WEBVTT

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The following program

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was funded by the National
Science Foundation.

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[music]

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From east to west,

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from south to north, the United States is a
magnificent patchwork quilt of unique landscapes,

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but it is not always looked like this,

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beneath its fabulous diversity of landscapes
lies the rich and turbulent geology.

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The North American continent.

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[music]

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With the help of science, we know a lot
about North America as geologic story,

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puzzling questions remain.

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Now geologists are banding together
to solve some of these mysteries.

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They’re part of a new 10-year project called
Earth Scope. The biggest survey of the US

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since the Lewis and Clark expedition
of 1804. When earth scope is done,

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we will not only have a better understanding
North America but we will have

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new clues to the forces
shaping the entire Earth.

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[sil.]

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When the west coast of the US,

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people don’t easily forget the powerful
geologic forces at play beneath their feet.

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The downtown section of Santa Cruz has
basically gone. All the old brick,

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and reinforced buildings had collapsed. Hey,
(inaudible). Excuse me. Along earthquake faults,

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major damage has been sustained
and lives have been lost.

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And more earthquakes will surely come.

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[sil.]

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Right here. Scientists have done
numerous earthquakes status.

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They put out instruments to measure
seismic energy coming from quakes.

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They’ve even set off
earthquakes of their own.

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6, 5, 4, 3, 2, 1.

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[sil.]

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Their efforts have yielded important
information, but some scientists that

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the studies need to go further.
One of the geophysicist,

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Mark Zoback has been pushing for 10 years
to get a closer look at earthquakes.

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Now with the help of Earth scope
his determination has paid off.

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In an unprecedented experiment
near Park Field, California,

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Mark and his colleagues are drilling
directly into the San Andreas Fault.

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One of the earth’s most dangerous Faults.

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[music]

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When the drilling finally started, Mark was elated. What we learned
through drilling is going to address questions that scientists

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around the world have been
asking themselves for decades,

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and it’s… it’s very gratifying to know
that we’ll have direct information

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that bears on these questions.

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The biggest question that we hope to
answer is, are earthquakes predictable?

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As we study the faults, and by being

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directly within it, as earthquakes are
about to occur, what is it that we see?

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This is one of the most
spectacular sections

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of the San Andreas Fault, and in fact, one of the
most spectacular sections of any fault anywhere.

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On the Earth’s surface, the San Andreas
Fault leaves an unmistakable gash

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across the landscape. But the
part of the fault scientists

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on afterlife deep below the surface,

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to get there, the drill positioned a mile
from the fault, penetrates straight down

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for about 5,000 feet.

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Then it turns and heads for the fault.

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The target is a zone, two miles down
with numerous small earthquakes,

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most less than magnitude
two occur every year.

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[music]

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Here earthquake monitoring
instruments will be placed

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right where quakes tear the Earth apart.

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Drilling was underway. When
a much larger earthquake,

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a long-awaited magnitude six ruptured
fault 15 miles from the drill hole.

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The CNN Headline News. The quake was
centered near the town of Parkfield

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known as the state’s earthquake capital, it
is one of the… One of Mark Zoback students,

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Naomi Boness was working at
the site when it happened.

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All of a sudden the trailer started shaking very
violently, and it took me a moment to realize

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what was going on and it was my very first
earth quake, so I’d nothing to compare it to,

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so I’m talking to Mark on the phones saying,
\"There’s an earthquake. It’s my first earthquake.\"

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[music]

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It was very exciting for us to capture this earthquake
which we’ve been (inaudible) happening 1988

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and that really happened much, much later.

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We actually have seismometers in the pilot
hole, that recorded that earthquake

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very accurately down at
depth umm… in the earth.

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The scientists will continue to take measurements
before, during and after earthquakes.

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Whatever they discover will be
disseminated on the internet.

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As part of Earth scopes plans to immediately share new
data the scientists worldwide. Shut it in. Shut it in.

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[music]

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Earthquakes aren’t the only
mysterious geologic force

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being explored by Earth scope.

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A curious puzzle lies in another
geologically turbulent area,

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the Basin and Range, the place with the
most Mountains in the continental US.

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Here, the thin crust of the Earth

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is stretching apart, but
how exactly is a mystery.

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[music]

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In the town of Winnemucca, Nevada, an intense
Earthscope experiment is aimed at solving this mystery.

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Okay. So 2219,. It’s actually it’s actually
being in and out twice as kind of 1135…

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With encouragement from the experiments
leader Simon Klemperer, students

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from several universities are loading
their equipment for days field work.

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We’re trying to understand the
structure of the Earth’s crust

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beneath northernmost Nevada and northeastern
California, and we’re doing this

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because we want to understand the tectonics of the basin
and range province, and how the cross stretchers.

