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♪ [ominous theme music]

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(male narrator) Boxing Day, 2004.

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The world was shocked

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by one of the worst natural
disasters of all time.

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Over 250,000 people died.

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The cause of this devastation

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was the most powerful kind
of earthquake on the planet,

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called a mega thrust.

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This event made us realize
how poorly prepared we are

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to face these huge geological catastrophes.

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And scientists are now
trying to work out

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where else is at risk.

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They have discovered

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that a megathrust as large
as the Sumatra quake

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could hit North America.

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♪ [music playing]

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Everyone knows that America
is going to be struck

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by a devastating earthquake.

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For years, the people of California
have been waiting for the day

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when the San Andreas Fault
unleashes the big one.

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But all the time

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an even more powerful hazard
has lain undiscovered.

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A giant megathrust earthquake
just like the one that hit Indonesia

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threatens America's Pacific Northwest.

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A huge area from northern California

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all the way to Canada is at risk,

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including major cities
like Seattle and Vancouver.

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(scientist) It's a major earthquake.

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(emergency worker) We were just
coordinating

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an emergency response that's going out.

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(narrator) The authorities have
started to prepare for this catastrophe.

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Rehearsals like this one help
to train the emergency services

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to deal with such an event.

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[screaming]

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(narrator) Children are now
being taught lessons in survival

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that could mean the difference
between life and death.

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The source of all this danger,

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lying underwater off
the Pacific Northwest coast,

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is a huge gash in the earth's crust,

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a subduction zone.

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The earth's crust is made up
of huge plates of rock

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that are constantly in motion.

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Where two of these giant
plates meet head to head,

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one of them can get pushed
down under the other.

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This is a subduction zone.

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It was a subduction zone
off the coast of Sumatra

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that caused the Boxing Day earthquake.

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And worldwide there are
many other similar faults.

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(Prof. Bill McGuire) There are
subduction zones all over the planet,

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but mainly they occur
around the rim of the Pacific,

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the so-called "Ring of Fire" and
lots of big earthquake occur there,

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most of the world's really
destructive earthquakes.

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(narrator) Subduction zones
cause earthquakes

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when the plate that's being
pushed down gets stuck.

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As it pushes, the upper plate
gets squeezed and distorted.

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Eventually the strain becomes too much.

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The upper plate slips creating
a megathrust earthquake.

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(Tim Walsh) A megathrust earthquake
happens when the subducting slab,

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which is diving under
the overriding plate,

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is locked and causes the overriding
plate to bulge upward.

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And then when that becomes unlocked,

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it slides suddenly creating
a huge earthquake.

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Worldwide, these are
the biggest earthquakes.

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They range in magnitude
up to nine and a half.

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(Prof. Bill McGuire) Generally speaking,
if you have two great masses of rock

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and you're scraping them,

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one underneath the other,

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they're not going to move very easily

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and you're going to get 
a lot of friction there.

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And I liken it to sort of two cheese
graters pushing past one another,

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very, very difficult to get any
smooth sort of movement there.

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(narrator) But as the 26th
of December showed,

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megathrust earthquakes have
another devastating consequence.

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(Prof. McGuire) In the case
of a megathrust earthquake,

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the overlying plate,

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which has been bent,

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pins back upwards into position.

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And it's that sort of pinning motion

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that transmits an enormous amount
of energy to the sea bed.

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That energy is then transmitted
to the water above it

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which oscillates up and down

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and then moves out 
as a series of huge ripples.

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And that, in a sense, 
is what a tsunami is.

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(narrator) A tsunami is very
different from a normal wave.

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In normal waves, only the water
on the surface is moving.

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But a tsunami involves the movement
of the whole water column,

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millions of tons of water.

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(Prof. McGuire) Normal wind driven
waves have very small wavelengths,

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that's from crest to crest.

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So it maybe a few tens of meters

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and the wave has crashed
and it's gone.

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Tsunami have a wavelength that
could be hundreds of kilometers long.

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So when that initial wave comes in,

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the water behind it is pretty much 
at the same level.

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And that can keep coming for five
or ten minutes as a huge flood.

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And that's why they're so destructive.

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It's not a simple wave that you can
hold your breath under and survive.

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(narrator) The combination of
massive earthquakes and tsunamis

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makes subduction zones
a deadly geological hazard.

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And so it should have been
a cause for concern

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that the Cascadia subduction zone,

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a 600 mile long fault,

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lies right off the Pacific Northwest coast.

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The strange thing was 
Cascadia didn't seem to be a danger at all.

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For years, scientists have been
monitoring seismic activity

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along the Cascadia subduction zone.

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They found that unlike
other subduction zones,

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it was virtually silent.

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(Robert) People saw that Cascadia had
many of the features of a subduction zone.

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It had an oceanic trench.

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It had a line of volcanoes
above the subduction zone.

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It simply didn't seem to
have big earthquakes

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and so they put it in a category of its own,

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the subduction zone that
doesn't have big earthquakes.

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(narrator) And there was
a simple explanation

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for why Cascadia wasn't creating earthquakes.

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If the plates were moving
smoothly past each other,

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there would be no strain being built up
and no earthquakes.

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♪ [music playing]

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This theory was backed up by
over 200 years of historical record.

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For as long as the Europeans
have lived here,

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there's no record of any significant
earthquakes from Cascadia.

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But in this region,

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there is another kind of history,

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a kind that isn't written down.

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For centuries before the Europeans arrived,

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this land was home to native peoples.

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Viola Riebe is a member of the Ho nation
on the northern Washington coast.

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As a child she was taught the legend
of the Thunderbird.

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(Viola Riebe) The Thunderbird
lives in the glacier

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at the headwaters of the Ho River.

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When he comes out,

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the ground would start to shake

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and he would even make
the waters troubled.

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(narrator) Could this legend
be describing a real event,

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a megathrust earthquake
that occurred long ago?

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Most geologists have no time
for such speculation.

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But one decided to take a closer look.

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♪ [guitar music]

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(narrator) Brian Atwater wondered whether
the native legends might be a warning

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that the Pacific Northwest could
be at risk from giant earthquakes.

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So he took to his canoe

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and started exploring the marshes
and rivers of the Washington coast.

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He was hoping that
the layers of mud here,

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laid down over centuries

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might provide a clue
to the events of the past.

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And buried in the marsh,

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he did find evidence
of an unusual event.

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(Brian Atwater) We're on
an ordinary coast,

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standing on a salt marsh like this one.

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Underneath we find salt marsh deposits,

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salt marsh deposits,

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salt marsh deposits,

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just steadily on.

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But here we have something
completely different.

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We've got a spruce forest here,

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underneath the salt marsh.

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We can dig out here

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the bark,

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the bark of Cyprus spruce.

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(narrator) These trees can
only grow on dry land.

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Yet this layer of trees
was covered with mud

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that must have been deposited by water.

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So the land here must once have been
higher and then at some point,

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it dropped down,

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plunging the forest underwater.

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(Brian Atwater) At the time that
the spruce forest dropped down,

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sand was laid down.

