All language subtitles for Yellowstone.Supervolcano.American.Doomsday.2021.1080p.WEBRip.X264-KOMPOST_track3_[eng]

[beep]

[music playing]

NARRATOR: On planet Earth,
there are 500 active volcanoes,

every one a potential killer.

BRYAN WALSH: When
a volcano erupts,

it's like nothing
else on this planet.

It's just a truly
awesome reminder

of the power of the earth.

NARRATOR: Once they erupt,
nothing can stop them.

CHRISTOPHER JACKSON:
Their activity can affect

millions to billions of people.

NARRATOR: And one of
the deadliest of all,

a super volcano, lies in America
beneath Yellowstone National

Park.

You can imagine what the scale
of this, the amount of material

that you'd be injecting
up into the atmosphere

would cover or blanket
most of the United States.

[explosion sound]

NARRATOR: A super
eruption here will

be like nothing seen before.

JOHN GRATTAN: Hurricanes
of superheated volcanic ash

traveling across the landscape
at several miles an hour

with burning
everything in its path.

CHRISTOPHER JACKSON: It would
look like hell on Earth.

NARRATOR: This
disaster could soon

overwhelm the United States
and have a global impact

that lasts for years.

[lightning strike]

BRYAN WALSH: There's no system.

There's no emergency
plan in place to deal

with anything on this scale.

NARRATOR: The human
cost, unthinkable--

Entire cities wiped off the map.

BRYAN WALSH: Potentially,
a super volcanic eruption

on the scale of
Yellowstone could

be a species-ending event.

NARRATOR: Yellowstone
is a ticking time bomb.

But amazing new
technologies are revealing

the inner workings of this
dangerous beast like never

before.

MATTHEW WATSON:
We're actually flying

smack dab into the
middle of the ash cloud,

as the volcano erupting.

NARRATOR: Can we survive
and how likely is

it to happen in our lifetime?

[explosion sound]

NARRATOR: Yellowstone--
Its breathtaking beauty

has attracted both
settlers and tourists

for thousands of years.

BRYAN WALSH:
Yellowstone is really

an amazing natural wonder.

There's a reason why it was
one of the first national parks

the US ever created.

NARRATOR: The park is home
to an extraordinary range

of wildlife.

It's been called
America's Serengeti--

From elk and bison, to super
predators like grizzly bears.

BRYAN WALSH: You get a glimpse
of what the US West used

to be like before
it was settled,

before it was clear, before
it was turned a bunch of it

into farmland.

NARRATOR: Yellowstone is more
than a haven for wildlife.

The forces that
shape the land makes

for a park like none other.

BRYAN WALSH: Yellowstone has
a sense of magic around it.

It's really being able to
see the workings of geology

in real time.

NARRATOR: Across the park,
there are more than 10,000

spewing colorful and wildly
energetic geothermal features--

From the mighty Old
Faithful geyser spouting up

to 8,400 gallons of water
every time it gushes,

to Mammoth Hot Springs--

A fantastical landscape
of limestone terraces.

But what is it that
fuels the rolling mud

and breathtaking geysers?

BRYAN WALSH: You know
you're seeing a landscape

that's being shaped by
the volcanic and geologic

forces beneath it.

NARRATOR: With forces this
powerful below ground,

the outcome is inevitable.

[explosion sound]

BRYAN WALSH: There's going to
be one day with Yellowstone

where enough pressure, enough
heat, enough energy will build

on that system that they will
actually burst to the surface

all at once.

NARRATOR: Yellowstone
is a disaster

waiting to happen with
the power to change

the face of the Earth.

To better understand the impact
of a modern day super-blast,

scientists look to
the deadliest eruption

recorded so far in US history.

Mount St. Helens sits
50 miles Northeast

of Portland, Oregon, part of
the Cascade Mountain range.

It's young in geological terms.

Its highest peaks only formed
within the last 100,000 years.

The Pacific Northwest of--
Of the USA is famous for its--

Its volcanoes.

There's-- there's a
long line of them going

up from California,
up through Oregon,

and into Washington State.

NARRATOR: People knew
it was a volcano.

But since there had been
no major eruption here

within living memory,
few visitors or locals

fear the mountain.

Like Yellowstone, it seemed
peaceful and dormant.

There were people living
on the margins of Spirit Lake

here.

And there were lodges.

There were summer camps.

This was a very active
recreational area.

And this was all a
dense, old growth forest.

NARRATOR: But then,
in early 1980,

this serene getaway started
to show its true colors.

An earthquake swarm.

An alarming series
of seismic events

indicated trouble was brewing.

[machine clicking sounds]

CLIVE OPPENHEIMER: The signs
of an impending eruption

really became obvious as
a flank of the volcano

was bulging out tens and
eventually about 100 meters.

This is a phenomenal
scale of what

we call ground deformation.

ALEXA VAN EATON: That
bulge was new magma coming

into the volcano,
and it was growing

at a rate of 5 feet per day.

So that alerted scientists.

It alerted locals that there
was something seriously

going on at Mount St. Helens.

NARRATOR: Geologist
Keith couldn't resist

getting a closer look
at this development

happening in real time.

KEITH RUNHOLM: I got there
in the afternoon with a six

pack of beer and a
science fiction novel

and sat there and watched.

And the mountain was very
similar to what you see today--

Just quiet, a mountain
off in the distance.

NARRATOR: Keith set up camp
at an observation point,

10 miles from the mountain.

If you think you're 10 miles
from the center of a city,

and a bomb goes
off, or something,

you're pretty safe because in
our normal day-to-day life,

nothing gets us from 10 miles.

NARRATOR: But then, at 8:32
AM, May 18, Keith witnessed

something he couldn't believe.

I glanced out at
the mountain, and

the entire north face of Mount
St. Helens was sliding down.

NARRATOR: The deadly
eruption had begun.

Immediately, a magnitude 5.1
quake triggered a landslide.

And not just any landslide,
this was the largest

in all of recorded history,
barreling down the mountain

at up to 155 miles per hour.

KEITH RUNHOLM: This cloud
kept coming-- coming

towards me and towards me.

And so I just said, I
have to get out of here.

NARRATOR: Keith
bolted to his vehicle

and raced down the mountain.

KEITH RUNHOLM: I was frantically
driving down the road,

trying to escape a
onrushing ash cloud.

There were golf-ball-sized
rocks coming through the trees

and cascading down around me.

NARRATOR: Narrowly
escaping death,

Keith survived mother
nature's wrath by following

another vehicle to safety.

Mount St. Helens was an extreme
and violent volcanic event,

a startling reminder of
the devastating power

of the volcanoes in America.

Scientists needed to
understand what had just shaken

the ground beneath their feet.

And luckily for them,
Mount St. Helens

left behind an amazing
trail of evidence.

ALEXA VAN EATON: We're
about four miles north

of the volcano, and we can
see these incredible layers

with a really sharp
contact between deposits

from that lateral blast and
pyroclastic flow deposits

from the afternoon on May 18.

[explosion sounds]

NARRATOR: While many eruptions
leave a similar record behind,

this one is clearer than most.

Now, what's extraordinary
about Mount St. Helens

is that we can pin these
layers down to the minute

because we have the visible
evidence and the stories

to reconstruct what happened
during this eruption.

NARRATOR: To the
trained eye, it's

possible to read each layer
and forensically reconstruct

the events that produced them.

In this lower section from the
deposits of the lateral blast,

you can see there are
big clasts in here.

These are rocks from
the bulge that blew out.

It was uncorked like a champagne
bottle and blew out laterally.

NARRATOR: This was
the first stage

of the eruption, the
explosive moment that punched

out the side of the volcano.

