A tidal wave swept the island nation of Papua New Guinea, leaving seven hundred confirmed dead and thousands injured. After a background report, Elizabeth Farnsworth discusses the origins of tidal waves with oceanographer Eddie Bernard.
JIM LEHRER: The killer wave. We begin with a report by Krishnan Guru-Murphy of Independent Television News.
KRISHNAN GURU-MURPHY: It must have been nature at its most terrifying, the Three Tsunami, the Japanese term for giant wave, swept over the villages ten meters high. There was no warning, no time to run.
MAN: So many children were killed-old age-and only those strongest and the fleetest people survived. The rest were killed.
KRISHNAN GURU-MURPHY: The bodies are being buried quickly. There are too many for ceremony or dignity, and the threat of disease is too great to wait even for them to be identified. The waters and swamps are full of bodies. Many were also washed out to sea. There are thought to be over 2,000 still missing. The villages have lost a generation of children. They were the weakest, and it was a public holiday. Those who survived say it sounded like a jet had landed as the waves came upon them. It started under the ocean floor with an earthquake. Part of the earth's crust was thrust under another part.
The movement created a wave of extraordinary power, moving towards the coast. As the wave reached shallow water, it was forced up to a phenomenal height. It hit the shore at around 50 miles an hour, doing as much damage again on the way back. The injuries are horrific-broken bones, terrible damage. The Australian defense force has set up a mobile hospital. The Red Cross and Red Crescent are there too, and the aid workers who are there say it's a lot worse than they'd anticipated.
JIM COUCHER: Disaster. Absolutely disastrous. It's far bigger than we thought it was going to be.
KRISHNAN GURU-MURPHY: There are at least 6,000 people left homeless and with literally nothing save the clothes they're wearing. For now they're in temporary shelters being supplied by the aid effort. But Papua, New Guinea is a poor country. The resettlement will bring with it a whole new set of problems. This is a land of superstition and magic. The disaster areas are fearful places now, and it's unlikely the people will return.
JIM LEHRER: And to Elizabeth Farnsworth in San Francisco.
ELIZABETH FARNSWORTH: And we're joined now by Eddie Bernard, director of the West Coast National Oceanic & Atmospheric Administration Research Lab. He has been researching tidal waves or Tsunamis for the past 30 years. Thank you for being with us. Mr. Bernard, you've seen a lot of tidal waves in your years of work. Is this one of the worst you've ever seen?
EDDIE BERNARD, National Oceanic & Atmospheric Administration: Well, this certainly ranks up among the most damaging in terms of loss of life.
ELIZABETH FARNSWORTH: Explain to us-I want to go back over the explanation that we just heard but in more detail. Start with the earthquake and explain what happens to cause something of this power.
EDDIE BERNARD: Well, you might want to think of a piece of ocean floor about a hundred miles long by about thirty miles wide and imagine that it lifts up very abruptly about six feet. And that's probably the scenario that they witnessed during the New Guinea earthquake. This automatically pushes the water-the surface of the ocean water up about the same amount of elevation, and then when gravity tries to restore the ocean back to its normal position, you create a series of waves, and then the first wave, which struck about five minutes after the earthquake, as eyewitness accounts said, that it was a roar, that's fairly typical.
Water will withdraw and expose the sea floor, and then as a new wave comes in, it makes a very loud sound as it comes barreling into the ocean-from the ocean into the coast line at about twenty-five to thirty miles per hour and destroying everything in its path. Then it will recede, and then another wave will approach some ten to twenty minutes later, and this process will be repeated about three waves, so the entire episode will last over an hour, with a series of three to maybe four or even five waves.
ELIZABETH FARNSWORTH: And the terrible injuries and destruction occur not only because of the force of water hitting but because there are pieces of all kinds of things in the water, houses and machinery, right, and you're being hit by that?
EDDIE BERNARD: Yes, that's correct. The first wave-and especially in this case I'm sure most of the houses there were made out of wood or some wood product, so they instantly became part of the Tsunami. And as the first wave broke everything up, then all of this material was in the water, and you're bringing swept back and forth at twenty-five to thirty miles an hour caught in-between these pieces of material that could be a coconut tree, could be a part of a house. But as these objects hit each other and if you're in-between 'em, then people will be knocked unconscious, broken limbs will occur, they'll be unable to swim, and they'll drown in this process.