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It's the first thing that covers
the peat is a little skin of sand.

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So that's the mystery.
How did that happen?

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(narrator) Since there's no sand nearby,

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there must have been 
a sudden rush of seawater

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that carried the sand in with it.

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This was no gradual change in land level.

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It must have been a violent collapse.

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(Brian Atwater) The easiest
explanation for that

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is that you had an earthquake

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that caused the land here to drop

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and also warped the sea floor.

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That warping of the sea floor set off a tsunami,

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and the tsunami then lays down the sand

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on the freshly down-dropped land surface.

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(narrator) Carbon dating
of the buried trees

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showed that this event had occurred
roughly 300 years ago,

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before Europeans had arrived.

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So the native legends might
indeed be about a real event.

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But it would need more than
just layers of mud

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to prove that there had been
a devastating earthquake here.

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The next piece of evidence was to
come from thousands of miles away.

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As the Indonesia earthquake has shown,

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megathrust earthquakes cause 
damage at astonishing distances

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because they create tsunamis.

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If such an earthquake really
had occurred in Cascadia,

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it should have created a tsunami capable
of traveling right across the Pacific

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to countries like Japan.

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Kenji Satake is a geologist who
studies earthquakes and tsunamis.

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When Satake heard about
Brian Atwater's theory,

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he realized Japan could hold the answer.

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(Kenji Satake) 300 years ago
is prehistoric time for Americans,

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but in Japan, we have documents

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that would record the tsunami
from Cascadia 300 years ago.

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So that's why we started
looking for the records.

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(narrator) What Satake was looking for

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was a very special kind of tsunami.

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Most tsunamis in Japan are
caused by nearby earthquakes,

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so they're accompanied
by shaking of the ground.

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But a few tsunamis arrive
without shaking

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because the parent earthquake is far away.

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When there's no known earthquake
that could have caused the wave,

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it's called an orphan tsunami.

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So Satake started hunting for
records of an orphan tsunami

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that could have come
from the Pacific Northwest.

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And in the coastal town of Miho,
southwest of Tokyo,

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there's a document that
describes just such a tsunami.

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(Kenji Satake) This page describes
a tsunami on January 28th of 1700.

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On that day, from morning,
tsunami arrived at this town,

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like a high tide,

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and the receding wave was like big river

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and it continued seven times
until the noon of that day.

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(narrator) The account told how
the villagers took refuge in a shrine

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that still exists today.

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The author also recorded

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that this tsunami was unlike any
that he had experienced before.

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(Kenji Satake) Writer note that
there was no earthquake

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but the tsunami arrived.

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So he was surprised.

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And he said such a strange thing

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should be passed 
to the future generation.

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(narrator) Crucially, the same tsunami
was recorded in four other accounts

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from different parts of Japan.

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So this couldn't be a local event.

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Satake thought this tsunami

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might indeed have come from
a huge megathrust earthquake

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5000 miles away in Cascadia.

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But still there was no proof

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that the tsunami had come 
from North America.

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The carbon dating only showed that

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the Cascadia event had happened 
at roughly the same time

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as the orphan tsunami.

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The final piece of evidence would
be found in a mysterious corner

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of the Pacific Northwest.

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A hundred miles southwest of Seattle,

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in a remote area of the Washington coast,

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is the ghost forest.

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These are trees that died
hundreds of years ago

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that remain standing to this day.

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(David Yumaguchi) Sometime in the past,

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this would have been an
in intact red cedar forest,

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large trees standing 100 feet
or more in the air

250
00:16:46,680 --> 00:16:50,760
and this landscape was filled with them

251
00:16:50,760 --> 00:16:55,280
and then one day, something
killed the trees here in place.

252
00:16:55,280 --> 00:16:59,120
And the mystery is,
"What killed them?"

253
00:16:59,120 --> 00:17:02,880
you know, what could kill an entire forest

254
00:17:02,880 --> 00:17:08,520
along 60 miles of Washington coast
just like this?

255
00:17:08,520 --> 00:17:11,400
[chainsaw starts up]

256
00:17:11,400 --> 00:17:14,480
(narrator) Tree specialist David
Yumaguchi has spent years

257
00:17:14,480 --> 00:17:19,440
trying to solve the mystery of
what happened to the trees.

258
00:17:19,440 --> 00:17:22,200
He wanted to work out
when they had died

259
00:17:22,200 --> 00:17:23,960
by looking at their tree rings.

260
00:17:26,839 --> 00:17:29,320
(David Yumaguchi) Most people
know that trees have annual rings.

261
00:17:29,320 --> 00:17:32,280
So depending on the climate
from year to year,

262
00:17:32,280 --> 00:17:36,720
the tree rings are either wide
or narrow or wide or narrow.

263
00:17:36,720 --> 00:17:40,640
And so the developing of bar code
going back in time,

264
00:17:40,640 --> 00:17:42,920
it's unique in time.

265
00:17:42,920 --> 00:17:44,680
(narrator) Using this pattern,

266
00:17:44,680 --> 00:17:49,440
David was able to work out exactly 
when the trees had died.

267
00:17:49,440 --> 00:17:51,720
And he found out that all of them

268
00:17:51,720 --> 00:17:56,560
had died around the early months of 1700.

269
00:18:05,320 --> 00:18:09,360
(David Yumaguchi) The summer
before the tsunami hit Japan,

270
00:18:09,360 --> 00:18:12,360
these trees were just growing
happily in the forest here.

271
00:18:12,360 --> 00:18:14,200
Then the winter came along

272
00:18:14,200 --> 00:18:15,880
and by the following summer,

273
00:18:15,880 --> 00:18:17,920
they were all dead.

274
00:18:17,920 --> 00:18:24,040
And so the tree ring story matched
the Japanese tsunami records perfectly.

275
00:18:28,360 --> 00:18:29,840
(narrator) There was now no doubt

276
00:18:29,840 --> 00:18:33,120
that the same catastrophe 
that had killed the ghost forest

277
00:18:33,120 --> 00:18:37,080
had also sent the tsunami across to Japan.

278
00:18:37,080 --> 00:18:39,240
And from the Japanese records,

279
00:18:39,240 --> 00:18:44,080
Kenji Satake could work out exactly 
when it had happened,

280
00:18:44,080 --> 00:18:52,440
on the 26th of January, 1700, at 9 p.m.

281
00:18:52,440 --> 00:18:54,080
On that winter's night,

282
00:18:54,080 --> 00:18:59,360
a megathrust earthquake just like
the Boxing Day earthquake of 2004,

283
00:18:59,360 --> 00:19:04,320
struck the Pacific Northwest.

284
00:19:04,320 --> 00:19:09,600
It drowned forests
and turned land into sea.

285
00:19:09,600 --> 00:19:13,400
It sent a tsunami hurtling
across the Pacific.

286
00:19:13,400 --> 00:19:15,520
And it spawned a legend

287
00:19:15,520 --> 00:19:19,400
that would be passed down
to a dozen generations.

288
00:19:27,360 --> 00:19:31,240
The scientists knew that
if it had happened here once,

289
00:19:31,240 --> 00:19:34,520
it would happen again.