And then, on top of this,
we can see that there's

a very, very slender
layer from that fine ash

that had been lofted up.

And then, it rained
right back down.

[crackling sounds]

NARRATOR: The
geology bears witness

to a deadly torrent of
superheated gas and ash,

known as pyroclastic flows.

ALEXA VAN EATON: After the
eruption column rose vertically

into the atmosphere
17 to 18 kilometers,

there were boil-over
pyroclastic flows-- meaning,

the eruption column
filled up the crater

and kind of spilled over.

And those pyroclastic
flows of ash and gas

traveled all the way
up here to the ridge

and deposited these
thin layers of fine ash.

NARRATOR: The nine-hour
eruption killed 57 people,

destroyed 200 homes, 47 bridges,
and 185 miles of highway.

But as large as it
seems, Mount St. Helens

is far from the biggest
volcanic event on record.

Volcanic eruptions are
measured on the VEI scale.

The volcanic explosivity
index takes into account cloud

height, amount of
material thrown out,

and how long the eruption
lasts on a scale from 0 to 8.

It's not that 5 is just
a little bit bigger than 4,

or 6 is a little
bit bigger than 5.

Instead, there's a 10-time
factor between each of these.

So a 5 is 10 times
bigger than a 4.

A 6 is 10 times bigger than a 5.

An 8 is 1,000 times
bigger than a 5.

So these are epically big
eruptions when we're talking

about VEI 8 scale explosions.

[explosion sound]

NARRATOR: The 2018
Krakatoa eruption

came in at a VEI 3, categorized
as a catastrophic event.

Pompeii, regarded as one of
the deadliest eruptions in

European history, hit a VEI 5.

But an event on the
scale of a super volcano

is almost off the charts.

With a mega-colossal
event from Yellowstone,

projected to
unleash a VEI eight,

an event last seen
over 630,000 years ago.

CLIVE OPPENHEIMER: When
we get up to magnitude 8,

if you've stuck it all
within the entire USA,

you know, you were
still knee-deep in ash.

NARRATOR: So what would
the immediate aftermath

of an eruption at the massive
Yellowstone volcano look like?

The initial impact
would be devastating.

A full eruption would launch 2
million tons of sulfuric acid

into the atmosphere, demolishing
Wyoming, Utah, and Idaho

in its kill zone, submerging
the states under 13

feet of ash and magma coverage.

The air would be toxic.

But there is only
one way to appreciate

the sheer awesome
size of Yellowstone,

and that's from the air.

[helicopter whirring]

[music playing]

NARRATOR: Volcanologist
Madison Myers

has been studying Yellowstone's
geology for many years.

She understands the terrifying
secrets hidden below the park's

picturesque landscape.

Today, she'll be flying overhead
to get a bird's-eye view

of this vast expanse.

MADISON MYERS: We're
flying over a really

large hydrothermal field.

And so this is shown by all
of this kind of white material

that we see.

We see hydrothermal
holes everywhere.

So this is the-- the signal
of Yellowstone saying,

I'm still here.

I'm a magma body.

Pay attention to me.

NARRATOR: It's this
intense heat, driven

by underground
magma, that's given

rise to many of Yellowstone's
most iconic sites.

Grand Prismatic is
the largest hotspring

in the US and third largest
in the entire world.

MADISON MYERS:
Grand Prismatic is

supplying the heat that
is necessary to fuel

this geothermal activity.

NARRATOR: Yet, the Yellowstone
ecosystem contains one

geological feature, so
large it simply cannot be

grasped from the ground level.

Its epic scale can only be
appreciated from way above.

MADISON MYERS: We
are approaching

Yellowstone caldera.

We're approaching the
edge here, and you

can see that there's
kind of a cliff feel

to what we're about to see.

NARRATOR: A caldera
is what forms

after a magma
chamber empties out

in a super volcanic eruption.

With nothing left to support the
ground above an empty chamber,

it collapses, leaving a
cauldron-shaped depression.

It's only from
this vantage point

that the full scale of the
Yellowstone caldera is visible.

MADISON MYERS: And to
give you perspective,

it's taking us about
20 minutes to fly

from one side of the caldera to
the other side of the caldera.

So it seems like everything
that Yellowstone does,

it supersizes.

NARRATOR: Geologists think
this gigantic caldera formed

in Yellowstone's last super
eruption 640,000 years ago

and measures 35
miles by 45 miles.

It would have been right at the
top of the volcanic explosivity

index.

The ashfall alone
from this event

would have had a
continent-wide impact.

You can imagine, with the
scale of this, the amount

of material that
you'll be injecting up

into the atmosphere, how
it would cover or blanket

most of the United States.

And this would be something
that would not be a quick event.

This would likely occur
over days or weeks.

NARRATOR: Within the first
24 hours of a new eruption,

scientists predict a
10-foot layer of molten ash

would spread up to 1,000
miles from the park.

Depending on wind direction, the
rest of Colorado, South Dakota,

Nebraska, and
Kansas are engulfed

in the primary ash zone as
the plumes of toxic clouds

choke the skies.

Any living creature
in America would

be in great danger, potentially
smothered by ashfall.

Before we understood that
Yellowstone was a volcano,

there was a smoking
gun for the destruction

these catastrophic
eruptions can cause

but in an unlikely place, about
1,000 miles away in Nebraska.

In 1971, paleontologist
Mike Voorhies

was out in the
field in Nebraska,

mapping rock exposures at
a farm, when a protruding

bone caught his eye.

MIKE VOORHIES: There happened to
be a skull of a baby rhinoceros

sticking out of this ash bed.

And once we started
checking it out,

it turned out that
there was not just one,

but hundreds, and hundreds,
and hundreds of skeletons

buried in this ash bed.

NARRATOR: Mike had
stumbled across

a giant prehistoric graveyard.

And now, he works in
a unique and active

museum, uncovering the mysteries
hidden beneath his feet.

This is the one place in
the world where you can stand

and see whole three-dimensional
skeletons of large animals

preserved in volcanic ash.

So it is something unusual
to turn up at the edge

of a cornfield in Nebraska.

When you dig down to the
bottom of the volcanic ash,

you would be looking at what
the bottom of the waterhole

looked like on the day
before the ash fell.

This was something that happened
almost 12 million years ago.

Herds of prehistoric
rhinoceroses,

camels, and horses met
their death in a waterhole.

NARRATOR: All these
animals were buried

in ash that remained
relatively soft,

so they're incredibly
well-preserved.

One rhino still bears
her unborn fetus.

And in others, we can
actually see the contents

of their last meal.

The question was, what had
killed all these animals?

It turns out, there was
a clue in the bones.

Dr. Winsome Eu is a
veterinary pathologist.

When cadavers arrive
at the lab, it's

her job to perform a necropsy
or animal autopsy to determine

the cause of death.

WINSOME EU: A normal,
healthy skeleton,

the bones will be smooth.

They'll be thin.

They won't have these bumps
and fluffy protrusions.

NARRATOR: This bone
growth is an affliction

known as Marie's disease.

WINSOME EU: So this
is excess bone growth

that would be
similar to what you

would see in Marie's disease
or hypertrophic osteopathy.

This is the rear
foot of a cat that

has these bony proliferations
around the toes, and then

the paw, and around
the nasal cavity--

And then, finally a little
bit here around the mandible.

Generally, in
veterinary species,

this happens due
to lung disease.

So it could be tuberculosis,
or some sort of pneumonia,

or most commonly, it
would be seen in cancer.

NARRATOR: The presence of
Marie's disease on the Nebraska

fossils was a sure
sign the animals

died from severe
respiratory problems.

When scientists compared
ash samples from Nebraska

and Yellowstone, their
similar compositions

confirmed a shared source.

