The relatively new technology is not without its glitches. Three of the six existing Pacific coast buoys have had malfunctions in recent months. Nonetheless the system has already proven its worth.
On November 17, 2003, after only a month in operation, real-time data from a DART buoy was employed to cancel a false tsunami warning set for Hawaii. Averting an evacuation saved the state an estimated 68 million U.S. dollars in lost productivityand possibly strengthened the effect of any real future warnings.
"It's imperative to prevent false warnings because evacuation is costly but also because people can get complacent," Prager said.
Experts like Walter C. Dudley, director of the Kalakaua Marine Education Center at the University of Hawaii at Hilo, stress that technical warning systems must be underpinned with effective public awareness campaigns and emergency response plans.
"Even if you have plenty of warning people have to understand that this phenomenon is not something that you can watch," he said. "You see this happen with floods because people don't understand the force of water. I think when it moves really fast it only takes about 12 to 14 inches (30 to 35 centimeters) to pick up a car."
Warning system effectiveness is also subject to just how close a tsunami-spawning earthquake occurs to populated coastlines. While mid-ocean quakes may allow sufficient reaction time, those occurring closer to shore may send devastating waves crashing in within minuteslittle time for even the best system to have much of an effect.
"With a local tsunami you may have only 15 minutes," Prager said. "In Sri Lanka I think they had something like two hours so they could have gotten a warning out. But in Sumatra they only had perhaps 15 minutes."
When warning times are short or nonexistent, knowledge becomes even more critical. "You need to explain the phenomenon so that people can recognize the natural signs," Dudley explained. "If you feel an earthquake near the coast it's time to head for the hills. If you see the water withdraw or even suddenly come in then it's also time to turn and head to high ground. Even without a warning system many of the people who died in this one might have been saved if they'd been educated."
In fact, knowledge did save some in the tsunami's path.
A Thai tribal leader is reported to have saved over 1,800 lives by recognizing imminent danger of the receding sea and evacuating his people to high ground. A man who knew about tsunamis from watching National Geographic television documentaries saved 1,500 people in India's Nicobar Islands. A ten-year-old British student saved her family and possibly others when she warned them to flee a beach. She had recognized danger signs after learning about tsunamis in her geography class. (See sidebar for more about this story.)
Education and awareness are top-of-mind issues, UNESCO's Kong said. "We have to make sure that the person on the beach who gets the warning knows what to do."
Mapping a Plan of Action
The December disaster showed that tsunami effects are not uniform but vary greatly from area to area due to coastline topography. Studies of such factors are another important part of warning preparedness.
"There certainly is a need for inundation maps," said USGS Senior Science Advisor for Earthquake and Geologic Hazards David Applegate. Applegate noted that such maps are currently being prepared in the Pacific Northwest. "[It's important] to understand what the local impacts are likely to be of a tsunami and those are so dependent on local shoreline topography."
"It's a key part of public education," he continued, "not only making people aware of the tsunami threat but what to do about it. They need to know where they should go so that they can get to areas unlikely to be inundated as quickly as possible."
Finally, nearly everyone agrees that not only educational but emergency response efforts must be better coordinated before disaster strikes.
"It's not rocket science to figure out what to do in the aftermath," Dudley said. "Tsunamis have struck before. You know what you'll need the antibiotics, the medical care. The emergency management community does a great job with the resources that they have, but it's not enough."
"There really was no emergency response infrastructure in place in those [Indian Ocean] countries," Prager said. "A warning system is not just the scientific instrumentation but the rest of it, the emergency response and education, which is a lot harder. The scientific community can put this information out but how do you get the message to people so that they know what to do?"
The great tsunami of 2004 was one of the worst disasters in history. Look at photographs, read our latest news stories, and learn how tsunamis are generated, where they can strike, and what you can do to protect yourself. Tsunami in Southeast Asia: Full Coverage
SOURCES AND RELATED WEB SITES