Tsunami Unleashes Mass Destruction | How the Earth Was Made (S1, E9) | Full Episode | History

earth a 4.5 billion year old planet still evolving  as continents shift and clash volcanoes erupt   glaciers grow and recede the earth's crust  is carved in countless fascinating ways   leaving a trail of geological mysteries behind water one of the most powerful forces on the  planet it plays a crucial role in creating life   and destroying it in forging landscapes and in  breaking apart the earth in its most dramatic form   it becomes a killer wave known as a tsunami   until recently predicting when these  monsters may next strike has been impossible but today scientists are starting  to understand these giant waves   by connecting clues as varied as ancient  japanese writings and landslides ancient corals   and buried native american settlements the  secrets of tsunamis are finally being unlocked tsunamis one of the most deadly forces of nature   giant waves that travel faster than a jet  plane they can cross entire oceans in just hours they have the power to smash  buildings vehicles anything in their way by itself you wouldn't think that water just  streaming into the coast would necessarily cause   so much damage but in fact they are very fast  moving and they pick up everything in its path so   it's not the water by itself it's what comes with  the water that is also a part of the big hazard   a tsunami isn't over in just a few seconds it is  a torrent of raging water that keeps coming the   main thing about the tsunami is the persistence  it comes on and on and on and just when you think   it has to quit it keeps coming and it's the power  plus the the duration that is unstoppable really tsunamis have ravaged the  earth for billions of years when the earth was first  created the moon was much closer   it filled the sky its gravitational  pull was much stronger and it generated   towering waves over half a mile high  that raced across the primeval oceans oh my god today tsunamis are still a threat  to coastlines all over the world tsunamis will always occur and have always  occurred throughout earth history but it's only   been more recently as population densities have  increased and people have moved and migrated to   the coastal regions that we've become much more  aware of the tsunami hazards the investigation   into what caused these monster waves began over  a thousand years ago on the islands of japan   this country is the world's tsunami hot spot   its coasts have been pounded with these enormous  waves more than anywhere else on the planet   evidence for this is the word tsunami itself  it is japanese and literally means harbor wave japan has the longest written tsunami  record of anywhere in the world   the records go back as far as 684 a.d by studying  these records it is possible to work out that on   average this country has been struck nearly  every seven years samurai writings speak of   people living on the coasts running for higher  ground as soon as they felt an earthquake the   japanese knew this was a clue a warning sign that  a deadly tsunami would soon follow but despite   their attempts to escape tsunamis have continually  brought death and destruction to these islands   in 1896 a wave that hit honshu in the northeast  claimed the lives of 27 000 people in 1933   the same area was smashed again this time  three thousand people were swept away   and in 1993 the island of akashiri  was rocked by an enormous earthquake   measuring 7.8 on the richter scale  buildings were leveled and fires raged   but worse was to come minutes after the shaking  had subsided an ominous white crest appeared on   the horizon a tsunami a gigantic wave swept  in flattening any buildings still standing   in japan the locals had already worked out the  connections between earthquakes and tsunamis   but there's another hot spot on  earth where tsunamis regularly strike   the hawaiian islands but very few of  them were preceded by an earthquake   the city of hilo on the big island has been  dubbed the tsunami capital of the world   dozens of these enormous waves  have hit these beautiful islands   and the mystery is why with no natural warning  to go on the people of hawaii must rely on the   world's biggest tsunami monitoring station set  up in 1949 it is connected to a network of buoys   spread across the pacific ocean these  buoys provide important clues they   monitor changes in sea level that indicate  the approach of any potential tsunamis in 1960 scientists got the breakthrough they  were looking for they were finally able to   work out the type of event at the root of hawaii's  mystery tsunamis an enormous quake on the coast of   chile the biggest recorded of all time  with a factor 9.5 on the richter scale   triggered a tsunami that swept across the  entire pacific ocean in just a few hours   the islands of hawaii were thousands  of miles away directly in its path   the tsunami warning center  was monitoring