Despite the volcano eruption
over 1,000 miles away,

the ash was falling thickly
enough here in Nebraska to kill

these large, powerful animals.

It was the first
evidence of how wide

the impact of a Yellowstone
eruption can be.

Scientists now think
Yellowstone sits

atop a volcanic hotspot,
a source of intense heat

from deep within the Earth.

CLIVE OPPENHEIMER: The heat
that is escaping from the Earth

as solid rock in the
mantle, and some of it

melts, generating volcanoes.

And it's a bit like having some
soup in a pan on a stove, where

it's being heated
from below, and it's

been cooled from above.

And this sets some currents
of-- of hot liquid that then,

as they cool, they
sink back down again.

NARRATOR: The
Yellowstone hotspot

has produced not one, but
three super eruptions over

the past two million years.

Could an eruption on that scale
happen again on a continent

that's now heavily populated?

BRYAN WALSH: The Earth
beneath Yellowstone

is literally moving
up and down every day.

It almost breathes
because that's

the power of the molten rock.

NARRATOR: It's an
ominous sign that this is

still a highly active system.

JOHN GRATTAN: There are no
indications at the moment

that the-- that the magma
chamber below Yellowstone

is cooling down
and settling down.

So certainly, there
is the potential

for a super volcanic
eruption from that site.

NARRATOR: One of the deadliest
effects of a Yellowstone

super eruption would
be the massive volume

of volcanic ash ejected.

Seattle, San Francisco, and Los
Angeles in the West to New York

and Washington D.C. in
the East would be covered

in between 6 to 10 feet of ash.

Yellowstone could once
again blanket all of the US.

But to learn more
about the risks,

it's vital scientists explore
volcanoes' inner workings.

And to do that, it's necessary
to venture deep underground.

There's a sleeping volcanic
monster beneath Yellowstone

National Park, a deadly
hotspot that's produced

world-shattering eruptions.

CLIVE OPPENHEIMER: Yellowstone
volcano has been responsible

for three super eruptions,
one 2 million years ago,

one 1.3 million years ago, the
most recent 640,000 years ago.

NARRATOR: Each of
these eruptions

had a devastating impact on
what is now the United States.

CLIVE OPPENHEIMER: These
are all colossal events

that dispersed ash
over a very wide

part of the American continent.

We can-- we can locate
still the ash deposits in--

In many places.

NARRATOR: Today, a super
eruption would cause power

grids to fail across the US.

Inhaling the toxic ash would
cause millions of deaths,

with people buried below it
like a modern day Pompeii.

But to understand the
subterranean causes

of Yellowstone's
previous eruptions,

you need to travel thousands
of miles across the Atlantic

to Iceland.

[music playing]

NARRATOR: Most of the
time as the name suggests,

this small island is
frozen and windswept.

But Iceland is also a
place of raging fire.

CLIVE OPPENHEIMER: Iceland
is a geologist's paradise.

It's a vulcanologist's paradise
because it's essentially

one great big volcano.

The whole thing is volcanic.

NARRATOR: Volcanologist
Freysteinn

Sigmundson studies Iceland's
extraordinary geology.

Today, he's heading
into the field

to explore a hidden giant.

Discovered in 1974,
its exact origin is

still something of a mystery.

NARRATOR: Rocky
landscapes like this form

when flowing lava
cools, solidifying

into bizarre rock formations.

Today, little more
than moss and grass

grow on the area's
exposed rocks.

NARRATOR: Freysteinn
is following

the trail back to its source.

It leads him to
the craggy summit

of the Thrihnukagigur volcano.

Currently inactive,
its last major eruption

was around 4,000 years ago.

Freysteinn is about
to do something

that would mean certain death
anywhere else in the world.

He's going to explore
inside a magma chamber.

NARRATOR: 4,000 years
ago, this chamber

was seething with molten rock
at over 2000 degrees Fahrenheit.

Just prior to its
eruption, the pressure

would have mounted,
eventually reaching

the point of no return.

Understanding this
behavior could serve

as a warning for Yellowstone.

Today, the chamber is
fully drained, leaving

only a huge empty cavern.

It extends almost 700
feet into the depths.

NARRATOR: This vast cavern was
once bursting with molten rock.

NARRATOR: Thousands
of years ago,

red hot magma forced its
way toward the surface

through these very cracks.

But the chamber provides
another vital piece of evidence

to the mind-bending
scale of an eruption.

NARRATOR: Freysteinn measures
each side of the chamber

to estimate its total
volume, and the results

are staggering--

Around a quarter of a
million cubic meters,

equivalent to nearly 400
Olympic swimming pools.

When it erupted, it was
a massive volcanic event.

But it would be dwarfed by
a super volcano eruption.

NARRATOR: A full-sized
super eruption

would be a geological event
on a totally different scale,

potentially big enough
to reshape a continent.

So just how large is the
present day magma chamber

sitting beneath Yellowstone?

Spanning from Wyoming
into Montana and Idaho,

Yellowstone supervolcano
will one day erupt again.

It will be a global
catastrophe with

the dangerous volcanic clouds
reaching as far as Europe

within the first 72 hours.

Ash and gases causing
toxic rainfall

would contaminate water,
kill crops, wildlife,

and bring most of the
world to a standstill.

If there were to be a
large explosive eruption,

then the ash entering
the atmosphere

would get high enough
that it would go global.

It would affect all
parts of the Earth.

The kinds of things
we would expect

to see before an eruption
would be unmistakable.

There would be tens of
thousands of earthquakes uplift

as the ground surface
rose due to magma

coming up from some depth.

That would cause the ground
to inflate like a balloon

by maybe meters over a
short period of time.

We would see changes in gas
emissions and thermal activity.

The temperature of the
ground would be changing.

These would be
unmistakable changes.

NARRATOR: Today,
hundreds of volcanoes

worldwide are within striking
distance of a town or a city.

Yet even with modern
technology, there's

little that can be done to halt
the advance of lava and ash.

You do not want to be trapped in

a fast, hot pyroclastic flow.

You will burn, and you will
choke because of the gases

it contains.

[explosion sound]

NARRATOR: A supervolcano
like Yellowstone

wouldn't just
threaten the survival

of one city, but hundreds.

Its initial blast
could flatten seven

states like a nuclear bomb.

So even as a
geologist, I am amazed

by the scale of the
magma chambers present

beneath Yellowstone.

We're talking about 3,000 to
11,000 cubic miles of material

under there.

That is jaw-droppingly huge.

NARRATOR: The dangers
recently became

apparent at another deadly
volcanic hotspot on US soil--

Hawaii.

And on May 3, 2018,
Kilauea volcano erupted--

Its largest eruption
in over 200 years.

New fissures formed
in the Earth,

causing a caldera collapse.

And lava began flowing
in large volumes.

As much as 3,500 cubic feet
per second, fountains of lava

reached over 260 feet high.

Flows swallowed roads, water
lines, and public parks.

And by June 25, a total of
657 houses had been consumed.

In total, the eruption caused
over $550 million of damage.

Hawaii shows that
even today, volcanoes

continue to threaten
the world cities,

perhaps more than ever before.

[explosion sounds]

NARRATOR: For those
caught up in these events,

it can be a
terrifying experience.

New Zealand's White Island had
long been a popular tourist

attraction, a place to
witness the steam and sulfur

of a slumbering volcano.

On the afternoon of
December 9, 2019,

there were 47
visitors on the island

when it suddenly
awoke in an eruption

lasting just a few minutes.

SPEAKER 1: Go inside.

Go inside.

Go inside.

[interposing voices]

NARRATOR: It produced
a massive ash plume

reaching 12,000 feet high.

