How the Earth Was Made: THE DEADLIEST NATURAL PHENOMENA *3 Hour Marathon*

foreign five billion year old Planet still evolving as continents shift and Clash volcanoes erupt glaciers grow and recede the Earth's crust is carved and countless fascinating ways the 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 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 we 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 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 [Music] this country is the world's tsunami hot spot coasts have been pounded with these enormous waves more than anywhere else on the planet evidence for this is the word tsunami itself it's Japanese and literally means Harbor wave Japan has the longest written tsunami record of anywhere in the world [Music] 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 [Music] 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 [Music] 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 a 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 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 inclusive 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 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 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 [Music] 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 caused 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 but 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 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 Copalis 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 lied buried thousands of years of History [Music] this is one of the dirtiest jobs in science hunting for evidence of earthquakes is a muddy business but it's worth it water 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 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 fire 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 ocean's incontinence 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 Mega thrust 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 we get two tectonic plates coming together such as the case of Indonesian tsunami in 2004 one plate pushes 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 the mega thrust a sudden movement of the seabed and that's what creates a phenomenal tsunami two factors made this Sunda Mega thrust earthquake so deadly the first was its size at Factor 9.2 on the Richter Scale this was the largest in nearly 50 years second was that it took place not far below the surface when we're talking about a mega thrust that's really where the seabed is just uh 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 a very intense then quite often you'll see the seabed itself moving and that's what creates a powerful tsunami [Music] investigating the ocean floor after the Quake revealed that more than 1 000 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 five miles so this side itself was about a thousand miles long we had this entire stretch of subsea moving which creates a huge wave so the whole thing was a phenomenal size certainly one of the biggest tsunamis in living memory that water is 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 Atwater 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 Copalis 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 Atwater 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 you're you're earthquake happened in 1700 specifically in the evening of the 26th 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 fast big difference is the scale The Wave It's typically three or four hundred miles long it's also not very high when it starts off life 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 the 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 Sharon shallow Waters it approaches a coastline the wave slows down the shallow water the slower the waves it goes from 500 to 400 300 to 200 much much slower the wave is still going full speed and so the whole thing piles up and that's why tsunamis are so destructive [Music] 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 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 kapalis 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 Japanese and Cascadia events were exactly the same January 1700 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 nine 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 their 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 Waters tireless detective 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 Copalis 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 5 000 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 [Music] the idyllic looking mintawi 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 megathrust 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 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 Sunda Mega thrust's turbulent history corals 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 corals 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 contained 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 micro atoll the great thing about this head 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 mantawi 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 uh of earthquake science of paleo seismology 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 but 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 to 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 13870s 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 dinner with 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 in the next 30 Years thanks to C'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 mentawi islands sea 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 rarer different type of wave is out there 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 [Music] 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 it's done scientists around the world tsunamis on this scale are incredibly rare but another mega tsunami triggered by a rock fall ten thousand 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 cumbrain Nueva 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 and 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 [Music] what we see here to my right are layers of volcanic rocks volcanic blocks here and layers of volcanic ash on all the west of the faults we see the same layers blocks and Ash and those before the fault moved were joined up and then when the full move they were separated and the rocks to my left moved down and to the West what we think will happen in some future eruption is that this fault would have gotten bigger and the whole of this Western sign 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 envisaged 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 massive 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 foreign 200 billion tons of rock would hurdle towards the ocean at top speed the resulting way would head straight out into the Atlantic that way of course would then spread out and separate out in smaller Lanes 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 structure Matra in 2004. Boston New York and even Miami could all be under threat from the giant waves this was a bold prediction they 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 teen 49 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 faults at the crash of the volcano would indicate just ending out 10 or 50 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 breached 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 and 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 [Music] 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 100 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 of the at the cumbriviera this ancient collapse of the old Cumbre 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 considering human terms we talk about a tsunami striking the east coast of North America and causing huge Devastation on the scale of the sumatristian 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 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 numerous and fascinating ways the trail of geological Mysteries behind in this episode investigators are exploring the driest place on Earth the Atacama Desert in Chile this Barren landscape is 50 times drier than Death Valley now scientists are piecing together the puzzle of how this desert was made from raging volcanoes the Colossal mountains oceans the clues they uncover also provide a window into the formation of the Earth itself Earth is a blue planet engulfed by water but in this desolate chunk of Northern Chile you won't find a single drop [Music] wedged between the Pacific Ocean and Coastal volcanoes to the West the Andes to the east is Atacama the driest desert in the world 600 miles long and narrow on average just 100 miles wide it's the same size as Iowa now scientists are on a mission to find out how it was made [Music] the investigation begins in the Sleepy town of kiagua [Music] a rare green Oasis its only Lifeline is a stream trickling 300 miles from the Andes to the Pacific it is home to the official government rain gauge so geologist John Houston has come here to find out how dry the driest place on Earth really is this is a preview meter it measures the rainfall every day okay for Marissa Vera a government scientist it's a job with few surprises how much rainfall has this instrument recorded in the last 50 less than 1 and once it's one millimeter a year yes but was it every year it rains only three years it's incredible exactly [Music] on average it rains three one hundredths of an inch a year it would take a century for atacama's rainfall to fill a coffee cup pair with other deserts here we have a cylinder and I'm going to show you the difference between the amount of rainfall per annum here and the amount of rainfall in other deserts so if I fill this jar up right up to about there that is roughly rainfall that you get in the Sahara now if I pour most of that away we get to that level that represents what we have in the Mojave Desert five inches per annum if I pour all that away except for that little drop in the bottom there and that's the equivalent of what we have here in the heart of the Atacama Desert so it is such a small amount of rainfall that it means it's the driest place on Earth in his quest to find out why Atacama gets so little rainfall Gustin leaves the Oasis behind and heads into the desert by the side of the Pan-American Highway a road which runs the length of the continent he discovers the first clue well here we are at the Tropic of Capricorn this is one of the most important latitudes in the world and it is absolutely critical in explaining why the Atacama Desert is in this location here most of the world's deserts straddle one of two special latitudes in the southern hemisphere the Tropic of Capricorn runs through Atacama and Africa's Namib and Kalahari deserts in the north the Tropic of Cancer runs right through the vast Sahara at these particular positions on the planet the air is extremely dry this instrument is called a whirling hygrometer what this does is to measure the relative humidity of the air and the reading on here gives us a relative humidity of 10 that's really low really low um there aren't many places in the world where you get a relative humidity as low as that [Music] back in the early 1700s scientists discovered why tropical air is so dry European ships sailing to America relied upon the trade winds to power their Crossings but English meteorologist George Hadley was mystified why they blew Westward when they should blow directly north his studies would lead scientists to understand how air circulates around the Earth [Music] at the equator moisture-rich air gets heated by the Sun and Rises as this hot wet air flows away from the equator it quickly sheds its water as rain by the time it reaches the two Tropic latitudes the air has lost nearly all of its moisture resulting in no rain on the land below [Music] the mystery