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In Search Of.. S1xE07 - Earthquakes
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00:00In 1964, two crewmen aboard an Alaskan freighter captured on film the eruption of a giant earthquake.
00:08While taking shots of the dock below, it struck.
00:15As the earth trembled, the harbor was sucked dry.
00:21A chasm opened beside the ship.
00:26A huge tidal wave smashed in.
00:29Much of Alaska was shaken apart.
00:59Earthquakes are nature's most frightening events.
01:04For when the earth is at war with itself, there is no place to hide.
01:14This series presents information based in part on theory and conjecture.
01:20The producer's purpose is to suggest some possible explanations, but not necessarily the only ones, to the mysteries we will examine.
01:31Since man first walked this planet, earthquakes have inspired both terror and awe.
01:36Ancient Greeks believed that earthquakes were caused by the dead fighting among themselves.
01:42Japanese folklore tells us that earthquakes result from the movements of a great spider, which carries the earth on its back.
01:49Today, we accept more scientific explanations.
01:53Yet, giant tremors can still strike suddenly and without warning.
01:58On April 18th, 1906, an earthquake shattered San Francisco.
02:13It was caused by a huge rupture in the fault line that runs below the city.
02:18A Hollywood film recreated that disaster.
02:22A pioneer news cameraman recorded the aftermath of the earthquake.
02:32The quake and resulting fires destroyed 28,000 buildings.
02:37Over 150,000 people were left homeless.
02:41450 died.
02:43Slowly, the dazed city pulled itself together to begin the awesome task of rebuilding.
02:50Today, the legacy of 1906 still haunts this beautiful city.
02:55Like the restless clouds of a gathering storm, the earth itself is alive and ever-changing.
03:01Stirring deep inside are dynamic forces of immeasurable strength.
03:19Science has learned only recently that the earth's crust is divided into a dozen gigantic blocks or plates.
03:26Most of the world's earthquakes strike along the seams of these plates.
03:30Together, they form a huge mosaic on the earth's surface.
03:35Nearly all of North America, plus a large part of the Atlantic Ocean, make up a block called the North American Plate.
03:46The volcanically active floor of the Pacific Ocean, from Japan to California, is another giant slab known as the North Pacific Plate.
03:56About 80 miles thick, each plate is under constant pressure to move.
04:01Driven by enormous forces that we know very little about, they float like rafts on the earth's soft mantle.
04:10Yet they do not float freely.
04:13Where they touch, there is constant strain and pressure.
04:17Each plate struggles to push, bump, and drive past the other.
04:27Cutting through California like a giant scar is a major fracture in the earth's crust.
04:32It is known as the San Andreas Fault.
04:42At about the speed that fingernails grow, each plate is grinding against the other in opposite directions.
04:49Over thousands of years, the fault's slow movement has displaced the course of riverbeds.
04:56In the city of Hollister in central California, the earth on either side of the San Andreas Fault moves freely and relatively quickly.
05:05Curb stones and sidewalks throughout the city are warped and displaced by the gradual slippage along the fault.
05:12The continuous movement of the ground leaves fences bent and twisted.
05:17At a nearby winery, solid block concrete walls are creeping away from their supports.
05:23It is dramatic evidence of an active fault.
05:27In southern California, near Los Angeles, the San Andreas Fault looks like a rocky ravine.
05:40For the last hundred years, this section of the fault has been locked in place.
05:45Eventually, it must catch up with the movement of other sections.
05:50When rock resists a constant pressure to move, it bends and distorts until finally, it fractures.
06:00That is an earthquake.
06:05Friday, March 10th, 1933.
06:09Hollywood's film studios are bustling with activity.
06:12On a sound stage at Paramount Studios, W.C. Fields has just begun a scene.
06:17It will probably save my life. Now, what can I do for you?
06:20Take us to Shanghai.
06:21Shanghai?
06:22Yeah.
06:26What's the matter?
06:27Earthquake.
06:30Take your time, folks. Everybody welcome.
06:32He's all right now.
06:33It's all right.
06:34It's all right.
06:35Okay.
06:36Hollywood is heavily shaken, but the earthquake's power is centered in the city of Long Beach, 40 miles away.
06:49One hundred fifteen people were killed, thousands injured.
07:04The toll would have been even worse if the quake had occurred two hours earlier, while the schools were still in session.
07:10The city's schools took the heaviest damage of any class of building.
07:16Most of the buildings still standing had to be demolished.
07:19Though its effect was devastating, the tremor that jolted Long Beach was only of moderate power.
07:33Computer technology is now being used to help record and analyze changes in the Earth.
07:41Much of the San Andreas Fault is now under close surveillance.
07:45It is bugged with a network of ultra-sensitive instruments.
07:49Each detects subtle movements and changes in magnetic fields which might precede a quake.
