Angry Earth

we take for granted the earth beneath our feet but is it as safe as you might think around the world millions live under the threat of an earthquake disaster killing thousands and destroying entire cities in seconds earthquakes don't feel people buildings do naked science asks the question what can science tell us about the fury of our angry earth in the last century more than 1 million people died in earthquakes over the next century it's fear that number could increase tenfold earthquakes really pose little direct danger to the human body people can't be shaken to death in a quake the real hazard is when an earthquake strikes in a heavily populated urban area can science do anything to protect us might we one day be able to predict the quakes or are we at the mercy of the awesome power of nature our quest begins by going back to basics looking at what triggers an earthquake in the first place earthquakes are the sudden explosive release of enormous pressures that build up within the crust of the planet to understand how such pressures are caused just look deep into the earth it's crust is formed from huge Oceanic and continental blocks called tectonic plates and they rest on the mantle that lies below the plates are constantly but very slowly shifting they move some two inches a year driven by movements in the mantle below and building up vast pressures along the plate margins meet dr. Lucy Jones scientist in charge of the Southern California earthquake hazards team there are 12 major plates that we look at on the surface of the earth and any place where they come together is going to be a place we have a concentration of earthquakes over time the edges where tectonic plates grind past each other to form and break creating cracks known as faults eventually pressures reach a critical point when rocks on each side of the fault slip and snap into a new position i way to understand this is actually snapping your fingers you snap your fingers you put a surface together you have friction that keeps it sliding you push hard enough you overcome the friction and we release a wave that makes the ground vibrate and the bigger the surface is the more energy you've got in the bigger the earthquake you have the spot on the Earth's surface above where the snap happens is called the epicenter once triggered the earthquake is stopping for no one it can travel along the entire fault line it's a bit like tearing a napkin earthquakes have to happen over a surface they don't happen at the epicenter but they begin at the epicenter and then you have a rupture that moves down the fall now if I pull like this it's too strong and it won't break I put a crack in it and then once I've got it started I've got a rupture that will move down the napkin once started an earthquake just keeps on rolling releasing all that pressure between the plates the longer the fault the bigger the earthquake to have a really devastating earthquake you need to have a very large event very near to a very large number of people as the global population grows ever faster more and more people are living in cities the population of Los Angeles has tripled in the last 60 years such growth leads to what scientists term the megacity defined as having a population in excess of eight million people in the world today there are almost 15 mega cities some such as Los Angeles Tokyo and Mexico City are under direct threat from an earthquake close to 100 million city dwellers face the constant danger of an earthquake disaster and still more people pour in every year as the building's get higher and higher so does the danger earthquakes don't feel people buildings do and we have many cities of the world that are located near some of these big faults and proximity can be ninety percent of the game in earthquakes when you're right on top of the earthquake you see a lot more shaking than even a small distance away so having the fault in the city is the recipe for real disaster if a large earthquake was to hit any of these megacities the destruction could be catastrophic potentially claiming millions of lives and major cities have been hit by large earthquakes 19:06 in San Francisco or 1923 in Tokyo we can see that the biggest earthquakes do an overwhelming level of damage and we have many many more people living in both those cities right now than we did a hundred years ago if financial centers such as these were hit by a large quake today the entire global economy would be shaken a natural disaster leading to an economic downward spiral that could last for months or years so it's more critical than ever that science seeks a reliable way of predicting where and when the next big strike will occur one region has had more large earthquakes than anywhere else the Pacific Rim circles the entire Pacific tectonic plate from the South China Sea across to California and down to South America volcanoes along its length give it the nickname the Ring of Fire the largest earthquake ever recorded happened here in 1960 the awesome magnitude 9.5 quake shook southern Chile triggering enormous landslides and killing over 2,000 people how powerful is a quake of that size