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Transcript: Interview with American Tsunami Expert Walter Dudley


Half an ocean away from the devastation created by the South Asian tsunami is Hilo, Hawaii -- home to the Marine Center at the University of Hawaii at Hilo, one of the world’s leading sites for tsunami research. A primarily agricultural region, the Hilo area suffered great losses in 1946 and again in 1960 when it was inundated by tsunamis generated by ocean-floor earthquakes thousands of kilometers away. The deaths and damage caused by the 1946 disaster prompted scientists to develop an elaborate regional warning system, which has been credited with saving many lives. Walter Dudley is a professor of oceanography and director of the Marine Center. He is also the author of Tsunami!, a book about tidal waves. In a conversation with VOA’s Robin Rupli, Mr. Dudley describes the challenge of building a reliable tsunami warning system for the Indian Ocean:

Walter Dudley: “First of all, there’s the matter of monitoring earthquakes. And the Indian government is quite good at that. So that’s an area that’s already in very good shape. But when you have a large earthquake that occurs, if you know if it’s big enough and where the epicenter is, if the epicenter’s under water, then potentially it could have generated a tsunami, and the next thing is to confirm whether tsunami waves have actually been generated. If you declare tsunami warnings every time there was an earthquake, you’d have system that very quickly would be ignored by the public because, fortunately, most earthquakes don’t generate tsunamis. So it’s really important to confirm that waves have actually been generated. The way the system works in the Pacific is there are really two parts. There are tide gauges, which sit in harbors. And those are not really great at accurately measuring the tsunami potential, but they would certainly show if something unusual was going on. But the newest part of the system are sea-floor gauges. And there are now gauges off the Aleutian Islands down the west coast, Central America, South America, and the Japanese have some of their own. And they sit on the ocean floor in very deep water and measure the actual tsunami waves going over head. And they transmit that information to a buoy on the surface which transmits it to a satellite. So these tsunami measurements can be measured at sea and that gives us a much better idea of what’s headed towards some coastal nation.

Robin Rupli: It’s my understanding that an earthquake took place two and a half hours before the tsunami hit. Is that correct?

WD: “It depends how far away people are from the earthquake. Those communities right near the earthquake would have been affected almost immediately. The tsunami in 1960 that came from Chile of course destroyed coastal communities in Chile immediately. It arrived in Hawaii 14 hours later and hit the coast of Japan a full 24 hours later and still killed over a hundred people there. So it really depends on the distance from the earthquake. My understanding is that most of the hardest hit areas were about two hours away.

RR: Two hours sounds like a fairly long enough time to be warned.

WD: “If there were a warning system in place, they could have gotten out at least some warning. There’s a second part of this problem and that’s one we still face in the Pacific. And that is public understanding of the tsunami threat. Most people really don’t understand what the phenomenon is. They have these images from movies that there’s one giant wave and it’s like a surfing wave and it’s not. It’s a series of waves that can last over a period of hours. It’s more like a coastal flood. There’s no weather indication, it doesn’t start raining, or have hurricane winds or anything like that. It can be a beautiful, sunny day at the beach. People need to understand how dangerous the threat is, they need to understand what the warnings mean and they need to recognize the natural signs of a tsunami. Because the areas that are half an hour or an hour away may never have a chance for adequate warning. But if people along the coast recognize initial signs from nature, they might have a chance to save their lives.

RR: What are some of the signs that the ordinary person could recognize?

WD: “If you’re at the coast and you see the water either, for no apparent reason, seriously withdrawing or coming in, then that’s an indication that something unusual and potentially very deadly is about to occur. Also, if you’re at the coast and you feel an earthquake or were to witness a landslide, those are things that would be an indicator that there is tsunami potential there.”

RR: What is your region doing as far as outreach to help victims of the current tsunami?

WD: “The state [Hawaii] has been very active in terms of tsunami prevention and education. I know the International Tsunami Information Center [in Honolulu] works regularly with different nations. Looking at the past, after the 1960 tsunami, there were a lot of nations that were struck by that tsunami who weren’t members of the warning system who soon joined up. And I expect that will be the case now. That nations that previously had no real tsunami threat, in spite of the fact that there had been historical information that those regions had been hit by tsunamis, it hadn’t been in recent years, say a half a century. So now I think they will feel the urgency of the situation and become members of the warning system and that will indeed help in the future.”

RR: Walter Dudley, thank you very much.

WD: “It’s been a pleasure talking with you, Robin.”

RR: Walter Dudley is a professor of oceanography and the director of the Marine Center in Hilo, Hawaii. I’m Robin Rupli.

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