07:54Dr. Peter Ward is chief of the Mechanics and Prediction Branch of the National Center for Earthquake Research in Menlo Park, California.
08:03We know that stress is building in California, and we know that stress will be primarily relieved in a major earthquake.
08:10When that earthquake will occur, we're not sure of, but we know that it will occur.
08:15Using the knowledge that certain physical changes occur in the Earth before some tremors,
08:20scientists have accurately predicted small, localized earthquakes.
08:25A tilt-meter detects tiny variations in the Earth's level.
08:30Slight movements are sometimes a signal that an earthquake will take place.
08:35Powerful laser beams measure the movements of Earth along the fault line, checking for sudden changes.
08:41Much of the San Andreas Fault is highly active.
08:45In Central California, about ten earthquakes are recorded every day.
08:54The Mojave Desert, just north of Los Angeles.
08:58A striking landscape lies on the center of a little understood and controversial geological event.
09:04It has come to be known as the bulge.
09:07It is a phenomenon that has preceded some major earthquakes.
09:11For 15 years, a vast area along the San Andreas Fault has been forced upward a full ten inches.
09:30It may be a signal of a giant quake to come.
09:37We know that a major catastrophic earthquake is inevitable in California, certainly in the Los Angeles area.
09:43We know from detailed studies of the Los Angeles area what the effects of this earthquake might be.
09:48If the earthquake occurs during the day, perhaps 12,000 people will be killed.
09:53If it occurs in the middle of the night, maybe only 3,000 people will be killed.
09:56But if one dam were to fail, perhaps tens of thousands of people will be killed and hundreds of thousands of people will be homeless.
10:02The threat of earthquakes is much too real.
10:07But there may be warnings of the giant quake to come.
10:14Not a day passes without earthquakes striking somewhere in the world.
10:19Often they are too slight to be felt.
10:21Inevitably, however, a giant quake occurs, convulsing with such magnitude it shakes the entire planet.
10:32The port of Valdez, Alaska.
10:34It is Good Friday, 1964.
10:37The China, the first freighter of the spring, has just come in to dock.
10:42Standing on deck, two sailors begin taking 8mm movies.
10:47They film the people and dogs on the dock below.
10:51At 5.36 p.m., the earth begins to rumble.
11:06The sailors hold on and keep filming.
11:11Suddenly, the water in Valdez Harbor begins to drain away.
11:19Formed 20 miles at sea, a 50-foot tidal wave smashes into Valdez Harbor.
11:44Anchorage, Homer, Sewer.
11:49Jolted with a force equal to thousands of atomic bombs.
11:53Tidal waves sweep Kodiak and Cordoba.
11:59A half million square miles feel the effect.
12:03Downed power lines explode oil tanks, which blaze uncontrolled.
12:14Broken gas mains set houses aflame.
12:18In Anchorage, the central business district is all but demolished.
12:22Large areas of ground turned liquid during the quake, dropping the streets and buildings as much as 30 feet.
12:28The Alaska quake was the largest to strike North America in this century.
12:33114 people were killed.
12:35Nearly 5,000 were left homeless.
12:37Valdez Harbor was destroyed.
12:41Scientists are looking in many directions for new ways to predict violent quakes.
12:56Up to 12 billion light years away, like fixed beacons in space, are points of light called quasars.
13:03They emit regular bursts of high-frequency radio energy.
13:09Radio antennas on opposite sides of the San Andreas Fault receive and measure signals from a quasar.
13:15By comparing the arrival times of these signals, minute movements of the Earth's crust can be detected.
13:22Subtle changes in the San Andreas Fault now reveal themselves in three dimensions.
13:29A sudden variation may be an early signal of a forming earthquake.
13:34Unusual animal behavior before earthquakes has been reported for hundreds of years.
13:41Zoo keepers have noticed monkeys and chimps act strangely just before quakes.
13:48They stay low to the ground and will not enter their shelters.
13:53Many household dogs have also seemed to know that a tremor is coming.
13:57They often bark for no reason or wander nervously around a room.
14:02On November 27, 1974, horses near Hollister, California became nervous and skittish.
14:09The next day, a moderate quake struck the area.
14:14A unique experiment is testing the idea that animals can predict earthquakes.
14:19The subjects are common cockroaches.
14:22A sensitive monitor continually records their level of activity, looking for sudden changes.
14:29It seems almost funny that a nervous cockroach may herald a major catastrophe.
14:34But it could turn out that the Earth's oldest living inhabitant could tell us something about our planet.
14:42At the University of California, scientists create their own earthquakes.
14:51Scale models of buildings shake under the impact of an earthquake simulator machine.
14:56Hydraulic arms slam a 45-ton concrete block in two directions at once, duplicating the ground motion of the most severe quakes.