the answer is terrifying the magnitude of an earthquake is measured using a system called the Richter scale which ranges from one to ten with each higher number the power increases tenfold a magnitude 5.5 quake for instance is more powerful than a Hiroshima sized nuclear bomb yet an earthquake measuring nine point five on the Richter scale is incredibly a hundred thousand times more powerful than the 5.5 an earthquake that big is more than a million times as powerful as the Hiroshima blast of 1945 a 9.5 striking a megacity could bring total destruction upping the ante for scientists looking to predict the next big one but before scientists have any chance of forecasting the future they need to analyze the disasters of the past naked science next explores the planets greatest ever earthquakes naked science is examining the awesome power of earthquakes so far we have learned that if a large earthquake was to hit one of the world's mega cities the human cost would be overwhelming with the potential to claim millions of lives earthquakes through history have shown just how great the death toll can be America's deadliest earthquake occurred in 1906 it's April 18th and San Francisco is hit by an estimated magnitude 8.3 quake the quake itself is devastating but it's the resulting firestorm lasting for days that totally destroys the city and kills more than 3,000 people but the highest-ever body count has come from earthquakes in China one 16th century earthquake reputedly killed almost 850,000 people and more recently the great Tong Shan earthquake of 1976 measured a magnitude eight on the Richter scale it killed three-quarters of a million as many as live in the u.s. cities of Miami and st. Louis combined earthquakes take their toll in other ways to livelihoods are destroyed and economies ruined the costly astir 'the quake of all time happened in Japan in 1995 early one January morning the city of Kobe is struck by a 6.9 earthquake in less than 30 seconds at least 120,000 buildings are destroyed more than 5,000 are killed and around 300,000 people left homeless the Japanese city is rocked for just 20 seconds yet the quake causes 200 billion dollars worth of property damage the Cobian tung-shun earthquakes were so costly in human and financial terms because they hit heavily populated industrialized cities the most powerful earthquake ever occurred off the coast of Chile in contrast it claimed 2,000 lives and did just a half a billion dollars worth of damage the 1960 quake measured a stunning 9.5 on the Richter scale but the United States has a history of massive earthquakes - the most powerful ever recorded hitting the US was also in a relatively unpopulated area in 1964 a magnitude nine point - struck Alaska near the city of Anchorage it was second in size to Chile's world-record quake in America the average strong earthquake in the past century lasts just 30 seconds but the Alaska earthquake traveling along a fault line over 2,000 miles long lasts 14 times longer than that for more than 400 seconds it literally shook the whole area to the ground one town was totally obliterated by the quake but its doom had as much to do with the type of land it was built on as with the power of a quake itself situated at the base of a glacier the small Alaskan waterfront town of Valdez was a disaster waiting to happen built on saturated fine-grained soils it had no chance of survival the soft ground exaggerated the earthquakes movements leaving Valdez a broken mass of rubble and destruction two survivors of that disaster mother and daughter Gloria day in Linda Guthrie will never forget how their world tour apart the people there were fishermen some old pioneers had false front buildings and wooden sidewalks and it was a close-knit little community that afternoon the steamship China docks on the main pier the ship is carrying the first supplies of fresh fruit and goods of the year there was a lot of entertainment in old town so so it was a big thing when the ship came in all the kids go down to the dock when the ship comes in because the cook on the ship makes candy and makes cookies and things like that form at 5:30 as the ship is tying up the town is shaken by a tremor normally when we have a tremor it'll be 15 seconds a minute at the most and this one just kept going on and on and on it keeps going on and on and on for an astonishing seven minutes I could hear the male pulling out of the boards in the house so I got scared and started to run down the stairways the movement bounced me off the walls going down the stair the pickup was sitting in front of the house and it was rolling back and forth two or three feet I remember thinking that we were sinking or thinking it was the end of the world the town stands on unstable sand and gravel when the huge quake hits the shock waves shake the unconsolidated ground so violently that virtually the entire town collapses I was scared to death I didn't think it was going to stop and I thought it was the end of the world that land at the waterfront opened up like a submarine landslide you could see the Jena from our house up in the air within seconds the pier collapses and the sea engulfs