290
00:19:34,520 --> 00:19:41,320
One day the people of the Pacific
Northwest will face a megathrust earthquake.

291
00:19:41,320 --> 00:19:44,000
So how big will it be?

292
00:19:44,000 --> 00:19:47,600
What damage will it cause?

293
00:19:47,600 --> 00:19:49,440
And when will it happen?

294
00:19:56,480 --> 00:20:01,240
The first question is, 
"How large will the earthquake be?"

295
00:20:01,240 --> 00:20:05,960
The power of an earthquake depends
on the size of the fault that breaks.

296
00:20:05,960 --> 00:20:08,480
In the case of the Boxing Day earthquake,

297
00:20:08,480 --> 00:20:10,840
it was huge,

298
00:20:10,840 --> 00:20:15,440
over 600 miles of fault ruptured.

299
00:20:15,440 --> 00:20:20,280
The Cascadia subduction zone 
is almost exactly the same length.

300
00:20:20,280 --> 00:20:25,880
So it's likely that it will create
an equally powerful earthquake.

301
00:20:25,880 --> 00:20:26,960
(Robert Muir-Wood) Now
we do not know exactly

302
00:20:26,960 --> 00:20:29,600
where the next Cascadia
earthquake is going to occur,

303
00:20:29,600 --> 00:20:30,440
but we do know that

304
00:20:30,440 --> 00:20:33,800
the impact of that earthquake
in terms of the ground shaking,

305
00:20:33,800 --> 00:20:36,360
the huge area impacted,

306
00:20:36,360 --> 00:20:39,080
the extent of land level changes,

307
00:20:39,080 --> 00:20:41,560
the size of the tsunami 
which will be generated,

308
00:20:41,560 --> 00:20:42,920
will be very comparable

309
00:20:42,920 --> 00:20:48,120
to that which was seen
on December the 26th in 2004.

310
00:20:48,120 --> 00:20:51,600
(narrator) Scientists believe
the next Cascadia earthquake

311
00:20:51,600 --> 00:20:54,720
will be one of the largest on the planet,

312
00:20:54,720 --> 00:20:57,080
up to magnitude 9.

313
00:20:59,760 --> 00:21:03,400
The Kobe earthquake
which killed 6000 people

314
00:21:03,400 --> 00:21:10,400
and devastated the Japanese
economy was a magnitude 6.8.

315
00:21:10,400 --> 00:21:12,960
The terrible Mexico City earthquake

316
00:21:12,960 --> 00:21:20,160
which killed over 10,000 people was 8.1.

317
00:21:20,160 --> 00:21:27,120
But a magnitude 9 releases many
times more energy than those.

318
00:21:27,120 --> 00:21:29,200
(Tim Walsh) The magnitude
scale is logarithmic,

319
00:21:29,200 --> 00:21:32,600
that is each one is 10 times bigger
than the previous number.

320
00:21:32,600 --> 00:21:34,760
But that's the amount of displacement.

321
00:21:34,760 --> 00:21:37,640
When you do that 
in terms of energy release,

322
00:21:37,640 --> 00:21:41,080
each one is 30 to 40 times
bigger than the previous one.

323
00:21:41,080 --> 00:21:46,640
So a magnitude 9 has 1000 times
more energy released

324
00:21:46,640 --> 00:21:48,320
than does a magnitude 7,

325
00:21:48,320 --> 00:21:50,760
30,000 more than a magnitude 6.

326
00:21:50,760 --> 00:21:53,320
So to put that in perspective,

327
00:21:53,320 --> 00:21:57,240
the Kobe earthquake that
was so damaging in Japan,

328
00:21:57,240 --> 00:21:59,640
was about a magnitude 6.8.

329
00:21:59,640 --> 00:22:03,200
So a Cascadia event that
would reach magnitude 9

330
00:22:03,200 --> 00:22:05,400
is more than 1000 times
bigger than that one.

331
00:22:09,920 --> 00:22:12,360
(narrator) Just as happened
in the Indian Ocean,

332
00:22:12,360 --> 00:22:17,200
this huge earthquake will cause
a sudden uplift of the sea floor.

333
00:22:17,200 --> 00:22:21,240
And that will create a tsunami.

334
00:22:21,240 --> 00:22:22,680
The Boxing Day tsunami

335
00:22:22,680 --> 00:22:27,360
devastated the densely populated
northwest coast of Sumatra,

336
00:22:27,360 --> 00:22:32,240
and almost totally destroyed
the town of Banda Aceh.

337
00:22:32,240 --> 00:22:35,600
The cities of Seattle, Portland,
and Vancouver

338
00:22:35,600 --> 00:22:40,160
will at least be spared that fate.

339
00:22:40,160 --> 00:22:42,000
(Robert Muir-Wood) One of the
fortunate things about Cascadia

340
00:22:42,000 --> 00:22:46,520
in comparison with northern Sumatra
is that the big towns and cities

341
00:22:46,520 --> 00:22:53,000
aren't located right out
on the open ocean coast.

342
00:22:53,000 --> 00:22:57,360
The complex of waterways in Washington
State means that the big ports

343
00:22:57,360 --> 00:23:02,120
are actually located someway inland.

344
00:23:02,120 --> 00:23:04,360
(narrator) However,
thousands of people do live

345
00:23:04,360 --> 00:23:07,040
on the Pacific Northwest coast.

346
00:23:07,040 --> 00:23:11,760
And in summer, the beaches
are a major draw to tourists.

347
00:23:11,760 --> 00:23:16,920
(Tim Walsh) A lot of the population
on the Washington coast is vacationers.

348
00:23:16,920 --> 00:23:21,040
The population can grow from just a
few thousand permanent population

349
00:23:21,040 --> 00:23:24,080
to tens of thousands of visitors.

350
00:23:24,080 --> 00:23:28,240
And if we have a Cascadia
subduction zone earthquake and tsunami

351
00:23:28,240 --> 00:23:31,920
the wave crest would arrive
at Ocean Shores and Long Beach

352
00:23:31,920 --> 00:23:33,760
within about a half hour

353
00:23:33,760 --> 00:23:36,320
and that's a very short period of time

354
00:23:36,320 --> 00:23:39,880
to be able to move a lot of people off
those peninsulas to high ground.

355
00:23:41,840 --> 00:23:45,480
(narrator) So even though there are
no major cities on the coast,

356
00:23:45,480 --> 00:23:50,800
there will still be many thousands
of people at risk from the tsunami.

357
00:23:50,800 --> 00:23:56,480
But far more people will be
affected by the earthquake itself.

358
00:23:58,000 --> 00:24:02,080
All the major cities in Washington,
Oregon, and British Colombia

359
00:24:02,080 --> 00:24:06,000
are going to experience
strong ground shaking.

360
00:24:06,000 --> 00:24:12,400
And this megathrust earthquake will
be very different from a normal quake.

361
00:24:12,400 --> 00:24:16,320
(Robert Muir-Wood) Magnitude 9
earthquakes have these special characteristics.