though is why Atacama gets so much less rain than any place else scientists hope to Crack the Case by figuring out how Atacama first formed [Music] on the hunt for Clues Houston travels deep into the true desert this closely guarded location was discovered during routine mapping by geologists back in the 70s but the huge significance of their find wasn't realized until 1998. this band of Boulders is the single most important clue to atacama's beginnings [Music] it's a delicate rock called gypsum a simple Test shows how fragile it is if I pour a little bit of water on top of that you will see that it very rapidly falls apart What's Happening Here of course is that when I'm putting water on this you see it dissolve I mean it's just going to fall apart the survival of gypsum is a solid rock tells scientists there hasn't been any Heavy Rain since the rock formed so the next step was to date it and figure out when this place became dry some can't be directly dated but by analyzing fossils in the surrounding rocks the awesome age of the desert was revealed Atacama is a staggering 150 million years old this gypsum here is an extremely special gypsum if there had been any rainfall greater than two inches in any one year this would have dissolved and have been washed away what that means is essentially that the Atacama Desert is the oldest deserts in the world for more than 150 million years while dinosaurs thrived and became extinct the Himalayas formed humans evolved Atacama has been a desert gypsum also holds the key to how this desert was made [Music] it's a chalky mineral which forms not in deserts [Music] but in water gypsum exists in a dissolved state in Shallow warm tropical Seas as the water is evaporated Away by heat it solidifies the existence of this one little rock is a key piece of evidence which reveals that before Atacama became a desert it was a sea bed this really insignificant looking piece of rock indicates that all this desert was once underwater so this gypsum in this location in the Atacama Desert is absolutely critical to understanding the whole history of the Atacama Desert [Music] the investigation so far scientists had pieced together evidence of how and when the desert first formed atacama's location near the Tropic of Capricorn means air is dry and no rain falls fossils found in the surrounding gypsum Rock reveal the age of the desert gypsum a rock that forms only in water reveals Atacama was once underwater now as scientists explore the mystery of how Atacama evolved from ocean floor to Pure desert they unearth explosive evidence in the investigation of how the driest place on Earth was made [Music] 150 million years ago the Atacama Desert was a seabed covered by ocean waters but today some areas in the desert are two miles above sea level [Music] in the journey to find out how this happened scientists take the investigation to the Eastern edge of the desert [Music] this strange landscape is the largest geyser field in the southern hemisphere Springs and geysers there's plenty of steam around and this is because the air is cool and the water is hot and so you have a lot of steam and and bubbling Springs boiling water is being heated deep underground the geysers and the hot water that you find up at El tatio are indications that you have a body of hot rock underneath us and another indication is you have a bunch of volcanoes surrounding this basin violently alive molten rock erupts onto the surface forming volcanoes fiery volcanoes and the boiling geysers are evidence of a turbulent process happening deep beneath the desert [Music] here the Pacific ocean crust is being forced underneath South America much like a spatula going underneath a pizza this geological process is called subduction you have the Pacific Plate colliding with the continental crust and the Pacific Plate is actually heavier and it slides underneath the continent crust and as it does so it Heats because it gets to a depth of about 60 miles and it becomes Molten this crucial depth is called a melting Zone hot molten rock then thrusts upward to form the active volcanoes that ring the El tatio geyser field this process gives scientists a hint to what lifted the desert out of the ocean more clues are found on the opposite side of the desert geologists know that these Coastal Hills were also once volcanoes today they're completely dead but modern dating techniques show that they first erupted over 195 million years ago it's a crucial piece of evidence which reveals when the Pacific Plate first began to force its way beneath South America at that time the desert indeed all of Chile was underwater [Music] over time the melting Zone was pushed further and further Inland first igniting the coastal volcanoes [Music] as the melting Zone passed beneath the desert it Formed new crust thickening and raising the land the Atacama Desert slowly emerged [Music] 50 million years ago this same process began to raise the endings [Music] today the melting zone is 140 miles inland and the molten rocket produces ignites volcanoes [Music] and fuels El tatio's geysers but as it passed under the Atacama Desert it also left behind this kamata the largest open pit copper mine in the world volcanic processes concentrated the copper ore here but it was the desert's unique climate that locked it in place this area of Northern Chile produces some of the largest the most important copper deposits in the world and this is largely due to the very dry climate most of the erosion on the earth's surface is caused by water so here where there's so little rainfall and there's very little surface water there's not very much erosion and so the copper deposit has actually remained intact as a result this Baron Wilderness is one of the most valuable pieces of land on the planet [Music] the mystery of how a desert can rise from the sea can be solved geysers provide evidence that molten rock exists deep underground [Music] the existence of active volcanoes shows the movement of one continental plate under another extinct volcanoes show this process began at the coast and pushed Inland raising the desert above the ocean the next step is to try and figure out what turned this ancient sea floor into the driest place on Earth a quest that spans 200 years of history and solves the riddle of what brought these penguins to the edge of the desert [Music] [Applause] the Atacama Desert is intriguing because it is the driest place on Earth deserts by their very nature are dry but Atacama is unique it 50 times drier than Death Valley in California and it's not because it's hotter Atacama averages around 80 degrees Fahrenheit during the day whereas temperatures in Death Valley regularly soar above 110. the search for what turned this strip of land from a regular desert into the world's driest place begins out on the Open Sea one of the curious things about the Atacama is that we actually see here penguins Penguins obviously like cold water and that's really confusing when you think of onshore we have really hot conditions in fact the temperature of the water here is about 55 degrees Fahrenheit whereas on land the temperature is something like 80 degrees Fahrenheit [Music] these penguins were first described by explorer Alexander Von Humboldt over 200 years ago while traveling along this Coast he was puzzled by the huge variety of marine life measuring the temperature of the water gave him an explanation it was 20 degrees colder than expected perfect for sea life like penguins centuries later meteorologists began to wonder if this chili belt of water called the humbled current after the Explorer was the reason Atacama became the driest place on Earth the Humboldt current comes all the way up from Antarctica ringing with it cold water and it is this cold water which creates this dull gray day that we see here with a fog over lying us it causes the air above it to cool forming a thick Bank of cold cloud and fog which clings to the shore hot dry air descends at the tropics here that hot air sits on top of the cold heavy rain clouds holding them down meteorologists call this an inversion layer trapped at three thousand feet the clouds can't rise up and shed their rain on the High Altitude desert the inversion lab prevents any moisture that may accumulate close to the sea from moving Inland so that is one of the reasons why this Humboldt current actually contributes to the dryness of the Atacama Desert that we see just over there [Music] inversion layer created by the humbled current that has turned Atacama into the driest desert in the world in the desert's Northern tip in a desolate place called cabrada aroma geologist Laura evenstar is looking for Clues to solve this riddle she's trying to put a date on when the desert became so very dry other deserts like the Mojave don't get much rain but when they do it's dramatic storms bring heavy rains and flash floods but not here in the cabrada aroma which is now totally dry one way to date the last time there would have been enough rainfall to cause a flash flood is to try to find out how long the rocks have been lying there undisturbed what we have here is a miniature demonstration of what goes on if we start having large amounts of rainfall so this is our rainfall here and what we you can see is that when we start raining on our desert surface it will pick up the boulders and move them around and then when there's no water here the boulders just sit still and don't move the surface of cabrada Aroma is strewn with rocks so she's cracking them open to reveal evidence of exactly when water last flooded the landscape what we do is we have to knock a bit off and then we examine it and have a look at whether it's got a very dark color and hopefully we can be able to see some of the black minerals which is what we're looking for tiny black crystalline minerals are pyroxenes [Music] their crucial evidence because like microscopic geologic clocks their chemistry changes when exposed to Cosmic radiation over time the sun is only producing a tiny bit of the radiation which will hit this rock the majority of it is coming from all the stars you see in the night sky what it does to the rock is basically uh just bakes it a bit like a really bad suntan so it just comes down hits it and Cooks It as The Rock gets cooked by cosmic rays the pyroxenes break down and produce a gas called helium-3 record how much helium-3 is within this RAV the longer that it has been exposed to Cosmic or solar radiation helium-3 gas is only produced in microscopic quantities so evenstar takes her samples to a lab 7000 miles away Glasgow Scotland [Music] so what we do are using a laser is we shoot the laser into one of the wells and vaporize our crystals and that's releasing the helium-3 then the helium-3 is going to go through all this complicated Machinery eventually run through the mass spectrometer foreign by analyzing this data she can figure out the last time the boulders were moved [Music] some who we've actually recorded has been 23 million years so what this means is that within certain areas of the Atacama Desert these Boulders have been sitting there and not moved by water for 23 million years is one of the oldest undisturbed surfaces in the world these Boulders were there before humans even started to exist they are incredibly old thank you even start has discovered that there are places in the desert which have been bone dry for 23 million years [Music] this date is a crucial clue in the investigation because it coincides with the birth of the Humboldt current South America was once joined to Antarctica but roughly 25 million years ago these continents split a channel opened freezing water began to circulate round the pole and thundered North along the coast this cold current formed an inversion layer trapping Coastal rain clouds and starting atacama's slow transformation into the driest place in the world but the humbled current is not the only culprit ironically the quest to find out how