the dock swallowing everything the entire waterfront is pulled into the sea the longshoremen and people that were down there on the dock just disappeared then the local oil tanks rupture causing a fast spreading fire that destroys most buildings left standing from the quake entire families perish soon afterwards the town is deemed geologically unsafe nothing will be built here again the site is abandoned forever there was a sense of awe we knew that something had happened that was catastrophic the survivors would never return but why was old valdez completely obliterated by the earthquake when a large earthquake shakes saturated land the intense shaking can create a phenomenon called liquefaction liquefaction happens where the soil is lightly packed and wet as the ground shakes the saturated soil starts to behave like a liquid and so acts like quicksand old valdez was built on silty water drenched soil it never had a chance of withstanding seven minutes of violent earthquake shaking when you shake the sand it's just like if you shook a canister of flour you'd see the level sink down old Valdez literally sank into the ground the new town of Valdez is built four miles away little remains of the original settlement apart from a memorial to the 32 men women and children who lost their lives terrifyingly there are major cities also built on unstable soil parts of Los Angeles and San Francisco will face serious liquefaction hazards if a big earthquake strikes and both cities lie on areas loaded with active faults including the San Andreas Fault where the Pacific and North American plates grind past each other it's not a crack it's not a hole it's rather the place where the two big plates come together and move past each other you can see it through the landscape as a straight Valley the entire system is more than 800 miles long it runs from 270 miles north of San Francisco and ends about 200 miles south of Los Angeles the two main plates of the San Andreas Fault move in opposite directions to each other here in California Los Angeles is moving toward San Francisco at about the same rate that most people's fingernails grow about one and a half to two inches a year the pressure built up by the moving plates is released by thousands of small tremors every year larger earthquakes are rare but when they do happen they are devastating San Francisco is very near the San Andreas and these big strike-slip faults cause much more intense shaking very near The Fault in San Francisco's going to get the full brunt of that the last major quake to hit San Francisco struck on October 17th 1989 that Tuesday many residents are settling down to watch the San Francisco Giants take on the Oakland A's in the third game of the World Series while many are glued to their TV sets the quake strikes for 15 seconds a magnitude seven point one quake rocks the San Francisco area Wow the Bay Bridge is damaged and part of the nimitz freeway collapses the quake injures over three and a half thousand people and causes massive damage to 20,000 buildings all over the Bay Area despite all this destruction fatalities are relatively modest 63 people lose their lives city officials were stunned that so many apparently earthquake-proof structures had collapsed the city of San Francisco had after all taken wide-ranging measures trying to insure their buildings were earthquake proof yet on a single block one building had collapsed while the one beside it had escaped untouched it made little sense when we return naked science asks why do some buildings collapse while others remain unscathed can we ever truly understand why and how earthquakes happen will we ever be able to predict them and even if that proves possible how will we protect ourselves from their devastating effects in the United States and Japan major cities under threat carry out extensive construction programs to try and make their buildings earthquake proof but even with these precautions in place when an earthquake strikes many buildings still collapse in the earthquake that shook Kobe Japan in 1995 more than 120,000 buildings were damaged but not all the structures fell down so why do some buildings collapse while others remain untouched some buildings collapse because of the effects of earthquakes shock frequency where mere vibrations can bring down a multi-story building to illustrate how such a thing can happen dr. Lucy Jones uses the music frequencies created by a cello false produce earthquakes for much the same reason that this string will produce a note when I push my bow on it we can actually use the instrument and the music we make as an analogy for earthquakes when two huge fault plates rub together drawn across a string the friction produces vibrations across a range of frequencies in the case of earthquakes the frequency produced depends on the length of the fault just as the note produced on the instrument depends on the length of the string depending on their size and construction every building resonates with a different frequency when the earthquake frequency matches a building's frequency the vibrations can cause it to shake even more violently than its neighbor and