its progress   revealing for the first time that a single  massive wave crossed thousands of miles of ocean   the warning center was a success they were  able to evacuate the communities closest   to the shore before the waves struck but  the homes they left behind were decimated   in hilo the tsunami was so strong it even bent  parking meters in half the wave continued past   hawaii to japan it had lost none of its power  pacific wide this tsunami cost more than 2   000 lives and caused millions of dollars worth  of damage devastating as it was the 1960 event   was a turning point in the study of tsunamis  it was the first time that scientists could   accurately measure how the size of an underwater  earthquake directly affected the size of a tsunami   and conclusive proof that a tsunami can  travel thousands of miles across the earth   and it was with this chilean earthquake  that we really could prove that   the undersea motions associated with the  earthquake are generating these huge effects now scientists had the evidence to confirm  that undersea earthquakes were directly   responsible for tsunamis the ancient  japanese suspicion was now scientific   fact in terms of modern tsunami study the 1960  wave was year zero the chilean earthquake was   you might say the perfect storm  it's when scientific understanding   had advanced to the point where scientists had  begun to see the link connecting everything so   it's a new science we're talking about something  which is really only less than 50 years old   there are more tsunamis in the pacific ocean  than any other so in 2004 the world was taken by   surprise when one of the largest recorded tsunamis  of all time took place in the indian ocean on december 26 2004 indonesia was rocked by  the second largest recorded earthquake ever   9.2 on the richter scale minutes later a 90-foot tsunami slammed  into the southeast asian coastline 225 000 men women and children lost their lives the indonesian earthquake had as  much energy in it as the total energy   consumption in the united states in one year this enormous burst of energy had been released  in just seconds once again the world had been   reminded of the earth's awesome power in the last  50 years scientists were finally able to confirm   a solid link between earthquakes and tsunamis by  monitoring the size of the chilean earthquake in   1960 scientists were able to prove conclusively  that earthquakes triggered these gigantic waves by following the path of this  tsunami they were able to prove   that a tsunami could travel  thousands of miles from its origin monitoring the earthquakes that  cause this incredible devastation   involves looking many miles underground by investigating the power at  the root of these giant waves   scientists can begin to figure out when  and where these waves may strike next these dramatic pictures of the aftermath  of the 2004 indian ocean tsunami   show the havoc a tsunami can unleash it's  almost impossible to imagine something like   that happening here in the pacific northwest  professor brian atwater believes that events   like the 2004 tsunami could one day happen  right here too he was intrigued by early   settlers accounts of native american folklore  tales that spoke of great waves sweeping inland   they convinced him that huge locally generated  tsunamis have struck here before and could strike   again posing a threat to tens of thousands of  people living on the pacific northwest coast   to find out if he was right he needed to  uncover evidence of past giant waves hidden in   this landscape to be really sure it's a tsunami  though he would also have to find evidence of   the earthquake that caused it atwater's starting  point is the copailis river in washington state   just a couple of miles from the long sandy beaches  that make this area a thriving tourist resort   in the banks of this estuary lie  buried thousands of years of history   this is one of the dirtiest jobs in science  hunting for evidence of earthquakes is a   muddy business but it's worth it atwater  has found signs of a potential tsunami   there's a clue in this bank that nature has  provided it's this notch and notches like this are   common where tsunamis have laid out sheets of sand  and then later currents and and waves come along   and they pluck the sand grains out of the bank but  they leave the mud atwater has to dig deeper to   find what he is looking for a layer of sand that  could have been swept miles inland by a tsunami okay so now you can see the sand what  deposited this sand maybe it was a tsunami   to prove that this was sand from a tsunami  atwater's muddy quest must continue he also needs   to find proof that the land here around the river  has moved up or down a sure sign of an earthquake   after some hard work atwater  finds what he has been looking for   clear evidence of both an earthquake and a tsunami  this time there was a human cost as well here we   have evidence for