the desert became so dry comes up against one of the wettest places on Earth on the other side of Atacama is the Amazon but the heavy rainfall from the rainforest doesn't get anywhere near the desert the reason why is in plain sight between the Amazon and the Atacama Desert lies the vast Andes mountain range geologic evidence suggests the Andes finally grew high enough some 10 million years ago to prevent any rain from reaching the desert it's called a rain shadow effect and it's the final factor which drove Atacama to become the driest place on Earth [Music] the evidence for what Turned Atacama so incredibly dry is mounting a humbled current creates a weather system that allows no rainfall helium-3 in Rock shows that the process of desiccation began 23 million years ago the rising Andes 10 million years ago made it drier still the investigation would seem to be conclusive Atacama has been a Barren essentially rainless landscape for millions of years but then something happened to blow that conclusion wide open tiny shards of stone revealed that an ancient civilization once lived here but how could people live in the world's driest desert the Atacama Desert is by far the driest place on Earth and by piecing together the evidence scientists believed it had been so for millions of years yet at a remote site called guanaqueros paleo ecologist Claudio Latorre made an intriguing discovery which paints a more complex picture this is an extraordinary find and this was probably a little knife or a scraper that's been broken off and discarded Zach's probably still cut to the untrained eye it looks like a simple Rock Shard but Latorre can see it's been worked into a tool and he's found hundreds of them they're clues that reveal ancient humans once lived here this was not just a temporary residence this was something where people were living and working and banging away at rocks and making artifacts and living off this landscape using the resources at hand as water is essential for life It seems impossible that any kind of plant animal or human life could survive here Latorre suspects that some regions of this 57 000 square mile desert were once much wetter not millions of years ago but during the time humans walked the Earth in 1997 he set off on a mission to hunt for evidence today he's retracing that Journey changes in the climate can be seen in the rocks so Latorre examines the cliff layer by layer he finds a crucial piece of evidence [Music] together this is actually where the interesting part of the story comes in this chalky rock is called diatomite it's made from the crushed remains of fossilized algae microscopic life forms which only live in fresh water what this rock is telling us is that we had basically a wetland whereas you look at the landscape across the day and we see that it's basically about as dry as you can get sometime in the past there was water on the surface of the desert La torre's next task was to find out when radiocarbon dating is one of the most accurate methods of dating but using this method means sampling something organic so latori combed the desert for Clues the way we work is basically poking our heads into every little hole in crevice that we can find when we found this place we couldn't believe our eyes foreign he accidentally and luckily stumbled upon the most important piece of evidence in this investigation at the back of the cave was a vast nest it's made from the feces of thousands of generations of tiny mammals the size and shape of the pellets told Latorre those animals were chinchilla rats and it also contained the critical clue he was searching for organic material when we found the site one of the most exciting discoveries that we made was the fact that it's full of grasses now look across the landscape today and tell me where those grasses are and we immediately knew that we were talking about some major vegetation change This Grass looks as fresh and crisp as if it was collected yesterday but when the Tory carbon dated grass from the nest what he found was amazing the grass was more than 11 000 years old but what I have in my hands here is an ancient ecosystem this is about as clear an indicator you can get better than anything else you can think of that water increased in the past in this area The Nest reveals strong evidence that plants and mammals did exist here and they weren't alone underneath the thick layer of Nest is another layer rich with tiny handmade tools if we look around you know we can find actually evidence of this past human quotation there's just full of little shards here on the floor some regions of Atacama have been constantly dry for 23 million years but this evidence shows that other regions like guanacaros were very different eleven thousand years ago it's a fossilized snapshot of a diverse ecosystem briefly bursting into life grasses grow and wetlands flourish in this wetter time tiny mammals Thrive and breed while game like vicuna and llamas meant humans could live in this rich and fertile environment so it's wonderful to know that by looking at something as mundane as a rodent Nest you can actually find clues that enabled you to understand the past human colonization of the Atacama Desert which is no mean feed in itself given the fact that it's such a harsh climb today the date of The Rat's Nest gives scientists a possible theory of where the water came from eleven thousand years ago the last ice age was at an end the global climate was changing more rain fell high in the Andes flowing down to the desert in rivers in some places groundwater pooled forming wetlands others remained Untouched by water as they had for millions of years but just a thousand years later the climate changed again Rivers dried up grasses died rats and humans disappeared now every drop of groundwater has been sucked down into the parched Earth Latorre demonstrates how deep that water is today so just to give you an idea of how much change has gone on since the Wetland was formally at the surface here's a little experiment that we can do this is a well and I'll drop this Little Rock and we're going to count and we're going to see how long it takes for that rock to hit the water so that takes almost four seconds to reach the water that's well over 200 feet below the surface is where the water table is today it's about as dry as it gets it's a it's what we call absolute desert no plants no Wildlife nothing no surface running water whatsoever the investigation of this driest place on Earth took a surprising turn tools show humans lived here diatomite reveals the climate was once wetter rats dung and grass dates a diverse ecosystem to 11 000 years ago yet this extraordinary desert has more secrets to tell not just about life in one of the most extreme environments on our planet but also about life on other planets today scientists suspect Atacama is the driest it has ever been so they're investigating whether there's any source of water left here at all and NASA scientist Alfonso Davila knows that if there's water there's a chance there could be life here too but when he first arrived the signs didn't look good when I came here for the first time I drove for a couple of thousand miles and when I got back to my base camp I realized that I didn't have a single insect I smashed against my windshield that has never happened to me anywhere else in the world and I think that's a very good example of how hard this environment is for life since the 1960s NASA scientists have been hunting for bacteria life in the desert's thin soils yet they found nothing until 2005 when they came across a strange white landscape [Music] by chance one of davila's colleagues picked up a rock smashed it open and discovered something completely unexpected yeah you can see very nicely a Green Layer inside the crust under the microscope the significance of this pale green blur zoomed sharply into Focus to our surprise we saw a green microorganisms living inside the rock so that came as a big surprise because nobody was expecting microorganisms in the middle of the driest place on Earth completely by accident hidden inside a rock they discovered life this mineral is sodium chloride otherwise known as halite it's a very common mineral in the Atacama Desert and it's also very common mineral in kitchens around the world as this is exactly the same salt we use to spice our food [Music] salt can preserve food by killing off bacteria but here strangely it was harboring a colony of green microbes to find out how they survive Davila laid out a series of sensors that measure humidity his research shows that although on average the air in the desert is around 10 percent humidity on rare occasions it rises as high as 75 percent this momentary increase in water vapor is the only source of water and it's this water that gives rise to life their distinctive property of salt is its capability to extract water vapor from the atmosphere and forms a liquid solution inside the rug as moisture from the air is sucked into the salt the microbes allow the rock to bring the water to them life is actually very robust it's very flexible and it can really adapt to some of the most extreme conditions that we see on Earth [Music] NASA believes this discovery in the Atacama Desert can reveal something about life on Mars [Music] in 1976 the Viking Lander detected water in Mars thin atmosphere in 2008 NASA's Mars Odyssey Orbiter found evidence of salt on the planet's surface now when humans finally get to Mars they won't be looking for life in the thin Martian soils but inside the rocks unfortunately it's going to be a long time until we see humans Walking on Mars until then we come to the Atacama Desert and we study this type of rocks which likely hold the clue to understanding life on Earth and also to understanding the potential for life in other planets in our solar system so it's possible that an accidental Discovery in the driest place on Earth will one day lead scientists to crack open a martian Rock and discover little green alien life [Music] the investigation into how the driest place on Earth was made has revealed an awesome Earth story spanning 150 million years gypsum a rock which forms in water shows the desert was once a seabed hot geysers show that immense volcanic activity Under the Desert raised it above the ocean tiny pyroxine crystals revealed the first areas of the desert which became completely dry 23 million years ago rat nests reveal a small pocket of life that bloomed in the desert at the end of the last ice age tiny green organisms in salt show that even here life clings on today this place is unique on Earth absolute perfect desert and the investigation into how it Formed has shed light on another chapter in the story of how the Earth was made [Music] Earth a 4.5 billion year old planet still evolving as continents shift and Clash volcanoes erupt and Glaciers grow and recede the Earth's crust is carved in countless fascinating ways in a trail of geological Mysteries behind one of the greatest is right here at Yellowstone National Park in Wyoming this is one of the world's most geologically active places shaken by up to 5 000 earthquakes every year with more geysers and hot springs than in the rest of the world combined why is Yellowstone so active how did it form and why here in the heart of the Rockies scientists studying Yellowstone are uncovering a violent past carved by water crushed by ancient glaciers blasted by the biggest volcanic eruptions ever known on the planet and even today Yellowstone is one of the most dangerous places on Earth [Music] Yellowstone National Park is one of the most amazing places on Earth and it's Unique it contains some of America's most stunning scenery and Wildlife that attracts 3 million tourists a year to understand where Yellowstone came from and why it is so active today we need to take a journey back into the distant past of the North American continent and deep into the Earth's interior Yellowstone sits 