eventually collapse across the u.s. many cities have tried to build structures that won't fall down Los Angeles has put enormous effort into making the entire city as earthquake proof as possible but when California's last major quake rocked Los Angeles once again many buildings were shaken to the ground January 17 1994 4:30 in the morning the residents of the Greater Los Angeles area received the ultimate wake-up call a magnitude 6.7 earthquake the city's emergency services race out to a city now disfigured with mangled ruins they need help from anyone who has urban search and rescue training one man with such training is captain Wayne Ivers of the Los Angeles Fire Department he was one of the first to the disaster zone it was very surreal there were broken gas maids on fire and a pretty much looked like a war zone one of the many buildings to crumble in the quake is a multi-story parking lot in Northridge the huge structure larger than two football fields has collapsed the only man there street-cleaner salvador pena is trapped beneath the 20 tons of rubble the three-story parking lot has fallen on top of him pinning him inside his vehicle wayne i Burres was the senior firefighter at the scene i thought i don't know how we're going to do this the task appears overwhelming but he has to come up with a plan quickly first they have to get into the flattened building there was some breaks in the concrete we have the wide nose with jackhammers Ivers and the team begin to strategically dismantle the many layers of concrete they have to work fast Ivor's knows that every second counts the rescue team has to crawl through the rubble in spaces just inches high while the men are trying to locate Salvador aftershocks threaten to bring everything down on top of them anytime you're working in a rubble you're always concerned about a secondary collapse killing you and your teammates Ivor's team carries on knowing that a further collapse could happen at any moment at last they find the car the first thing is to check the victim is breathing Salvador's legs and right arm are trapped under the dashboard he is alive but losing strength when I could see mr. Payne I couldn't believe he was alive Ivers has to constantly check that the area is safe enough for his team to continue working the vehicles gas tank is ruptured it's leaking fuel and is in danger of going up in flames the fuel is cleared but it's vital for Salvador to be pulled to safety as soon as possible to massive concrete slabs have crushed the front and back of the car the rescuers are in constant fear of the massive aftershocks we had aftershocks in excess of five on the Richter scale those really got your attention outside paramedics are ready to whisk the injured man to the hospital first Salvador has to be extracted from the wreck of his car powerful airbags raise the crushing concrete by a few vital inches then the specialist hydraulic cutters and other jaws of life get to work cutting the vehicle apart in about york on earth again Ivor's major worry is that in the process of trying to rescue salvador he might actually kill him he knows that relieving the weight off Salvador's compressed legs could cause crush syndrome a condition that can lead to shock kidney failure and death salvadore is finally pulled free his thighs have been crushed to just two inches in width but he survives and doctors are able to save Salvador's legs even more amazingly he doesn't have a broken bone in his body I think the thing that drives us into situations like that is the overwhelming desire to help and to make a difference for somebody that can't help themselves many other buildings collapsed in the earthquake and many other victims were less fortunate than Salvador 57 people died and 9,000 were seriously injured and with the constant movement of tectonic plates it's only a matter of time before another strong quake hits a major city so what can we do to prepare ourselves for when the next big one hits since the Los Angeles quake of 94 building codes have been tightened responses to a massive mega City earthquake are being improved new facilities are being built to Train rescuers at College Station Texas a state-of-the-art mini city has been specially designed disaster City is the home of the Emergency Operations training center this training facility has been designed to replicate exactly what urban search-and-rescue teams will encounter when they enter a disaster zone established in the year 2000 the $6,000,000 site covers 52 acres every year it trains hundreds of rescue specialists from all over the world the base also has an international rescue team on constant standby capable of preparing equipment within minutes and flying to any part of the world to help in search-and-rescue efforts the terrible instantly destructive nature of earthquakes is clear but earthquakes also pose other less immediately obvious dangers to learn of these naked science meets professor Costas Sinha lacus in California what we discover from him is alarming earthquakes are catalysts for another deadly force the overwhelming power of tsunami naked science has learned that another one of nature's