ELIZABETH FARNSWORTH: And so many children died because they are too small to resist it, right, they can't swim their way out?
EDDIE BERNARD: Absolutely. This is the-the tragedy of these events is that usually the weak portion of society is the one that dies-the children and the elderly.
ELIZABETH FARNSWORTH: How common is-and by the way-should we say Tsunami or Tidal Wave?
EDDIE BERNARD: It's your preference. Tsunami is the Japanese word. Tidal Wave is an apt description of the process. It looks like a very rapid tide to people who live along the coast-whatever word works for you.
ELIZABETH FARNSWORTH: How common are they?
EDDIE BERNARD: Well, in the Pacific Ocean over the last hundred years there has been one destructive Tsunami per year on average. So they are very frequent in the Pacific Ocean. This ranks among one of the most destructive-probably "the" most destructive one was in 1896 off the coast of Japan, where 23,000 people perished.
ELIZABETH FARNSWORTH: And what causes them besides earthquakes?
EDDIE BERNARD: In addition to earthquakes volcanic eruptions, explosive types like Crakatowa, underwater-
ELIZABETH FARNSWORTH: Crakatowa was the volcano in what is now Indonesia, right?
EDDIE BERNARD: That's correct. Crakatowa in Indonesia. Underwater landslides can also generate Tsunamis. And in some instance earthquake is accompanied by an underwater landslide, so the combination can make a Tsunami larger than the earthquake would produce by itself. And then a final way to produce a Tsunami, although we have no direct evidence of this, is, of course, a meteor hitting the Pacific-any ocean-any body of water that could actually create a cavity in the ocean surface. That too would produce a Tsunami.
ELIZABETH FARNSWORTH: What difference did it make in this case that the earthquake occurred not far off the coast?
EDDIE BERNARD: Well, that means it's particularly dangerous because the time from-the time the earthquake stops to the Tsunami arrives is very short, giving the residents almost no time to react. But also, it probably made it more efficient. In this particular part of the world-
ELIZABETH FARNSWORTH: By efficient you mean powerful?
EDDIE BERNARD: By efficient I mean powerful, that is, the transfer of energy from the earthquake to the water was very efficient, because it was near the shore, near the coast line and all the energy went directly into the wave formation. In addition, this has a very steep ethemmetry off the coast there, so it's quite possible that there was an accompanying landslide. In terms of earthquake magnitudes, this is a relatively small earthquake that produced a large Tsunami. So this is something that a survey team will investigate when they arrive in New Guinea about August 1st.
ELIZABETH FARNSWORTH: And I didn't understand what you said. Did you say that it might have made a difference that the coast was so steep there?
EDDIE BERNARD: Yes, it will make a difference. It can make a difference in two ways. One is that if it's a steep coast, the likelihood of an underwater landslide is greater, and two, if it's a steep coast, the Tsunami can arrive from the open ocean to the coastline without any degradation in its energy. It arrives without any resistance by the coastline.
ELIZABETH FARNSWORTH: Mr. Bernard, you were director of the National Tsunami Warning Center in Hawaii for a while. Can there be warnings of these things?
EDDIE BERNARD: For this type of event the warning is almost impossible, because the time is only minutes. The warning center in Honolulu and in Palmer, Alaska are designed to issue warnings on the order of ten to fifteen minutes after the earthquake happens. In this case the warning could not-would not have been issued by any warning system.
So the best mitigation process that we could have for a situation like this is education. Surely the people of New Guinea felt the earthquake. If as soon as they felt the earthquake, then they would have taken evasive action by heading for high ground. This occurred about dinnertime, so it's not quite clear if their activities would have precluded them observing how intense the earthquake was.
ELIZABETH FARNSWORTH: But if somebody in California say feels an earthquake and they're on the coast, they should just run the other way, is that right?
EDDIE BERNARD: That's certainly-nature's warning you that there's something about to occur, and certainly you should take nature's heed and move inland as quickly as possible. If you're lucky and there's no Tsunami, there's no problem, you just have a little energy. But if there is a Tsunami, you've saved your life.
ELIZABETH FARNSWORTH: Well, Mr. Bernard, thank you very much for being with us.
EDDIE BERNARD: You're welcome.