it is one of the greatest tragedies of modern times a quake so powerful it knocks the earth off its axis a tsunami leaves tens of thousands feared dead parts of Japan shift ten feet out to see parts of the coast drop over three feet what forces create this epic disaster now a team of scientists is looking for answers never before have we had such as a surplus of data there are no mysteries in this earthquake we know exactly what happened Japan's coast lies in ruins incredibly it could have been worse [Music] scientists understanding of earthquakes and tsunamis saved lives but as this disaster shows there is much more to learn Japan's killer quake right now on Nova [Music] major funding for Nova is provided by the following David H coke [Music] and discovering new knowledge HHMI and the Corporation for Public Broadcasting and by PBS viewers like you thank you additional funding is provided by Millicent Bell through the Millicent and Eugene Bell foundation it is 96 hours since Japan's largest earthquake in a thousand years strikes professor Roger bilham from the University of Colorado is one of the first geologists to survey the aftermath so we're flying right over the coast right now and that much of the coast has sunk about a meter the extent of the damage is truly amazing the tsunami picked up everything in its path cars houses warehouses and just tumbled them relentlessly inland on and on and on one of the things I'd like to see is exactly how far it went what kind of debris get gets left behind on these gigantic tsunami every detail of the disaster is recorded by seismometers strain gauges and tidal gauges [Music] now bilham looks to piece it all together to find out exactly what happened and why so many lives have changed forever methods and on nights later with the keymaster how did this happen [Music] March 11th 2011 2:46 p.m. Japanese time sixty miles off the northeast coast a massive earthquake seismic waves raced towards Shore the fastest waves called P waves travel at four miles a second 15 seconds later they hit land Japan's detection systems instantly picked them up within seconds automatic warnings flash across the country a computer-generated announcement interrupts a Japanese Parliament broadcast the coastal city of Sendai lies just 80 miles from the epicenter there's almost no warning before slower more destructive seismic waves called s waves hit the town these slower s-waves violently shake the ground from side to side these are the waves that make earthquakes so damaging already northeast Japan is descending into chaos the seismic waves travel on 93 miles southwest of the epicenter they slam into fukushima daiichi home to an aging nuclear power station housing six reactors this video from a hospital near the reactor reveals the earthquakes power sensors at the plant automatically shut down the reactor cores the reactors are in lockdown when the s-waves hit but the intense heat generated from the nuclear reaction process does not simply dissipate when you think shut down you think uh you know it's the dangers gone because it's shut down but the reactor core was still extremely hot you know if you have a pan in the oven and you shut the oven off that oven continues to heat inside even after you've turned it off with the reactors stopped there's no power to drive the cooling pumps the reactor cores heat up emergency diesel generators take over pumping coolant through the reactor the Fukushima plant survives the earthquake intact scientists 3800 miles away at the Pacific Tsunami Warning Center in Hawaii receive emergency alerts researchers around the world see the event unfold Japan has lots of seismometers so there was a lot of information fast so the earthquake was still going on when we got our page first indications a magnitude of around seven but as data floods in the numbers start to climb 7.5 7.7 up into the eights the immediate reaction of everybody was that's not right because in the history of Japan there has never been an earthquake larger than 8.4 really heightened our in the intensity of what we were doing because we knew we were dealing with something very big and something that could affect the whole Pacific Basin we realized oh this is it and and then immediately you realize this is horrible for Japan the source of this disaster lies 62 miles off Japan's coast four miles below the surface the earth is distorting caught in a vast slow-motion collision the Earth's crust is made up of several continents sized slabs of rock tectonic plates Japan lies at the point where the Pacific plate rams into the Eurasian Plate at three inches a year about the same speed your fingernails grow Japan is on the Eurasian Plate it compresses and buckles as the Pacific plate drives underneath it snagging and catching as it goes over centuries immense stress builds up until suddenly the plates snap causing an earthquake the energy that drove this earthquake had been building up for a couple of hundred years caused by the movement of the Pacific plate towards the Eurasian Plate think of it as a giant elastic band