Solomon Disaster Exposes Earthquake Monitoring System Weaknesses

By | April 10, 2007

Two years before a deadly earthquake-triggered tsunami pummeled the Solomon Islands, scientist Fred Taylor’s request for U.S. funds to set up a Pacific seismic monitoring network was flatly rejected.

Then there is Phil Cummins of Geoscience Australia, who is still waiting for money from his government to help train South Pacific officials to study corals for clues to the region’s tsunami history.

Experts say Taylor’s and Cummins’ cases underscore a larger problem: a failure by donors, nongovernment and international agencies to finance the science needed to build an accurate record of Asia-Pacific earthquake and tsunami activity.

Without it, disaster experts say Asia will keep being caught off guard — as it was last week, when a 5-meter-high (16-foot-high) tsunami hit the Solomons, killing at least 34 people and leaving tens of thousands homeless.

The Solomon Islands waves came ashore minutes after a magnitude 8.0 quake struck Monday morning 10 kilometers (six miles) beneath the sea floor, about 345 kilometers (215 miles) northwest of the capital, Honiara.

The Solomons joined the Pacific Tsunami Warning System after the 2004 tsunami, giving them access to earthquake and tsunami alerts from worldwide sources.

There had been few signs, however, that a large quake threatened the impoverished nation _ a situation that may have been helped by a network that could have picked up increased seismic activity.

“Given there have been a number of large events, it’s surprising there hasn’t been more focus on assessing the hazards, which tells us the potential for large events where they haven’t occurred yet,” Cummins said.

“There have been other magnitude 8.0 or high 7.0 (earthquakes) in the Solomons, but not in this particular area,” he said. “Could we get a magnitude 9.0 in the Solomons? I’d like to say no. But I can’t because the fundamental data doesn’t exist.”

Cummins and other scientists say what is needed in places such as the Solomons _ a geologically active area where the Australian tectonic plate is slipping beneath the Pacific plate at about 80 millimeters (3.15 inches) a year _ is a GPS network to monitor increased seismic activity.

But they also called for research into understanding the region’s history of quakes and tsunamis, so scientists can better predict when one might strike.

That means studying corals for signs of uplift or submergence, which could indicate that a tsunami had struck hundreds or even thousands of years ago.

By doing that, scientists could possibly understand a quake cycle and chart where an area is on that cycle in an effort to determine when the next big one would hit.

Until now, predictions have largely depended on instrumental data going back only a century.

“Observations the past 100 years are not sufficient,” said Taylor, a research scientist at the University of Texas Institute for Geophysics. He plans a trip to the Solomons as early as next week.

“We need to use geological methods such as coral blocks that have been thrown on shore by large waves that might be tsunami, and look for evidence of uplifted or subsided shorelines,” he said. “The danger is that there will be other areas where people think there aren’t earthquakes. But if you looked at the long-term history, there were.”

While endorsing the use of such geological methods, University of Washington Geophysics Prof. Heidi Houston warned that predicting the times of future quakes remains difficult.

“A lot of people think that in order for it to be useful, it has to be on very short time scale, and that is very hard to do,” Houston said.

One area where such research has been done is off Indonesia’s Sumatra island, where a 2004 quake spawned a massive tsunami that left some 230,000 people dead or missing in a dozen countries.

Using a GPS network and coral records, California Institute of Technology’s Kerry Sieh has found a pattern of large earthquakes about every 230 years, with the last major ones in 1797 and in 1833. He used that data to predict that an earthquake and tsunami will hit Sumatra’s Padang area in the coming decades.

“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 last year. “I’d be surprised if it were delayed much beyond 30 years.”

That has prompted a massive campaign to teach Padang area resident how to respond to a quake. Property prices have plummeted along the coast, indicating that many take the threat seriously.

But work like that in Padang is often ignored in favor of funding high-tech solutions such as the US$130 million (euro97 million) Indian Ocean Tsunami Warning and Mitigation System.

“I think in many locations in the world, a tsunami comes too quickly for any warning system to be effective,” said Bruce Jaffe, a U.S. Geological Survey research oceanographer who is examining sediment around the Indian Ocean for signs of past tsunamis.

“You need to have information on tsunami-prone areas

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