Those trapped on the island
soon found themselves

in the middle of a nightmare.

Clouds of superheated toxic
ash and gas engulfing the land.

SPEAKER 2: No, no, no, no.

NARRATOR: Tragically, 22 people
lost their lives, while others

suffered severe burns.

The White Island tragedy
is a reminder of how deadly

even the smallest
volcanic eruptions can be.

But a future Yellowstone
super eruption

would make White Island look
like a pinprick in comparison.

[sirens wailing]

NARRATOR: Fatalities could
number in the millions.

But is the world ready
for this super event?

Will we have time
to save ourselves?

Clues may lie with
a very different

geological phenomenon, one that
can be every bit as deadly--

Earthquakes.

[glass shattering]

Quakes have their origin deep
within the Earth's crust--

Often, where tectonic
plates collide.

CHRISTOPHER JACKSON:
Earthquakes form

due to the rocks which
are being stressed,

so they're being pushed.

And then, suddenly, there's
a catastrophic release

of that energy.

And that energy
is an earthquake.

NARRATOR: The results
frequently create carnage.

[objects collapsing sound]

CHRISTOPHER JACKSON: 2009,
there was the L'Aquila

earthquake in central Italy.

And that caused
intense ground shaking.

And that ground shaking caused
many buildings and villages

to-- to fall to the ground.

NARRATOR: And it
can be far worse.

In the 2010 Haiti quake,
between 100 and 300,000 people

lost their lives.

Entire towns were flattened.

Despite the destruction
earthquakes cause,

there are things we
can learn from them.

One day, this knowledge
may help prevent

loss of life in a super volcanic
eruption, such as Yellowstone.

[machine clicking]

It's thanks to a technique
known as seismic imaging

that lets scientists peer
into the inner workings

of the planet.

CHRISTOPHER JACKSON:
So we're trying

to use the ways in which seismic
waves-- so acoustic sound waves

travel through the Earth to
try and image areas of velocity

change within the Earth.

NARRATOR: With this
tool, they can hunt down

and measure the size of
pockets of molten magma

below the ground.

CHRISTOPHER JACKSON: So
we'd expect a seismic wave

to take-- you know-- a
certain amount of time

to travel through a
rock which isn't molten.

But if there is
some melt in there,

that seismic wave will
travel more slowly.

And so it's that an
anomaly which might tell us

about the composition of the
Earth or those compositional

anomalies.

NARRATOR: Using this
approach, scientists

have built up a complex 3D
model of volcanic hotspots

around the world.

And when they look at the
ground below Yellowstone,

the results are alarming.

CHRISTOPHER JACKSON: It
reveals an incredibly complex

and quite unusual picture.

We probably have in our head
that most volcanic centers are

underlain by one magma chamber.

But Yellowstone actually seems
to have two underneath it

at different levels.

And they are made of
different types of magma.

NARRATOR: Not only are there
two chambers instead of one,

but the scale of each
is simply terrifying.

CHRISTOPHER JACKSON:
So these magma

reservoirs underneath
the Yellowstone

are absolutely enormous.

The shallow one is
about 3,000 cubic miles,

and the deeper one is four
times the size of that-- almost

12,000 cubic miles.

I can't in my head visualize
how much melt that is.

NARRATOR: These chambers could
contain enough magma to fill

the Grand Canyon 14 times over.

It's clear evidence
that Yellowstone could

still pack a massive punch.

CHRISTOPHER JACKSON: Geological
history would tell us

that Yellowstone
in the future will

have a big, big
catastrophic eruption again.

Whether we're here
to see it is a--

Is a different thing entirely.

But it's likely to happen again.

NARRATOR: The wait could be
as long as a million years,

or it could be next month.

[explosion sound]

The Yellowstone
supervolcano is big enough

to threaten towns and cities
hundreds of miles away.

And in the past,
even small eruptions

have shown just how
disastrous they can

be for anyone in their path.

[sirens wailing]

Southern Italy, the
glittering Bay of Naples--

Beaches, fertile
farmland, vineyards.

Also scattered across this
area, the telltale signs

of volcanic activity.

SOPHIE HAY: In the West
of the Bay of Naples,

there's the Solfatara,
which is constantly

sort of smoking and cracking.

And the smell of sulfur
is-- is overwhelming

in-- in places as well.

So you do feel like
that whole area

is sort of a-- a ticking bomb.

NARRATOR: Most threatening
of all is Mount Vesuvius.

SOPHIE HAY: It just sit there as
a-- as a black sort of pyramid

in front of you.

And you-- you do feel its
sort-- sort of ominous presence.

The volcano is active,
and it's completely

surrounded by heavily
populated areas,

like the major city of Naples.

The proximity of population
in general to that volcano

is incredible.

Many of them have lived
there for generations.

NARRATOR: It's thought,
up to three million people

could be impacted by
a future eruption,

700,000 of them living
right in the danger zone.

But despite the obvious threat,
even 2000 years ago, the area

was drawing vacationers.

SOPHIE HAY: It attracted
a lot of wealthy Romans

to it to come and have their
sort of summer residences.

It's a stunning, stunning area.

NARRATOR: At the
time, the biggest town

was Pompeii, with a
population around 13,000.

In 79 AD, it was struck
by one of history's

most infamous eruptions.

A famous Roman writer,
named Pliny the Younger,

kept a record of
the tragic events.

It's actually
Pliny's mother who's

first spots on the horizon
this strange cloud in the sky.

Pliny the Younger describes
it as "a pine tree."

It's like a huge
trunk with branches

splaying out at the top.

NARRATOR: Even today,
eruptions with this type

of distinctive plume are
still known as Plinian.

Within hours of
Vesuvius awakening,

ash and pumice started
to fall on Pompeii.

SOPHIE HAY: The sun, it
became very, very dark.

And I think, a lot
of people start

thinking that the open
spaces are actually

safer because as this
pumice is accumulating,

it's weighing down
on the rooves.

Things are beginning
to collapse.

NARRATOR: Many people
tried to flee the town.

SOPHIE HAY: There's
a sense of panic.

I'm sure that they
were absolutely

terrified in all of this.

NARRATOR: Then, at around
6 AM came the fatal blow.

Pyroclastic flows,
liquefied ash and gases

headed straight for Pompeii.

SOPHIE HAY: They flow
down the side of Vesuvius

at speeds of up to 150
kilometers an hour.

And they're hot.

They-- they reached temperatures
of up to 400 degrees Celsius.

They come shooting
down the mountain.

And at that point, you
know, there is no escape.

That seals the fate
of the individuals.

[people screaming]

NARRATOR: The 18-hour
eruption completely

buried the town in ash.

Nobody knows for
sure how many died.

But the remains of over 1,000
victims have been discovered.

Their decomposing bodies left
voids, from which archeologists

have made plaster molds.

SOPHIE HAY: We see this sort
of horror in-- in the casts.

It's incredibly poignant.

We suddenly become
sort of face to face

with-- with this horrendous
end to their lives.

NARRATOR: This human
tragedy is a lesson

about the threats
posed by volcanoes

close to populated areas.

SOPHIE HAY: The end of an
entire settlement really

does bring home the--
The power of the volcano.

As humans, we-- we
don't always stand

a chance against these things.

And we are mortal.

And in the face of natural
disasters, we're-- you know--

We're on the losing side.

NARRATOR: A Yellowstone
eruption has the potential

to change the face of our
planet, the initial blast

killing millions.

Its fallout would be felt
across the US, South America,

and Canada, with toxic
ash clouds reaching

Europe within 72 hours.

Weeks later, parts
of the Earth would

be covered in sulfuric
acid aerosols,

as we attempt to survive
a nuclear winter.