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In our experiment, we’re
trying to look down

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30, 40, 50 kilometers and understand
how the entire crust has responded

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to the stretching process. To take
a snapshot of the Earth’s crust

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beneath Winnemucca, nine teams of
students are setting up a network

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of 1,000 seismic instruments and a
carefully planned grid. Thirty one.

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What we’re doing is we’re deploying

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seismic instruments for study, we’re seeing
now basically sensors called geophone

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and all these instruments are gonna
sensing the vibrations in the ground.

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You know, stops getting closer to (inaudible).
Yeah! To generate those vibrations,

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the scientists set off explosions
in the still hours of the night,

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when traffic and other
unwanted noises at minimum.

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Three, two, fire in the hole.

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[music]

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Seismic waves from the explosions
travel down through the ground below

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and bounce back up to the sensors
put out by the students.

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The data the sensors record will tell the scientists the
kind of material through which the waves have traveled

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and that information the scientists hope

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will help reveal the deep hidden force
that is tearing apart the basin and range.

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724 Victor 430 (inaudible) box.

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430 (inaudible) ahead. Yeah, can you give
me an old faithful prediction please?

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Next eruption is 1:20 PM. Copied, than you.
It’s uh… 1:20.

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[music]

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In the US the hotbed of
geologic activity is

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unquestionably the West,

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volcanoes, earthquakes they’re all here.

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What is driving this turmoil?

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Clues to that puzzle, surprisingly,
by all the way across the country

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in the heart of the Appalachian Mountains.

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[music]

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Geologists working here have
found that the Appalachians

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had been wildly folded and compressed.

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Lab studies showed that some
of the rocks are very old

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and had been subjected to tremendous
pressures and high temperatures.

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A powerful force must have been
exerted against these rocks

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but what was it? According to
the theory of plate tectonics,

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the continents are rigid plates of rock,

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floating on the Earth’s hot mobile mantle.
About 300 million years ago,

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the huge landmass of
Europe and Africa collided

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with North America to form
the super continent Pangaea.

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The enormous buildup of rocks and the
collision zone, created a mountain range

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as tall as the Himalayas,
the ancient Appalachians.

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[music]

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But how did those rocket giants become the
Softly rounded low shapes we see today.

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[sil.]

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Through much fieldwork, geologists
concluded that the Appalachians

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are greatly eroded version of that
original giant mountains range.

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Dirt and rocks streamed off the mountains
and are carried away by rivers.

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[sil.]

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Eventually, the material built up into thick sediments to
create the coastal plain where familiar cities now sit.

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[music]

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Essentially this is the ancient
geologic story of the eastern US,

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but what does it have to do
with the story out West?

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After the collision

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that created the Appalachian, a rift developed
along the east coast of North America,

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hot magma welled up from
the rift and hardened

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into new crust.

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Ocean water and moved in,
as rifting continued,

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the continents were forced apart
and North America moved westward

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oddly. Some pieces of ancient

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Europe and Africa broke off and
stayed on the North American plate.

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One piece of Africa is now called Florida.

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As the continents drifted westward,

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Pacific oceanic plate
had to make way for it.

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This set off a chain of events that forever linked
the geologic story of western North America

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with that these heavier Pacific Plate

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began to dive or sub-duct under the
more buoyant North American Plate.

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This piled up great chunks
of the Earth’s crust,

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creating rugged mountain ranges
up and down the ancient coast.

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One of those mountain ranges became
the magnificent Cascade Range

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of the Pacific Northwest.

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But subduction continued and the oceanic plate
melted as it sank into the hot mantle below.

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The melted crust became
magma, that rose backup

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through fractures in the rock
to create powerful volcanoes.

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The most active of the volcanoes
today is the explosive

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Mount St. Helens in Washington.
Other volcanoes,

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now it stinked(ph) and eroded away.
Made up the original Sierra Nevada,

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the towering granite walls of Yosemite

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were once subterranean magma chambers
that fueled the ancient volcanoes above.

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But geologists who are drawn

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to study the awesome force of subduction,
still have many unanswered questions.

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Okay. We’re ready to start the
engine at any time. Okay.

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This is made subduction,
the focus of another

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large-scale earth scope experiment. Okay.

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All over the west,
Geodesists are installing

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hundreds of sophisticated global
positioning system stations to capture

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subduction live in real time.

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We’re out here building a continuous GPS
station Global Positioning System station

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that’ll run continuously all of
the time, uh… runs of batteries

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and solar panels and we get the data through cellular
technology and we’re out here monitoring earth moving.

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The other part to this the
station that we have here

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is a constellation of 29 satellites
that are orbiting the Earth

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and these satellites send out
signals that are picked up

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by antennas, such as the one that
we just finished constructing here.

