Original subtitles

[explosive noise] It was global event, it was an exotic event,

and it was a big event.

NARRATOR: From the majestic beauty of Yellowstone‐‐

We don't know how long it's going to just sit there

before it decides to go off.

NARRATOR: ‐‐to the tropical islands of Hawaii‐‐

ROBERT TILLING: The Hawaiian islands are probably

the best example of what geologists call

a volcanic trail of a hot spot.

NARRATOR: ‐‐the cataclysmic eruption of Krakatoa.

STEPHEN SELF: An island two thirds gone, vanished.

NARRATOR: ‐‐and the notorious prominence of Vesuvius‐‐

GIUSEPPE MASTROLORENZO: It could even erupt next year.

is both profound and apocalyptic.

GERARD FRYER: It truly is biblical.

NARRATOR: Earth, air, fire, and water,

essential for human survival.

But in the extreme, destructive to everything and everyone

in their path.

MAN1: Coming down, right now, major tornado.

MAN 2: Man, that's a monster.

NARRATOR: These are stories‐‐

MAN 1: Oh, big time black.

MAN 2: Wow.

Whoa, whoa

NARRATOR: ‐‐of "Apocalypse Earth."

[music playing]

Volcanoes, beautiful and fierce.

These fire mountains are stunning, majestic, ominous,

and terrifying.

Towering over the landscape, these volatile giants

have the ability to wreak untold havoc locally

and around the globe.

In the last century, American volcanoes, such as Mount St.

Helens and Novarupta have served to keep the population

on notice that a volcano's sleep is often not eternal.

[explosion]

On May 18, 1980, Mount St. Helens erupted.

Not from its peak, but from its side.

Located in Washington State, only 50 miles

Northeast of Portland, Oregon, this

was the first major volcanic eruption in the lower 48 states

in generations.

And the deadliest‐‐

57 people were killed.

The reawakening of Mount St. Helens

greatly intensified volcanology in the United States.

But it's the June 1912 eruption of Novarupta in Southwest

Alaska that holds the record as the largest

such event in the 20th century.

It was 10 times more powerful than Mount St. Helens

and is ranked as the fifth largest eruption in recorded

history.

The activity continued for three days, devastating area wildlife

for a decade and generating a large volume

of pyroclastic flows that came to rest on the place that

is now known as the Valley of 10,000 smokes.

But chief among volcanic wonders in the US

is that breathtaking spectacle in the heartland, Yellowstone.

It's dance of geysers is one of nature's greatest displays.

It's why millions of visitors come each year to America's

oldest national park.

Yellowstone's spectacular beauty inspired President Ulysses S.

Grant to protect these 2 million acres of northern Wyoming

wilderness back in 1872, and it's

been a haven for outdoor enthusiasts ever since.

It's incredible hot springs, bubbling pools of mud,

unearthly ponds, and the most celebrated natural feature,

the Old Faithful geyser, are some of nature's greatest

wonders.

But beneath this primal beauty simmers a hidden threat.

Five miles below the waterfalls and mountain peaks

lies the heart of a supervolcano, a constantly

moving cauldron of molten rock the size of Mount Everest.

Over countless million years it filled with lava

to the breaking point.

Like a bomb with a hidden timer, it finally explodes.

We don't know how long it's going to just sit there

before it decides to go off.

NARRATOR: If sometime in the future it were to erupt,

as it has before, the Yellowstone volcano

would overwhelm everything within 100 miles

and disrupt lives across the globe for years.

There are 1,500 volcanoes around the world,

but there are fewer than 10 supervolcanoes, the ones

with the potential to not only destroy the surrounding

area but to create a global disaster.

And Yellowstone is one of these supervolcanoes.

Unlike a conventional volcano, with its crater

atop a mountain, Yellowstone's crater

is so large it can only be seen from the air.

This is the rim of a monstrous crater called a caldera that

collapsed into the magma chamber during the last supereruption.

It's large enough to hold the city of Los Angeles.

HANK HEASLER: People drive 35 miles, 45 miles,

commuting to work in that.

Well, that's the distance across this caldera.

NARRATOR: And this is only the last

of three monstrous calderas formed over the past two

million years.

The volcanic history of Yellowstone

is really marked by these three giant, cataclysmic eruptions

of the scale that we haven't seen in the history of man

really.

The first eruption vented somewhere around

600 cubic miles of material.

And if you took all of that and you spread it out

over the state of Texas, you'd have about 12 feet

thick of deposits.

NARRATOR: The second eruption was hundreds of times

larger than Mount St. Helens, and it's

the smallest of the Yellowstone supereruptions.

