Published on Friday October 30, 2020 - 8:08 AM
* Earthquake *
NARRATOR: Three months after the tsunami, what have we learned about this catastrophe? Why did it occur? And will we be better prepared the next time? Wave that Shook the World, right now on NOVA.

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NARRATOR: It's early morning, December 26th, 2004: Southeast Asia awakes to what should be another ordinary day. Fishermen are on the water in Sumatra. In Sri Lanka, 1,500 people take a train along the coast, among them, a tourist named Shenth Ravindra.

SHENTH RAVINDRA: I was going to do some scuba diving around the coral sanctuary. My dad was very keen for me to catch the train because of the beautiful scenery I would encounter on the way down.

NARRATOR: In Thailand, Tom Travers and Richard Anthony open their beachfront restaurant.

TOM TRAVERS (Tsunami Survivor): I went down, put some laundry in; Richard came back, and I ordered some breakfast in—yeah, another normal day, basically.

NARRATOR: And in Hawaii, scientists at the Pacific Tsunami Warning Center carry out routine tests of their equipment. All these people are unaware they are about to be caught up in one of the worst natural disasters ever.

It begins shortly after dawn and without warning, when a huge earthquake tears apart the floor of the Indian Ocean.

The Earth's crust is divided into giant rafts of rock called tectonic plates. The plates are always on the move. When they collide, enormous amounts of strain build up. Where the plates grind past each other, earthquakes occur. Under the Indian Ocean, one plate is pushing beneath another in a process called "subduction." It's been doing this for 40 million years.

On December 26th, something snapped.

PHIL CUMMINS (Seismologist, Geoscience Australia): The Indo-Australian plate is, what's called "subducting," beneath Indonesia: it's sliding beneath the plate Indonesia is situated on. That interface has what's called "stick slip friction" properties, and that means it drags the upper plate down with it. And it pulls it down and deforms, the upper plate builds up strain energy. Eventually the stress on that contact exceeds the strength of the contact and the upper plate snaps back into position.

NARRATOR: The earthquake's epicenter is 155 miles from the Indonesian island of Sumatra.

BILL MCGUIRE: The rupture, the fault that actually tore in the Earth's crust, is about 1,200 kilometers long.

THOMAS HEATON (Engineering Seismologist, California Institute of Technology): The continental plate shoved out over the oceanic plate by about 10 to 20 meters. Most of the motion was horizontal, but some was vertical because the plate boundary, the fault, is inclined.

PHIL CUMMINS: Most of the energy travels perpendicular to the strike of the subduction zone, so it, more or less, went east-west, towards Sri Lanka to the west and towards Thailand to the east.

NARRATOR: The earthquake continued for about four minutes. Soon after it ended, this seismogram, recording the event, appeared in California, 8,000 miles away. It will be several hours before analysis will confirm at least a Magnitude 9, one of the most violent on record.

THOMAS HEATON: For every unit you increase in magnitude you go up by a factor of thirty in the radiated energy. So it would take 30 magnitude 8 earthquakes to match the energy of a magnitude 9.

NARRATOR: In Sumatra, the city of Banda Aceh feels the full force of the earthquake, and buildings collapse.

It's more powerful than all the world's earthquakes over the last five years put together. Half way around the world in Hawaii, a few minutes after the earthquake, computers at the Pacific Tsunami Warning Center spring to life as they pick up seismic signals. The Warning Center was founded in 1949, after a tsunami struck Hawaii, devastating the town of Hilo and killing 159 people. Today, the Warning Center operates around the clock, monitoring the Pacific Ocean for tsunamis. In any earthquake over magnitude 6, scientists on duty are automatically paged.

BARRY HIRSHORN: I had just fed my cats. I was lying down for kind of a nap, and it had been three or four days I had been on duty already. I was on the verge of falling asleep when my pager went off. I looked at the pager very briefly. I could tell from the message that I was dealing with something probably larger than a 6. And I was here within about a minute, and Stu Weinstein was already looking at them.

STUART WEINSTEIN: I noticed that the trace of this seismogram was very full. It appeared as just, kind of, one thick line going across the screen, and that told me that it was a substantial earthquake.

NARRATOR: To detect and pinpoint earthquakes, the Warning Center relies on data from a network of seismic stations. But not all earthquakes spawn tsunamis, so they use coastal tide gauges and deep ocean pressure sensors to figure out if one has formed. Located on the ocean floor, these sensors monitor the depth of the water above them. A change could mean a deadly tsunami is passing overhead. Data is relayed to a buoy on the surface, up to a satellite, and down to the Warning Center. There are six of these sensors in the Pacific Ocean.