362
00:24:16,320 --> 00:24:19,600
One of them is that it takes
several minutes

363
00:24:19,600 --> 00:24:22,600
for the fault to break 
from one end to the other.

364
00:24:22,600 --> 00:24:25,960
The fault rupture spreads out
a few kilometers a second,

365
00:24:25,960 --> 00:24:29,120
but it still may take two or three minutes
to get from one end to the other.

366
00:24:29,120 --> 00:24:31,320
And that means the earthquake
shaking goes on

367
00:24:31,320 --> 00:24:35,400
for a very long period of time.

368
00:24:35,400 --> 00:24:40,720
(narrator) If the full 600 mile length
of the Cascadia subduction zone ruptures,

369
00:24:40,720 --> 00:24:44,600
it will mean the earthquake will
continue for as long as five minutes,

370
00:24:44,600 --> 00:24:48,640
just like the Indonesian earthquake did.

371
00:24:48,640 --> 00:24:52,000
(Prof. McGuire) The duration
of the event is very unusual

372
00:24:52,000 --> 00:24:55,200
and in that sense alone 
it can cause more damage.

373
00:24:55,200 --> 00:24:56,840
An earthquake that goes on for longer

374
00:24:56,840 --> 00:25:00,400
causes more damage generally than one
that is over within 10 or 20 seconds.

375
00:25:02,920 --> 00:25:06,880
(narrator) So what damage will
several minutes of shaking do

376
00:25:06,880 --> 00:25:08,560
to cities like Seattle?

377
00:25:13,440 --> 00:25:17,480
Even though the Boxing Day earthquake
and the next Cascadia earthquake

378
00:25:17,480 --> 00:25:19,920
may be very similar,

379
00:25:19,920 --> 00:25:23,160
they could have very different effects.

380
00:25:23,160 --> 00:25:27,640
In Indonesia, most of the damage
was caused by the tsunami

381
00:25:27,640 --> 00:25:29,840
not the earthquake itself.

382
00:25:31,800 --> 00:25:34,360
(Robert Muir-Wood) Most people's
houses are built out of wood.

383
00:25:34,360 --> 00:25:38,640
There's some more modern
concrete construction,

384
00:25:38,640 --> 00:25:41,160
but typically only one or two story buildings,

385
00:25:41,160 --> 00:25:43,760
so these buildings are not sensitive

386
00:25:43,760 --> 00:25:46,560
to the very long period ground motions

387
00:25:46,560 --> 00:25:49,680
we can expect from 
a magnitude 9 earthquake.

388
00:25:51,560 --> 00:25:55,320
(narrator) But the modern high-rise
structures of the Pacific Northwest

389
00:25:55,320 --> 00:25:58,200
may react very differently.

390
00:25:58,200 --> 00:26:05,800
♪ [piano music]

391
00:26:05,800 --> 00:26:10,840
Tom Heaton is an earthquake
engineer from California.

392
00:26:10,840 --> 00:26:14,880
He was brought in to advise on the
construction of a nuclear power station

393
00:26:14,880 --> 00:26:17,560
near the Washington coast.

394
00:26:17,560 --> 00:26:23,880
In the end, the project ran out of
money and was never completed.

395
00:26:23,880 --> 00:26:27,120
But ever since, 
Heaton has been concerned

396
00:26:27,120 --> 00:26:31,560
by the question of what damage
a Cascadia earthquake could do,

397
00:26:31,560 --> 00:26:34,680
particularly to skyscrapers.

398
00:26:35,920 --> 00:26:40,080
(Tom Heaton) My fear is that in
a Cascadia event these buildings

399
00:26:40,080 --> 00:26:42,240
may sway some large distance

400
00:26:42,240 --> 00:26:45,600
as we get a very long
duration of shaking

401
00:26:45,600 --> 00:26:49,600
that the swaying may grow in intensity

402
00:26:49,600 --> 00:26:52,480
and the buildings may begin to be damaged.

403
00:26:54,600 --> 00:26:58,800
(narrator) But not everyone agrees.

404
00:26:58,800 --> 00:27:01,000
John Hooper is a buildings engineer

405
00:27:01,000 --> 00:27:05,240
who has worked on many
of Seattle's tallest buildings.

406
00:27:05,240 --> 00:27:08,440
He believes that the modern
skyscrapers, at least,

407
00:27:08,440 --> 00:27:12,200
should be strong enough
to avoid serious damage.

408
00:27:12,200 --> 00:27:13,720
(John Hooper) The majority
of the high-rises here,

409
00:27:13,720 --> 00:27:14,600
they'll move.

410
00:27:14,600 --> 00:27:15,840
And they'll move a lot.

411
00:27:15,840 --> 00:27:19,760
But they're designed to withstand
that motion and that energy absorption

412
00:27:19,760 --> 00:27:23,680
and they go through that
8 or 10 foot drift, back and forth

413
00:27:23,680 --> 00:27:25,520
during the earthquake for several minutes,

414
00:27:25,520 --> 00:27:27,040
scaring a lot of people probably,

415
00:27:27,040 --> 00:27:30,560
but the damage should be related
mainly to the nonstructural components

416
00:27:30,560 --> 00:27:33,440
and not to the major structural
elements themselves.

417
00:27:34,920 --> 00:27:36,560
(narrator) The reality is,

418
00:27:36,560 --> 00:27:39,160
no one knows for sure.

419
00:27:39,160 --> 00:27:42,000
Because there has never been
a megathrust earthquake

420
00:27:42,000 --> 00:27:45,480
near a modern high-rise city.

421
00:27:45,480 --> 00:27:48,320
(Tom Heaton) These very large
earthquakes don't happen often

422
00:27:48,320 --> 00:27:52,760
and for us to understand what it is
we need to do in the first place

423
00:27:52,760 --> 00:27:55,760
so the building codes have
never really been tested

424
00:27:55,760 --> 00:27:58,000
by an earthquake of this nature,

425
00:27:58,000 --> 00:28:00,480
at least not for tall buildings.

426
00:28:00,480 --> 00:28:03,480
The lessons haven't been learned yet.

427
00:28:03,480 --> 00:28:06,080
So what concerns me is that

428
00:28:06,080 --> 00:28:08,600
we may learn the lesson
in a very difficult way.

429
00:28:13,080 --> 00:28:17,320
(narrator) But there is a type of building
that everyone agrees will be at risk.

430
00:28:21,080 --> 00:28:27,960
The older brick buildings known as
unreinforced masonry, or URMs.

431
00:28:29,240 --> 00:28:31,400
(John Hooper) These buildings we see
around here in [inaudible]Square

432
00:28:31,400 --> 00:28:33,280
are like many cities on the west coast.

433
00:28:33,280 --> 00:28:36,320
They are constructed of
unreinforced masonry,

434
00:28:36,320 --> 00:28:38,720
brick stacked upon brick,
separated by mortar

435
00:28:38,720 --> 00:28:40,800
and so if an earthquake shaking happens,

436
00:28:40,800 --> 00:28:44,080
those brick end up sliding
past one another,

437
00:28:44,080 --> 00:28:47,080
they lift apart.