The most recent one, known as the Lava Creek eruption

occurred 640,000 years ago.

At the time, early man had yet to arrive on the scene.

Exotic prehistoric animals roamed the North American

continent.

Five miles beneath the earth, however, a magnetic cauldron

three times the size of New York City was coming to a boil.

There would have been hundreds to thousands of earthquakes

becoming fairly large.

So there'd be a lot of shaking as the hot rock was moving up.

NARRATOR: A million tons of molten rock heated to 1,800

degrees Fahrenheit pressed its way to the surface.

Jets of superheated water suddenly burst

through cracks in the Earth's surface, shooting into the air.

Hundreds of geysers were erupting over 500 square miles.

We get explosions out of the hydrothermal system

that put holes in the ground as big as a mile across.

So they're big events.

Well, after about a 90‐minute nap,

Old Faithful has roared back to life.

It wasn't actually napping, it was recharging.

The temperature of the water with increasing,

the system was pressurizing.

NARRATOR: But this was just the overture before the main event.

After days of increasing earthquake and geyser activity,

under mounting pressure from magma and superheated gases,

Yellowstone's last supereruption began.

ROBERT SMITH: The material may have started to leak out

on one side, perhaps forming part of the edge

of the fracture zone.

As you start to decrease the pressure,

it starts to then explode.

NARRATOR: With the power of a hydrogen bomb,

a monstrous cloud of searing ash and melted rock

shot into the stratosphere at supersonic speeds.

The heavier debris fell back to the ground,

turning into a colossal pyroclastic flows.

It was sort of like a hurricane made up of 800‐degree

ash, and pumice, and hot gases‐‐

just wipes things out completely.

NARRATOR: For miles, these lethal rivers of ash and gas

cook animals alive in brushed forests aside like twigs.

ROBERT SMITH: They extend actually outside of Yellowstone

into Idaho and into the Teton region.

Some of this material flowed down actually covered parts

of the floor of Jackson Hole.

So these scenes extend tens of miles

away from the actual eruption location.

NARRATOR: For days the Yellowstone volcano

continued to heave tons of molten debris into the air

and devastated the nearby terrain.

Then, across the caldera, another colossal explosion,

then another.

Eruption after a eruption began shooting more and more lava

and pulverized rock into the air.

JACOB LOWENSTERN: Typically, when these eruptions begin,

they begin at a single event.

And the event may then get larger,

moving out along some sort of a fracture system.

NARRATOR: Yellowstone had turned into a supereruption.

NARRATOR: Yellowstone's last supereruption

occurred 640,000 years ago.

It started as a single massive volcano,

but soon turned into a series of eruptions,

exploding with the full force of a supervolcano.

The entire sequence of pyroclastic explosions

that formed the Yellowstone caldera may have taken as

little as two weeks to happen.

During the eruption of all this material,

that's when the caldera would have started forming.

NARRATOR: In a final massive display of nature's fury,

hundreds of square miles of mountain

dropped thousands of feet into the pit of roiling magma.

ROBERT SMITH: The Gallatin range,

and the Madison range, and the Mount Washburn range

to the north continued somewhere into the Yellowstone region.

These mountain ranges were destroyed.

Now, when I say destroyed, I don't

mean they're blown to smithereens

into the atmosphere.

Much of it just then fell back into the magmatic system‐‐

just fell back into the cauldron, if you wish,

of the caldera itself.

JACOB LOWENSTERN: We're talking about mountains that might be

12,000 feet high that are now the ground

surfaces on the order of 8 to 9,000 feet high.

So 3,000 foot of mountain that is no longer there.

NARRATOR: Finally, after perhaps weeks of constant activity,

the Yellowstone volcano subsided.

But the devastation was far from over.

A global disaster was about to begin.

2 and 1/2 trillion tons of sterile volcanic ash

drifted with the winds and buried 2,000 square miles

of the North American plains, destroying much

of the continent's plant life.

HANK HEASLER: The volcanic ash that's

ejected high up into the atmosphere

and then falls many, many miles away,

that goes as far as Louisiana and some of the states

along the Mississippi River.

So quite an ash cloud.

NARRATOR: The lighter particles remained

in the air for more than a year, forcing temperatures to plunge

across the hemisphere.

It acts as as a veil and cuts out the sunlight.

And so it cools the climate below.

I think there was certainly big climatic changes

do to Yellowstone.

We estimated a 3 to 5 degrees Celsius drop

in temperature, which is quite severe on a global basis.

NARRATOR: 5 degrees was enough to kill off

much of the tropical plant life across the globe.

Over the next year, animals died from lack of food,

as the ash continued to block out the sun.