8 000 feet up on a remote Mountain plateau primarily within Wyoming but stretching into parts of Idaho and Montana the park covers 3468 square miles 63 miles north to south and 54 miles east to west and it's on top of one of the world's most unusual and deadliest geological structures what's unusual about the park are the wildlife unusual no is the wide open space unusual no you've got it all over the Western U.S what's unusual it's a very unusual geology that created the park [Music] Yellowstone was founded as the world's first national park because of the geology [Music] it's this strange geology that attracts teams of scientists to the park their task to piece together the story of the incredible processes that built this unique extraordinary landscape by digging deep into Yellowstone's past the geologic history of Yellowstone goes back to the formation of the North American continent some of the rocks in Yellowstone are 2.8 to 3.2 billion year old rocks some of the oldest in North America only by traveling back into the past can we figure out why in this particular location there are 2 400 miles of rivers more than 300 waterfalls and the world's greatest concentration of 10 000 hot water Springs bubbling mud holes gas vents and geysers what do these features reveal about this landscape and how it was formed the investigation begins at Yellowstone's star attraction Old Faithful it's a key clue to what's going on underneath the surface [Music] located in the southwest of Yellowstone Park the geyser puts on an explosive display every 90 minutes or so blasting out thousands of gallons of scalding hot water Yellowstone is like no other place on Earth there is so much heat coming out here it's really a singular phenomenon well after about at nap Old Faithful has roared back to life it wasn't actually napping it was recharging the temperature of the water was increasing the system was pressurizing beneath Old Faithful is a rather complex Plumbing Systems filled with caverns and conduits and constrictions [Music] rain water saturating the ground around the geyser slowly fills its underground reservoir Hot Rocks below ground heat the water under pressure for around 90 minutes suddenly some water spurts through a tiny five inch wide crack in the rocks this causes a drop in the pressure within the water chamber in an instant thousands of gallons of water are turned to steam and blasted up into the air the pressure builds up enough steam bubbles start rising to the surface the system depressurizes and the full eruption can occur Old Faithful shows that rocks below the surface are very hot scientists find Clues to a violent past 34 miles Southeast of the hot springs on the shores of a circular lake called Indian ponds as a field geologist my job is to basically be a rock detective and so I try to determine what their origin is and what the history is of that particular Rock okay now in this particular case let's look at this this rock when it started it was just a loose sand you could just put your fingers through it the solid Boulder is formed from millions of individual grains of sand microscopic analysis reveals the grains have been cemented together by chemicals and pressure deep under the ground but how did The Rock get to the surface Morgan has chemically dated the rocks and discovered that three thousand years ago the boulder was blasted out of the ground by the hot water explosion of a gigantic geyser you would see boiling water fine muddy material being ejected up into the air as high as three to five thousand feet and then at some point material would start raining down from this explosion column now you wouldn't want to be standing next to one of those Indian ponds is the crater that the guys are left behind but it is dwarfed by the Crater Morgan has found at Mary Bay in Yellowstone Lake Morgan has dated this geyser explosion to 13 000 years ago so here we are in the middle of Yellowstone Lake and it says you can see a beautiful day and it's nice and Placid but on the floor of Yellowstone Lake it's anything but quiet Morgan's research proves that geysers were exploding around the lake and even under the water between thirteen thousand and three thousand years ago and their size suggests that whatever was powering them was huge but is it still active today a clue comes from underwater vents at the bottom of the geyser crater they pump out vast quantities of hot water and gases to find out what's creating the gases Jake lowenstern and his assistant collect samples from the hot springs in the center of the park funnel they use is designed to collect up gas bubbles before they reach the surface so that they're not contaminated by ordinary air is a very complex mix of gases and but we have a lot of tools that we can use to try to unravel this rather complicated information so we'll look at all of the gases that are coming out we can learn about the different kinds of rocks beneath Yellowstone and try to understand how things might be changing from from week to week or year to year or or decade to decade analysis of the gases reveals that they are a mix of carbon dioxide sulfur dioxide and hydrogen sulfide it is the same mix that is found coming out of volcanoes but the final clue to what's actually going on underground is found on the edge of the same Hot Springs so these are quartz crystals that we collected on the side of the pool there this stuff is what remains it gets tossed up it forms a little berm around the side of the pool it's all a beautiful little quartz crystals some of them have a little bit of iron staining and other things but most most of them are are nice shades of yellow and clear quartz crystals like these can only have formed as a hot molten rock lava flow slowly cooled after being erupted onto the surface from deep underground so the crystals are clear evidence that under the springs is a volcano Yellowstone's hot water features all point to one conclusion Yellowstone must be powered by the heat of a volcano geysers only erupt if the rocks are hot enough to turn water into steam gases from underwater have the same composition as those from volcanoes ports in the hot springs must have come from volcanic lava there is an immense amount of energy coming out of the ground that's expressed by the geysers the mud pots the hot springs and the steam vents where's all that heat coming from it's coming from the molten rock associated with the Yellowstone volcano but that leaves a big question unanswered in this gentle rolling landscape where's the volcano [Music] [Music] Yellowstone's unique volcanic geology is potentially deadly dangerous it makes it crucial to monitor what's happening under the ground the Yellowstone volcano is a very very active volcanic system and so it really requires observation everything that we do here has a research component but it also has a volcano monitoring component and uh you know if if activity picks up here we're going to want to know something about the plumbing system beneath us here to try and predict when Yellowstone's hidden volcano will erupt in the future scientists study its geological past part of our task is to look at the landscape and read the geologic Story and there's so many Clues and so much evidence here to look at that it's a fascinating place to work foreign scientists began investigating Yellowstone even before it became the world's first national park in 1872 but observations of this astonishing land began long before that dating ancient arrowheads shows that Native Americans first lived here 11 000 years ago their Legends of Yellowstone's angry spirits who made the ground tremble were passed onto early explorers such as Lewis and Clark later reports from Trappers explorers and mountain men like John Coulter and Jim Bridger told of geysers that fired 70 feet into the air and spring so hot that meat was readily cooked in them but these were thought to be tall tales until the 1860s when geologists investigated and found that the lava flows and hot vents were signs of volcanic activity but something clearly wasn't right nobody could actually find the Yellowstone volcano we say that Yellowstone is one of the world's most active volcanoes people come out here visitors other scientists and they say what do you mean I I don't see a smoking volcano I don't see a big steep volcanic uh crater all the things that one normally thinks of for an active volcano so without obvious signs of a volcano scientists hunted for other Clues they would find them in the sweeping forests of Lodgepole Pines these are the only plants that thrive on the poor soil that comes from a particular type of lava called rhyolite and Yellowstone's constant plagues of mosquitoes also reveal the presence of that same rhyolite lava impermeable and so in it creates these little ponds of water that never go away and those are a wonderful breeding grounds for mosquitoes there are a lot of mosquitoes if you can't see them flying around my head so the pine trees and the insects both indicate that there's a lot of rhyolite in Yellowstone that's important because rhyolite lava creates incredibly violent volcanic eruptions it's much more like a bread dough it's about a thousand to a million times thicker or more viscous we put a bunch of gas in it we can have a very explosive eruption but if rhyolite lava is that explosive how big a bang did it produce to find that out scientists looked not inside Yellowstone Park but in a Far Away River Valley at Meadow Creek Wyoming cutting down through the land over millions of years the river has exposed an unusual thin layer of Black Rock in The Cliff face a nearby Road cutting lets investigators examine the mysterious dark Rock [Music] if you look at the sample in detail up close you can see that here's a pumice fragment these these red fragments here are our little rock fragments and if we were to make a thin section of this rock and look at it under the microscope you would in fact see compressed glass shards the black layer that geologists call obsidian is actually a type of glass it's crucial evidence that the rocks and soil here came out of a volcano because obsidian is forged when boiling hot ash and gas rapidly cool under great pressure and that's just what happens when hot volcanic clouds roll out across the landscape obsidian forms in the very bottom layers cooled from below and crushed by the weight of hot debris on top the ash layer that crushed the obsidian at Meadow Creek is still visible today its base is characterized by this very thick dense obsidian as as the Flow came to rest and was compacted and then Above This dense glass layer is it grades upwards into a tan sort of region and continues up for about an additional 30 feet and then up on top of that as it's exposed today a modern soil has formed and we can see growing up there various sorts of vegetation trees and grasses and things of that sort studying the mineral composition of the ash proved that it came from an ancient volcanic blast in Yellowstone Park and there's only one way that so much Ash could have been blasted so very far away from its source the eruption must have been larger far larger than anything ever seen by man so big scientists now label it as a super eruption [Music] we're looking at this deposit from a super eruption and yet we're over 50 miles from the source of the of the eruption geologists have recreated what must have happened here on the day that Yellowstone exploded incandescent Avalanches of Ash raced out of the park in all directions this is traveling at very high velocity easily over 100 miles per hour across the land surface and obliterating everything in its path it was extremely hot when it arrived here and perhaps as hot as as 1500 degrees Fahrenheit to it twice a pizza oven I mean it's just very hot so what would it have been like to be standing on this spot hundreds of thousands of years ago a day when the Yellowstone ash cloud roared Over the Horizon the impact of this would