abrupt lowering of land and we  also have evidence for the associated tsunami in   this case humans are involved this was a fishing  camp here you have the remains of that fishing   camp in the form of fired crack rocks which were  the rocks were used to heat water mainly okay so   fishing camp overrun by tsunami because the  land dropped after the tsunami the tides   came in and covered the fishing campsite and  made sure that people wouldn't use it again the land the fishing camp  was built on was dragged down   during the earthquake the tsunami  deposited sand over the remains   and finally the tide covered the settlement  with mud where it remained undisturbed until now   atwater finally had the proof he needed his native  american myths of giant waves were no mere legend but what was it that caused the earthquake the  prime suspect lay 50 miles offshore the cascadia   fault cascadia is a major weakness in the earth's  crust although the earth may seem to be a solid   sphere beneath the oceans and continents it is  divided into eight major and many minor segments   known as tectonic plates where they meet they can  grind and jostle against each other at fault lines   causing earthquakes geologists had long thought  that the cascadia fault line was incapable   of generating a major quake but atwater's  investigation has proved that it was highly active   the big worry for atwater and the  thousands of people who live in this region   is that the cascadia fault line bears an uncanny  resemblance to another highly active fault line   the sunda megathrust it was an earthquake along  this fault that was responsible for the indian   ocean tsunami that killed nearly a quarter of a  million people where they get two tectonic plates   coming together such as the case of the indonesian  tsunami in 2004 one plate pushes it beneath the   other plate and creates lots and lots of friction  and tension and drags the upper plate down with it   and that process can take hundreds of years  even thousands of years it's a very slow process   but eventually the pressure of this one trying  to push back up again wins and it flips like that and that creates a mega thrust a sudden move into  the seabed and that's what creates a phenomenal   tsunami two factors made this sunda megathrust  earthquake so deadly the first was its size   at factor 9.2 on the richter scale  this was the largest in nearly 50 years   the second was that it took place not far below  the surface when we're talking about a mega thrust   that's really where the sea bed is disturbed  dramatically sometimes if the earthquake is   deep in the earth's crust then you see very  little surface manifestation of that earthquake   if it's quite close to the surface or very intense   then quite often you'll see the sea bed itself  moving and that's what creates a powerful tsunami investigating the ocean floor after  the quake revealed that more than one   000 miles of fault line had fractured and  sprung up by 60 feet this massive jolt pushed up   billions of tons of water enough to cover  manhattan to a depth of nearly 5 miles the rift zone itself was about a thousand miles  long we had this entire stretch of sub-sea moving   which creates a huge wave so the whole thing was  a phenomenal size certainly one of the biggest   tsunamis in living memory atwater's determined  research showed that the pacific northwest was   at risk from this level of devastation too  but he didn't want to unnecessarily alarm   the coastal inhabitants until he had collected  all the evidence he could attwater needed to   find out precisely when this tsunami struck  this coastline to see if there could be more   he first tried radiocarbon dating the soil along  the kapales river but the result could only take   him so far they showed that the earthquake and  tsunami occurred somewhere between 1680 and 1720.   more importantly atwater still needed  precise evidence of how big it had been but so far his investigation has uncovered two  extraordinary facts by unearthing the abandoned   fishing camp atwater could see that a cascadia  earthquake here had caused the land to drop   the notch in the bank was proof that this same  earthquake had generated a tsunami but what   these clues didn't tell at water was just how big  the tsunami was he had no way of pinning down the   size of the threat to the pacific northwest his  investigation was about to take an unexpected turn   with clues coming from not only thousands of  miles away but also from hundreds of years ago japan has the oldest record of  tsunamis of anywhere in the world   samurai writings told of a huge tsunami in 1700  that had swept over the east coast of japan   it hit without warning and  destroyed entire settlements   japanese scientists were baffled as to where this  wave had come from there had been no earthquake   to warn the villagers to make for higher ground  the mystery wave was dubbed an orphaned tsunami back in the u.s brian