It took years for the planet to recover,

for sunlight to reach the Earth's surface,

for plants to push through the layers of ash,

for animals to repopulate the continent.

This Yellowstone eruption, 640,000 years ago,

changed the face of North America.

With a history of multiple cataclysmic eruptions,

Yellowstone is becoming the most studied supervolcano

in the world.

And its hundreds of yearly earthquakes, thousands

of guises, and massive magma chamber

make it one of the most geologically active regions.

In fact, in May of 2020, Yellowstone

registered just under 300 earthquakes alone.

As the research continues, scientists

are realizing how little they really know

about the Yellowstone volcano.

HANK HEASLER: We know there's enough magma left.

We know there is enough heat.

We know that there will be future eruptions

in Yellowstone.

But we don't know if there ever be

another catastrophic eruption.

JACOB LOWENSTERN: Since humans haven't seen an eruption

of this magnitude, we're somewhat

challenged to know exactly how the systems work.

NARRATOR: One thing is known for sure,

if Yellowstone erupts again, pyroclastic flows

will destroy everything near the volcano,

and its ash cloud would overwhelm humanity

across the globe.

MICHAEL RAMPINO: This is one of the rules of geology.

If it happened in the past, it'll

happen again in the future.

We know that there will be supereruptions, and probably

one to Yellowstone, and it's going

to have catastrophic effects.

[explosion and rattling debris]

[waves rolling]

NARRATOR: The beautiful island chain of Hawaii

is known the world over for its magnificent scenery.

The eight main islands of Hawaii are home to 19 volcanoes.

There have been over 75 recorded eruptions in the last 200

years.

The Hawaiian islands are probably the best example

of what geologists call a volcanic trail of a hot spot.

They are formed by the passage of the Pacific Tectonic Plate

over an exceptionally hot spot beneath the crust of the earth,

and it's sort of analogous too if you

had a slab of paraffin wax passing over a candle flame.

NARRATOR: Except that it's rock that's melting, not wax.

Over time, this molten rock, or magma,

rises 20 miles to the surface, creating and feeding

the volcanoes above.

MICHAEL POLAND: Now, because the plates on the Earth's surface

are moving, they actually move over this fixed hot spot.

And that means that new volcanoes are popping up

all the time.

NARRATOR: Magma that reaches the surface is called lava.

The lava collects and forms land.

Each island of the Hawaiian chain in fact

started as a volcano.

As the path of plate is followed from northwest to southeast,

the volcanoes are larger, more densely situated, and far more

active.

The so‐called Big Island is twice as large

as all of the other islands combined.

It's not just one, but five volcanoes growing together‐‐

Kohala, Mauna Kea, Hualalai, Kilauea, and Mauna Loa.

MICHAEL POLAND: Over a million years ago,

there was no big island of Hawaii.

It started as a very small island,

which was the volcano of Kohala, which grew out of the ocean.

Over time, more volcanoes started to grow.

Mauna Kea and Hualalai came next growing,

into tremendous mountains.

Mauna Loa was the next volcano to grow.

And Kilauea is the youngest of the Big Island's volcanoes.

NARRATOR: Kilauea earned the title World's Safest Volcano

for its stunning lava fountains and slow‐moving flows that can

be viewed from close proximity.

ROBERT TILLING: The current eruption of Kilauea

actually began in 1983.

In fact, it's been erupting virtually continuously

since that time.

And it has now become the longest‐lasting eruption

in historical time in Hawaii.

NARRATOR: But Kilauea hides an even more dangerous secret.

It is home to the biggest explosive eruptions

in Hawaii's history.

FRANK TRUSDELL: In 1790, there was an explosive eruption which

accounts for most of the gravel‐like surroundings

that you can see in the field of view here.

The cloud had to be somewhere in the vicinity of 28,000

to 30,000 feet, which had put it up akin to the eruption

column of Mount St. Helens and looked just as dark and ugly

as that.

NARRATOR: At least 80 Hawaiian warriors were killed instantly

by asphyxiation and heat in the 1790 eruption, the highest

death toll from any American volcano.

What we have to remember is that we've still

seen only a very small portion of what Kilauea can do.

Yes, Kilauea can be very benign, but it can also

be very dangerous under other circumstances.

NARRATOR: May 3rd, 2018, proved to be one

of those other circumstances.

Kilauea took scientists by surprise

when it's lava flow invaded nearby residential areas,

forcing 1,700 people to evacuate their homes.

The eruptive destruction did not quiet

down until September 2018, when volcanic activity subsided

significantly, remaining at its lowest

since it started erupting in 1983.

But of greater concern to officials

is the enormous volcano to the west.

Its name is Mauna Loa.