438
00:28:47,080 --> 00:28:50,920
(narrator) URM buildings are
very weak and very brittle.

439
00:28:50,920 --> 00:28:55,200
So the long duration of shaking that
a megathrust earthquake will produce

440
00:28:55,200 --> 00:28:58,600
could cause many to collapse.

441
00:28:58,600 --> 00:29:02,880
(John Hooper) URM buildings have
been noticeably not very resistant

442
00:29:02,880 --> 00:29:04,520
to earthquakes in general.

443
00:29:04,520 --> 00:29:06,200
And if you don't do some renovations

444
00:29:06,200 --> 00:29:07,720
and start connecting the pieces together,

445
00:29:07,720 --> 00:29:09,160
they're very susceptible to damage,

446
00:29:09,160 --> 00:29:12,560
especially during a long event
like the Cascadia.

447
00:29:12,560 --> 00:29:15,560
And so even those that do have some
improvements made to them,

448
00:29:15,560 --> 00:29:17,000
they still might be challenged.

449
00:29:17,000 --> 00:29:18,760
But those that don't' have any,

450
00:29:18,760 --> 00:29:21,560
their chances of surviving
is probably fairly limited.

451
00:29:24,160 --> 00:29:27,280
(narrator) There are thousands of
these unreinforced masonry buildings

452
00:29:27,280 --> 00:29:29,560
in the earthquake zone.

453
00:29:29,560 --> 00:29:35,400
They are used as homes,
offices, and schools.

454
00:29:35,400 --> 00:29:40,480
The collapse of such buildings is likely
to be a major cause of death and injury

455
00:29:40,480 --> 00:29:43,480
when the next Cascadia earthquake occurs.

456
00:29:46,200 --> 00:29:48,520
So the big question is,

457
00:29:48,520 --> 00:29:50,360
"When will it happen?"

458
00:29:56,120 --> 00:29:59,400
Predicting earthquakes is impossible.

459
00:29:59,400 --> 00:30:00,520
No one could have known that

460
00:30:00,520 --> 00:30:04,000
the Indonesian earthquake
was about to happen

461
00:30:04,000 --> 00:30:08,840
and no one can say
when Cascadia will strike.

462
00:30:08,840 --> 00:30:12,480
But it is possible to look back
at the geological record

463
00:30:12,480 --> 00:30:18,640
and see how frequently earthquakes
occur on a particular fault.

464
00:30:18,640 --> 00:30:20,200
Sure enough,

465
00:30:20,200 --> 00:30:22,680
the Washington coast does hold traces

466
00:30:22,680 --> 00:30:25,920
of several past megathrust earthquakes

467
00:30:25,920 --> 00:30:29,240
from even before 1700.

468
00:30:29,240 --> 00:30:32,560
(Brian Atwater) About 2,500 years
of earthquake history,

469
00:30:32,560 --> 00:30:37,520
one, two, three, four events recorded.

470
00:30:37,520 --> 00:30:39,560
Radio carbon ages show that

471
00:30:39,560 --> 00:30:44,840
this event happened
about 600 years BC

472
00:30:44,840 --> 00:30:51,000
and that this event happened
about AD 400.

473
00:30:51,000 --> 00:30:57,000
So something about 1000 years
between this event and this event,

474
00:30:57,000 --> 00:30:59,800
a very, very long time.

475
00:30:59,800 --> 00:31:02,600
This event's from about AD 700.

476
00:31:02,600 --> 00:31:07,680
There are only about three centuries
between this event and this event.

477
00:31:07,680 --> 00:31:11,640
This is about the same amount of time
as between here and today.

478
00:31:11,640 --> 00:31:14,440
So this is why it would not be
surprising if,

479
00:31:14,440 --> 00:31:15,560
while we're standing here,

480
00:31:15,560 --> 00:31:17,880
another one of these great
Cascadia earthquakes happened

481
00:31:17,880 --> 00:31:19,360
and we have to run to high ground.

482
00:31:24,720 --> 00:31:27,480
(narrator) And that is the problem.

483
00:31:27,480 --> 00:31:32,320
The next megathrust earthquake
may not happen for centuries.

484
00:31:32,320 --> 00:31:34,640
Or it could be imminent.

485
00:31:34,640 --> 00:31:37,640
No one knows.

486
00:31:37,640 --> 00:31:41,080
We don't know whether the entire
Cascadia fault will rupture

487
00:31:41,080 --> 00:31:43,760
like it did in 1700.

488
00:31:43,760 --> 00:31:47,840
We don't know how badly affected
the modern cities will be.

489
00:31:51,880 --> 00:31:55,880
But Yumei Wang, director
of Geo Hazards for Oregon,

490
00:31:55,880 --> 00:31:58,720
believes we must still take action.

491
00:31:58,720 --> 00:32:02,320
(Yumei Wang) We know that a
Cascadia earthquake is inevitable.

492
00:32:02,320 --> 00:32:04,280
We can't prevent earthquakes.

493
00:32:04,280 --> 00:32:08,720
But one thing that we can do
is prevent a lot of the damage.

494
00:32:08,720 --> 00:32:11,600
We can save lives if we prepare now.

495
00:32:15,760 --> 00:32:19,840
(narrator) That preparation must be
based on our current understanding

496
00:32:19,840 --> 00:32:26,040
of what the next Cascadia
earthquake will be like.

497
00:32:26,040 --> 00:32:28,440
What follows is a reconstruction

498
00:32:28,440 --> 00:32:33,320
based on the knowledge of leading 
experts of what may happen;

499
00:32:33,320 --> 00:32:39,560
what it would look and feel like to
experience a megathrust earthquake.

500
00:32:50,120 --> 00:32:52,680
(Tim Walsh) We don't know what
actually sets the earthquake off.

501
00:32:52,680 --> 00:32:57,880
But typically it would probably start
at some rough spot on the fault.

502
00:33:02,320 --> 00:33:07,440
(narrator) The rupture is most
likely to start at one end of the fault.

503
00:33:07,440 --> 00:33:13,320
It would then spread along the fault
at over 7000 miles per hour.

504
00:33:13,320 --> 00:33:17,720
As it tears, the North American plate
which has been pushed inward

505
00:33:17,720 --> 00:33:21,760
would spring back, releasing the strain.

506
00:33:21,760 --> 00:33:25,120
(Robert Muir-Wood) There may be
a region 4 or 500 kilometers long

507
00:33:25,120 --> 00:33:32,400
where the seafloor has suddenly
risen up by 2 or 3 meters.

508
00:33:32,400 --> 00:33:37,560
It happens so fast that it lifts up
the whole body of the water on top of it.

509
00:33:37,560 --> 00:33:42,520
And as a result, suddenly the sea
surface finds itself 2 or 3 meters higher

510
00:33:42,520 --> 00:33:43,520
than it was before,

511
00:33:43,520 --> 00:33:46,680
over a large area, 
and that sets off a wave.

512
00:33:50,240 --> 00:33:52,800
(narrator) This is the tsunami

513
00:33:52,800 --> 00:33:56,240
which would radiate out in all directions.