atwater's investigation into  the mysterious cascadia earthquake and tsunami   needed more evidence he had no accurate way to  pin down either the size or the date of the event all he knew was that it had taken place sometime  between 1680 and 1720. but atwater's dates were a   revelation to the japanese scientists could this  event be the birthplace of their 300 year old   orphan tsunami and they said by the way we have  this tsunami we've been trying to find a home for   in 1700 so we think your your earthquake happened  in 1700 specifically in the evening of the 26   january 1700 and it was of magnitude 9. a cascadia  earthquake that produced a wave with enough power   to cross the entire pacific ocean to japan would  have had to be a factor nine at the very least   this is roughly equivalent to the  enormous indian ocean earthquake earthquakes like this have so much power that  they can send a tsunami across an entire ocean   with ease the amount of energy involved is very  hard to estimate it's hard to put it into sort of   terms that people can understand we  are looking at the phenomenal forces of   several hiroshimas hundreds of hiroshimas in fact  but tsunamis are not just a very big wave they're   fast the big difference is the scale of the wave  it's typically three or four hundred miles long   it's also not very high when it starts off live  it's usually about two or three foot high but it's   moving very fast it moves at a speed determined by  the water depth the deeper the water the faster it   moves so in the deep ocean this wave is moving at  over 500 miles an hour deceptively as a tsunami   speeds through deep water it may appear completely  harmless and scarcely detectable close to shore   the wave becomes a deadly killer it is only  then that a tsunami's true power becomes clear as the wave gets to shallow and shallow  waters it approaches the coastline   the wave slows down the shallow water the slower  the waves it goes from 500 to 400 to 300 200   much much slower back the  wave is still going full speed   and so the whole thing piles up and  that's why tsunamis are so destructive it is this immense speed and power that  reveals how events here in cascadia could   devastate a coastal village in japan how an  earthquake in chile could decimate hawaii   and how the indian ocean earthquake could  kill almost a quarter of a million people   if a quake like this happened in cascadia the  damage it would do to the pacific northwest   coastline would be catastrophic but to  be sure about the scale of this threat   brian atwater has to be 100 certain that  the dates of the two tsunamis were the same   after fully exploring the estuary of the kapailis  river he found one site that might hold the   information he was looking for a ghost forest  this spruce route marks the remains of a forest   that includes the ghost forest behind us dropped  down into tidewater during the cascadia earthquake this ghost forest is made up of the  standing dead trunks of western red cedar   and they were killed on account of the land here  dropping and then tides coming in and surrounding   these trees bringing in salt water this area  would once have been covered with a dense forest   but today only the bleached trunks of the rot  resistant western red cedar remain in place   when atwater and expert tree ring specialists cut  them open and studied the lines of growth inside   they finally cracked the  300 year old tsunami puzzle the dates of the japanese and cascadia events  were exactly the same january the japanese orphan   tsunami finally had a parent maybe there's a  certain amount of justice to it that that a   place that doesn't have written records has these  outstanding geological records the link between   the two events made it certain that the cascadia  earthquake had been at least an awesome magnitude   9. and ominously it is almost certainly not the  only time that cascadia has rocked this area atwater believes he has found proof of a whole  series of tsunamis stretching back 5 000 years   each layer of sand in this sample  represents a separate tsunami there are places at cascadia where i've seen  nine stacked up in a column about 20 feet long   nine buried soils some of them  coated with little sand sheets and   and you know you you say okay it's not a  question of if but it's just a matter of when atwater's tireless detected work alerted officials  to the increased tsunami threat as a result the   towns along the washington state coast have been  able to prepare for this potential catastrophe   if a cascadia quake occurred the first  waves could arrive here in just 25 minutes   tsunami warning signs line the roads and sirens  stand ready to warn of an approaching wave   the lives of thousands of people are safer thanks  to the work of atwater and to some 300 year old   japanese writings this is a hazard that shows  its face often enough for us to take precautions   to fasten the seat belt against it