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And what the… the satellites do for
us is it enables us to calculate

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our position on the surface of the Earth
very accurately to within a few millimeters.

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Scientists will measure how
fast and in what direction

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the Pacific and North
American plates are moving.

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This could tell them something they
badly want to know, precisely where

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and how fast is subduction
occurring in the western US.

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Answers to these questions are vital

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for millions of people living in cities like
Seattle, which sits in the shadow of the dormant

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but not extinct volcano, Mount Rainier.

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Anywhere up here. The access can be north.
Earth scopes intensive study of subduction

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also promises to give us a much better
picture of the entire Western US.

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For subduction is the major force in
the building of this rugged land.

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[music]

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But understanding subduction role did not
come easily to geologists working here.

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The more they looked, the
stranger the story became.

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What was very revealing to geologists
that we’re mapping very carefully

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in California, also in Alaska and
even places in British Columbia

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is that you would often have two
areas, right next to each other

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that were so different
in rock type and age.

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How could these odd arrangements
of rocks be explained?

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Maybe we can run some tests. I wanna get
something that isn’t quite as weather(ph).

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Okay. Scientists discovered that
some of the rocks that formed out

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in the ocean. Volcanic islands

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and chunks of crust on the pacific plate,
instead of diving under the continent

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that docked with the continent,

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this meant that the West Coast we see
today did not even exist far back

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in geologic time. In fact,
the original west coast

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was a thousand miles
inland from today’s coast.

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It is marked by the Rocky Mountains, a great
mountain range pushed up by subduction long ago.

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Most of the land to the west
of the Rockies was tacked on

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to the original Continent by subduction.

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The land to the east of the
Rockies is called the crater.

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This is the flat stable
original part of the continent.

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The North American continent
is split into a stable part

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which is the east and more active part
which is the west, more active part

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we’re familiar with through the movements of the
San Andreas Fault or Mount St. Helens volcano

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and the opening of the basin and range,

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but what’s the transition between the west
and the east? The east is important too

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because it’s very old, much older than
the west. It has recorded history

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of how continents go assemble
something that the west doesn’t have.

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And if we understood the transition
from the west to the east,

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maybe we’d be able to understand some of
the forces that cause continents to move

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and that cause continents to deport(ph).

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[music]

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Some scientists believe

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that the best way to really see how the
restless west and the steady east fit together

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is to conduct. For the first time eve, r
a seismic study of the entire country

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and that is what earth
scope is set out to do.

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In a corner of a vineyard
in (inaudible) California,

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geophysicist Marcos Alvarez and
his colleagues are installing

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one of the first seismometers
of this network.

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This extremely sensitive instrument
will detect the faint ground motion

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generated by earthquakes on the other side of
the globe in China or Indonesia or Afghanistan.

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Technique to image the
Earth is very similar

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to a (inaudible) technique just as a few go into
the doctor and vibrate when part of your body

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and they receive and on the other end, they make a map of your
body where basically the earthquakes are vibrating the earth

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and we’re receiving at these stations, and then
in about 10 years we’ll get a most beautiful

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image of that entire Earth, and its Earth
exploration more than anything else.

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[sil.]

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Okay. Now we’re gonna cover this up, the
next time we say it will be in two years.

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This is the 13th one of
these, only 387 more to go.

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This is one station out of 400 sessions

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that will be deployed around the West Coast United
States in an array. About seven kilometer grid

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between each station and after
that first footprint is installed

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which will take about 18 months to two years,
we’ll start picking up the first ones that

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we installed, it kinda roll it like
a carpet across United States.

00:20:50.000 --> 00:20:54.999
And then about 10 years, we’ll reach Maine.

00:20:55.000 --> 00:20:59.999
Although Seismic Network is starting

00:21:00.000 --> 00:21:04.999
where the action is in the West,

00:21:05.000 --> 00:21:09.999
Marcos predicts there will be surprises in story
elsewhere, below the craton, for example.

00:21:10.000 --> 00:21:14.999
Well, there’s central part of the United
States like kind of this is people think

00:21:15.000 --> 00:21:19.999
there’ll be nothing interesting there because there are
any mountains but nobody’s really liked, so we’ll see.

00:21:20.000 --> 00:21:24.999
There’s been spotty experiments in
different places that not a huge

00:21:25.000 --> 00:21:29.999
wholesale network going through
the interior part of a continent.

00:21:30.000 --> 00:21:34.999
[music]

00:21:35.000 --> 00:21:39.999
What is known about the
Central US, the craton

00:21:40.000 --> 00:21:44.999
is that it is extremely
old, billions of years old.

00:21:45.000 --> 00:21:49.999
One place to see the ancient rocks of the
craton is on the shores of Lake Superior,

00:21:50.000 --> 00:21:54.999
which lies in the very heart of the
original continental landmass.