most deadly natural phenomena the tsunami can be triggered by the awesome power of an earthquake under the sea the antics of a performing killer whale are used as an analogy for how this can happen by tsunami expert professor Costas Sinha lacus when we see a killer wave jumping out of the water falling down this huge circular wave this is very similar to what happens when an earthquake rips the seafloor that circular wave is created by the massive impact of Shamu the five-ton killer whale landing flat out on the surface of the pool the massive jolt displaces a huge volume of water that has to go somewhere similarly when an earthquake jolts the Earth's crust upwards under the seabed the same sort of circular wave is formed in the ocean waters above like throwing a giant boulder into a pond the water forms a wave that radiates out in all directions the difference is one of scale and power and speed in the deep ocean tsunami will move incredibly fast can reach 500 miles per hour tsunami lose hardly any of their power as they travel through the deep waters of the open ocean but approaching the shallower water close to land the huge waves slow down and increase in height when they reach land even after traversing an ocean the result can be catastrophic tsunamis are a very underrated hazard in the past half century tsunamis have killed more people in the United States than all the earthquakes combined people can be sitting on a beach totally unsuspecting then suddenly tsunami will come in and everyone who's sitting on the beach will get completely destroyed tsunami happened in all the world's oceans but are most common in the Pacific around the Ring of Fire small tsunami are common but waves of 100 feet or more have been recorded on rare occasions the largest earthquake ever recorded in 1960 in Chile sent an enormous tsunami across the Pacific Ocean the wave traveled halfway around the world in just 22 hours engulfing the coast of Japan the United States too has suffered the terrifying effects of the tsunami the last major one to hit the US mainland arrived in 1964 the huge earthquake that rattled Alaska generated a series of giant tsunami the waves climbed to heights of more than 220 feet as high as a 31 storey building moving at high speed they reached as far south as Crescent City in California devastating twenty-nine city blocks and killing 11 people the effects of the wave were seen as far away as South Africa but in 1998 another tsunami totally changed how scientists study these devastating waves up until 1998 we thought that all giant tsunamis who were generated by bigger fish like the 1964 Alaska earthquake but in 1998 as relatively moderate earthquake in Papua New Guinea sensed our entire perspective July 17th 1998 a magnitude 7 quake rocks Papua New Guinea off the northeast coast of Australia about 12,000 people inhabit the villages up and down the coastline living close to the water line in traditional wooden houses within minutes of the earthquake a roaring noise is heard people on the beach see the ocean dramatically received a mysterious dark line appears on the horizon as the wave approaches the villagers begin to run away but too late the 50-foot wave sweeps them all away destroying the villages more than 2,000 people die what astonishes the scientists is the fact that a relatively modest quake could cause such a devastating wave scientists had previously thought that tsunami could only be caused by huge earthquakes directly under the seabed here we have an earthquake the likes of which we get somewhere around the world once a week and it generates a huge way and then the question is why at Papua New Guinea the earthquake epicenter was on land not underwater but the shock waves rippled offshore setting off a massive underwater landslide sediment and rock spewed across the ocean floor displacing vast quantities of water and almost certainly creating the wave but could this happen elsewhere Papua New Guinea made scientists take a fresh look at coastlines around the world seeking similar offshore formations their research led to a chilling discovery they identified many places off California very similar to the Papua New Guinea coastline of San Diego of Los Angeles of Santa Barbara in Monterey Bay just a few miles off the coast of California lies a multitude of similar unstable underwater canyons scientists are worried that small quakes along the San Andreas Fault could cause any of these underwater canyons to collapse and create a major tsunami how likely is it that a tsunami will strike here the dangerous for genomic California our very real I'm afraid that within my lifetime we're going to experience a tsunami in California it is not clear how big this tsunami will be but there is a clear danger a network of detection devices is in place but their warnings may come too late an earthquake triggered tsunami could reach the coast in minutes only predicting the earthquake itself could offer any hope for this coastline how possible is that predicting earthquakes is very hard predicting tsunamis is even harder if we had reliable ways to predict earthquakes then we could predict when it tsunami strikes