by dating the  ghost forest along the kopaelis river to precisely   1700 atwater had the final proof that cascadia  was capable of creating a pacific wide tsunami   uncovering the multiple layers of tsunami  debris in the riverbank dating back five   thousand years show that monster waves have  struck here many times this is an ongoing threat   atwater knows that another earthquake is due  here but he has no way of knowing exactly when   back in the indian ocean  the site of the world's most   lethal tsunami in 2004 one man has taken the  investigation of tsunamis to a new level he   believes that he has found a way to make the  earth's fault lines give up their secrets   and accurately predict when the next  deadly tsunami could be on its way the idyllic-looking mantawi island chain in  indonesia hides a violent secret one that   makes it today one of the most dangerous places  on earth these islands lie directly on top of the   sunda megathrust south of where the enormous  indian ocean earthquake triggered the 2004   tsunami the sunda mega thrust is  one of the largest fault lines on   the planet since it caused the 2004 earthquake  it has also become one of the most notorious predicting earthquakes here is  tricky but professor kerry c   has a good track record he has successfully  forecast two along the sunda mega thrust already the key to successful tsunami prediction is to  forecast when and where earthquakes will strike   and to do this scientists must look into the past  if you want to answer questions about earthquakes   that only happen every few hundred years or a  few thousand years well you've got to find some   some geological instrument that allows you  to see those earthquakes professor c has   found an unusual way to unlock the secrets  of the cinder megathrust's turbulent history   corals these coral atolls are built from the  limestone skeletons of millions of tiny creatures   each generation builds on the remains of the  last over time the atoll gets bigger and bigger   as long as the corals remain underwater they  flourish but once they're above water they die   earthquakes are responsible for killing all  the coral stranded above water on this beach   this beach contains corals of many different ages   altogether professor c has nearly a thousand  years of history at his fingertips but to unlock   the secret history the corals contain he and his  team have to take a less than delicate approach   we're looking at a saw cut that we  just made through a coral microatol   and the great thing about this hat is it records a  sudden drop of about foot and a half down to here   it died down to here because the island rose  the new low tide is way down here everything   that was so bold is to grow up this high dies  the shape of the coral records the fall of the   matawi islands as they are literally pulled down  by the sunda megathrust but crucially the corals   also record the moments when the islands are  thrust up out of the water during an earthquake   between quakes the islands are once again  pulled down by the fault in a never-ending cycle you have to imagine that rocks actually  are elastic take a diving board the diver   the diver walks out on the platform and  it bends like this and then he jumps and   he springs up and he jumps off and when he  jumps off the diving board doesn't stay here   it doesn't go like it doesn't go like this you  know the diving board springs back up it's elastic   well rocks are the same rocks are elastic too  so when the indian plate goes down it pulls the   sumatran section down too and then it later it  fails so it just springs up like a diving board   by analyzing corals all over this beach professor  c has discovered a regular pattern to this cycle a major earthquake rocks these  islands roughly every 200 years what we have here in sumatra with the corals is  what i call the holy grail of earthquake science   of paleoseismology and that is a long record that  has many cycles in it a thousand year long history   of earthquakes but when the geologist looked even  closer he saw that the cycle was more complex   when we cut a slab we can see it in much more  exquisite detail because we can see what we call   the stratigraphy or the the layering and how  the layering relates the changes of the tide   so what we can see over here then is the annual  bands of growth right here so there's about 10   years between this earthquake and this earthquake  professor c had discovered a major clue the corals   record that not only does a major earthquake and  tsunami hit here every 200 years but that they are   always accompanied by a number of smaller quakes  this is a cycle within a cycle a super cycle   and by counting back the layers of growth within  the coral the geologists can put an exact date   on all of these earthquakes we know there's a  sequence in the 1350s 1370s we know there's a   sequence in the 1560s to 1600s 1600 we know  there's a sequence 1797 1833 