would be absolutely unimaginable it would be I think you would be disarticulated burned and and unrecognizable and it would be very difficult to find any of you all of the evidence about the size of the super eruption helped solve the mystery of the missing volcano scientists realized that the super eruption was so enormous that it must have blown the volcano to pieces [Music] swarms of mosquitoes show that explosive rhyolite lava underlies parts of the park obsidian glass 60 miles away reveals that Ash flows spread from miles around Yellowstone and thick layers of debris confirmed how gigantic an explosion this must have been the problem now is the explosive Legacy that the super volcano left behind because a deadly danger still lurks here hidden deep under the ground for nearly a century after Yellowstone National Park was established nobody realized one astonishing fact that the park is located inside one of the biggest volcano craters on Earth it wasn't until the late 1960s that American geophysicist Robert Christensen realized that rock formations he had been studying for several years all around the edges of the park in fact formed a giant circular Ridge he compared his findings on the ground with a series of NASA pictures taken between 1966 and 1970. confirming that the ring was the rim of a giant crater 45 miles across parts of the Crater Rim are still clearly visible today but the other Edge is almost out of sight ing the crater coincided with another scientific discovery in a totally different part of the country in California scientists identified a strange thin layer of Ash buried underneath the modern day soil the ash matched material from the Yellowstone crater dating the soil layers proved that the ash arrived 640 000 years ago scientists at last had a date for the Yellowstone super eruption [Music] Ash was later found all over the Western U.S confirming the huge size of the eruption at least 80 times the size of the 1883 explosion that destroyed the island of Krakatoa and 2500 times bigger than the 1980 eruption of Mount Saint Helens the almost unimaginable size of the Yellowstone blast means that scientists now call it a super volcano but that creates another mystery this peaceful landscape where is the steaming hot crater that the volcano must have left behind today when you're looking out across the landscape you see Rolling Hills and and trees so obviously there's not a big hole left in the ground from the eruption of the of the Yellowstone volcano so something else has happened one of the first processes was infilling with all sorts of volcanic lava flows and if you look just down from the landscape toward those trees you'll see one of the oldest lava flows that happened after the 640 000 year eruption over hundreds of thousands of years this flow has weathered into soil and been covered with trees but elsewhere in the park are a different type of lava deposit still bear of vegetation because this lava was still erupting up until about 100 000 years ago the later lava was far less explosive and more runny and cooled slowly smooth the harsh volcanic landscape into Yellowstone's softer Countryside [Music] that made Yellowstone at first more tranquil but there's evidence here that the land was soon buried once again This Time by freezing snow and ice the ice that polished the Rocks has a story to tell it offers crucial evidence about volcanic forces still shaping the park to this day [Music] Hill unfolds through the tiniest of Clues scratches on the Rocks reveal which way the ice was moving they show the glaciers always slid the same way outwards and downwards from an ice cap at the heart of the park the only conclusion is that something pushed up Yellowstone Park so much higher than the surrounding Hills that glaciers formed on the top but what force could possibly be powerful enough to have raised Yellowstone's Peaks up into the air [Music] the first clue to help answer that question comes from Yellowstone's numerous earthquakes when the ground deforms it creaks and groans like a Stradivarius violin and the creeks and groans are essentially earthquakes the Quakes are recorded by seismometers all over the park the earthquake monitoring is a critical part of the picture because it's basically it's the stethoscope that we have to really see and sense the heartbeat of the system is investigating a puzzling geological mystery Yellowstone has up to 5 000 earthquakes a year even though it's in the stable heart of the North American continent scientists needed to know what was happening underground to shake the park so much to find out they plotted the precise locations and depths of earthquakes under the ground so why are there so many Quakes the answer had to wait until the mid-1980s whenever more powerful computers first let scientists see into the Earth seismic waves spreading out from earthquakes travel rapidly through cold Rock but slow down when the rocks are hot the varying wave speeds can be translated by computers into color 3D images revealing exactly where hot rock lies under the ground seismic waves propagate through the Earth just like x-rays go through a body so we use the same physics to reconstruct the structure of the geology of the earth beneath us the seismic waves have outlined the Park's underground structures revealing a graphic history of what's happened under Yellowstone they reveal this gigantic reservoir of molten rock which created Yellowstone's crater When lava erupted out and the ground above collapsed into the space left behind and the seismic waves still slow down under Yellowstone today showing that the magma chamber still lurks under the park it's more than 30 miles long 25 miles wide and 10 miles in depth but its size Alters from year to year as it fills or empties with semi-liquid rock at an incredible 1500 degrees Fahrenheit this is the hidden Beating Heart of Yellowstone Park the way it moves deforms the ground above explaining the fault lines and the earthquakes they produce and its heat ultimately Powers all of Yellowstone's hot water pools and geysers [Music] Subterranean Yellowstone is giving up its secrets seismographs record thousands of earthquakes in the park [Music] and the evidence of earthquake waves reveals a massive magma chamber miles under Yellowstone's surface but the Yellowstone investigation is far from finished because there's evidence of another even more monstrousized structure under the park [Music] by the beginning of the 21st century scientists investigating how Yellowstone was made had images of what lay under the park there was a problem technology only allowed a view of a few miles below the surface then as more and more data was fed into more and more powerful computers there was a breakthrough in April 2006 geologists published new diagrams of hot structures far deeper under the park and computers painted more detailed pictures the results were startling [Music] investigators saw For the First Time The Sleeping monster that lies below Yellowstone Park snaking down hundreds of miles into the Earth far deeper than the relatively shallow magma chamber is a colossal volcanic pipe nobody's certain how deep it goes but they can picture it down to 400 miles or more twice the distance between Washington and New York foreign Smith makes an educated guess about what the underground plume is like our best estimates now is to start doing the physics and the Dynamics of these things it's like a conduit of melted rock like a chimney that chimney called a hot spot pumped up enough heat to melt the rocks of the crust and fill the overlying magma chamber which then erupted to blast out Yellowstone's vast crater understanding how the crater formed was an important moment for the investigation [Music] because there was evidence that similar eruptions had happened before many times before [Music] throughout the 1960s various teams of geologists studied the Snake River plain to the southwest of Yellowstone Park and found traces of ancient volcanic craters [Music] the crater rims had long been eroded but their outlines were confirmed by aerial pictures over the following decade [Music] they ran in a straight line along the plane heading for the heart of Yellowstone Park on average each crater was a couple of million years older than its neighbor investigators realized that these are the remnants of earlier super volcano explosions an unbroken chain stretching far back into geological history [Music] seemed clear that time after time the hot spot had blasted out a super eruption and then moved on hotspot appeared to have traveled hundreds of miles but that pose yet another riddle How could a hot spot anchored to the core of the planet the moving an important clue had been found in 1985 by American volcanologist William Scott he realized that plotting the location of 30 000 earthquakes around Yellowstone produced an amazing pattern the Quakes traced out a giant v-shape on the surface of the Earth the v-shape wrapped around the hot spot's location it seemed at first to confirm that the hot spot was still moving Rippling up the land around it with fault lines and tens of thousands of earthquakes but the real answer lay with the theory of plate tectonics it showed that it's the American continent not the hot spot that's moving and the chain of craters on Snake River plain is there because for millions of years the moving American continent has continually pushed new land over the stationary hotspot but as a North American Plate moved across this source of heat that pops through the lid and creates The Hot Spot track that's the sink of her plane Yellowstone is just the active component today the repeated Hot Spot explosions on land have made Yellowstone unique [Music] spots have been identified around the world like the one that has created the island chain of Hawaii but Yellowstone is the only place where a hot spot has erupted in the middle of a continent which of the earlier explosions blew the original mountains to bend the land smoothed over with later flows of more runny lava that was released from deep under the Earth's crust thank you [Music] multiple strands of evidence combined to reveal Yellowstone's slumbering monster the gigantic Hot Spot plume lying under the park earthquake maps show the hot spots location [Music] seismic waves reveal the depth of the plume the earlier craters prove regular super eruptions over millions of years all of which leads to the most frightening question of all when will Yellowstone erupt again [Music] measuring the amount and geographical spread of ash fall from Yellowstone super eruptions produced some terrifying figures 640 000 years ago the eruption poured out around 240 cubic miles of material enough to bury the whole of New York State tens of feet deep in Ash if it happens again thousands will die vast areas of the United States will be buried in volcanic debris but when will Yellowstone erupt again one clue to when that next eruption will happen comes from investigating the eruptions of the past The Hot Spot punches out a super eruption on average every six hundred thousand years and the last one was 640 000 years ago but geologists expect that there will be warning signs before Yellowstone explodes again volcanic eruptions are usually preceded by an increasing number of earthquakes [Music] the Quakes are a sign that underground volcanic Chambers are filling with molten rock and expanding to stretch and deform the land up above Yellowstone Park usually experiences an average of 12 tiny earthquake Tremors every day most are too weak to be felt by tourists and register only on the most sensitive seismometers but in early 2009 more than four times as many Quakes started striking every day over one 10-day period there were more than 500 Quakes some of them up to magnitude 3.9 powerful enough to frighten the visitors and put the scientists on alert there's a second indicator of increasing volcanic activity if more molten rock does inflate the