that's being wound up for 200 years 100 seconds since the fall blind slipped the destructive s waves reach Tokyo the city has 60 seconds warning the quake lasts an unprecedented five minutes an American geologist is in Tokyo we expected it to end after 10 15 20 seconds something like that maybe a minute at the most about minute three or four we were just all kind of astonished that it would just kept going and going and going [Music] I'm just looking at each other going is this over yet no it's not it's still going [Music] what is different about a big earthquake is that it begins but it doesn't stop it was kind of a growing realization that it was just getting bigger and bigger and bigger and it had to be fairly close [Music] an American tourist captures the ground opening up at his feet the footage reveals a frequent characteristic of earthquakes liquefaction see the crack was not there rock is being bigger and smaller going back and forth and there is water coming up all over loosely packed and waterlogged ground near the surface starts to behave like a liquid as the ground compresses liquefied dirt pumps to the surface most buildings still stand Japan's earthquake warning systems work scientists upgrade this quake to a magnitude nine a thousand times more powerful than the devastating 2010 Haiti earthquake but everyone in Japan knows this is far from over the earthquakes explosive energy is about to unleash another destructive force for centuries the Eurasian Plate is dragged downward by the Pacific plate grinding under it the whole upper plate behaves just basically like a rubber block it just compresses and like a spring like this and when the earthquake happens it springs back the upward motion thrusts a four mile deep mass of water upwards when the dome collapses back immense waves race out across the ocean just three feet high and over 60 miles from front to back the waves travel at a blistering speed a tsunami is born the energy Eve DUP the seafloor that displaced vast amount of water that we can see made it its way on land it made its way off around the Pacific one side of the wave takes off across the Pacific the other races towards the coast of Japan tsunamis travel very fast at the speed that depends on the water depth in because in the deep ocean tsunami travels very fast reaching at times the speed of a jet aircraft traveling at over 500 miles per hour the wave takes just minutes to reach the coast here the shallower seafloor slows down the front of the wave the waves fast moving rear races in it soon catches up with the front the increasing pressure pushes the seawater up into a rising swell three miles from shore a Japanese Coast Guard crew witnesses the growing wave the tsunami swells up as the seafloor gets shallower once they crest the first wave a second one is upon them the crew is lucky to survive near the coast the swell becomes a breaking wave it piles up a wall of water races towards shore the very first thing that seems to have happened is that the seat left the land some of the footage we we've seen shows a huge shoreline being exposed and then the tsunami built up of shore and the dynamics of the way carried in in land probably a cubic kilometer of water just just lost land would and kept going until it ran out of steam this is the moment the first wave roars in the tsunami has arrived but there appears to be no clear pattern to when or where the tsunami strikes first it hits in the north then in the south then it strikes in the north again the height and intensity of the wave varies dramatically from town to town but why part of the answer lies in the varying depths of the seabed the tsunami travels faster in deep water and reaches land more quickly another critical factor is the layout of the land cliffs bays and inlets along the shoreline help determine how a tsunami behaves it boils down to how the wave is focused and D focused by the geography or the topography of the coastline itself 3:15 p.m. Japan time the wave hits the town of ofin Otto deep water off the coast here offers little resistance to the 26 foot high tsunami wave there is little time to get to high ground the best early warning system people would have had would have been the fact that there was an earthquake and people got used to the fact that if you have an earthquake there is a possibility of a tsunami that will follow but in the times here they had there was rental time or very little opportunity for escape [Music] the tsunami hits open Auto 20 minutes after the earthquake [Music] Walter that actually hit the coast will be well in excess of a billion probably ten billion tons of water that's a little bit like taking a million swimming pools and it's empty went on to the coastal areas of Northeast Japan [Music] fifteen minutes later the tsunami hits Sendai 70 miles south of Ofunato [Music] the area around the city is mostly farmland low-lying and flat [Music] [Music] the airport here is overwhelmed in minutes [Music] it's very low-lying areas there's nothing to stop it moving inland and so it can move inland six to seven