those sequences   are about 200 to 200 yeah 230 years apart this  is crucial information for the people of the   mantawi islands who have no written history but  professor c's work doesn't stop here by uncovering   their history in the corals he believes that  he can now predict the future for these islands   and he's already had some success professor c  began his work here in 1993 and soon realized   an earthquake was imminent the mantawi islands  were about to start their next deadly super cycle okay experience an earthquake in september  2007 he was proved right when an earthquake   shook the islands just enough to generate a  small tsunami that wrecked homes and schools history is repeating itself  exactly as he predicted it would   a much bigger earthquake and more  dangerous tsunami could be due any day one section hasn't failed since 1797 so since  george washington was president united states   we know we're now in a sequence of at least three  giant earthquakes we're expecting another one   the question is whether the earthquake and  tsunami will be in the next 30 minutes or the   next 30 years thanks to sea's research the people  of these islands have had time to prepare when   the wave comes they will be ready earthquakes are  forecastable if you if you have enough information   about how they've behaved over the last thousand  years or two or three or four cycles you can   really make significant forecasts that people  living in the area actually can do something about education is key children here are now taught that  as soon as they feel the shaking of an earthquake   they should run for higher ground newly built roads snake up steep hills from  waterside villages to allow rapid escape from the   deadly waves i'll bet that young children alive  today if they certainly if they live to be 60   they're going to see that earthquake and in fact i  think there's a better than 50 percent chance that   it'll happen within the next 30 years by analyzing  the shape of the corals on the mantawi islands   c has proved that a major tsunami cycle starts  here every 200 years by dating the lines within   the coral he can be even more exact they show  that these cycles contain not just one but   several deadly tsunamis the sunda megathrust is  the clear culprit for tsunamis here but not every   tsunami is generated by an earthquake a rarer  different type of wave is out there a mega tsunami although earthquakes are by far  the most common cause of tsunamis   there is another source for these  deadly waves landslides and these   tsunamis have the potential to be so big  that they have been called mega tsunamis scientists had long suspected that  waves could be generated in this way   but conclusive photographic  proof wasn't available until 1958 a landslide into latoya bay in alaska triggered a  wave that reached heights of several thousand feet this footage shot just after the tsunami  struck shows the waves enormous power   the trees here once stretched all  the way down to the shores of the bay   but were ripped off the slopes by a wall of  water leaving nothing but bare exposed rock the tsunami was generated when  a relatively small earthquake   triggered a single enormous landslide  of rocks and debris into the bay the resulting wave was higher  than the empire state building   and stunned scientists around the world  tsunamis on this scale are incredibly rare but another mega tsunami triggered  by a rock fall 10 000 times bigger   than latoya bay could be on its way from  a small island across the atlantic ocean the canary islands off the coast of africa  are formed from a series of volcanoes   the youngest is the island of la palma it is  formed from two volcanic ridges the first is   the extinct cumbranueva to the north of the island  the younger active cumbre vieja lies to the south it erupted as recently as 1971. geologist dr simon day's research was crucial  in developing the la palma mega tsunami theory   it began with an unusual rift that had opened  up during a major volcanic eruption in 1949 we're standing here in the fault and  it runs way down to the south along   the crest of the volcano for two and a half  miles so it's one continuous long structure day believes this fault is evidence of a  geological time bomb the beginning of a   giant landslide what we see here to my right are  layers of volcanic rocks volcanic blocks here   and layers of volcanic ash and on the west of  the fault we see the same layers blocks and ash   and those before the fault moved were joined up  and then when the fault moved they were separated   and the rocks to my left moved down into the west  what we think will happen and some future eruption   is that this fault would have gotten bigger and  the whole of this western side will slide away   in a giant landslide into the  ocean to create the tsunami this landslide would send the entire southwest  section of la palma one-sixth of the island's   total mass crashing into