underground chamber the ground above will rise and that too seems to be happening right now unusual evidence to prove it comes from an unlikely source the Waters of Yellowstone Lake around 100 years ago small steam ships carried tourists on sightseeing trips across the lake but one of the ships caught fire and sank forever below the surface of the lake but now Yellowstone's astonishing geological forces have resurrected the ship's remains from their watery grave here we have a boat which burnt down to water level and so this tells us something about the deformation of Yellowstone and basically what's happened is that the floor of the lake has risen bringing the boat out of water the reappearance of the wreck shows that land under and around the lake is rising because of the expansion of the magma chamber even more alarmingly the rate at which it's rising seems to be increasing in geological terms a huge area of Yellowstone Park is positively soaring up into the air faster than it's ever done before the biggest uplift of all has been recorded just a few miles from the shore of the lake there's a GPS system here a much more sophisticated version of the one in your car measures not only its surface position but also its exact altitude to within fractions of an inch there's a small radio antenna about the size of your thumb that sits on top of this steel rod and it's anchored in two to about three or four feet so if the ground moves up and down the antenna moves up and down foreign the GPS and the land on which it's anchored are moving upwards we're above the magma chamber and beginning in late 2006 this whole area of ground started to rise at the order of two to three inches per year and as of today this whole system right here has risen about that much and it's still moving today and so we're measuring and keeping close track of the deformation the of the uplift that we're seeing at this station but does the uplift mean that Yellowstone supervolcano is threatening to erupt once again the question of what lies in Yellowstone's geologic future is fascinating and I and all of my colleagues would love to know the answer to that question the scientists keep a careful watch on the volcano's activity the idea of science is to understand the process and so we have a responsibility to see how this system is deforming and how it's working and we have to be aware there is still a possibility of volcanic eruptions or earthquakes after all that's what made this system and there's no reason to think that volcanism is stopped the Yellowstone investigation has shown that the Park's sleeping super volcano is still alive and dangerous Old Faithful underground plumbing reveals volcanic Heat obsidian glass tells of a massive eruption seismographs record thousands of earthquakes while the earthquake waves reveal terrifying underground Chambers and the reappearance of a sunken boat shows that the land is rising yet the ultimate Yellowstone geological question remains to be answered when will the super volcano erupt once again we know there's enough magma left we know there's enough heat we know that there will be future eruptions in Yellowstone but we don't know if there will ever be another catastrophic eruption so the investigation is left with a deadly serious warning on the time scale the geologists work to coming super eruption in Yellowstone May well be right around the corner that corner could be ten thousand or a hundred thousand years in the future could be tomorrow new and devastating chapter in the ever-changing story how the Earth was made 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 numerous and fascinating ways leaving a trail of geological Mysteries behind in this episode The Great Lakes of North America the largest expanse of fresh water on the planet are investigated they hold 20 percent of the world's fresh water and provide drinking water for nearly 10 percent of Americans these five lakes are among the world's greatest natural wonders but their Origins are a mystery now geologists are investigating piecing together the clues that lie hidden in this extraordinary landscape delving deep into a vast Underground Salt Mine behind the torrential flow of Niagara Falls climbing a mile high glacier where Clues to understanding the Great Lakes formation also provides a window into the formation of the Earth itself [Music] the five Great Lakes Superior Michigan Huron and Erie pour over one of the world's great waterfalls Niagara into Lake Ontario the mighty torrent of the falls empties excess water from four of the five Great Lakes out to the Sea for geologists the lakes are a natural wonder and a puzzle scientists are on the trail of how they were formed with rocks as their Clues an ice lava and water as their suspects their investigation begins at these seemingly ordinary industrial buildings beside Lake Huron hundreds of feet below ground here there's a remarkable Secret [Music] deep below Lake Huron and also Lake Michigan are vast salt mines carved out directly beneath freshwater lakes here right now we're 1750 feet below the surface of the Earth We're in the largest Underground Salt Mine in the world and we're below Lake euron a large freshwater lake amazingly this salt deposit was uncovered by accident they were joined for oil and they hit salt and that was the end of looking for looking for oil they just kept on digging for the salt this salt deposit is the investigator's first clue evidence that there was once an ancient sea here many years ago the salt was formed in a Great Salt Lake and the evaporation dry seasons the salt dropped out evaporated out and formed the salt that we're actually mining in there are hundreds of layers of salt leading investigators to conclude the sea must have dried up and refilled hundreds of times scientists would later prove this sea finally evaporated millions of years ago 35 percent of North America's salt comes from these mines salt used to melt ice on frozen roads and sidewalks salt used to season food the remains of million year old Seas all coming from beneath Lake Huron and Lake Michigan the salt deposit is massive there's probably trillions of tons of salt in the deposit it extends all the way down to Detroit all of Lake Huron the salt is under it and of Michigan the salt is soft and over millions of years the salt layers should have worn away why haven't they it's because the salt is protected by a vast impenetrable layer of rock that lies like a giant Basin beneath Lakes Michigan and Huron and stretches under Lake Erie like the porcelain lining a bathtub the rocky Basin holds the Lake's fresh water geologist John zawiski and a team of divers are hunting for Clues to the rocky basin's Origins they're heading for Thunder Bay a small island at the edge of Lake Huron as he walked along the beach zawiski discovered some crucial evidence seemingly insignificant rocks that were overlooked for decades but the whiskey suddenly realized what he was looking at fossilized remains of ancient sea creatures [Music] I was seeing something that many geologists had never seen when they visit this island there were the heads of giant lime secreting sponges that were some of the main Reef builders zwiski uncovered a perfectly preserved fossil of a giant sea sponge that must have come from an ancient coral reef [Music] for the past five years zawiski's divers have been surveying the lake to discover the size of the ancient coral reef they believe it's hundreds of feet thick and extends deep below Lake Huron and zawiski has proof these rocks are extremely old the time period can be pretty confidently bracketed at right around 385 million years ago America was then a very different place 385 million years ago its land mass lay in the southern hemisphere a land covered by ancient warm Coral Seas this region was just south of the equator in tropical conditions and shallow Seas had swamped many of the land areas of the Earth at that time year in year out coral reefs Decay naturally and turn into a soft rock limestone and much of the Rock's Whiskey's divers find under Thunder Bay Island consists of layer upon layer of this Limestone from successive coral reefs but millions of years ago some of this soft limestone near the surface was changed when the salty Briny sea evaporated it turned the Limestone into a second much harder Rock something which would decide the very shape of the Great Lakes this rock is limestone this other piece was once the exact same material however it's been converted by a process of brines creating a conditions for recrystallization into a rock that we call Dola Stone it's much harder than Limestone more weathering resistant and I can easily demonstrate the difference between these two calcium carbonate calcium magnesium carbonate to show the relative hardness of the two rocks the whiskey uses an essential tool in the geologist's Arsenal let me uh put a little acid on here acid easily attacks and dissolves soft rocks first how will the Limestone react we see a very violent reaction there carbon dioxide gas is being released from the limestone next the hard dollar Stone let's go ahead and do the acid test on it and you can see we don't get this violent reaction almost no reaction at all the whiskey has proved the dollar Stone layer is harder and more resistant than the limestone the ancient ocean salty water converted the top layer of the Limestone deposit into a cap of hard resistant dollar stoned Rock this that forms the super tough Rock Basin under three of The Five Lakes Michigan Huron and Erie scientists were beginning to piece together the chain of events that led to the formation of the Great Lakes the clues uncovered so far vast salt deposits provide evidence of an ancient ocean the Briny ocean changed soft fossilized Limestone into hard dollar Stone Dola Stone makes up the rocky Basin under Lakes Michigan Huron and Erie the tip of the rock Basin the rim forms steep Cliffs that Tower above these Three Lakes this immense wall of rock called the Niagara escarpment forms the boundaries of these Lakes and makes possible one of the world's greatest natural spectacles Niagara Falls over this hard dollar Stone Cliff three thousand tons of water a second Tumble from four of the five lakes but it's more than just a miracle of nature Niagara Falls is a vital clue that helps scientists date when fresh water first began flowing into what we now call the Great Lakes [Music] the Great Lakes of North America geologists have discovered three of the Lakes were formed in a vast Rock line Basin laid down by an ancient Lagoon the question is when and they think the answer lies here Niagara Falls behind this curtain of water lies the evidence to when the Lakes were made like the Overflow from a bathtub excess water from four of the five lakes Superior Michigan Huron and Erie spills over the falls into Lake Ontario all that water is changing the falls change that can be measured and used to calculate the age of the Lakes themselves The Falls were first studied by one of modern geology's founding fathers Charles Lyle who'd pioneered the early understanding of Earth's Secrets was intrigued by the concept of geological time Charles Lyon came to Niagara region in the 1840s and he made very important observations at Niagara Falls Lyle was using the principle that things that we see are going on today can be used as examples for what went on in the past okay Lyle believed the world wasn't shaped in a few days or even years but by slow change over millions and billions of years this directly contradicted the much shorter time biblical Scholars said the world had been in existence Lyle realized that dramatic geological change was going on in front of his eyes at Niagara Falls if he could measure it he might be able to calculate the Falls age Lion's technique was brilliantly simple he noticed below the Falls was a great Gorge which locals said was steadily increasing in length as the water wore away the ledge of the falls