This system has saved countless lives, warning countries around the Pacific of killer tsunamis. But in the Indian Ocean, there is no such system and no warning center, although seismic sensors do exist.

In the first few minutes after the earthquake, data from these seismic stations alerts Weinstein and Hirschorn to its location and size, causing them serious concern.

BARRY HIRSHORN: I then estimated the magnitude at a magnitude 8. Our response was, "Wow. That's a fairly large event." And we issued our first official product, which was a Tsunami Information Bulletin.

NARRATOR: The bulletin informs countries around the Pacific Ocean of the earthquake, but not all magnitude 8s form destructive tsunamis, and with no network of tsunami sensors in the Indian Ocean, they do not know if this quake triggered one.

BARRY HIRSHORN: The seismic analysis can only take you so far. We also looked at what water level information might be available, and, because this was the wrong ocean, the answer was "none."

STUART WEINSTEIN: We had no tide gauges. So at this point we had no evidence that there was any wave generated.

BARRY HIRSHORN: And this was a tremendous crippling, frustrating experience because, without water level gauges, we don't know if there's been a tsunami.

STUART WEINSTEIN: We were, unfortunately, flying blind.

NARRATOR: As they watched events unfold, their frustration would soon turn to despair. When an earthquake occurs under the ocean, its energy can dissipate as shockwaves through the crust or as tsunamis through the water.

SIMON BOXALL: Whether that shockwave turns into a tsunami, into a water wave, depends on where in the Earth's crust the earthquake takes place. In this case, it took place very near to the surface of the seabed.

BILL MCGUIRE: This earthquake was only about 30 kilometers deep, which is very, very shallow. If it had been 200, 300 kilometers down, it would not have generated a tsunami.

NARRATOR: As the seafloor lifted, it displaced billions of tons of water above it in a process called "tsunami initiation." This released as much energy as 23,000 Hiroshima-sized atom bombs.

THOMAS HEATON: As a result of the earthquake, part of the ocean floor has been uplifted and part has been dropped down along the fault surface. Because the sea floor changes, so does the water column above the sea floor. So some parts go up here and some parts go down.

NARRATOR: Seconds later, the tsunami undergoes a transformation as the displaced water column splits.

THOMAS HEATON: The uplifted area basically collapses, and the water rushes away from the uplifted area, creating a tsunami wave that's traveling radially away from the uplifted area. The tsunami wave is now speeding off to some distant shore at 1,000 kilometers per hour.

SIMON BOXALL: The main pulse can cover the ocean quite rapidly, which means that, in the initial few minutes, the north-northwest part of Sumatra would have been hit.

NARRATOR: In Sumatra, 10 minutes after the earthquake, people are unaware that an enormous wave is charging toward them at over 500 miles an hour. In the open ocean, tsunamis are virtually undetectable. This simulation shows how a boat in deep water is only slightly affected. Fishermen at sea barely notice a tsunami passing under their boat, but as a tsunami nears land, it rears up into a monster, growing by a process called amplification.

SIMON BOXALL: As the wave approaches, the land the front of the wave slows down; it slows down to 400, 300, 200 miles an hour. The back of the wave is still going at 500 miles an hour, and the back of the wave catches up with the front, and then you get this big buildup of water.

NARRATOR: The amplifying wave can have a curious side effect. Before hitting land, it draws water from the leading edge, exposing the seafloor for as much as a mile. This phenomenon would lure thousands to their deaths.

BILL MCGUIRE: One of the big problems about trying to prevent deaths due to tsunami, is trying to stop people rushing down to the beach when the sea goes out. And that happened here. People went down; they saw fish flapping about on the beach...went down to pick them up.

SIMON BOXALL: If you see the sea start to come out, you don't stand and watch in awe, you run.

NARRATOR: Unlike a classic surfer's wave, tsunamis do not roll towards land. Instead, they surge forward like a flood. The leading face builds into a wall of water. Tsunamis are so deadly because the volume of water that follows is so great.

BILL MCGUIRE: Tsunamis have wavelengths—which is the, the distance from the crest of one wave to the next wave—of hundreds of kilometers. It will keep coming in, maybe for five minutes or more, and it has enormous mass behind it.