During a super eruption
at Yellowstone,

as much as 5 million
tons of material

could spew into the
atmosphere every second,

equivalent to the weight
of 50,000 blue whales.

And it could go on for
days, weeks, or months.

But however huge the
blast, what goes up

must eventually come down.

Alexa Van Eaton has modeled
the projected ashfall for such

a world-shattering event.

I've printed off the
maps that show the results

of numerical simulations, where
we've tried to examine what

would happen in the
extremely unlikely

event of a super eruption
from the Yellowstone volcano.

NARRATOR: The results of her
simulation are terrifying.

ALEXA VAN EATON:
What we can see here

is that the ashfall dispersal
reaches from coast to coast

here in North America-- so
from San Francisco all the way

to New York.

NARRATOR: There's no way to
know how long a Yellowstone

super eruption would last.

So Alexa modeled three
different scenarios.

If we change those timescales
and look at an eruption that

lasts only a week,
or only three days,

we can see that the model
distribution of volcanic ash

dramatically changes.

But no matter how we cut
it, even if New York only

receives about an
inch, that would

have dramatic consequences.

NARRATOR: Alexa's simulation
includes comparative data

from other recent eruptions.

ALEXA VAN EATON: Downwind of
Mount St. Helens in Yakima,

Washington, the catastrophic
effects of only about

10 centimeters or so of volcanic
ash are really well documented.

NARRATOR: Within an
hour of the eruption,

day turned into night
in Yakima, 90 miles

downwind of the volcano,
as ash blanketed the city.

The area was crippled by
major power and water outages.

Rooves collapsed from the
sheer weight of the ash fall.

The fine particles persisted for
weeks, destroying $1.1 billion

of agriculture.

Ash from a Yellowstone
super eruption

could have an alarming
impact on the health

of millions of people.

To assess the dangers of
inhaling this material,

it's essential to understand
its chemical properties.

ALEXA VAN EATON: What we can
see about these particles

is that they really are solid.

They don't dissolve in water.

They don't melt away like snow,
and they don't biologically

degrade like wildfire ash.

NARRATOR: It turns out
that volcanic particles

aren't really like ash
from combustion at all.

ALEXA VAN EATON: Wildfire ash
is chunks of combusted plant

matter, but volcanic ash is made
up of tiny particles of rock--

Tiny little crystals and
older oxidized or rusty

looking pieces of rock
excavated by the eruption

and fresh pieces of
frothy magmatic glass.

NARRATOR: These
tiny pieces of rock

wreak havoc inside the body.

ALEXA VAN EATON: If the
particles are very small,

smaller than the
width of a human hair,

we can breathe them
right into our lungs.

And that can cause
lung damage and have

impacts on the whole
cardiovascular system.

NARRATOR: One terrible disaster
showed just how serious

and long-lasting the
effects of ash inhalation

can be for human beings--

The 9/11 terrorist attacks.

Michael O'Connell
was a newly qualified

firefighter at the time,
based at ladder 129 in Queens.

MICHAEL O'CONNELL: I got a
phone call from a friend saying

that the towers were struck.

I threw the news on real quick,
realized that there was a plane

into the World Trade Center,
the first one had-- had--

Had flown in.

And I knew right away I was
going to have to get to work.

NARRATOR: While
Michael was in transit

to the Twin Towers site,
the first tower came down.

29 minutes later, the second--

Between them, they contained
10 million tons of cement,

steel, and window glass--

All of which was
instantaneously pulverized.

MICHAEL O'CONNELL:
What you're seeing is--

Is 220 stories of
office building.

And as you're on top of the
pile, and you're digging,

the only thing
you could think of

is like, I have to
get these guys home.

I have to-- I have to find,
you know, some of my brothers

that are under this pile.

NARRATOR: The
building materials,

along with thousands
of computers,

miles of electrical cable, and
heating and cooling ducts, jet

fuel and asbestos became
a deadly cocktail of dust,

suffocating survivors
and rescue workers.

MICHAEL O'CONNELL: They were
covered in just white film dust

and debris all over them--
Caked into their hair,

caked onto their face.

NARRATOR: None of Michael's
crew had respirators

or masks of any kind.

There was no option but to
work and breathe in the dust.

MICHAEL O'CONNELL: I guess in
the magnitude of everything

that was going on, you weren't
really thinking of yourself

or the environment you were in.

You had stuff up your nose
and your mouth the whole time

you were there.

I remember going back
to the firehouse,

and I was, you know, blowing
stuff out of my nose--

You know-- for a full day,
you know, spitting stuff up.

NARRATOR: Over time, many
firefighters started to develop

health complications.

They had something called
the methyl choline test

and all these lung
function tests

that they were starting to do.

So I remember just thinking
to myself-- at the time,

I was 25 years old.

I-- I just had it
in my head that this

is going to be a long haul.

NARRATOR: Countless survivors
and first responders

experienced symptoms.

It became known
as the 9/11 cough.

For Michael, the effects
appeared years later.

MICHAEL O'CONNELL:
I started really

having inflammation
all over my ankles,

my knees, my elbows, my--

My wrists.

And I looked at my wife.

I said, something's wrong--
Like, I don't feel right.

NARRATOR: He was eventually
diagnosed with a rare disease

called sarcoidosis.

MICHAEL O'CONNELL: I
don't think there's ever

been a case of sarcoidosis
in the history of the New

York City Fire department.

And now post 9/11, we have
hundreds upon hundreds

of firemen, and--
And police officers,

and volunteers that are being
diagnosed with sarcoidosis.

NARRATOR: The exact cause
of sarcoidosis isn't known.

But many firefighters believe
their exposure to the 9/11 dust

may have been a factor.

Volcanic dust could
potentially cause

similar long-lasting damage to
organs, especially the lungs.

Today, Yellowstone
may be a serene place

where visitors come for fresh
air and the great outdoors.

A pristine wilderness,
free of the smog that

pollutes the world's cities--

But at any moment,
this beauty spot

could be transformed into
a choking fume-filled hell

on Earth.

And Yellowstone's ash wouldn't
stop at national borders.

To help estimate just
how far it might reach,

scientists traveled to
the most remote place

on Earth, the icy
expanse of Antarctica.

It could happen within the
decade or several thousand

years from now.

But Yellowstone
supervolcano will

erupt again on a massive scale.

And when it does, it
will have an impact

on the entire planet
with the power

to plunge the world
into a nuclear winter.

Clues about what we can expect
lie hidden all over the globe.

In the remote, frozen
wasteland of Antarctica,

scientists search for
priceless and unique data.

These scientists aren't
drilling for oil or gas.

They're actually
drilling for ice.

The deeper they drill,
the older the ice.

ROBERT MULVANEY: The reason
why we go to Antarctica

is that ice, when it
falls, it collects

material from the atmosphere.

And it has some memory of
what was in the atmosphere.

And as it settles
on the surface,

it doesn't really melt
from one year to the next.

So the layers build up year,
after year, after year.

NARRATOR: Like rings in a
tree, the air bubbles trapped

in ice layers provide a
record of atmospheric changes

over the centuries.

The oldest, deepest ice
dates back millennia.

It's a vital resource
for scientists

studying climate change.

ROBERT MULVANEY: We can look
at what-- what the greenhouse

gases were, for example,
in the atmosphere

going back over 800,000 years.

So we're able to reconstruct
the climate from the snow itself

and the atmosphere from the air
trapped in the-- in the snow.

NARRATOR: And crucially, for
volcanologists, the ice bubbles

also contain tiny
particles of glass

and ash from ancient eruptions.

ROBERT MULVANEY:
So there's very,

very tiny particles that are
not really visible to the eye.

