Tuesday, December 13, 2005

"INDIAN OCEAN TSUNAMI: Girding for the Next Killer Wave"

Read the full article by Richard Stone and Richard A. Kerr in Science (subscription required.

The Indian Ocean tsunami killed some 230,000 people in a dozen nations, including 168,000 in Indonesia's Aceh province at the tip of the island of Sumatra. The lesson in ill-preparedness has sparked a multinational effort "to create a tsunami warning system for the Indian Ocean. As the first anniversary of the disaster approaches, an alarm network is beginning to emerge--a loose web of deep ocean sensors, tide gauges, and seismic stations operated by individual countries, along with mechanisms for sharing data and disseminating public warnings.

"Last month, for example, Indonesia, the country deemed most vulnerable to the next big Indian Ocean tsunami, deployed two sea-floor pressure sensors and associated buoys, the vanguard of a 10-sensor network.....By establishing warning centers, Thailand and other countries have begun to fill a lethal void.......

"Representatives of Indian Ocean nations met in Bangkok last January to begin planning for a tsunami alert system. Discussions bogged down over who would host a regional warning center. By spring it was clear that each country would establish its own center, although the Intergovernmental Oceanographic Commission of UNESCO was invited to coordinate an Indian Ocean Tsunami Warning and Mitigation System, the subject of an IOC meeting next week in Hyderabad, India. It is expected to cost $200 million to bring the system online over the next few years.

"IOC is counting on five nations--Australia, India, Indonesia, Malaysia, and Thailand--to cover the entire Indian Ocean, with other nations enhancing the coverage. "No single nation can protect itself or provide protection to others alone," says IOC executive secretary Patricio Bernal. Real-time data will stream into one or more "sub-regional centers," he says, where it will be rapidly processed and fed back to national warning centers, which would decide on their own whether to issue tsunami advisories to their citizens......

"the network won't come cheap, nor will it come quickly: The U.S. factory that produces the buoys was inundated by Hurricane Katrina, so production is lagging, sources say. Thailand plans to buy two and have them in place in the Andaman Sea by early 2007. India expects to deploy up to a dozen, and Malaysia will place three more in the Straits of Malacca, the South China Sea, and the Sulu Sea.....

"Through IOC, the United States is kicking in $16.6 million over 2 years for these efforts, primarily in India, Indonesia, the Maldives, Sri Lanka, and Thailand."

Risk of Future Tsunamis

The magnitude of 9.3 earthquake off Aceh province of Indonesia last December is thought to have shunted stress southward beneath the sea floor, contributing to an earthquake on the same fault line on 28 March -- one that struck at a hefty magnitude 8.7. "The next section of fault down the line--from 1°S to 5°S, offshore of the Sumatran city of Padang--could well be poised for disaster. This segment last failed in 1833; the accumulated stress could drive a quake larger than magnitude 8.5. A subsequent tsunami would threaten a million people along 500 kilometers of low-lying Indonesian coast.

"New findings underscore the risk. Earlier this week, at the fall meeting of the American Geophysical Union (AGU) in San Francisco, California, the Ulster group, with colleagues at the National Institute of Geophysics and Volcanology in Rome, reported preliminary computer simulations of possible south Sumatra tsunamis. They first modeled a range of possible earthquakes of magnitude 8.0 to 9.0 and then used the resulting sea-floor movement to drive a model of tsunami wave generation. Initial results show that the coast from Padang south could be devastated."

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