SIMON BOXALL: People see water as being very soft, gentle, something fairly benign, but bear in mind that water is very heavy, and a cubic meter of water weighs a ton. So if you've got one of your kitchen units at home full of water coming towards you or falling on top of you, that's a ton of water. That's like having a car land on top of you.

BILL MCGUIRE: The sort of waves that we've seen in the, the Indian Ocean tsunami of 2004, are probably able to deliver, for every one and a half meters of coastline, a hundred thousand tons of water, which is an extraordinary figure. And that is, is coming into the, into the coastline, hitting the coastline with incredible force.

SIMON BOXALL: And as the tsunami progresses, as it goes through the coast, it's picking up stones, it's picking up debris like a tornado almost. And that debris—cars, people being thrown at you at 40 miles an hour—that's going to hurt, that's going to kill you.

NARRATOR: Just 15 minutes after the earthquake, northern Sumatra is the first to be hit by the tsunami. This street is three miles from the sea. This is the aftermath of such destructive power. Virtually no footage of the wave hitting Sumatra survives. It was simply too big.

SIMON BOXALL: Many of the areas that were totally decimated were devastated by this wave. The cameraman either was very busy running away or, unfortunately, is no longer with us. So I have no doubt there is plenty of video footage showing a far more destructive wave which will never be found.

NARRATOR: The city of Banda Aceh is in ruins. Even those used to disaster zones have never witnessed anything like it. Few people have seen more destruction than cameraman Geoff Mackley.

GEOFF MACKLEY: I just never thought I'd ever see anything like this. I've been to more than 30 hurricanes and 35 volcanic eruptions, so I sort of thought I'd seen everything nature could throw up. But it's got nothing on this; this is chaos on an industrial scale—just unbelievable, you know? All these buildings here, and debris up the side of the hill for 60 meters, probably a hundred feet up the hillside—it's beyond belief, really.

NARRATOR: Mackley's camera shows where vegetation was stripped off the rocks, indicating the height of the wave.

GEOFF MACKLEY: These people now look like ants, and you can see how high up the cliff face the wave went.

NARRATOR: With little public education about tsunamis, hardly anyone expected a wave of water to follow the earthquake. In Banda Aceh, even those living far inland were overwhelmed by the onrushing sea.

TRANSLATOR : After the earthquake, 20 minutes after earthquake, people see the sea have water, wave.

GEOFF MACKLEY: How big? How high?

TRANSLATOR: Higher than coconut tree.

GEOFF MACKLEY: That's incredible. What was he thinking when he saw this wave?

TRANSLATOR: After they saw the wave, to...higher, they didn't thinking anything, they run.

NARRATOR: But for most people, there was nowhere to run. The water reached enormous speeds, picking up anything in its path.

BILL MCGUIRE: The waves will break up buildings, they'll break up cars. They'll carry these things inland, and, of course, people will be carried for kilometers along with all this debris and bashing against it and being prevented from actually getting out of the water by a virtual layer of debris at the top.

NARRATOR: Evidence of the tsunami's colossal power litters the coastline.

GEOFF MACKLEY: This is what's left of the Banda Aceh cement works and the wharf area. A ship's been totally trashed there. Here, we've got these huge big sections of breakwater, and they've just been sheared off and thrown over here like rag dolls. And these pieces, here, must weigh hundreds of tons. And it just defies belief, really. It kind of gives us some idea of just how awesome this thing was.

NARRATOR: The damage to this cement factory is another indication of the height of the wave when it hit.

GEOFF MACKLEY: Just this area we've been walking around here today is like the aftermath of an atomic bomb, maybe worse.

NARRATOR: Under this wreckage lie thousands of bodies. About three quarters of the tsunami's victims died here in Sumatra.

Just a few minutes later, the wave hits the Andaman and Nicobar Islands north of Sumatra. More than 7,000 die or go missing.

NEWS REPORTER: For those who have been rescued, a refugee center has been set up in Fort Blair, the tiny capital of these islands. Fifteen hundred were there when we visited, with more arriving all the time. Relatives search desperately for the name of a loved one on the admissions board.

NARRATOR: Forty-five minutes after the earthquake, scientists at the Pacific Tsunami Warning Center are still analyzing the data, assuming, by now, that a local tsunami might have struck northern Sumatra.

BARRY HIRSHORN: This is an evolving story, more and more data is coming in at more and more stations, at increasing distances from the earthquake, and now we were dealing with a much larger event. Eight and a half is much larger than 8. Stu suggested, you know, that we should really issue a second message on this with some kind of upgrade. "Why don't you call Chip?" And I said, "Good idea." We called Chip, and I basically told him the situation.

