaking.
"The people will be washed away," Bahar said.
On the morning of December 26, 2004, the most powerful earthquake in four decades lifted up the seabed west of Sumatra by several metres, propelling waves at jetliner speeds across the Indian Ocean that reared as high as two-storey buildings before smashing into coastal communities, beach resorts and towns in 12 nations.
In hardest-hit Indonesia, Thailand, Sri Lanka and India, the waves surged kilometres inland, tossing ships, swallowing entire villages and leaving behind a blasted landscape of cement foundations and rubble littered with tens of thousands of bodies.
On Sumatra island - home to more than half the victims - volunteers and emergency workers took three months to recover all the corpses, which were dumped into mass graves with mechanical diggers.
Based on more than a decade of research
Warnings of another tsunami-spawning quake are adding urgency to efforts to establish a warning system covering the Indian Ocean rim similar to the network of hi-tech buoys in the Pacific that alerts Japan, the United States and other nations to sudden tidal changes.
The worst-affected countries have begun installing sirens on threatened coastlines and three buoys with sensors capable of detecting waves generated by seismic activity are in the water, but the network is several years from completion, officials say.
Making sure the system works from end-to-end is a "daunting task", said Curt Barrett, from the US National Oceanic and Atmospheric Administration.
"Once the warning goes out, people have to know what to do," he said. "All of these people at the community level, that's where it really has to work. All of this information is useless if it doesn't get to the person down on the beach."
The warnings of another tsunami are based on more than a decade of research by respected US geologist Kerry Sieh and a team of scientists studying a section of the fault that ruptured so catastrophically in 2004.
His conclusions are shared by scientists at other universities and government institutions.
The fault, which runs the length of the west coast of Sumatra about 200km offshore, is the meeting point of the Eurasian and Pacific tectonic plates that have been pushing against each other for millions of years, causing huge stresses to build up.
Using historic accounts of earlier quakes, measurements of coral uplift and data from a network of Global Positioning System transmitters on nearby islands, Sieh has found a pattern of large earthquakes about every 230 years, with the last major jolts in 1797 and in 1833.
The 2004 jolt, as well as another strong quake on the same fault three months later that killed 1 000 people on nearby Nias island, has loaded it still further, says Sieh, who is from the California Institute of Technology.
"We are not saying the quake is going to happen tomorrow or next week, but on the other hand we don't want people to forget about it and be lax," he said, predicting it would come within the next three decades. "It is a virtual certainty."
- AP
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