So to see them,
you've really got

to-- to be able to melt the
ice, filter it, and then

look for these glass shards.

NARRATOR: These
clues help scientists

figure out the scale of volcanic
events in the distant past.

The bigger the volcano,
the more material that's

injected into the stratosphere,
the more sulfuric acid

into the stratosphere,
the more we'll

see deposited in an ice core.

NARRATOR: Atmospheric
sulfuric acid levels

surge when large eruptions
pump out large volumes

of sulfur dioxide gas.

ROBERT MULVANEY:
The sulfur dioxide

will tend to react with
water to form sulfuric acid.

And it will tend to sit into
the stratosphere for months,

or even a year, or two on end.

And then, it can circulate
through the whole globe.

And we'll see that
sulfuric acid being

deposited in the polar regions.

NARRATOR: This fact helps
solve a long-standing

climate mystery--

An unexplained mini ice age.

ROBERT MULVANEY: There was a
period around about 1,500 years

ago, where they believe there
was a climate event that

lasted maybe 10 or 15 years.

And people really didn't
know what that climate

event resulted from.

By looking very carefully
in the ice cores,

we can actually see now that
there was several volcanoes

over a period of 15
years-- two or three

volcanoes that probably
could have been the source.

NARRATOR: Atmospheric sulfuric
acid from big eruptions

reduces the sunlight
penetrating Earth's atmosphere.

And a super eruption
like Yellowstone

could significantly cool
the planet for years on end.

A mysterious discovery
in East London

reveals more about the toll of
volcano-driven climate change

can have on humans.

The Spitalfields
Market Archeological

Project was one of
the biggest digs

ever completed in Britain--

A 30-year project
undertaken ahead

of the major redevelopment
of this whole area.

Dr. Amy Gray Jones
was part of a team

focusing on the remains
of a 13th century

priory and cemetery.

AMY GRAY JONES: In
the pits, the burials

were still laid out
carefully on their backs,

in their orientation.

But they were stacked
on top of each other,

and stacked next to each other,
and kind of quite tightly

packed.

NARRATOR: This method
of stacking and crowding

was unusual.

There were a total
of 10,500 burials--

2 and 1/2 times more
bodies than expected.

For the team, this presented
a real historical anomaly.

AMY GRAY JONES: It's
always a bit of a mystery

to try and work
out why you've got

this kind of different
burial practice

and larger numbers of
people in a cemetery

than you-- than
you might expect.

NARRATOR: At first, the team
considered the Black Death,

but the dates didn't
match the major outbreaks,

nor was there any evidence
of any major injuries

caused by battles on
the skeletal remains.

In the lab, the team used
every available technique

to analyze the remains.

And it wasn't long
before a pattern emerged.

So some of the signs of
poor diet that we can see

are interruptions to the
growth of the long bones

and interruptions
to the development

and growth of the teeth.

And that's usually visible
as little lines interruptions

in the-- in the
crown of the tooth.

NARRATOR: There were
also visible signs

of iron deficiency.

AMY GRAY JONES: On the
skeleton, the signs of anemia

are generally porosity,
which means lots

of pinprick holes in the bone.

And we see that in
the upper border

of the orbits of the eye.

NARRATOR: It looked like
these people starved to death,

but could historical
records help explain why?

AMY GRAY JONES: And they
really documented a series

of poor harvests and cold--

Extra cold summers
and wet winters, which

led to food shortages,
and essentially

famine in the large cities.

The team then identified a large
eruption thousands of miles

away in Indonesia
the Samalas volcano.

It erupted around the
time of the burials.

The theory might
seem far fetched,

but there's further
evidence that volcanoes

can affect our ability to grow
food even thousands of miles

away.

And it gives us a glimpse
into how a mega eruption

at Yellowstone would
impact millions

of people across the planet.

[explosion sound]

NARRATOR: Nordstrom is a natural
threat with unimaginable power.

A year after a
modern day eruption,

we could expect major effects
on our global food supply.

Unprecedented changes in
worldwide temperatures

could cool the Earth,
lasting up to a decade,

sparking a modern ice age.

But with its last eruption
hundreds of thousands of years

ago, scientists turned
to more recent eruptions

to predict behavior.

Over the centuries,
Iceland has seen

hundreds of major eruptions.

Thorvaldur Thordarson is one of
the country's top geologists.

Usually, he's on the edge of
a volcano doing field work.

But today, he's
exploring the country's

historic archives in Reykjavik.

The National Library of
Iceland contains manuscripts

dating back over 900 years.

Within this vast collection
are clues to the country's

geological history.

Thor's searching through
records from the late 1700s

when the infamous Laki
eruption took place.

NARRATOR: In an era
before volcanoes were

properly understood,
Erickson could have

had no idea what lay ahead.

But another diary
entry from a few days

later reveals further
warning signs.

NARRATOR: Over the
next few hours,

things went from bad
to a whole lot worse.

NARRATOR: This acid
rain is evidence

the volcano was pumping out
huge quantities of sulfur.

NARRATOR: The Laki
eruption measured 4 on

the volcanic explosives index.

But its effects would be
unusually far-reaching.

For the first time, weather
stations all around the world

captured data on the eruption.

NARRATOR: The records prove
that the Laki volcano changed

global weather patterns.

NARRATOR: The eruption disrupted
rainfall patterns as far away

as India with dire consequences.

NARRATOR: And it
didn't stop there.

Even Japan, 5 and 1/2 thousand
miles away felt the effects.

NARRATOR: These events
took place several

hundred years ago
at a time when life

was less globally connected.

[explosion sound]

A super eruption
like Yellowstone

could be thousands of
times bigger than Laki,

and its impact on
climate could even

threaten humanity's survival.

Yet, it would affect more than
just our global food supply.

It could bring our
modern day transportation

to a grinding halt.

Volcanoes a fraction
the size of Yellowstone

can pump hundreds of
thousands of tons of ash

into the atmosphere.

And this material can have an
impact far from the eruption

zone, even when invisible to
the naked eye, particularly

for air travel--

A mode of transportation
we take for granted.

While even a moderate ash
ejection can cause problems

to air traffic patterns, a
major volcano like Yellowstone

could cause disruption
on an unimaginable scale.

One pilot experienced
this firsthand,

and the event impacted air
travel protocols ever since.

On June 24, 1982,
BA flight 9 was

en route to Perth, Australia.

ERIC WOODY: When we took off
into the darkness, yeah, we--

We used to sit back
and flew up, flew

straight up to 37,000 feet.

We'd put the autopilots in.

It was a normal flight.

NARRATOR: But a
couple of hours later,

the first officer
noticed something

outside the everyday routine.

It looked as though in each
of the cores of the engine,

there was a bright white light,
like a searchlight shining

forward from each
of the engines.

We were watching this odd
display when the engineer said,

number 4 engine has failed.

NARRATOR: Losing one engine
in flight isn't unheard of.

But that wasn't the end of it.

ERIC WOODY: Then, my
flight engineer-- yeah,

he wasn't finished.

He said, number 2 is gone.

Number 3 is gone.

NARRATOR: Soon, the plane
had lost all four engines.

The pilots had no idea
what caused the failures.

They had to stay
focused on keeping

the plane and passengers safe.

They knew an unpowered 747 will
glide 15 miles for every 1 mile

it descends.

In theory, they could make it to
the nearest airport, Jakarta--

Except there was an
obstacle in their way.

ERIC WOODY: We didn't have
enough height to glide over

the 10,000 or 11,000 feet high
mountains along the-- the West

Coast of Java.

NARRATOR: The flight
was now facing disaster.

ERIC WOODY: At the moment,
it looks like you're

going to land in the
sea, which is a no-no as

far as I'm concerned.