kilometers without being impeded there's not much to slow it down and because the wavelength of the tsunami is so big it's it's not going to stop unless until it reaches something reaches some sort of high ground and it'll just keep on coming next the wave slams the Miyako coast 110 miles north of Sendai this area has good tsunami defenses the residents are well prepared they should be safe last time a tsunami hit here was half a century ago in the aftermath of that tsunami they built these 30-foot high sea walls tsunami drills are a regular feature of life everyone knows what to do when the sirens sound so yeah we're leaving where do we go go to the hill on March 11th the sirens sound the tsunami is minutes away there's a hill outside of town that we're gonna try to get to confusion rules some search for high ground some aren't sure what to do well it's a precautionary measure but I mean you know you never know this this town has a lot of history but tsunamis and a lot of death from it so they're taking it pretty seriously obviously the warning saves the lives of some there comes the tsunami easily breaches the coastal defenses me ACOs high walls are useless the tsunami is 30 feet high so why did the 30-foot high walls fail data from thousands of sensors along the coastline suggest a stunning answer the fact that the shoreline has actually subsided means that the sea had plenty of space to go and it he basically filled up the empty space left by the sinking so will the legitimate just be completely ruined with no survivors and the human death toll is obviously going to be up in the ten thousands when when the five counties the earthquake causes the whole coastline to drop by up to 3 feet lowering by acos walls and making the tsunami much worse all along the coast this sudden drop in the height of the land puts towns in danger you've got the tsunami way of coming in you know on top of what would be essentially a two meter higher vacuum of subsided land as it as it sweeps in and there's not much to stop it until it hits a gets higher ground somewhere Fukushima's shut down nuclear power plant is exposed there is an 18 foot high defense wall but the ground has sunk several feet the wave smashes over the wall and floods the diesel generators cooling the reactor cores Japan as part of its normal defenses against tsunamis has along its shoreline a tsunami wall and this wave of water was several times that height and just blew right past it the coastline goes down so do all their power intakes and if they have a gigantic wave coming at them is going to short out everything electrical backup batteries take over to keep the pumps going batteries with just an eight hour charge the tsunamis destructive March inland overwhelmed seawalls erases whole towns and sets Japan on the path to a nuclear crisis [Music] and it isn't over yet now all that water pulls back out to sea [Music] huge suction as the wave retreats and drags the debris it's created on the way in the cars that Laura's the buses the trains that the building is the people and so they're sucked back out into the ocean from miles offshore the ocean is a churning mass of currents huge whirlpools form boats like this are no match for its power sadly I think many thousands of people would have been dragged out to see and I suspect tragically we're going to find bodies washing up along the coast of Japan for some months to come during the night fires rage across the wasteland oil from factories and natural gas from ruptured lines set hundreds of square miles of debris on fire in Tokyo the train system is paralyzed millions sleep in offices and wait for dawn eight hours after the quake the tsunami wave continues to spread across the ocean countries all around the Pacific Rim watched nervously in Hawaii the tsunami warning center is on full alert very quickly we realized that that this was this was basically the first big ocean crossing tsunami that had happened in 40 years we'll the tsunami hit Hawaii if so when and how big will it be readings from deep ocean sensors suggest the wave is up to three feet high now that is monstrous on the deep ocean for a tsunami to be that big and at that point we went to a Pacific white warning which means another message and now lots and lots of phone calls Hawaii issues an evacuation alert people head for higher ground the way hits Hawaii as predicted it's three feet high for more than an hour it surges over the islands absolutely massive it's not my shoes this is strict coming straight over the wall onto the main road it's absolutely unbelievable here comes again poor boy you can see a car making a run for it out there I'm completely stranded now between the wall and the road there is tens of millions of dollars in damage the wave pulls cars and houses out to sea Hawaii's early warning system gives people time to get away from the coast here unlike Japan no one loses their life so the warning system works incredibly well but obviously if the event happens literally no back doorstep there no warning system that today ever be conceived it could be