CHARLES MCCREERY: We discussed it and agreed we needed to issue a second bulletin to let people know that this was bigger than we initially estimated and there was the possibility of a tsunami being generated in the region of the epicenter.

BARRY HIRSHORN: Stu and I crafted a second message and sent it out. We also knew at that point that, because of the proximity of the earthquake to Sumatra, that by now they were already inundated.

NARRATOR: Southern Thailand, one hour after the earthquake: cities are waking up and beaches beginning to stir. People have no idea a massive tsunami just struck Sumatra and is about to hit them.

TOM TRAVERS: It was just moving so quick that I bolted.

DONALD (TSUNAMI SURVIVOR): I was on the roof. I was not going to let the water take me away.

IAN DICK: It was just something out of a science fiction book.

MAN: Oh, my God!

BILL MCGUIRE: One of the extraordinary things about tsunami is that they...their, their destructive power, their, their height, how far they go inland, et cetera, is hugely determined by the morphology of the coastline. And that is fantastically well demonstrated on the west coast of Phuket Island.

NARRATOR: Bill McGuire has been studying natural disasters, including tsunamis, for more than 25 years.

BILL MCGUIRE: If you look at Bang Tao beach here, the waves came in like this. This area was almost completely destroyed, whereas in the northern part of the bay, here, which was relatively protected, there was less damage.

NARRATOR: When tsunamis hit, they can seem like chaotic walls of water, but the damage they cause is anything but random.

BILL MCGUIRE: If we go further down the coast, here, we see the same sort of thing again: Kamala, here, almost completely obliterated. The headland here, as well, might have caused some refraction of the wave, because they do interact in quite a complex manner. You may get an area which is virtually unaffected, whereas a few kilometers down the coast you may get complete devastation.

NARRATOR: Amid the devastation along Thailand's coastline, one bay with a steep underwater slope was virtually untouched by the wave.

BILL MCGUIRE: Here, where we have Surin Beach, the, the seabed actually rises quite steeply, and it looks as if that helped to act as a barrier to the tsunami. In addition, you have this protective headland here as well. The whole morphology of the seabed and how quickly it rises as it approaches the coast is a critical element in terms of how high the tsunami will be and how quickly and how rapidly and how far it will move inland.

NARRATOR: Ian Dick is a lifeguard who helps run a bar on Surin Beach.

IAN DICK: This is where the water came to, just over to our restaurant bar here, which is quite amazing. You can see here the water only came to this depth, whereas on the next beaches it went from seven to eight meters and went a kilometer inland. We've been blessed here, absolutely.

NARRATOR: But just a few miles away, Kamala Beach suffered some of the worst damage. Not only was it fully exposed to the tsunami, but the gentle gradient of its seabed amplified the wave's destructive power.

BILL MCGUIRE: The actual rate of shallowing of the seabed as you, as you approach the coast seems to be quite important in determining the destructive capacity of the tsunami and how far it goes inland. At Kamala here, it looks as if the, the, seabed is very, very shallow over a long distance, so there's very little to, to stop the wave building, to stop it coming in. And the land behind there, also, is very low lying, so the waves penetrated kilometers inland in those positions.

NARRATOR: In Kamala, Tom Travers and Richard Anthony were having breakfast on the balcony of their restaurant when they saw the tsunami approaching.

RICHARD ANTHONY: It probably went from about 300 meters out to the break wall here in less than a minute. And then it came 'round under the restaurant, took out the whole beach, went onto the road just a little bit, and took out our lower deck.

TOM TRAVERS: We both look down, and, sure enough, the deck is completely gone. It's not just broken, it's missing. I could see the entire bay littered with umbrellas and beach chairs for about 150, 200 meters out. Everything was just cloudy. And I just think, "Wow. Something very serious has happened."

NARRATOR: Travers began videotaping the damage. Fifteen minutes after the first wave, just when it seemed like the worst was over, a deadlier second wave struck.

MAN: It's coming again! It's coming again! Oh, my God!

NARRATOR: Thousands more are caught by surprise.