Open sea is very difficult
and almost impossible.

NARRATOR: To this day, no
747 has ever successfully

ditched in the ocean.

The crew frantically
tried to restart

the engines as their
plane dropped 13,000 feet.

ERIC WOODY: There was
every opportunity for this

to be 247 people plus 16
crew going to their death

in the southeastern Indian
Ocean and probably nobody really

ever finding out.

It's the deepest trench
in the world we were over.

NARRATOR: Incredibly,
as the plane

approached 8,000 feet,
three of its four engines

sprang back to life.

The remainder of
the flight wasn't

easy with the pilots barely able
to see out of their windows.

But Captain Moody
and his crew battled

their way to Jakarta
airport and landed

without further incident.

Investigations revealed
the plane had flown

through a thin cloud of ash.

It had come from a minor
eruption of the nearby volcano

at Mount Galunggung.

At that time, ash levels
were not widely monitored

nor reported to air
traffic control.

And at high altitudes,
volcanic particles are so fine,

they can be invisible
to the naked eye.

MATTHEW WATSON: It's
actually quite easy

to fly into an ash cloud
because concentrations

can be quite low.

And you need a tiny amount
to actually start impacting

on-- on-- on a jet engine.

NARRATOR: Over time, the
microscopic particles

can cause serious damage.

MATTHEW WATSON: The problem
with ash is, once it gets hot,

it just sticks to everything.

Air is designed to flow in
very, very specific places

to keep bits of it at
different temperatures.

And if you start blocking up
little holes or little veins,

it-- it just-- it just
doesn't work as well at all.

NARRATOR: At the
very least, ash can

lead to engines consuming
more fuel, potentially more

than the plane is carrying.

But it can also have a
much more immediate effect.

What happens over time is
your engine gets less efficient,

which makes it more
expensive to run.

But you are also running a
slight risk of the engine just

gives up the ghost in flight.

And that's, you know,
potentially disastrous.

NARRATOR: But thousands
of long haul flights

still regularly pass close
to an active volcano.

MATTHEW WATSON: If you're flying
from somewhere in the Pacific

Northwest like Seattle
to Tokyo, you'd

fly up the Cascades,
along the Aleutians,

down the [inaudible], ,
into Japan.

You're probably flying over
a couple of hundred volcanoes

that have the potential to
be active or have been active

in the last 10,000 years.

NARRATOR: Fortunately,
for air travelers today,

there's a huge global
network of scientists

monitoring the skies.

MATTHEW WATSON: Every time
you get on an aircraft,

there is somebody somewhere
looking at a computer screen,

giving the pilot
enough information

to make good decisions
ahead of the flight,

so that that aircraft
doesn't hit an ash cloud.

NARRATOR: In 2010, when the
Eyjafjallajokull volcano

in Iceland erupted,
nobody took any chances.

Over 100,000 trans-atlantic and
European flights were grounded

at a cost of around $3 billion.

That was considered an
average-sized eruption

as a VEI 3.

But the effects of a super
eruption like Yellowstone

could be global in their impact.

The volume of a large
super volcanic eruption

could basically flood
the entire atmosphere.

NARRATOR: If Yellowstone
does its worst,

it could mean no
planes in the skies

for months, or even years.

The world's economy
would be brought

to a complete standstill.

The potential consequences are
so great that scientists must

do all they can to
better understand

how volcanoes behave,
even if that means putting

their lives on the line.

[explosion sounds]

NARRATOR: The
inevitable eruption

of the Yellowstone super
volcano will be unlike anything

seen in modern times.

Yet, scientists are constantly
working to better understand

the risk posed by
volcanic eruptions,

in hopes of better
predicting their behavior,

and ultimately saving lives in
our globally connected world.

CLIVE OPPENHEIMER: It's
a tremendous thrill

to be out in the field in--

In a remote area in the
face both of the weather

and of what the
volcano is doing.

NARRATOR: Often, there's
simply no alternative

to getting up close and personal
with a magma-spewing monster.

CLIVE OPPENHEIMER: We couldn't
make the kinds of measurements

we want without actually
going up close to the mouth

of the volcano to measure gas
emissions in great detail,

to install a seismic sensor,
to collect rock samples.

NARRATOR: It's something
that no team will ever

undertake lightly
without a full assessment

of potential dangers.

Lava temperatures
in a flow feel can

reach 1,000 degrees centigrade,
enough to blister exposed skin.

Most of us, you know, in our
line of work have colleagues--

Know of colleagues who have
been killed in-- in the line

of duty, doing field work.

NARRATOR: Conventional
monitoring

relies on measuring
devices put in place

at active volcanic sites.

It's vital these systems
are well maintained.

CLIVE OPPENHEIMER: There are
people in volcano observatories

who have an operational
24/7 duty and responsibility

to monitor volcanoes,
to-- you know--

Repair equipment that stopped
working because it's been

hit by a lava bomb--

You know-- and put
themselves in harm's way.

NARRATOR: In recent years,
an incredible new technology

has changed the rules.

Instead of risking
life and limb,

now, volcanologists only
have to risk their drone.

MATTHEW WATSON: It's annoying
when you lose a drone.

But if you're
flying it sensibly,

and you're not putting
anybody at risk,

it is in the final analysis
just a bit of a plastic

and not really expensive
bit of plastic.

But it is a bit of plastic.

NARRATOR: Drones allow
scientists to get

completely new kinds of data.

MATTHEW WATSON: The
combination of drones

and these small sensors that
weigh a few hundred grams are

completely revolutionizing what
we know about volcanic plumes

because rather than making
observations at a safe distance

at the stuff that's falling
out, we're actually flying

smack dab into the
middle of the ash cloud

as the volcano is erupting.

NARRATOR: These
remote-controlled gadgets

are able to venture right into
the heart of an eruption plume.

MATTHEW WATSON: And
what we've been doing

is mounting little ash
collection devices onto drones

and flying them
into the ash cloud,

grabbing, sucking
up some of this ash,

bringing it back down, then
analyzing it in the lab

afterwards.

NARRATOR: Matt and his team have
focused on one particular South

American volcano.

The most interesting
place that I work

is a volcano called
Fuego in Guatemala.

And the reason we go
there is because it does

constitute some risk to
the local population.

But it also produces
ash extremely regularly.

This thing goes off
for 5 to 10 minutes.

NARRATOR: Fuego's last
major eruption was in 2018.

Deadly pyroclastic flows
swamped nearby villages.

Around 25 miles
away, the country's

main international airport
was shut down by ashfall.

At least 69 people
lost their lives.

Many more remain
unaccounted for.

So it's imperative
that scientists

are better able to predict
future eruptions here.

Matt and his team work
relentlessly to collect

the data to make this possible.

You can get up every
morning at 5 o'clock,

put the drone on the catapult,
fire it up into the sky.

It goes up.

It collects ash.

It comes back down.

It lands safely.

You collect the
sample, and you do

that five or six
times until the clouds

come in every day for two weeks.

NARRATOR: By measuring the
ash particles collected

from inside an ash cloud, the
team gets more extensive data

than ever before.

In the event of a
Yellowstone super eruption,

it could help predict
exactly where ash will fall

and in what quantities.

This, in turn, could
improve disaster responses

and ultimately save lives.

[sirens wailing]

But drones aren't the
only new technology

helping predict future
volcanic super eruptions.

Another is found in space.

New technology is transforming
the study of volcanoes.

A super eruption at
Yellowstone would profoundly

impact North America,
so the more ways

we can monitor,
predict, and prepare

for a record-breaking event,
the better chance we have

of surviving.

One new potentially
life-saving development

relies on observations
made from space--

Satellite remote sensing.