and this would give us extra warning time to evacuate more people of the beach and then we would save many more lives an earthquake generated tsunami could happen at any time science must develop techniques that will predict such an event naked Sciences next stop is UCLA where this man is working on a formula that has the scientific world talking could he have found the answer to how earthquakes may be predicted naked science is looking at the science of earthquakes so far we know where and why earthquakes happen and that more than 100 million people in the world's mega cities live in constant danger of a catastrophic quake with accurate earthquake predictions cities could be evacuated and rescue services placed on high alert but understanding the seemingly random behavior of earthquakes remains an elusive goal humans have tried to foresee earthquakes for thousands of years in the ancient world animals and fish were watched for any change in behavior that would give clues to a coming disaster but although some research suggests that animals may change their behavior before a major earthquake it is to say the least an unreliable method serious scientific study into prediction only began in the 1970s scientists back then investigated various methods of prediction some thought for a while they had cracked it they carried on with wild and wonderful theories but remained dogged by the inconsistency of their results nobody's had repeatable success some people have been lucky but nobody's been lucky twice until recently science seemed no closer to finding a reliable method the current technique relies on analyzing the past activity of known faults we can tell where they're most likely what magnitude were likely to have what the consequences of any of those earthquakes are experts are convinced that an earthquake will hit Los Angeles or Tokyo because they have done repeatedly in the past the problem is when and how big will it be most scientists still believe that earthquakes are impossible to predict but there could now be a major breakthrough one of the world's leading seismologists is challenging the accepted thinking and earthquake prediction professor vladimir Callas Barak is Russian and still speaks with the sounds of his native tongue he look at the symptoms of approaching l-square like doctor looking at the symptoms of disease he heads an international research team made up of experts in pattern recognition geosciences seismology and chaos theory from institutions around the world he spent over 20 years fine-tuning and honing his revolutionary technique his method is quite simple he's worked out a formula to predict earthquakes to get a result he feeds into the formula the number size and frequency of earth vibrations in a given area the result that the calculation comes up with gives the location and a ballpark date of the earthquake the formula is being continuously fine-tuned in the future he hopes to pinpoint the date of an earthquake to within weeks or even days but the theory is controversial I'm a scientist I always believe that knowledge is better than no knowledge and if we could do it I want to do it and I'd like to find ways in which we can use it there's been heated debate but at the moment the calles Barak theory is the only viable option that science can offer has he found the scientific Holy Grail so far he and his team have had very positive results in June 2003 his team predicted that an earthquake measuring magnitude 6.4 would strike central California within nine months six months later a 6.5 did strike San Simeon and then they predicted a magnitude seven in the hokkaido region of japan less than three months later and even larger quake struck the kelas Borup team had hit the earthquake prediction jackpot but was it no more than blind luck fellow seismologists suggests that kelas barack needs to make at least 10 accurate predictions before the results can be deemed scientifically reliable it's just a matter of time before we will know if his theory is right I do not know if dr. keyless Barack will prove correct I hope he's correct because if he's correct it means prediction is possible and I'd love that to be true but I don't know yet we have seen the terrible threats that earthquakes pose to human life the dangers to our mega cities we can't control earthquakes but science is at last attempting to predict their arrival success would offer real hope for the future you

Channel: Naked Science

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Keywords: naked, science, angry, earth, documentary, television, national, geographic, earthquakes, earthquake, protect, predict, devastating, quakes, seismic, activity, nature, world, disaster, apocalypse, biblical, event, killer, buildings, populations, mega, city, pressure, crust, oceanic, continental, tectonic, plates, plate, tectonics, mantle, shifting, faults, san, andreas, fault, line, stick, slip, behaviour, tremors, friction, wave, energy, focus, epicentre, america, francisco, los, angeles, tokyo, alaska, old, valdez, magnitude, tsunami, papua, new, guinea

Id: mq8lTZ83P_Y

Length: 50min 4sec (3004 seconds)

Published: Wed Jan 22 2014