BILL MCGUIRE: In any particular earthquake, you'll get a different, what we call "tsunami train." There isn't just one wave; there's usually several waves. And it doesn't follow any particular rules. Sometimes the first wave is the biggest one. Sometimes there are maybe two, three, or even more, relatively small waves, and then you get a huge one in the middle and then some smaller ones. But, normally, you do get more than one wave, and they are of different height and they arrive over different periods of time. And it, it can be tens of minutes, even hours between the first wave and the last wave.

MAN: Grab my camera. Grab my stuff, please.

NARRATOR: Travers and Anthony continue to film as the second wave engulfs their restaurant.

RICHARD ANTHONY: The first wave came through just like a normal wave—in the same sort of direction—and then the second wave seemed to go more towards the northern end and sweep around the whole bay. And it seemed to pick up momentum as it came 'round.

TOM TRAVERS: Almost out of nowhere it was like a Class IV, Class V rapids just started moving up, like freestanding waves coming towards us with a bigger wall behind it. That's when everyone started screaming, "Run!" You couldn't see the road, half the temple was under water, and just horrendous sounds of crunching and breaking and smashing. It was just horrifying, just looking out there going, "What about the people in town?" You know, people in shops, stores? It was a sick feeling, just knowing anybody that would have been on ground level, just gone, swept away. Hopefully they floated to higher ground, but anyone in the shops would have been in serious trouble.

NARRATOR: After the waves pummel Kamala, the water retreats, sucking everything out to sea.

MAN: God, I hope there's no one in there...big disaster...huge disaster here.

TOM TRAVERS: When the water was being drawn out with equal force, there were cars floating by. Fishing boats were being smashed into trees.

NARRATOR: Those lucky enough to survive are left in total confusion.

RICHARD ANTHONY: The first one came through, it was big. The second came one knew if third or fourth. No one knew, at that stage, what was going on. Everyone was in panic.

TOM TRAVERS: We were being told to get out of here, to get onto the mountain because there could be a bigger one on the way. And after seeing what the second one had no mercy.

NARRATOR: It's 9 a.m. in Sri Lanka, two hours since the tsunami first reached land: on vacation, Shenth Ravindra is crammed onto a train with 1,500 others. Like all of the passengers, he is unaware that he is minutes from one of the worst rail disasters in history.

SHENTH RAVINDRA: The train was absolutely packed because it was a Buddhist bank holiday, so, you know, everyone was going back home to see the family and also spend time at the resorts. The atmosphere is very different. You get people walking up and down the train, people offering to sell you tea, you know, sweets and stuff. Also, the trains had loads of children, so a lot of noise, so a very vivid experience.

NARRATOR: The train follows the coast of Sri Lanka, about 1,000 miles from the epicenter, and is never far from the ocean.

SHENTH RAVINDRA: The train just stopped. And I was a bit frustrated because I thought, "Oh, my god, we're going to be stuck here for a couple of minutes. I just want to get off this train." I heard a lot of screaming and shouting outside, and so I peered outside and I saw what was mainly women running away from the coast towards inland. And I didn't really know what was going on. At first I thought it might have been a game of sorts, and then suddenly I realized why they were running. I heard the water. And it just came like this...I didn't see a wave as such, it just came like a flood. And then, all of a sudden, it came and started hitting the train.

And it hit the train to such an extent that the carriage got detached from the other carriages behind us and in front of us and shunted off the tracks. And then the water started to spill in, and I felt it come all the way up to my chin. I thought, "Well, I've, I've got to get out of here."

I was able to climb through this doorway and make my way onto the corner of the roof and the wall. At that moment in time there was a lot of chaos and pandemonium and worrying and screaming. And people were using any escape route they could, and people were passing their children through whatever gaps that they could, and I was helping put these children onto the train.

NARRATOR: These photos, taken by Ravindra, show the derailed carriages after the wave hit.

SHENTH RAVINDRA: I didn't have a clue. I just thought it might have been a freak wave, a one-off. I thought it would have just happened along that part of the coast between Ambalangoda and Hikkaduwa, and it was just a freak tide that came in. People were quite lighthearted about it, saying, "That was a bit strange. Lucky we survived." We were just sort of relaxing and speculating about what happened. And, you know, there were kids around me who were hugging me, and just comforting them and making sure they were all right. And we thought that there would be some helicopters and some sort of help would be on its way.

NARRATOR: But no help is forthcoming. Like thousands along the coasts of Sri Lanka and India, survivors of the first wave cannot imagine that a second, even bigger wave is minutes from impact.

