How the Earth Was Made

>> 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

and fascinating ways, leaving

a trail of geological

mysteries behind.

Water. One of the most powerful

forces on the planet. It plays a

crucial role in creating life

and destroying it, in forging

landscapes and in breaking apart

the Earth. In its most dramatic

form, it becomes a killer wave

known as a tsunami. Until

recently, predicting when these

monsters may next strike has

been impossible.

But today, scientists are

starting to understand these

giant waves. By connecting clues

as varied as ancient Japanese

writings and landslides, ancient

corals and buried Native

American settlements, the

secrets of tsunamis are finally

being unlocked.

How The Earth Was Made 01x09 Tsunami Original Air Date on April 7, 2009

== sync, corrected by elderman ==

Tsunamis. One of the most deadly

forces of nature. Giant waves

that travel faster than a jet

plane, they can cross entire

oceans in just hours.

They have the power to smash

buildings, vehicles, anything

in their way.

>> MAN: 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 a

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.

>> MAN: Oh, my God!

>> Today, tsunamis are still a

threat to coastlines all over

the world.

>> MOONEY: Tsunamis will always

occur, and have always occurred,

throughout Earth's history. But

it's only been more recently, as

population densities have

increased and people have moved

and migrated to the coastal

regions, that we've become much

more aware of the tsunami

hazards.

>> The investigation into what

caused these monster waves

began over a thousand years ago

on the islands of Japan.

This country is the world's

tsunami hotspot. Its coasts have

been pounded with these enormous

waves more than anywhere else on

the planet. Evidence for this is

the word tsunami itself. It is

Japanese and literally means

"harbor wave".

Japan has the longest written

tsunami record of anywhere in

the world. The records go back

as far as 684 A.D.

By studying these records, it is

possible to work out that, on

average, this country has been

struck nearly every seven years.

Samurai writings speak of people

living on the coasts running

for higher ground as soon as

they felt an earthquake. The

Japanese knew this was a clue, a

warning sign that a deadly

tsunami would soon follow. But,

despite their attempts to

escape, tsunamis have

continually bought death and

destruction to these islands.

In 1896, a wave that hit Honshu

in the northeast claimed the

lives of 27,000 people.

In 1933, the same area was

smashed again. This time, 3,000

people were swept away.

And in 1993, the island of

Okushiri was rocked by an

enormous earthquake measuring

7.8 on the Richter scale.

Buildings were leveled and fires

raged. But worse was to come.

Minutes after the shaking had

subsided, an ominous white

crest appeared on the horizon -

a tsunami. A gigantic wave swept

in, flattening any buildings

still standing.

In Japan, the locals had already

worked out the connections

between earthquakes and

tsunamis. But there's another

hotspot on Earth where tsunamis

regularly strike - the Hawaiian

islands. But very few of them

were preceded by an earthquake.

The city of Hilo on the Big

Island has been dubbed the

Tsunami Capital of the World.

Dozens of these enormous waves

have hit these beautiful

islands, and the mystery is why.

With no natural warning to go

on, the people of Hawaii must

rely on the world's biggest

tsunami monitoring station.

Set up in 1949, it is connected

to a network of buoys spread

across the Pacific Ocean. These

buoys provide important clues.

They monitor changes in sea

level that indicate the

approach of any potential

tsunamis.

In 1960, scientists got the

breakthrough they were looking

for. They were finally able to

work out the type of event at

the root of Hawaii's mystery

tsunamis. An enormous quake on

the coast of Chile, the biggest

recorded of all time, with a

factor 9.5 on the Richter scale,

triggered a tsunami that swept

across the entire Pacific Ocean

in just a few hours. The islands

of Hawaii where 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 wave

struck. But the homes they left

behind were decimated. In Hilo,

the tsunami was so strong it

even bent parking meters in

half. The wave continued past

Hawaii to Japan. It had lost

none of its power. Pacific-wide,

this tsunami cost more than

2,000 lives and caused millions

of dollars' worth of damage.

Devastating as it was, the 1960

event was a turning point in

the study of tsunamis. It was

the first time that scientists

could accurately measure how the

size of an underwater earthquake

directly affected the size of a

tsunami. And conclusive proof