15:06Information gained from such tests may lead to new building standards and possibly save countless lives.
15:13In 1982, a rare and perhaps ominous event will take place in our solar system.
15:28For the first time in nearly 200 years, all nine planets will form a straight line on one side of the Sun.
15:34Two British astronomers believe that this unusual alignment will cause an epidemic of giant earthquakes.
15:44Their theory states that the combined gravitational fields of the planets will create an enormous increase in the Sun's magnetic activity.
15:56Huge storms of sunspots and solar flares will explode into space.
16:01Radiation from the turbulent surface of the Sun will severely affect the Earth's atmosphere.
16:24Phenomena like the Northern Lights will be greatly intensified.
16:28Prevailing patterns of world weather will be radically altered.
16:36Prevailing patterns of world weather will be radically altered.
16:45Changes in high-altitude winds will slow the rotation of the Earth.
16:49Predictably, the sudden strain will cause swarms of earthquakes along the world's active faults.
16:54If this theory holds up, the strained fault line near San Francisco would be highly vulnerable.
17:01Ten miles south of San Francisco, hundreds of houses stand on unstable ground directly above the San Andreas Fault.
17:10In the last several years, the backyards of numerous homes have eroded away.
17:14They've dropped into the fault.
17:18A large tremor on this area would have a devastating effect.
17:20In San Francisco, the prospect of a major earthquake is frightening and grim.
17:23Every morning, as thousands of commuters swell its population, San Francisco becomes a setting for potential disaster.
17:27That a great quake will jolt this city is, to scientists, inevitable.
17:28Many seismologists believe it is already overdue.
17:29Many seismologists believe it is already overdue.
17:30In San Francisco, the prospect of a major earthquake is frightening and grim.
17:36Every morning, as thousands of commuters swell its population, San Francisco becomes a setting for potential disaster.
17:46That a great quake will jolt this city is, to scientists, inevitable.
17:51Many seismologists believe it is already overdue.
17:57Several detailed studies of the city have been made.
18:01They project what would happen if a tremor the size of the 1906 quake occurred again.
18:07It is a bleak scenario.
18:10Suddenly, the earth begins to tremble and sway.
18:14In the crowded financial district, high-rise buildings shiver and sway like blades of grass.
18:21Inside, people are flung across rooms.
18:25Fires break out.
18:26Elevators jam.
18:27Walls crack and collapse.
18:30Plate glass windows pop out of their frames.
18:33Large chunks of broken glass sail through the city's streets.
18:39Most of this area stands on unstable landfill.
18:43As the earth continues to shake, much of the soil turns to liquid.
18:48The street level drops instantly.
18:51Earthquake-proof skyscrapers fall into the void.
18:59Along Chinatown's famed Grant Street, the shaking is severe.
19:04Built almost entirely of unreinforced brick, it is especially susceptible to tremors.
19:10Virtually all of Chinatown collapses in on itself.
19:13It becomes a mass graveyard.
19:16Loose bricks and balconies are the first to go.
19:20Throughout the city, parapets, ornamental sculpture, and facades smash down on the people below.
19:30Everywhere there are exploding fires from ruptured gas mains.
19:45Cars on the freeways are tossed about like little toys.
19:56Sections of asphalt break away in huge chunks.
19:59The elevated highways slither, then fall.
20:04The cars below are crushed.
20:06The stench of raw sewage mixes with smoke from hundreds of houses that burn uncontrolled.
20:12The approaches to the Golden Gate Bridge have collapsed.
20:18The ground beneath them has liquefied and run off.
20:22The bridge itself whips back and forth like a giant snake.
20:26Cars are hurled into the water below.
20:28The human toll is enormous.
20:38At least 10,000 are dead.
20:41300,000 are injured.
20:43Nearly everyone is homeless.
20:46This is the projection for a disaster that probably will occur.
20:51We just don't know when.
20:53Perhaps one day we will predict and control our planet's violent quakes.
20:58Until then, we are well advised to look for warnings in any form.
21:03And heed them, if there's time.
21:12For over 4 billion years, earthquakes have shaken and reshaped the Earth's surface.
21:18They are a violent expression of our planet's continuing evolution.
21:22In California, along the San Andreas Fault, the frequency of earthquakes is high.
21:26Yet an active fault line cuts through New York City at 125th Street between the Hudson and East Rivers.
21:34The regions around Boston and Charleston, South Carolina, have as high a seismic risk as Los Angeles or San Francisco.
21:41In fact, the U.S. Coast and Geodetic Survey has determined that one-third of our nation's population lives in areas of high earthquake probability.
21:51Science is challenging the idea that earthquakes are unpredictable.
21:56Yet we are still far from truly understanding the powerful forces that are working deep within our planet.
22:02The U.S. Coast Guard
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