quick enough tsunamis are simply unstoppable but they can be tracked the Hawaii warning team monitors the Japan tsunami across the Pacific we couldn't let our guard down because of course the tsunami has continued on and we have a we had a continuing responsibility to the rest of the Pacific the scientists effectively warn the world as the tsunami spread across the ocean at location after location we realized oh the our predictions are pretty darn good Japan's tsunami surges toward the u.s. its power diminishing with every passing mile there's a very intensive way but as it spreads out that energy is being distributed along a bigger and bigger circumference ten hours later in over 5,000 miles from the quake the tsunami now smaller and weaker finally hits California the wave still creates havoc along the coast there certain parts the coach to focus the wave so although it was any one meter in Hawaii it actually became two meters in places like Crescent City in California and again because people were warmed there was very little destruction or damaged send it to human life one person did lose their life their life in in California north of Crescent Bay because they rushed down to the beach to take photos of the tsunami as they came in back in Japan the crisis continues to escalate different locations suffer different effects veteran journalist Callum McCray sets off along the coast to discover how far-reaching the tsunamis damage is this is the isolated mountain community of kahoku [Music] [Music] we are up in the mountains eight kilometers from the coast and what's happened here is that the tsunami has created a huge surge which has climbed all the way up the river and then flooded here the result is stunning a new saltwater lake among mountains miles from the sea so you put the music on I cried tsunami tsunami Moni if Amir Khan about a leader you have me a very crappy nation and I did it anymore go home isn't it oh it's Anushka me so you gotta see my character isn't in I know what does it targeting more talent you need nothing the locals here fear the receding waters will expose bodies swept up from the coast traveling north McCray reaches open ATO at first the town seems untouched [Music] damaged they've got power and everything here that's just so strange closer to shore it is a different story [Music] and as if often Atta didn't have enough problems scientists reckoned that this whole area this region has subsided well over a meter and in the next couple of days the region's also expecting the highest tides of the [Music] to see is some 500 meters down there and yet up here we have this it's a remarkable sight by any standards a huge chunk which has been brought all the way up here by the tsunami and what's remarkable about it well what's even more remarkable about it is that that what it says about the size of the tsunami because the Japan Meteorological Center just produced provisional estimates saying that the tsunami that hit this region was about three and a half meters high now we're seven eight meters above sea level here and even given the search the fact that he could bring that all the way up here does suggest that the tsunami here was a lot higher than three and a half meters boats trucks and cars are dumped on top of buildings much higher than the recorded height of the wave that happens because as the water's pushing through with streets in areas like the streets of towns and villages it's being effectively funneled and the waters got to go somewhere and so it goes up the peasants squeezed and funneled and pushes material pushes cars onto ruse sometimes as high as 50 feet so in areas the the impact of this will be even greater particularly where you get narrow streets once the wave starts to pick up part of a town the warehouses along the dock the debris and all that then it becomes more like a glacier you know it's it's a moving wall of debris and the more mass it has the more power it has as it comes in it doesn't really look like water beyond some point it looks like the entire town is flowing in and and it is so all the mass of all the buildings cars refrigerators and everything that's in that wall it's essentially a debris glacier at that point and it just keeps coming in this is Minami Sanriku a town that has been virtually wiped off the map 95% of the buildings destroyed over 10,000 people half the population missing this place symbolizes the tragedy more than anywhere an entire town wiped out by the force of nature [Music] it's almost difficult to imagine one's thoughts as one Caesars coming toward you and as it hits the coast is then picking up all the debris is picking up buildings cars and things and you then under this sort of really quiet horrific mass moving through towns villages across fields causing complete destruction I mean it would be bad enough if it was only water but because it's full of cars and you can't you can't swim against it or flow with it or do anything you're just in a like in front of a bulldozer of moving the entire town it's funny that when you hear that sound of an