Massive earthquakes have historically

preceded every major eruption at Mauna Loa.

Feared most is a repeat of what occurred in 1868.

Little in the way of photos or illustrations

exists, but early missionaries recorded well

over 300 earthquakes in a span of four days.

The largest of these is believed to have measured magnitude 8.

But this was all just a preamble to the lava flow

from Mauna Loa.

FRANK TRUSDELL: The eruption started at about 5,000 feet

and zoomed down to the ocean in a matter of two hours.

NARRATOR: Lava from a smaller eruption in 1950

followed the exact same flow path.

Well, the 1950 eruption of Mount Loa

was probably very, very spectacular.

There was a fissure system that propagated and stayed open

over a 15‐kilometer length.

Along the entire length, there was lava gushing out

of the ground.

NARRATOR: The lava formed what's called a curtain of fire,

literally a wall of molten rock 600 feet high and two

miles long.

Well, most eruptions from Hawaiian volcanoes,

and Mauna Loa included, usually start out

with fissures that open up.

And you get what we call just a curtain of fire,

as lava seems to fount along a long stretch of fissure that

can be miles long.

Over time, this fissure tends to focus at a single point.

And that's where most of the fountaining activity

is concentrated.

NARRATOR: 35 minutes later, the flow entered the ocean.

But it would continue on for 23 days

and become the most voluminous eruption ever recorded

in the island's history.

[rumbling and crackling]

The Big Island of Hawaii has been rocked

by volcanic eruptions and earthquakes

throughout its history, and scientific monitoring

shows that these monsters still have

plenty of life left in them.

With the devastating earthquakes and eruption of 1868,

Mauna Loa quickly became recognized

as one of the most dangerous volcanoes on the island.

Less than a million years old, an infant in geological terms,

Mauna Loa has grown to almost 14,000 feet above sea level,

making it the tallest active volcano on the planet.

60 miles wide at its widest point,

its name translates as long mountain.

FRANK TRUSDELL: Mauna Loa covers approximately 51%

of the surface area of the island of Hawaii,

which makes Mauna Loa almost larger

than all the other Hawaiian islands put together

as far as surface area.

NARRATOR: Yet this is only a fraction of its total size.

What most people don't appreciate

is that this structure extends below sea level.

So if you follow that to the sea floor

and calculate the volume of that particular volcano, Mauna Loa,

it is indeed, by far, the largest volcano in the world.

Since a more detailed record began in 1832,

Mauna Loa has erupted an astounding 39 more times.

In the last eruption of Mauna Loa in 1984,

Mauna Loa was putting out one million cubic meters per hour.

So things happened quickly.

NARRATOR: But the 1984 event also demonstrated something

just as disconcerting, that eruptions

could come from more than one volcano at the same time.

FRANK TRUSDELL: The 1984 eruption of Mauna Loa

was noteworthy in the sense that, yes, both Mauna

Loa and Kilauea erupted.

NARRATOR: It's proof that literally anything

can happen on the Big Island.

GEORGE PARARAS‐CARAYANNIS: It's not completely ridiculous.

You could have a Mauna Loa, Kilauea, and Hualalai

at the same time.

It's possible.

NARRATOR: When most people think of volcanoes,

they imagine violent, explosive eruptions, definitely not

a potential vacation destination.

Yet the Hawaii Volcanoes National Park on the Big Island

is the single most popular tourist attraction

in the state.

MICHAEL POLAND: Well, a lot of people

come to Hawaii, especially the Hawaii Volcanoes National Park,

expecting to see a Mount Rainier or Mount St. Helens‐like

volcano.

And that's a common question‐‐ where is the volcano?

Well, one of them is Kilauea, which we're standing on now.

And it appears very flat.

We call these volcanoes shield volcanoes because

of their shape.

You can look in behind me at Mauna Loa.

It's got these very smooth, sloping flanks.

It's like a warrior's shield if it's put on its end.

The sides of the volcanoes here are gently

sloping, because those lava flows can just run out

as they need to.

The lava flows at places like Mount Rainier and Mount St.

Helens, being very sticky, stay close to the volcano

and build up very steep‐sided volcanic cones.

NARRATOR: The slow moving yet voluminous flows help create

the unique shape of the so‐called shield volcanoes

here.

But the sluggishness also makes it possible for tourists

to get up close and personal.

Approximately 2 million visitors

come to the park every year.

We figure about 1,000 visit the active eruption site a day.

ROBERT TILLING: It is probably one of the few places

in the world where an outsider can observe an eruption safely

under the right kinds of conditions.

Another interesting feature of Kilauea eruption

are these periodic very high lava fountains‐‐

very dramatic features that are a great attraction to tourists.