514
00:33:56,240 --> 00:33:59,880
Part of it would head out into the Pacific.

515
00:33:59,880 --> 00:34:04,000
And part would head directly
for the coast of North America.

516
00:34:05,040 --> 00:34:08,400
(Tim Walsh) It travels at the same
speed roughly as an airliner

517
00:34:08,400 --> 00:34:11,440
out in the open ocean,
perhaps 600 miles an hour.

518
00:34:14,040 --> 00:34:15,480
(narrator) Even at that speed,

519
00:34:15,480 --> 00:34:19,800
it would take many hours to
reach the other Pacific nations.

520
00:34:19,800 --> 00:34:23,080
It would take 5 hours to reach Hawaii.

521
00:34:23,080 --> 00:34:27,000
And more than 10 hours to reach Japan.

522
00:34:27,000 --> 00:34:30,639
Thanks to the sophisticated Pacific
tsunami network,

523
00:34:30,639 --> 00:34:33,000
those countries would get a warning.

524
00:34:37,679 --> 00:34:41,239
(Prof. McGuire) The quake will be
detected by a network of seismographs.

525
00:34:41,239 --> 00:34:43,320
The tsunami, if they form,

526
00:34:43,320 --> 00:34:48,000
will be spotted and identified
and tracked by seabed sensors

527
00:34:48,000 --> 00:34:50,239
which will send,
via buoys on the surface,

528
00:34:50,239 --> 00:34:52,400
a radio message, via satellite,

529
00:34:52,400 --> 00:34:55,280
to the emergency authorities in
the countries around the Pacific Rim

530
00:34:55,280 --> 00:34:56,520
who might be affected.

531
00:34:56,520 --> 00:35:01,840
It's then their job to tell their populations
to evacuate the coastal region.

532
00:35:01,840 --> 00:35:04,160
(narrator) This warning system
should make the distant effect

533
00:35:04,160 --> 00:35:05,560
of a Cascadia earthquake

534
00:35:05,560 --> 00:35:08,960
very different from
the events of Boxing Day.

535
00:35:08,960 --> 00:35:10,560
(Prof. McGuire) I think that
the loss of life remote

536
00:35:10,560 --> 00:35:14,680
from the actual location of the Cascadia
earthquake will be small

537
00:35:14,680 --> 00:35:16,640
when the next big event occurs.

538
00:35:16,640 --> 00:35:17,720
And this is because,

539
00:35:17,720 --> 00:35:20,560
although the waves travel
at the speed of a jumbo jet,

540
00:35:20,560 --> 00:35:23,960
maybe 8 or 900 km an hour
across the Pacific,

541
00:35:23,960 --> 00:35:25,720
it's s huge ocean basin

542
00:35:25,720 --> 00:35:29,360
and it will take many hours for the wave
to reach places like Hawaii, Japan,

543
00:35:29,360 --> 00:35:30,920
which will probably be badly hit,

544
00:35:30,920 --> 00:35:36,080
but they will have plenty of time
to evacuate people to safe ground.

545
00:35:36,080 --> 00:35:40,800
(narrator) But the situation in the
Pacific Northwest would be very different.

546
00:35:40,800 --> 00:35:45,320
The tsunami would arrive there
in half an hour.

547
00:35:45,320 --> 00:35:51,160
And they'd have the earthquake
to deal with first.

548
00:35:51,160 --> 00:35:53,640
The seismic waves
which carry the shaking

549
00:35:53,640 --> 00:35:57,680
would be travelling through the earth
at over 10,000 miles per hour,

550
00:35:57,680 --> 00:36:02,120
much faster than the tsunami.

551
00:36:02,120 --> 00:36:07,320
In just a few seconds 
the earthquake would reach the land.

552
00:36:11,480 --> 00:36:15,440
The earthquake would be at its
most violent here on the coast.

553
00:36:15,440 --> 00:36:17,400
(John Hooper) There right
at ground zero, the shaking.

554
00:36:17,400 --> 00:36:20,160
So the shaking they feel will be
the largest of anybody

555
00:36:20,160 --> 00:36:22,320
because they're nearest
to the fault rupture.

556
00:36:27,080 --> 00:36:30,920
(narrator) But the shaking wouldn't
have reached the inland cities yet.

557
00:36:30,920 --> 00:36:36,200
People here wouldn't even know
that an earthquake had started.

558
00:36:36,200 --> 00:36:40,680
However news would have reached
the emergency services.

559
00:36:47,000 --> 00:36:51,360
This is the Washington State
Emergency Operations Center.

560
00:36:51,360 --> 00:36:54,360
It would be one of the first places
to receive an alert

561
00:36:54,360 --> 00:36:57,720
from the tsunami warning center.

562
00:36:57,720 --> 00:37:00,360
(male # 1) Magnitude 9.

563
00:37:00,360 --> 00:37:05,800
(male # 2) We're activating our EOC
to a phase 3 for a tsunami.

564
00:37:05,800 --> 00:37:08,960
(narrator) Horizon filmed them
rehearsing for a major earthquake.

565
00:37:11,920 --> 00:37:15,880
The two on duty officers would
immediately activate the center

566
00:37:15,880 --> 00:37:17,800
and start calling in staff.

567
00:37:19,600 --> 00:37:22,760
(male #2) And what could be
your possible ETA to the EOC?

568
00:37:22,760 --> 00:37:27,720
(narrator) Their job would be to
coordinate the emergency response.

569
00:37:27,720 --> 00:37:30,800
But there would be no time
to issue a public warning

570
00:37:30,800 --> 00:37:33,400
before the earthquake hits the big cities.

571
00:37:38,840 --> 00:37:41,960
Up to two minutes after
the start of the earthquake

572
00:37:41,960 --> 00:37:47,280
the seismic waves would
reach the city of Seattle.

573
00:37:47,280 --> 00:37:48,960
Because of the distance,

574
00:37:48,960 --> 00:37:52,600
the different types of seismic wave 
would have separated out

575
00:37:52,600 --> 00:37:57,360
with the faster compression waves
reaching the city first.

576
00:37:57,360 --> 00:38:02,160
(John Hooper) The first thing you
sense is a vertical acceleration.

577
00:38:02,160 --> 00:38:03,520
You get pushed up a little bit

578
00:38:03,520 --> 00:38:06,680
and you think it's maybe 
it's the jolt of a train going by

579
00:38:06,680 --> 00:38:08,080
or something of that type.

580
00:38:10,400 --> 00:38:11,480
(Tom Heaton) But then later,

581
00:38:11,480 --> 00:38:15,000
maybe 20 seconds even later
you might feel,

582
00:38:15,000 --> 00:38:19,280
start to feel the shear waves coming in
which are shearing motions in the earth,

583
00:38:19,280 --> 00:38:21,520
the kind of motion that
does most of the damage.

584
00:38:26,640 --> 00:38:29,880
(narrator) These shear waves would
move the earth from side to side

585
00:38:29,880 --> 00:38:32,880
by as much as a meter.