ambulance it kind of actually gives you hope that they might offend somebody alive although that must be happening fewer and fewer times between anyone who did survive and was trapped we'd almost certainly died of hypothermia by now at the town of Rikuzentakata 25 miles up the coast rescue workers hunt for survivors and discover the dead they find a buddy invade for the large stick in the ground the flag attached to it usin minsan task in fact they're not just looking bodies they're also collecting personal mementos as well which they find and like this [Music] [Music] afraid what we have here is more bodies waiting to be taken away within days scientists gather more data from Japan's earthquake and tsunami than from any other disaster in history [Music] / Tokyo professor Roger bilham returns from his aerial survey the city's vulnerability is clear there are 30 million people within about two meters of sea level and a tsunami here of course would be absolutely devastating suddenly there is a problem really we've just learned from the ground that there was an earthquake that damaged the heavy heavy ports they're checking for damage right now we don't know how big the earthquake was but it was obviously a very nearby aftershock a massive aftershock hits Tokyo magnitude 6.2 in the week that follows the main quake there are over 500 aftershocks this is the actual data from seismometers around Japan the larger the circle the bigger the aftershock finally bilham's helicopter receives the all-clear to land the helipad is damaged I noticed that the tarmac here which should be beautifully dark everywhere in fact stained wise in places and you can see that in fact sand has come out of this crack and there's another one over there another one over there we're very close to the shoreline and the lurching motion of the ground during the earthquake is caused the subsurface liquefied sands to come belching out on the top here there is evidence of liquefaction the strange phenomenon filmed earlier over here is an old old it's about three days old you can see how the mud came pouring out of the top there so we're 200 miles from the epicenter here and here's a crack in the heliport landing area it continues all the way along here you can actually see down about 3 feet in places it splits into two here this goes over here you can see an offset in the in this trim around the the tarmac as the Earth's crust shatters during the main quake new stresses spread along the fault relieve the pressure in one place and it builds up somewhere else triggering aftershocks what you're seeing here is how those aftershocks happened over a period of about a week after the main shock and that orange region delineating by those Warren's dots essentially gives you a feeling for the area of the fault along the plate boundary that ruptured in this event every aftershock takes its toll on an already frightened population and every aftershock potentially triggers another woman that man shock was followed by hundreds of magnitude fives and dozens of magnitude six earthquakes and a handful of magnitude sevens once you had a pattern of a an earthquake happening followed by a bigger one you never know if it's going to happen again unrelenting tremors are just one of the new realities facing the Japanese people hundreds of thousands are homeless in the regional capital of Sendai the temporary shelters are full [Music] but in this darkened ravaged City people do their best we're in Sendai 3 or 400 meters from the shore front in a senior chaos it's cold it's dark there's no power anywhere and yet up there in that abandoned block of flats on the top floor there's one light one man one family perhaps trying to survive in this chaos the following day on the main road back to Tokyo the artery that connects north and south is empty a reminder that this country has ground to a halt already one of the worst nuclear accidents in history if it stopped right now and we're dealing with multiple meltdown right here radioactive substances CVM and iodine were detected near the number-one reactor at the plant on Saturday Fukushima nuclear base is about 60 kilometers that way that's about 38 miles or so I think and you know we've got the windows closed we're driving fast who knows whether it's safe the advice is very conflicting the American government says that put an exclusion zone of 80 kilometers and of course we're well within that on the other hand the Japanese government say it's fine as long as for the 30 kilometers away so I mean you can tell us but we'll be the windows closed and I'll put on a mask [Music] Mosque looks good at Fukushima power plant the nuclear crisis worsens the emergency batteries are dead there is no power to cool the reactors temperatures quickly rise water levels drop pressure builds the incredible heat of the fuel rods generates hydrogen gas the hydrogen explodes desperate plant workers inject seawater into the reactors in an effort to cool them essentially those plant operators at the time said we're going to commit plant suicide we're going to go ahead and