The Falls they said were moving slowly Upstream head to the base of the falls and you can see why The Cliff face is being worn away The Falls are formed by a cliff capped with a ledge of the same hard dollar stone rock created as we've seen by sea water beneath the tough Dola Stone cap is a layer of much softer rock called shale as the water crashes over the Galla Stone it erodes out these soft shales that are underlying the dollar Stone and the blocks can fall down from the face on the right then you can see these massive blocks of dollar stone that have fallen down at the bottom of the waterfall each time the dollar Stone ledge collapses The Falls move further Upstream Lyle believed this process had been going on for thousands of years and was still continuing [Music] it had begun as the Lakes were first formed when water began wearing away the hard dollar Stone ledge of the falls to discover the age of the falls all Charles Lyle needed was some simple math he realized that the Falls had started at the Niagara escarpment which is about 35 000 feet from here so if the falls receded at one foot per year and receded 35 000 feet that would give an age for their present position of 35 000 years Lyle's calculation was based on simple measurements but wrong guesswork he thought the Falls were receding by one foot a year but today we have much better records to go on plaque commemorates cable Rock which is where the Falls were in the beginning of the 19th century since that time they've receded about 600 feet to my right so in the last 200 years The Falls have steadily retreated at a rate of not one foot but an astonishing three feet a year so instead of Lyle's calculation of 35 000 years old the Niagara Falls were a third of that figure just 12 000 years old a mere blink of an eye in Earth's 4.5 billion year history in the search to find what created the Great Lakes scientists now had a crucial clue the age of one of their key features born at the same time the Falls is the Overflow for all the upper Lakes into Lake Ontario and the sea so if the Falls have only been around for 12 000 years then it means the Lakes themselves must also be incredibly Young now that scientists had worked out when the Lakes were created the next question was how what immense Force could have created not one but five huge Lakes a force so powerful it must have left a trail of incriminating evidence across the region [Music] geologist John Menzies scans the landscape to track the mysterious force that created the Great Lakes and he spotted something unusual strange teardrop shaped Hills one after another called drumlins some are small fat and streamlined some are extremely elongated this one is about almost a mile in length 150 feet high and about 200 feet across this is the evidence that John Menzies has been looking for there are many Drummond fields in North America but this one is a particularly large field has anywhere between 60 and 80 000 so it is truly an enormous German field foreign points in the same direction North to where an immense Force came from this tells Menzies they were all created by the same powerful object but what was it the answer lies four thousand miles away high in the Swiss Alps here the culprit is plain to see snow and ice Switzerland is home to some of Europe's largest glaciers they're giant rivers of ice that flow down mountain valleys glaciologist Dr Andreas bowder studies how glaciers can transform the landscape what he discovers here could also point to how the Great Lakes were made we measured the movement of the ice this reflector reflects the laser signal coming from a theater light giving us the position of this stake and then we can calculate the movement my colleagues down here are drilling the poles down to the base of the glacier to install instruments to understand how the glacier is changing here foreign er's measurements reveal this Glacier moves over 10 feet every month here a seemingly stationary Glacier is shown moving down the mountain recorded by time lapse photography over a year find out what's driving it louder climbs high up the glacier this Glacier is thousands of years old and almost a mile thick in some places ice that's a mile thick weighs a colossal 3.8 billion tons per square mile that's the weight of 59 000 fully laden super tankers and it's this immense weight that makes the glacier such a force to be reckoned with its weight is slowly pushing the glacier down the valley Gathering anything in its path collecting rocks and debris [Music] the Rocks act like the blades of a giant bulldozer scouring the ground digging up yet more and more rock and soil but when the temperatures rise the glacier melts retreating up the valley and leaving rocks and debris behind in huge piles this is how the teardrop shaped drumlands back in North America were formed they were bulldozed landscaped by a powerful glacier a glacier that may also have gouged out the Great Lakes the evidence is coming together Niagara Falls dated just 12 000 years old this suggests the Lakes themselves are very young the presence of thousands of drumlands pointing to ice that carved out the Great Lakes Vincent case but there's one problem the Great Lakes cover an area five times the size of Switzerland no glacier that size has ever been known to exist geologists were on the hunt for something even more powerful that could have created such huge destruction a kind of prehistoric monster roaming over North America foreign ists are scouring the landscape searching for evidence of a massive Force one that was capable of gouging out 12 trillion tons of solid rock enough to create the Great Lakes of North America it would be a body of ice so large that it would break every record defy all logic geologist John Menzies hunts for evidence of this prehistoric monster just south of Niagara Falls this whole area was covered by the ice with a tremendous turn of sediment and water between the ice and this bedrock and as a sediment moved across which produced these superb striations and parallel scratches and marks and there's another clue giant Boulders of hard crystalline rock called granite these hard massive rocks sit in a flat Sandy landscape they shouldn't be here [Music] this is what we refer to as an erratic Boulder it's Granite it weighs some 80 to 100 tons it would actually be frozen up into the base of the ice and then move kind of like a conveyor belt along on the base of the ice down to this part of Southern Ontario some four or 500 miles to the south from the Canadian Shield where with ice Retreat and the eventual melting of the ice this Boulder's been left to sit as we see it today erratic Boulders moved hundreds of miles from northern Canada scratches on the Bedrock and Drumlin Hills the evidence is mounting there was ice here once lots of ice geologists mapped these glacial features together and an extraordinary picture emerges not of a glacier but of a vast ice sheet one mile thick and over 2 000 miles long stretched all the way from the North Pole as far south as Chicago and New York leaving a trail of Destruction in its path here was a force powerful enough to create the Great Lakes but even this vast sheet of ice couldn't have gouged out basins that are over 1300 feet deep it seemed the culprit wasn't working alone [Music] at Scarborough Bluffs just 100 feet from Lake Ontario John Menzies has spotted an unusual deposit at The Cliff face layers of rock provide him with a kind of geological time machine the deeper he looks the further back in time he goes you could see that this is a journey through the last sixty thousand years of geological history in this part of Canada this lower formation is 65 000 to about 40 000 years ago the next layer is between 25 000 and 10 000 years ago Menzies focuses on the dark layers sandwiched between the light ones what we have here is a sequence of sediments which illustrate the movements of the ice front back and forward across this part of Canada these dark layers Mark the exact end of each Ice Age formed of organic material when plants grew again at warmer temperatures here John Menzies has proof that ice ages return twice to this spot during their cycles of Destruction in fact across the Great Lakes region geologists have found evidence of up to 10 separate enormous ice sheets as each new ice sheet advanced IT carved the Great Lake basins deeper and wider eventually forming the largest lake system in the world but the ice left vast areas unscathed it suggests there was some other Force at play something in the Lake's ancient past that set them apart from the surrounding landscape making them particularly vulnerable to the ice sheets attack Menzies decided to dig deeper down to the landscape that existed before the ice ages going back 2.5 million years he found evidence of a chain of ancient Rivers flowing across what's now the Great Lakes region the pre-glacial Topography of the Great Lakes Basin mirrors the existing Great Lake system and Great Lakes basins that we see today the ancient River's pattern and flow exactly mirrored the shape and position of today's Lakes it's no coincidence these rivers formed valleys that affected the way the ice sheets moved as the lay sheep Advanced to the South it would tend to follow the three glacial rivers and so you get these really fast moving zones of ice which create a tremendous amount of erosion in these pre-existing depressions the ancient river valleys funneled the ice sheets into fast-moving super ice flows Menzies believes the coarse sediments the rivers Left Behind dramatically accelerated the ice sheets flow this sediment acts as a kind of lubricant a bit like ball bearings underneath the ice it would actually speed it up quite quite appreciably these fast streams of super ice were even more destructive to the landscape [Music] case is coming together drumlins clustered across the landscape testify to the vast ice sheets brutal power dark layers of rock reveal the ice Was a Serial attacker while a network of ancient Rivers left some areas more vulnerable to these attacks turning slow lumbering ice into destructive fast-moving super ice these gouged out all the loose Rock and sediment down to the hard dollar Stone layer the rocky Lake floor the result the basins of the Great Lakes closed for three of the five lakes inside the rocky basin but not for the other two Lakes Ontario and Superior are Outsiders the theory doesn't fit there's simply too deep in an attempt to find out why a daring underwater Expedition would investigate Lake Superior the largest deepest greatest Lake of all [Music] The Hunt is on to discover what form the Great Lakes of North America geologists have found compelling evidence that the Central Lakes lie in a vast rock-lined Basin laid down by an ancient Lagoon gouged out by giant ice sheets but when it comes to Lake Superior the theory doesn't fit the greatest of all the Lakes at over 1300 feet deep it could almost submerge the Empire State Building and it lies outside the rocky basin Lake Superior isn't just deeper than the other Lakes its floor is the lowest place on the North American continent over half of this Mighty lake lies below sea level the question is why Canadian geologist Henry Halls was convinced the explanation could be found at the very bottom of the lake the opportunity came up to study a very remote part of the lake it's almost in the geometrical Center and it's called Superior Shoal and people didn't know what the Rocks were there and they didn't know why it was there in the summer of 1987 Halls LED an expedition to the Lake's dark unexplored depths we went down it took us about 15 minutes to go down and it gets completely black apart from the searchlights of the submersible and when we reached the bottom the the pilot he said this is very strange he said I'm getting Echo sounds coming back he said more or less from all directions does look almost vertical it is where to go it's more than right more than vertigo we've