SHENTH RAVINDRA: It was a sunny day in Sri Lanka that day, but when I saw the second wave coming, I don't know whether it was the way my memory is remembering it, but everything became really grey and, you know, dark. And, you know, everything lost its color. All I could see was a wall of water that took up about 80 to 85 percent of the horizon; the sky was blocked, limited to about 10 to 15 percent. I could tell the sort of power of it by the fact that you could see it rippling as it's coming towards us, and by the fact that it had consumed so much of the houses that were around; it gave me a real scale of how big it was. And this wave came along, and at this point there was a lot of children surrounding me, and they started clinging on to me and hugging me. And I was losing my balance a little bit on the train.

I was expecting that this wave was going to push the carriage to a point where the carriage would just tip over. We'd all fall into the water, and then, you know, whatever would happen, would happen. But luckily it just pushed the carriage quite neatly along to the point where it wedged against the house.

NARRATOR: Ravindra jumped from the train onto the roof of the house. He was one of only a handful to survive.

SHENTH RAVINDRA: My carriage was completely submerged under water, and the water level was rising quite rapidly. I looked at the other carriage, which was behind us, that was still on the track, that had been tossed around, you know, tossed around and swiveled completely ninety degrees, and I could see, like, people still in the train. And they were obviously dead.

NARRATOR: As the train disappeared beneath the water, it killed nearly everyone on board.

Throughout Sri Lanka and India, over 45,000 lives were lost.

More than three and a half hours have passed since the earthquake. At the Pacific Tsunami Warning Center, the horror of the disaster soon becomes apparent as a news report posted on the internet confirms everyone's worst fears, that the earthquake has generated a tsunami. But the damage caused by the tsunami seems too large for the size of the earthquake.

BARRY HIRSHORN: We were shocked at the enormity of the casualties. We thought we were still dealing with a magnitude 8.5. We were all wondering, "How can an 8.5 produce this kind of damage?"

NARRATOR: An email from a special seismic analysis station at Harvard explains what they are seeing: the earthquake is an 8.9, four times larger than an 8.5.

STUART WEINSTEIN: At that point things started making sense. Then we started to figure out, "Who can we contact that's ahead of the wave?"

BARRY HIRSHORN: No contact points, no organization, no warning systems that I know of, in the area. Picking up the phone and thumbing through the phone book or thumbing through the Web is useless. In fact, it can be dangerous because you're not concentrating on warning someone who can actually do something for the people. So we're brainstorming basically, "Who can we call?"

STUART WEINSTEIN: We then created a tsunami travel time map for the Indian Ocean basin. This gave us an idea of how much time we had in order to warn people. It told us where the wave was presently. And then, immediately, we started to try to contact nations that were ahead of the wave.

NARRATOR: Less than four hours since the earthquake: the Maldives are next in the tsunami's path of destruction. With the wave charging across the ocean at the speed of a passenger jet, it seems like a losing battle, but using their travel time map, scientists at the Warning Center realize there's still time to alert Africa.

CHARLES MCCREERY: We contacted our State Department, and we advised them that this was a very large earthquake and there was the possibility of tsunami waves striking the east coast of Africa.

BARRY HIRSHORN: The State Department operations immediately patched us through to the embassies of Madagascar and Mauritius and we gave them a warning.

STUART WEINSTEIN: ...their embassies in East Africa. We also contacted people in positions of authority to try to get some sort of warning to the east Africa coast.

UNIDENTIFIED MAN IN TRUCK WITH LOUDSPEAKER: (inaudible).. 20 meters above sea level!

NARRATOR: The news reaches Kenya with enough time for people to evacuate the coast; there is only one fatality.

STUART WEINSTEIN: I heard reports that some warning filtered out there, and if we were the genesis of those warnings, that would make us happy.

NARRATOR: The tsunami dissipates as it progresses beyond the Indian Ocean. Over the next 24 hours, disturbances are detected in all the world's oceans.

For most, the tsunami of 2004 was totally unexpected. But this was not the first one to hit Southeast Asia. In 1883, the volcanic island of Krakatoa was blown apart, triggering tsunamis that proved catastrophic for Java, Sumatra and the surrounding islands. Like Krakatoa, the 2004 earthquake was one of the most violent geological events on record. Though there's debate about whether the earthquake was a 9.0 or 9.3, it was at least the fifth largest in history, so big it shifted the entire planet.

RICHARD GROSS (NASA Jet Propulsion Laboratory): The force of the earthquake has caused the Earth to wobble.