00:21:55.000 --> 00:21:59.999
The only reason we can see these
rocks is because glaciers plowed

00:22:00.000 --> 00:22:04.999
through this region during the Ice
Ages, scraping off layers of sediment

00:22:05.000 --> 00:22:09.999
that once covered the rocks.
In the process,

00:22:10.000 --> 00:22:14.999
the glaciers gouged out the great lakes.

00:22:15.000 --> 00:22:19.999
But in the rich agricultural
breadbasket of the Midwest,

00:22:20.000 --> 00:22:24.999
the ancient rocks of the craton remain
deeply buried under miles of sediment,

00:22:25.000 --> 00:22:29.999
but the glaciers never made it this far.

00:22:30.000 --> 00:22:34.999
These hidden rocks are for
the most part stable,

00:22:35.000 --> 00:22:39.999
asleep geologically. But
near Memphis Tennessee,

00:22:40.000 --> 00:22:44.999
something woke up these
rocks in the year 1812.

00:22:45.000 --> 00:22:49.999
[music]

00:22:50.000 --> 00:22:54.999
A massive earthquake, measuring
8.3 on the Richter scale rattled

00:22:55.000 --> 00:22:59.999
the entire eastern half of the US.
Seismic activity

00:23:00.000 --> 00:23:04.999
continues here today.

00:23:05.000 --> 00:23:09.999
Monitoring these earthquakes, scientists
were surprised to find evidence

00:23:10.000 --> 00:23:14.999
of a deeply buried Fault. The
New Madrid(ph) seismic zone.

00:23:15.000 --> 00:23:19.999
It’s related to the initial
breakup of Pangaea,

00:23:20.000 --> 00:23:24.999
250 million years ago, some of
their rifting or spreading apart

00:23:25.000 --> 00:23:29.999
began there but never went to completion.

00:23:30.000 --> 00:23:34.999
But if the rifting stopped long ago,

00:23:35.000 --> 00:23:39.999
why was there an earthquake so recently?

00:23:40.000 --> 00:23:44.999
What caused the buildup of enough
stress to shatter the Earth?

00:23:45.000 --> 00:23:49.999
Scientists hoped that earth
scope rolling seismic study

00:23:50.000 --> 00:23:54.999
will shed light on these strange
events in an otherwise stable craton.

00:23:55.000 --> 00:23:59.999
[music]

00:24:00.000 --> 00:24:04.999
There are other burning questions
waiting earth scopes probes.

00:24:05.000 --> 00:24:09.999
A big one is how sick the
crust and upper mantle

00:24:10.000 --> 00:24:14.999
are beneath the craton. Recent
studies indicate that they may be

00:24:15.000 --> 00:24:19.999
much deeper than previously thought.
If this is true,

00:24:20.000 --> 00:24:24.999
it would have major implications for geologists
most important theory, plate tectonics.

00:24:25.000 --> 00:24:29.999
Instead of having thin
continental plates, it may be

00:24:30.000 --> 00:24:34.999
that the continents are in fact thicker barges
that are just plowing through the upper mantle.

00:24:35.000 --> 00:24:39.999
If that’s the case, we have to revisit our
understanding of plate tectonics and the forces

00:24:40.000 --> 00:24:44.999
that drive the plates. There you go.

00:24:45.000 --> 00:24:49.999
There’s (inaudible)… As earth scope
moves forward, new discoveries

00:24:50.000 --> 00:24:54.999
will undoubtedly lead to new questions
about out restless continent.

00:24:55.000 --> 00:24:59.999
If you look at the textbooks there’s some very
beautiful images and that seems… seems as

00:25:00.000 --> 00:25:04.999
if we know everything that’s down there, but in fact, every
time that we do an experiment somewhere in the world,

00:25:05.000 --> 00:25:09.999
we discovered something else is not
quite what those cartoons for sure.

00:25:10.000 --> 00:25:14.999
So we should go from that ring and…

00:25:15.000 --> 00:25:19.999
And that throws the door wide open for young
people who are getting involved in Earth scope.

00:25:20.000 --> 00:25:24.999
For them, the possibility
of making a contribution

00:25:25.000 --> 00:25:29.999
to scientific knowledge and to people safety
and geologically active areas is very real.

00:25:30.000 --> 00:25:34.999
Very interested in earthquakes

00:25:35.000 --> 00:25:39.999
and the impact that they have
on society and understanding

00:25:40.000 --> 00:25:44.999
how earthquakes happen and
might eventually lead to

00:25:45.000 --> 00:25:49.999
prediction of earthquakes which would
in turn help people all over the world.

00:25:50.000 --> 00:25:58.000
[sil.]

00:27:40.000 --> 00:27:45.000
Funding for this program was provided
by the National Science Foundation.