kill these plants knowing that they'll never work again but that that was a better option than not letting the cooling system fail and risking even a worse outcome there's been another blast at a stricken Japanese nuclear power plant the second hydrogen explosion in three days the Japanese military use helicopters to scoop up seawater to dump on the reactors it doesn't work the long-term consequence of what is happening at Fukushima remains unknown the humanitarian disaster continues estimates put the death toll from the quake and tsunami at over 20,000 for scientists the analysis goes on from all the data they have acquired one threat is still very real for years experts have warned of a large quake and tsunami off the coast near Tokyo Japan's recent disaster happens 260 miles north but now the fault lines below Tokyo are even more stressed what's been expected is slip of the Philippine plate relative to the north of the Eurasian Plate and what has actually occurred is slip of the Pacific plate relative to the Eurasian Plate sometimes a great earthquake will cause the next patch of the plate boundary to slip so all eyes are on on what's happening how this earthquake has stressed the neighboring part of the plate boundary but understand this this whole region is in a very high state of stress and ready to go and they've been expected to go any minute so this recent earthquake is going to brought that closer the question is how much close when an earthquake like this happens it basically all of the stress that it relieves in the Earth's crust essentially gets transferred somewhere else it doesn't go away it actually adds loading to other parts of the crust the densest areas of populations survive largely unscathed next time could be different one area of extreme concern is Tokyo the world's largest city there could be a major event in Tokyo that would be extremely damaging to this very densely populated region if you're going to choose somewhere to put one of the the major industrial economies on the planet that part of the Pacific Rim is not the place you would choose it could be happening as we speak and what it might not happen for a decade the critical thing is has this particular earthquake shake and that region up so that it brings forward the timing of that earthquake it's foolish to think that we can stop natural phenomenon what we've got to do is to learn to live with them and minimize the consequences when they happen and minimize also the recovery time it's very difficult the science to protect against earthquakes and tsunamis what science can do is help town planners engineers to make building stronger to make designs of buildings and cities more resilient we cannot stop these things happening we can't prevent it we can prepare for it scientists believe Japan's tsunami holds valuable lessons for the u.s. one of the interesting things about this earthquake is that it's it's really a template for what might occur on the northern coast of Oregon Washington we know we are expecting us at almost identical sized earthquake stretching from Vancouver Island to Northern California is Cascadia a vast and volatile fault line here like Japan one plate is driving beneath another squeezing and compressing it tremendous pressure builds [Music] Cascadia could rupture in a huge magnitude 9 quake a mega quake off the pacific northwest coast would create a tsunami similar to japan's Roger bilham scans the coast of Japan for clues he hopes to understand what could happen to America's West Coast like this coastline is long and flat parts of the Oregon coast are mountainous that not maybe a problem where we have what Matt my gland is we've got to expect a similar fact a little bit like like airplane crashes the people go in and try to figure out what happened and learn from that and unfortunately we learn from these disasters but it makes people stronger for the next one the world has seen what happened in Japan the question is are we prepared we compared to Japan where the preparation level is higher than what we have in the US and we see that the Japanese had still quite a ways yet to go it's a little sobering think about how many decades of work we have in front of us to just to get to where the Japanese were and then we have to get probably beyond that as well the exploration continues on Nova's website where you can watch any part of this program again hear from a leading experts on what Japan's nuclear crisis will mean for the future of nuclear energy and go inside the training center at a u.s. nuclear power plant to see how engineers prepare for the worst dig deeper into the natural forces on planet earth with expert interviews Interactive's teacher resources and more follow Nova on Facebook and Twitter and find us online at pbs.org major funding for Nova is provided by david h coke and discover new knowledge h h mi and the Corporation for Public Broadcasting and by PBS viewers like you thank you additional funding is provided by Millicent Bell through the Millicent and Eugene Bell foundation [Music] [Applause] [Music] [Music]