NARRATOR: Richard Gross of NASA's Jet Propulsion Lab used seismic data to make some startling calculations.

RICHARD GROSS: The earthquake has caused the mass of the Earth to be out of balance, which has caused the Earth to wobble by about two and a half centimeters. This is just like the tire on your automobile. If your tire is not balanced it will not spin smoothly.

NARRATOR: The violence of the earthquake also shortened the day, by making the planet spin faster.

RICHARD GROSS: This is a just like a skater spinning on ice, moving her arms closer to her body. As she moves her arms closer, she spins faster. As the mass of the subducting plate moves down closer to the center, the earth spins a little faster, making the length of the day shorter by about three millionths of second.

BARRY HIRSHORN: The size of the earthquake shocked us: probably the largest earthquake in 40 years, since any of us have been working in this field, and since the advent of modern seismographs. So we were all shocked to be witnessing the largest earthquake on modern record.

NARRATOR: But was the 2004 earthquake just a freak event? As Krakatoa showed, the region has a history of catastrophic geological activity and tsunamis.

PHIL CUMMINS: I started this work a little over a year ago, and I tried to look at the wider perspective in what other hazards might be presented in the entire Indian Ocean. And then I realized that these massive earthquakes do occur off Sumatra that are so large that they can cause tsunamis that might affect the entire Indian Ocean basin. In 1833, a massive earthquake occurred off Java, and we know that the massive tsunami created by the displaced water wiped out whole villages along the coast of Sumatra.

The 1883 eruption of Krakatoa did cause a massive tsunami. The primary area that was affected by that was Indonesia. In 1977, a very large earthquake—magnitude 7.8—occurred just off the island of Sumbawa, and this earthquake was responsible for the largest tsunami observation in Australia, which was six meters on the northwest Australian coast.

NARRATOR: Cummins and other scientists called for a tsunami warning system in the Indian Ocean over a year ago. A warning system like the one in the Pacific might have saved countless lives.

BARRY HIRSHORN: When I first saw the footage of the tsunami inundation, I found it depressing, and I found it frustrating.

CHARLES MCCREERY: There was no sea level data, there were no designated contact points in any of those countries, there was no tsunami education in place. All of the critical elements needed for a warning system were missing in the Indian Ocean.

STUART WEINSTEIN: We knew that if this happened in the Pacific Basin the loss of life is certainly something we could have prevented. It wouldn't have been anything on that scale.

NARRATOR: Most tsunamis occur in the Pacific.

But earthquakes are not the only cause of these killer waves.

PHIL CUMMINS: There are at least four causes of tsunami. There are earthquakes which cause tectonic displacement of the sea floor. There are asteroids which are thought to have caused very massive tsunami but are very infrequent. There are also volcanic eruptions which can lead to landslides, and an explosive eruption beneath the sea floor would cause a tsunami. And there are also spontaneous landslides that occur above the water and insert mass into the water column or underneath the ocean that change the shape of the ocean floor. But if you are actually going to take concrete steps towards mitigating these kinds of hazards you really have to do some kind of risk analysis to decide where the risk is greatest, so you can concentrate resources there.

NARRATOR: It's estimated that tsunamis pose some degree of risk to almost a quarter of the world's population. A number of scientists fear that in Canary Islands, off the west coast of Africa, 120 cubic miles of the Cumbre Vieja volcano could collapse into the Atlantic Ocean, creating an enormous tsunami.

BILL MCGUIRE: That may generate waves a hundred meters high in the Canary Islands, themselves, and maybe seven to 10 meters on the south coast of the UK. And waves that are 20 meters high all down the eastern coast of the US, when they hit the east coast of the United States, they're estimated to expend the same energy for every hundred meters of coastline as was generated by the collapse of the Twin Towers. And that's for thousands of kilometers all the way down the east coast.

NARRATOR: Scientists disagree over the likelihood of this scenario, but there's virtually no disagreement about the risk of a tsunami hitting the west coast of North America.

CHRIS GOLDFINGER (Marine Geologist): The risk in the Pacific Northwest is severe, really. There's really no difference at all between the Pacific Northwest and Sumatra.

NARRATOR: Like Sumatra, two tectonic plates converge just off the coast of Oregon and Washington in a place known as the "Cascadia Subduction Zone." And many think it's not a matter of if an earthquake will cause a tsunami here, but when.