JULIET J BIGGS:
Satellites can detect

many different types
of volcanic activity,

including pre-eruptive activity.

But there are also
techniques that

allow us to measure thermal
emissions from lava fields

when the volcano is
actually erupting.

NARRATOR: Right now,
satellites are observing many

of the world's volcanic
sites, and new satellites

come online all the
time, sending back

ever-increasing amounts of data.

SentinelOne, which is
the European satellite that

we're using most often,
is-- we think it's going

to be producing about a million
images of volcanoes every year.

So it's really revolutionized
the number of volcanoes

we're able to study.

NARRATOR: Using AI, scientists
are looking for tiny changes

in ground level that could be
an indication of underlying

volcanic activity.

JULIET J BIGGS: We're
looking for very tiny changes

in that distance
between the satellite

and the ground surface.

NARRATOR: As magma
moves upwards,

it raises the ground
above, sometimes

by only a tiny amount.

JULIET J BIGGS:
Satellite techniques

can now measure rates as small
as a millimeter per year.

You can also measure it
over very large areas,

which means that it
wouldn't necessarily

be visible to the naked eye.

There's no way you're going to
be able to see that visually.

But we can detect that
with-- with the satellites.

NARRATOR: Juliet
keeps a particularly

close eye on a little known
volcanic system in East Africa.

JULIET J BIGGS: It's
right next to the rapidly

growing town of Hawassa.

We think there's about 1 and
1/2 million people living within

100 kilometers of this volcano.

And we also know that
it's been uplifting

at a rate of about 6
centimeters every year

for the past 10 years.

NARRATOR: Currently, there's
no cause for concern,

but things can change
quickly with any potentially

eruptive volcano.

JULIET J BIGGS: If
we're monitoring things,

and we start to see
unprecedented levels

of activity, unprecedented
numbers of earthquakes,

unprecedented amounts
of deformation,

that might tell us that
something unprecedented

is about to happen.

NARRATOR: For vulcanologists,
the ultimate goal

is to be able to predict when
and where a major eruption

could take place.

For a super volcano
like Yellowstone,

that knowledge could save
tens of thousands of lives

and mobilize rescue
operations more rapidly.

JULIET J BIGGS:
The final frontier

really is forecasting what--

What that means for--

For future eruptions
and for the people

living around the volcanes.

NARRATOR: For now, eruption
remains an inexact science.

Nobody knows for sure
whether a super eruption

is 10 years away or 10,000.

But scientists on the
ground at Yellowstone

are reacting to whatever
mother nature throws their way.

They must keep a watchful eye
on this ticking time bomb.

Mike Poland is the
park's chief scientist

responsible for
monitoring activity.

MIKE POLAND: We have
many different tools

we can use to monitor
activity at Yellowstone.

There are dozens of
seismometers scattered

all throughout the park that
measure subtle vibrations

of the ground.

We've got many tens
of GPS stations

that measure how the ground
moves up and down all

over the Yellowstone region.

We sample gases.

We sample waters.

We even measure the
chemistry of the rivers.

NARRATOR: Today, Mike's
using an ingenious new piece

of technology--

A gravity monitor.

MIKE POLAND: Depending on
how much material is beneath,

gravity might pull a little
harder or a little less hard,

and we can measure that.

And by looking for changes
in gravity over time,

we might be able to
see whether there's

more magma beneath our feet.

NARRATOR: It's a new
approach for Yellowstone

but one with proven results.

MIKE POLAND: Gravity is
showing a lot of promise

worldwide for helping
forecast volcanic activity.

For example, at
Kilauea, as magma

accumulates beneath
the surface, we've

seen increases in gravity.

We're hoping that we might be
able to apply the technique

here in Yellowstone as well.

NARRATOR: These different
monitoring techniques

help Mike and his team develop
a clear understanding of

the region's unique character.

Volcanoes are like fingerprints.

The kind of background
activity we see at Yellowstone

might be alarming
at another volcano.

But it's normal
here at Yellowstone.

And by understanding
that background level,

we can learn to recognize when
things truly get anomalous.

NARRATOR: Only by measuring
Yellowstone's baseline activity

can they identify
changes that might

indicate an imminent eruption.

MIKE POLAND: We can
kind of characterize

the way Yellowstone should
be acting when it's quiet.

And when Yellowstone
is quiet, it

turns out it's really
noisy-- there's

all kinds of earthquakes, the
ground moving up and down,

geysers stopping and starting.

That's how Yellowstone behaves.

NARRATOR: And it's not just
ground-based monitoring.

Mike also relies on even
more high-tech methods.

Thanks to radar
satellite imaging,

Mike discovered a
previously unknown feature.

We've actually managed to detect

new thermal areas using
satellites that we

didn't even know existed--

Way in the back country, places
where people just don't visit,

as we've seen one
get hotter, trees

died around it and started
seeing even small amounts

of sulfur gas being emitted.

NARRATOR: But changes like
this might not indicate

an eruption any time soon.

Scientists are only
beginning to understand just

how energetic
Yellowstone really is.

MIKE POLAND: It's
incredibly dynamic.

It's always changing.

And the fact that we
can see these changes

both on the ground and from
space is incredibly exciting.

NARRATOR: Yellowstone is one
of the most closely watched

volcanic sites in the world.

But no amount of monitoring
can actually stop an eruption.

It may not happen until
far into the future,

but when a super
eruption is unleashed,

it will be truly spectacular.

JOHN GRATTAN: It would appear
that Yellowstone is broadly

due for an eruption, but that
might not be for, you know,

plus or minus 10,000 years.

And it's inevitable
it will happen.

NARRATOR: So how might
such a disaster unfold?

MIKE POLAND: If there
were an eruption that

were about to happen, magma
rising towards the surface,

we would see incredible
uplift, the ground

inflating like a balloon.

NARRATOR: Once a
full eruption began,

things would very quickly
start to feel apocalyptic.

BRYAN WALSH: A super
volcanic eruption

would have the explosive
equivalent of thousands,

upon thousands,
upon thousands of

Hiroshima-scale nuclear bombs.

NARRATOR: With a
state-wide area,

the outlook would be bleak.

BRYAN WALSH: The area around
the park for hundreds of miles

would be utterly devastated.

We would have no
Yellowstone after this.

NARRATOR: Some of
the volcanic effects

would reach far beyond the park.

JOHN GRATTAN: One could then
conceive of pyroclastic flows,

which are hurricanes of
superheated volcanic ash

traveling across the landscape
at several hundred miles

an hour, traveling
for-- potentially

for-- for 1,000 miles or more.

So something that's 400
degrees centigrade burning

everything in its path--

If you're in its way,
you're going to die.

NARRATOR: Before long,
immense quantities of ash

will be pumping
into the atmosphere.

75% of the US landmass could
be buried in volcanic ash.

BRYAN WALSH: There's no system.

There's no scenario.

There's no emergency
plan in place to deal

with anything on the scale.

The closest we can
kind of imagine really

is quite honestly a nuclear war.

NARRATOR: And this would
only be the beginning.

The millions of tons of sulfur
dioxide in the atmosphere

could potentially change
the global climate.

BRYAN WALSH: You end up with
what's known as potentially

a volcanic winter, where
temperatures drop by 10, 15

degrees or more-- which is
enough to really utterly change

human life as we know it.

NARRATOR: But this wouldn't
be the first time human beings

have faced such a test.

JOHN GRATTAN: We as a
species are common ancestors.

We're walking on the planet
during massive super volcanic

eruptions that devastated
the environment,

and we have survived.

And we went on to thrive.

NARRATOR: The human
species may survive,

but will America survive
this volcanic doomsday?