586
00:38:32,880 --> 00:38:35,320
There would also be surface waves,

587
00:38:35,320 --> 00:38:38,560
like ocean waves, rippling
through the solid earth.

588
00:38:39,360 --> 00:38:42,080
(Yumei Wang) If you are in a parking lot,

589
00:38:42,080 --> 00:38:47,040
it's likely that you see waves
rolling across the parking lot

590
00:38:47,040 --> 00:38:49,360
like if you took a carpet and shook it.

591
00:38:52,640 --> 00:38:55,920
(narrator) As the shaking
becomes more and more intense,

592
00:38:55,920 --> 00:39:00,520
people would realize that
this was no ordinary earthquake.

593
00:39:00,520 --> 00:39:03,120
(John Hooper) That shaking
will continue to build.

594
00:39:03,120 --> 00:39:04,760
You'll feel the first sway

595
00:39:04,760 --> 00:39:06,880
and it'll start to build and build and build

596
00:39:06,880 --> 00:39:08,560
and you'll wonder
when it's going to stop.

597
00:39:10,800 --> 00:39:14,760
(narrator) Indoors, objects and
furniture will be hurled about the room.

598
00:39:14,760 --> 00:39:17,480
Parts of the building may start to fall.

599
00:39:17,480 --> 00:39:19,840
(Yumei Wang) Right when you feel
the earthquake shaking,

600
00:39:19,840 --> 00:39:25,240
what we train people to do
is to duck, cover, and hold.

601
00:39:25,240 --> 00:39:27,680
[children screaming]

602
00:39:27,680 --> 00:39:31,600
(narrator) Schools and offices now
practice this life saving maneuver.

603
00:39:31,600 --> 00:39:35,040
Going under a strong desk
and holding onto it.

604
00:39:37,880 --> 00:39:40,680
(Yumei Wang) Anything that might
fall won't fall on you directly.

605
00:39:40,680 --> 00:39:42,200
It will fall on the table

606
00:39:42,200 --> 00:39:46,280
and the whole time you protect
your [missing audio].

607
00:39:46,280 --> 00:39:47,560
(narrator) For people outside,

608
00:39:47,560 --> 00:39:51,880
the major hazard will be falling
debris and shattering glass.

609
00:39:51,880 --> 00:39:53,840
(Yumei Wang) If you're outside somewhere,

610
00:39:53,840 --> 00:39:57,040
the best thing to do is to move
quickly into open space

611
00:39:57,040 --> 00:40:01,360
such as away from a building
where you might have falling objects.

612
00:40:04,240 --> 00:40:07,280
(narrator) Buildings would now
be exposed to huge forces

613
00:40:07,280 --> 00:40:11,360
as they're shunted back and forth.

614
00:40:11,360 --> 00:40:13,640
They unreinforced masonry buildings

615
00:40:13,640 --> 00:40:17,440
would be the first to suffer damage.

616
00:40:17,440 --> 00:40:21,200
(Yumei Wang) The weakest points
start to fail, in most cases,

617
00:40:21,200 --> 00:40:23,160
because they're older structures.

618
00:40:23,160 --> 00:40:24,240
It's the mortar.

619
00:40:24,240 --> 00:40:25,840
(John Hooper) The elements
that support the building vertically,

620
00:40:25,840 --> 00:40:27,000
if they start to come down,

621
00:40:27,000 --> 00:40:29,680
the floors themselves
potentially can come down.

622
00:40:32,360 --> 00:40:35,760
(narrator) Collapsing URMs
could cause many fatalities

623
00:40:35,760 --> 00:40:41,200
throughout the region.

624
00:40:41,200 --> 00:40:45,960
The shaking in Seattle would now
have been going on for two minutes.

625
00:40:45,960 --> 00:40:49,520
But we'd only be hallway through.

626
00:40:49,520 --> 00:40:51,120
(Yumei Wang) For a typical earthquake,

627
00:40:51,120 --> 00:40:55,640
if a building gets damaged
in the first 20, 30 seconds,

628
00:40:55,640 --> 00:40:58,720
it very likely can remain standing.

629
00:40:58,720 --> 00:41:03,760
But if that damaged building is
shaken for another three minutes

630
00:41:03,760 --> 00:41:07,960
then that damage can
propagate into collapse.

631
00:41:10,840 --> 00:41:13,760
(narrator) Meanwhile, the large
movements of the ground

632
00:41:13,760 --> 00:41:17,600
would be making skyscrapers
bend further and further.

633
00:41:17,600 --> 00:41:22,320
(Tom Heaton) you may see the buildings
begin to sway more and more violently

634
00:41:22,320 --> 00:41:26,520
to the point where they start
to perhaps lose windows.

635
00:41:26,520 --> 00:41:32,240
They may, in addition, start to
have some fracturing of welds

636
00:41:32,240 --> 00:41:35,360
in steel frame buildings.

637
00:41:35,360 --> 00:41:39,360
What happens after that
is anybody's guess.

638
00:41:42,600 --> 00:41:46,120
(narrator) The worst case scenario
would be the total collapse

639
00:41:46,120 --> 00:41:47,880
of a high-rise building.

640
00:41:52,760 --> 00:41:55,160
Meanwhile, buildings on higher ground

641
00:41:55,160 --> 00:41:58,400
would be suffering their own problems.

642
00:41:58,400 --> 00:42:02,360
(Tim Walsh) Earthquakes this large
can generate landslides at distances

643
00:42:02,360 --> 00:42:07,480
of up to hundreds of miles away.

644
00:42:07,480 --> 00:42:10,960
(John Hooper) The classic worst
case scenario where you're on a hill,

645
00:42:10,960 --> 00:42:12,680
the land slides,
your house goes with it

646
00:42:12,680 --> 00:42:14,760
and the house will obviously be destroyed.

647
00:42:28,880 --> 00:42:31,240
(narrator) Five minutes after
the start of the earthquake

648
00:42:31,240 --> 00:42:34,600
the rupture would have reached
the northern end of the fault.

649
00:42:34,600 --> 00:42:38,720
Vancouver would still be
experiencing powerful shaking,

650
00:42:38,720 --> 00:42:42,560
but in Seattle, the earthquake
would finally be subsiding.

651
00:42:48,720 --> 00:42:51,920
For people in buildings that
have suffered structural damage,

652
00:42:51,920 --> 00:42:55,120
now it would be time to evacuate.

653
00:42:55,120 --> 00:42:59,160
What would have felt like the longest
few minutes of people's lives

654
00:42:59,160 --> 00:43:01,320
will finally be over.

655
00:43:03,680 --> 00:43:05,400
But on the coast,

656
00:43:05,400 --> 00:43:08,480
the ordeal would have only just begun.

657
00:43:13,080 --> 00:43:16,240
The tsunami unleashed
by the earthquake,

658
00:43:16,240 --> 00:43:19,880
would be minutes away.

659
00:43:19,880 --> 00:43:21,840
For the Pacific Northwest

660
00:43:21,840 --> 00:43:26,800
the tsunami warning system
that should save lives across the world,

661
00:43:26,800 --> 00:43:30,560
would be virtually useless.