heard in fact it's hanging over us deep in the center of the lake on the border between Canada and America Halls came across a strange rock formation the pilot said it seems that we're in some sort of a chimney or something like this he said I'm not sure what it is halls and his submersible were in a deep Canyon 1200 feet below the surface intrigued he took an even closer look at the canyon walls and as we climbed I started to see striations like this they were actual glacial strei on the sides of what presumably was a canyon We are continuing to move up this vertical phase Halls had uncovered a vast Canyon lined with striations or scratches from the glacier that had carved out the lake but it was the type of rock that was the clue to Lake superior's exceptional depth he used the sub's robotic arms to take Rock samples from the canyon walls the canyon was made of dark basalt rocks discovery of this rock took the investigation in a surprising Direction Basalt could only have been formed by intense volcanic activity Basalt is created when hot magma deep within the Earth Wells up to the surface a billion years ago immense forces pulled the Earth's crust apart here forming a rift valley hot magma seeped up through the cracks in the thin crust as it cooled it lined the valley with a layer of hard basil then over millions of years the rift was filled with soft sedimentary rocks it was a tremendous thickness of infill in that Lake lying above those volcanic rocks and all of this is relatively soft many geologists believe the exact same volcanic action accounts for the formation of the fifth and final Lake thank you Ontario on average is the second deepest lake a separate Rift Valley appeared here much later than the one under Lake Superior the volcanic split in the landscape stretched as far as the ocean creating Lake Ontario and the Saint Lawrence Seaway millions of years later the mile high ice sheet easily carved out the weakened Rift Valley structures under Lake Superior and Lake Ontario [Music] extraordinary story of how the Great Lakes were made is almost complete ice sheets repeatedly carved out soft rock down to the hard basins of the Central Lakes and to the north ice attacked billion-year-old rift valleys to make the deepest lake Lake Superior the same action was repeated at Lake Ontario when the ice melted for the last time fourteen thousand years ago it filled the lakes with fresh water it sounds straightforward but there's a problem there's so much ice the Great Lakes should be many times bigger than they are today just when geologists thought they'd solve the mystery of how the Lakes were formed a new puzzle emergence where did all the water go [Music] geologist John Menzies is investigating exactly what happened at the end of the last ice age when a vast ice sheet one mile thick and stretching to the North Pole started to melt believes it was so large it should have created far bigger Lakes than the ones we see today he's looking for evidence of one of these prehistoric Lakes as the ice sheet melted a vast freshwater lake appeared that geologists call Iroquois then later as Lake Iroquois dried up it left beaches which can still be seen today Menzies believes he can detect these ancient beaches in the gently sloping landscape surrounding Lake Ontario as Menzies drives uphill away from the present day Lake he's traveling back in time across Lake Iroquois ancient Shores we're crossing one Shoreline after another the reason we know the shorelines is that they contain large zones of sand beach Sands and beach bars and spits the oldest big about 12 000 years ago they lock bottom Shoreline being about six thousand years ago getting to the top of the hill 400 feet above the level of today's Lake Ontario Menzies is standing on the ancient shore of the original Lake the present-day Lake ontarius off there in the mist and we're sitting about 400 feet Plus on this beach which is was formed maybe ten thousand eleven thousand years ago and then the ultimate oldest Beach is about 12 000 years ago and beaches now buried under the surrounding landscape are evidence of a colossal freshwater lake we're looking at a vast amount of water when you think of the water it stretched from here to beyond the present Lake away in the New York State Beyond in the Rochester so it's a huge enormous Inland Sea despite their size the Great Lakes today are just a small fraction of these vast prehistoric Lakes the water has vanished geologists want to know how they empty 50 miles east of Toronto at India River Canyon Menzies picks up the trail of the missing water torrents okay what we have here is an enormous subglacial pothole formed by subglacial melt water exiting underneath the ice sheet typically formed with a large rollerball which rolls around in these really torrential vortices the Mel water is chock full of Boulders and sediments and in this instance it's drilled itself the whole way through these potholes are evidence of a catastrophic flood of huge volumes of water moving at high speed this flood needed an Escape Route and Menzies believes he's found the place this would be an enormous taunt possibly at least a couple of miles across and could easily have been two three four hundred feet deep moving at an incredible velocity nearby a steep Gorge yet more evidence of the flood waters terrifying power the stream that remains today couldn't have cut such a huge amount of Rock and what we've got left is what we call a misfit stream which is the fairly small Indian River and this if you like is the remnant of that enormous torrential flood [Music] geologists believe as the ice sheet retreated it uncovered this ancient India River Outlet allowing vast amounts of melt water to tear down towards the sea finally twelve thousand years ago the ice retreated freeing the Saint Lawrence Seaway and allowing the lakes to settle into their present flow the story of the Great Lakes is coming together ice sheets repeatedly ground out deep basins digging out ancient weaknesses in the Earth's crust prehistoric beaches show that when the final ice sheep melted the water flooded the Basin to create vast super Lakes like Iroquois and as the ice finally retreated twelve thousand years ago the excess water drained away to leave the Great Lakes we know today but even now as we know how the Great Lakes were formed they are still changing and scientists predict one day the Lakes might disappear forever [Music] the Great Lakes evolved over a billion years today they're a vital link between the cities bordering the lakes and the sea they provide over 20 million people with drinking water and irrigate crops throughout the Midwest but in the past few years fears have grown about the Great Lakes future water levels are falling people who have worked the lakes for years believe they can already see a change we noticed a drastic decrease in water levels right after the September long weekend where the water in a week dropped a foot and throughout the remaining of the Fall it went down about another two feet and you can notice that by the Pinker or the brighter colored Rock versus The Rock that's typically exposed to the weather than what we saw there was a clear example of how the water has dropped a good three to four feet many have been quick to blame global warming for the fall and lake levels but geologists believe there is another Force at work the ice sheet that cut out the Lakes was so heavy it pushed down on the Earth's crust now the ice sheet has gone the crust is bouncing back incredibly nine thousand years since the end of the last ice age the ground is still lifting in the north where the ice was thickest land has risen by as much as 1800 feet since the ice melted away Toronto's famous CN Tower appears to be getting higher as the crust bounces back the land it's built on beside Lake Ontario Rises nearly an inch each year the ciento is part of the landmass here so in fact it's rising out of the land in fact the whole land surface is rising slowly Lake Nipissing today is a small body of water to the north of Lake Huron 12 000 years ago when the ice began to melt and Lake Nipissing first formed it lay at sea level singing an enormous Lake there again as the land rebound so the lake eventually drained out and the land Rose slowly so the land is now 400 450 feet above sea level geologists call this crustal rebound and it dramatically affects the delicate balance of the network of small rivers that feed the Lakes this is an interesting example if we if we think of trying to trying to explain Crystal rebound and we look at this River as it flows out into the lake at the moment if we have crossed a rebound the land comes back up this River in fact will cease flowing out into this Lake it's this crustal rebound that's partly responsible for the Fallen level of the Lakes and as the Lakes empty their weight decreases allowing the crust to bounce up even faster lake levels will fall so the amount of water in the Basin will in fact become less and the effect of that will increase the rate of Crystal rebound the land will come up even faster than it's already doing and continues to do as the crust Rises the lake slowly empty but in a few thousand years the Lakes will face another even more dramatic change one of the exciting things about geology these days is not only looking at the past but just looking at the future in other words something the ability to start to predict what might happen in the next several millenniums and the future is here at Niagara Falls at least in geological terms every year the Falls are retreating three feet upriver only 12 miles and 21 000 years to go before they're back into Lake Erie when that happens Everything Will Change and fast if the Falls eroded all the way back to Lake Erie which would take some thousands of years the levels of all the upper Great Lakes here on Superior and Michigan would adjust to the lowered level of Lake Erie by dropping as well the land between the falls and the lakes acts as a block it's the Niagara escarpment topped with hard dollar stone rock when the Falls Cuts its way through this rock the water levels in all the lakes to the West would drop by a staggering 180 feet the height of Niagara Falls almost all of Lake Erie would drain away one day the Lakes may disappear altogether but geologists also predict a new cycle of ice ages will Begin Again so an Ice Age We Begin and the side stage would then cover we would expect at least 30 percent of the land surface as it did in the previous ice ages and when the ice Returns the lake basins will be cut even deeper before filling again with water the largest freshwater lake system in the world has had an extraordinary past a basalt-lined canyon discovered at the bottom of Lake Superior shows that two great Rifts opened up below Lake's Superior and Ontario fossilized sea sponges are evidence of an ancient Briny sea that laid down the rocky bowl that holds Lake's Michigan Erie and Huron thousands of Drumlin Hills are proof that vast ice sheets repeatedly scoured out the lake basins born just 12 000 years ago the Great Lakes as we know them today are just a transient feature they've only existed for the geological blink of an eye but their story hasn't ended yet the Great Lakes are changing and evolving an endless process like the Earth itself [Music]

Channel: HISTORY

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Keywords: history, history channel, history shows, history channel shows, the history channel, documentary history channel, history documentary, documentary, history channel full episodes, documentaries, history channel documentaries, How the Earth Was Made, How the Earth Was Made streaming, How the Earth Was Made full episodes, How the Earth Was Made scenes, How the Earth Was Made clips, marathon, nature, KILLER Waves & Earth-Made MONSTERS, killer waves, earth-made monsters, monsteres, waves

Id: -mwoMdLmKsA

Length: 179min 14sec (10754 seconds)

Published: Sun Jul 23 2023