CHRIS GOLDFINGER: What we're looking at is a computer model of the Oregon continental margin. So here's the coastline—the Cascade Mountains in the background—and what we're looking at here is the plate boundary between the North America plate and the Juan de Fuca plate. And we see strong parallels between the detailed structures in Sumatra and in Cascadia.

NARRATOR: Just like in Sumatra, one plate is diving under another in Cascadia, building up huge amounts of strain that are released in massive earthquakes. Geologists have discovered that 19 large earthquakes occurred in the last 10,000 years along this fault, an average of one about every 500 years. The last one was 300 years ago.

CHRIS GOLDFINGER: So we're now essentially in the same position Sumatra was on Christmas day, where we know there's a subduction zone there. We know how long it was since the last one. We know quite a bit about all the previous events going back 10,000 years. The only thing we don't know is what day the next event is going to happen.

NARRATOR: So is there anything we can do to protect ourselves against these deadly forces of nature? No place on earth has experienced more tsunamis than this building at Oregon State University. Inside is a wave tank, half the size of a football field, the largest in the world devoted just to tsunami research.

DAN COX (Civil Engineer, Oregon State University): Compared to most natural disasters, we know a lot less about tsunamis, just because they're so rare and they're so unpredictable. There's really, practically speaking, no way for us to stop it, but we can certainly prepare for it and plan better. And that's the nature of the work being done here.

NARRATOR: This is a scaled down model of a coastal city, complete with buildings and cars. The scientists will inundate this city with a tsunami and study its effects.

DAN COX: One of the questions during the inundation scenario is what happens when this wave comes through? What are, for example, the largest forces that buildings experience—so we can better design foundations? And what happens to debris—so when a wave hits things like cars and other smaller they'd be moved.

NARRATOR: Instead of an earthquake, a machine called the "Wavemaker" generates tsunamis here.

MAN: Okay, Shin. You want to run a wave?

MAN: Standby...go.

DAN COX: Typically, for an experiment, what we'll do is instrument it with gauges to measure the height of the wave, the speed, and then also the force or the pressure of the wave as it hits the buildings.

NARRATOR: The experiments will provide valuable information that cannot be obtained when a real tsunami comes along. The information will be scaled up to help identify structures that are most at risk in a tsunami, design buildings and bridges that can withstand the force of the waves, and plan emergency evacuation routes.

DAN COX: The tsunami community is certainly a global one. The data that are collected here will be used by scientists around world to help better their areas for preventing tsunami disasters.

NARRATOR: The wave tank is just a few years old, so how well it can help predict events in the real world is not yet known.

Meanwhile, the United States is adding 32 new buoys to the existing tsunami warning system to increase protection in the Pacific, Atlantic and Caribbean. And world leaders are calling for a warning system in the Indian Ocean, where there are seismometers, but no tsunami sensors.

BILL CLINTON (President of the United States, 1993-2001/News Footage): We've got to try to help them rebuild and help them have an early warning system, have systems that mitigate disasters that do occur, so fewer people die in the future.

NARRATOR: But technology is not the only solution.

DAN COX: One of the big issues about warning is that after you've told people that a tsunami is coming, they also have be educated on what to do and where to go.

CHRIS GOLDFINGER: To us that have been working on subduction earthquakes for a long time, we see the tsunami warning system as, really, not just buoys in the ocean, but it's really three parts. It' part is the buoys in the ocean; one part is educating the people; and the third part is research. But without the other parts, the warning system alone is not really enough to do the job.

NARRATOR: Even the most sophisticated warning system would have given northern Sumatra only 15 minutes to alert and evacuate those at risk. But a warning system combined with public education programs would have saved many who died in the other countries affected.

PHIL CUMMINS: In retrospect, the scientific community should have been aware that these massive earthquakes do occur off Sumatra, and probably a little more emphasis should have been focused on the Indian Ocean, where it's documented that massive earthquakes occur.

BILL MCGUIRE: There's a, a simple choice: we either make a conscious decision and say, "Although these catastrophes will happen, they may not happen for a hundred years or more. We're going to do nothing about them, and we're going to accept the consequences." Or we say, "All right, they're very infrequent, but we at least need to plan for them so that when this happens we can save as many lives as possible.

CHARLES MCCREERY: It's been a heartbreaking thing for all of us in the tsunami mitigation community. On reflection I'm sure every one of us wishes we had done something in advance, and that we could have done something to prepare for this terrible tragedy. But we hadn't. And the tragedy unfolded, with its devastating consequences that are going to take years and years to recover, and those families may not ever recover.