662
00:43:30,560 --> 00:43:33,480
(Tim Walsh) There won't be time
for the tsunami warning center

663
00:43:33,480 --> 00:43:35,120
to detect that earthquake,

664
00:43:35,120 --> 00:43:37,880
make a determination
whether or not it was tsunamigenic ,

665
00:43:37,880 --> 00:43:41,440
then send a warning down to
emergency managers in Washington

666
00:43:41,440 --> 00:43:43,400
who will then send it to the people.

667
00:43:43,400 --> 00:43:47,680
That would waste valuable time.

668
00:43:47,680 --> 00:43:50,200
People need to know that
when they feel strong shaking

669
00:43:50,200 --> 00:43:51,440
if they're on the coast,

670
00:43:51,440 --> 00:43:54,120
they need to go to high ground and/or inland.

671
00:43:54,120 --> 00:43:58,200
♪ [music playing]

672
00:43:58,200 --> 00:44:00,480
(narrator) The tsunami will
have started out as a wave

673
00:44:00,480 --> 00:44:02,640
of only a meter or two high

674
00:44:02,640 --> 00:44:05,600
travelling at huge speed.

675
00:44:05,600 --> 00:44:07,480
But as it nears the coast,

676
00:44:07,480 --> 00:44:10,320
it starts to rise up.

677
00:44:10,320 --> 00:44:11,640
(Tim Walsh) Those waves can grow.

678
00:44:11,640 --> 00:44:15,480
They can amplify as more and more
water piles up in shallow water

679
00:44:15,480 --> 00:44:18,480
and all of that energy 
then causes the wave to

680
00:44:18,480 --> 00:44:20,800
slow down and grow in amplitude

681
00:44:20,800 --> 00:44:25,240
and create waves that have been
known to be hundreds of feet high.

682
00:44:25,240 --> 00:44:29,000
(Robert Muir-Wood) That first wave
is often simply a step in the water level

683
00:44:29,000 --> 00:44:33,040
and the water level then
stays up high for 5 or 10 minutes

684
00:44:33,040 --> 00:44:35,200
before it eventually drains away again.

685
00:44:38,200 --> 00:44:40,640
(narrator) Just as happened in Indonesia,

686
00:44:40,640 --> 00:44:42,840
within half an hour of the earthquake,

687
00:44:42,840 --> 00:44:45,640
the tsunami would rush onto the land,

688
00:44:45,640 --> 00:44:51,600
more like an ever growing tide 
than a normal wave.

689
00:44:51,600 --> 00:44:55,920
Anyone who doesn't manage to get
inland and to high ground in time

690
00:44:55,920 --> 00:44:57,640
would be unlikely to survive.

691
00:45:08,040 --> 00:45:13,640
The tsunami will devastate
hundreds of miles of coast.

692
00:45:13,640 --> 00:45:20,280
In total, more than 50,000 square
miles will be affected by the earthquake.

693
00:45:20,280 --> 00:45:23,040
(Yumei Wang) Unfortunately, 
I don't think people understand

694
00:45:23,040 --> 00:45:27,000
that a Cascadia earthquake
is going to be so very different

695
00:45:27,000 --> 00:45:30,440
than the other types of earthquakes
that we've all experienced,

696
00:45:30,440 --> 00:45:33,760
or many of us have experienced.

697
00:45:33,760 --> 00:45:39,000
One of the main differences is that
it's going to affect such a large region.

698
00:45:39,000 --> 00:45:43,280
(John Hooper) It's not just going
to be city of Seattle or city of Portland.

699
00:45:43,280 --> 00:45:47,960
It could be an 800 mile stretch of
Washington, Oregon, and California

700
00:45:47,960 --> 00:45:49,040
that gets affected.

701
00:45:54,760 --> 00:45:56,560
(narrator) Until recently,

702
00:45:56,560 --> 00:45:58,240
many people would
have found it difficult

703
00:45:58,240 --> 00:46:02,360
to imagine that scale of devastation.

704
00:46:02,360 --> 00:46:06,040
But the Boxing Day disaster
changed all that.

705
00:46:09,080 --> 00:46:12,000
(Prof. McGuire) The Indian Ocean
earthquake and tsunami

706
00:46:12,000 --> 00:46:15,240
will remind these people that are
living in the Pacific Northwest that

707
00:46:15,240 --> 00:46:17,920
this is something they
will have to face in the future

708
00:46:17,920 --> 00:46:20,240
and the window of opportunity
that now exists

709
00:46:20,240 --> 00:46:22,160
should be used to make sure that

710
00:46:22,160 --> 00:46:24,520
the people that live in that
part of the word are educated

711
00:46:24,520 --> 00:46:28,000
in terms of how to respond
when the earthquake happens.

712
00:46:28,000 --> 00:46:30,000
(teacher) Quickly.
Quickly, all of you.

713
00:46:30,000 --> 00:46:32,760
(narrator) The simple knowledge
that after an earthquake

714
00:46:32,760 --> 00:46:34,840
people should move away from the ocean

715
00:46:34,840 --> 00:46:36,520
and to high ground

716
00:46:36,520 --> 00:46:39,200
can save lives.

717
00:46:39,200 --> 00:46:42,120
The scientists who
discovered this threat

718
00:46:42,120 --> 00:46:44,240
are now playing their part 
in spreading the word

719
00:46:44,240 --> 00:46:45,520
to as many people as possible.

720
00:46:45,520 --> 00:46:50,040
(Brian Atwater) That line goes
all the way up to a salt marsh.

721
00:46:50,040 --> 00:46:52,240
(narrator) Before the next earthquake.

722
00:46:54,920 --> 00:46:57,800
(Yumei Wang) We knew that this
Cascadia earthquake is imminent .

723
00:46:57,800 --> 00:46:59,800
It's imminent in geologic time.

724
00:46:59,800 --> 00:47:03,360
So basically we're in a race against time

725
00:47:03,360 --> 00:47:05,600
and the more we can get done now,

726
00:47:05,600 --> 00:47:07,080
the more lives we'll save.

727
00:47:08,960 --> 00:47:12,000
(David Yumaguchi) If we have
10 years, is that enough?

728
00:47:12,000 --> 00:47:12,840
Probably not.

729
00:47:12,840 --> 00:47:15,400
If we have 50 years, maybe, you know.

730
00:47:15,400 --> 00:47:18,160
If we have a century,

731
00:47:18,160 --> 00:47:19,640
you know, maybe we'll really be ready.

732
00:47:19,640 --> 00:47:22,440
But do we have a century?

733
00:47:22,440 --> 00:47:23,840
We don't know.

734
00:47:23,840 --> 00:47:27,280
♪ [music playing]

735
00:47:27,280 --> 00:47:29,080
(narrator) The Indonesian earthquake

736
00:47:29,080 --> 00:47:31,840
has given the people of the Pacific Northwest

737
00:47:31,840 --> 00:47:36,840
a glimpse of what
they will one day face.

738
00:47:36,840 --> 00:47:40,680
Now they must heed it's warning.

739
00:47:40,680 --> 00:47:41,400
♪ [theme music plays]