the atlantic ocean in  a single giant landslide what we envisage is the   whole of this coastline and the slope extending  up all the way to the crest of the volcano that   is now in the clouds all of that mass of rock  would slide away in a single massive landslide   into the ocean and pushing the water up in front  of it to create the tsunami wave initially this   wave would be over 30 times bigger than the 2004  indian ocean tsunami more than 3 000 feet high the 1980 eruption of mount saint helens was proof   that a volcano could collapse  in this terrifying fashion   this was impressive but the collapse of the  cumbre vieja would be 200 times the volume of this 1 200 billion tons of rock would  hurtle towards the ocean at top speed the resulting wave would head straight out  into the atlantic that wave of course would   then spread out and separate out in smaller  waves but even so after crossing the atlantic   and piling up again on for example the eastern  seaboard of the united states or in the caribbean   or in northern brazil the waves there we  predict would still be between 30 and 100   feet high so that's as large as if not larger  than the tsunami that struck sumatra in 2004. boston new york and even miami could all be  under threat from the giant waves this was a bold prediction day needed  more evidence to back up his theory   as he was about to see the rift in la palma's  landscape was far worse than he expected the 1949   eruption had left a different type of geological  scar on the island evidence of a more serious   weakness within la palma came from a series of  eerie looking lava flows dotted across the island one of the characteristics of the 1949 eruption  that's unusual is that instead of starting at one   vent just continuing there a series of volcanic  vents opened up in different parts of the island   when day plotted these weaknesses on a  map he came to a frightening conclusion   the rift was far bigger  than he had first suspected   the area that's potentially affected is very  much greater than the length of the fault at the   crest of the volcano would indicate extending  out 10 or 15 miles from the crest out to sea   this growing body of evidence proved that the  rift wasn't just a mere crack in the surface of   la palma but a deep fissure that reached hundreds  of feet down into the island's foundations   it is la palma's volcanic heritage that is the  key to this tsunami threat the big hazard here   isn't the eruptions themselves it's the fact  that the volcano is building up building up   over time and becoming more and more unstable  so that will eventually lead to a collapse   and it seems that this is not the first time  a la palma eruption may have triggered a giant   landslide proof lies in the north of the island  in these sheer cliff faces formed 65 000 years ago   what we see in the north of la palma is the  landslide scar left when the old volcano in the   north of la palma experienced a giant collapse  and produced a giant landslide off to the west   so that was a huge collapse it removed as much  as a hundred cubic miles of rock and deposited it   out into the ocean so it's the sort of event  that we think is going to happen again in   the future at the at the cambridge aircraft this  ancient collapse of the old cumbria nueva volcano   is almost certain to have  generated a gigantic wave and the next collapse might not be that far  away this tsunami could strike in our lifetime even though it seems so extraordinary when  we consider it in human terms we talk about   a tsunami striking the east coast of north america  and causing huge devastation on the scale of the   sumatra scene army but this is what happens in  the geological record this is what earth does   although tsunamis have been documented for  thousands of years it is only in the last century   that geologists have been able to prove how  they are connected to the movements of the earth by analyzing data from the great chilean  earthquake of 1960 scientists were finally   able to firmly link earthquakes with tsunamis  unearthing buried native american settlements   proved that the cascadia fault line in the  pacific northwest was an active tsunami threat   corals in the indian ocean proved that some  earthquake-generated tsunamis follow a pattern   and strike the same area with regular  intervals and the giant rift in la palma's   landscape shows that tsunamis generated  by landslides are also a very real threat   mega tsunamis which could prove to be the  biggest waves that threaten our coastline   tsunamis are an inevitable part of earth's dynamic  structure their capacity to destroy is awesome   but as scientists begin to understand  more about the origins of tsunamis   they are coming closer to predicting  where and when these monsters may strike you

Channel: HISTORY

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Id: YAu0lLjJ5zg

Length: 45min 12sec (2712 seconds)

Published: Sat Dec 05 2020