[splashing and gurgling]

[rapid camera shutter]

NARRATOR: And they can even see new land being formed.

ROBERT TILLING: Some people call them lava shells.

Other people call them lava deltas or lava benches.

So a variety of names are used for these features.

When the lava finally reaches the ocean, after traveling

for about eight or nine miles from where it's first erupted,

it forms these shells.

NARRATOR: But the beauty can be deceptive.

There are countless earthquakes that

strike the island every year.

Many are too small to be felt, But some can't be ignored.

And such an occurrence could be the precursor

to another major event‐‐

a volcanic eruption.

The Hawaii Volcano Observatory is run by the United States

Geological Survey, or USGS, to study and attempt

to forecast future activity.

The first sign of unrest that we might look for at a volcano

is heightened earthquake activity.

Perhaps something we call seismic tremor, which

is essentially a constant earthquake, where

the shaking never really stops.

And seismic tremor has always been associated

with magma moving.

NARRATOR: As the earthquake frequency increases,

it becomes easier to determine when and where an eruption

might occur.

So we start with a few earthquakes per day,

and then over weeks to months times,

they may go to 10 earthquakes per day.

And then, finally, just before the outbreak,

it's not impossible for us to get even in the thousands

of earthquakes per day.

NARRATOR: But there's more to volcanoes than earthquakes.

To gather as much data as possible,

the USGS has literally wired up the islands volcanoes.

So this is a telemetry mast for one of our tilt meters,

which is buried in the ground.

NARRATOR: If the ground is tilting or changing shape,

then there's a good chance magma is on the move below.

MICHAEL POLAND: We have a couple of places on the island where

we're actually getting real‐time camera feeds from cameras that

are positioned out in the field.

You can actually see movies of the activity that's occurred.

We have five fountaining of piston events,

where lava levels rise and fall, of collapses at the coastline,

where whole sections of land fall into the ocean.

NARRATOR: This data is used to anticipate

when an eruption might happen.

MICHAEL POLAND: Suddenly, many of these instruments

would just start going.

The signal would go exponential or change drastically.

NARRATOR: But forecasting when a volcano might strike

is only half the equation.

The key to the future is to look to the past.

And so, so far we've been able to map over 500 lava flows

on Mauna Loa.

NARRATOR: But no matter how well the system works,

mother nature always seems to be one step ahead.

FRANK TRUSDELL: We're sort of at a disadvantage.

Here we are on the surface, scratching around,

and a lot about what we need to know

is occurring miles below our feet.

NARRATOR: To fix this problem, the Hawaii Scientific Drilling

Project decided to bring the depths of the earth up

to ground level.

DONALD THOMAS: So what you see here

is a conventional drilling rig that we have modified to allow

us to collect a continuous sequence of samples of lava

flows that have been produced by one of Hawaii's

typical volcanoes.

NARRATOR: Mauna Kea was chosen because of its age

and relative inactivity.

A specialized drill bit has reached more than 11,000 feet

below.

Ground water, centuries old, actually

helps to bring up hardened magma samples like these.

The project began in 1999.

The goal is to someday reach the Earth's crust, somewhere

between 15 and 19,000 feet.

DONALD THOMAS: This borehole currently

is the deepest hole that's ever been drilled into an ocean

island volcano.

And as we have drilled, even in the first, say,

3,000 or 4,000 feet of drilling, we

discovered a tremendous amount of new information

about the history of Hawaiian volcanoes.

Prior to the start of the project,

everyone had assumed it was about a half a million years.

What we've been able to show is that that's less than half

of the lifecycle of a Hawaiian volcano.

NARRATOR: It's proof that volcanoes such as Hualalai

have much more life left in them than previously thought.

In fact, the more that's discovered,

the more it's clear how little we actually

know about hotspot volcanoes.

DONALD THOMAS: We had really some of the best people

in the world, most knowledgeable people in the world,

on volcanic processes, and we debated endlessly

over what we would see when the borehole was drilled.

Much of what we thought we knew about Hawaiian volcanoes

turned out to be incorrect in some way.

NARRATOR: It's going to be a long time before we

can accurately predict when the next major eruption will occur.

Life in Hawaii means living in the shadow of volcanoes,

a choice that can sometimes lead to a devastating tradeoff.

[dramatic music playing]

Hawaii, America's 50th state.

The pristine beaches, hidden getaways, and dramatic sunsets

draw millions of vacationers to the Big Island of Hawaii

each year.

A lucky few actually call this Polynesian paradise home.

As a young bride in 1980, Julie Beardsley

settled down in Kalapana Gardens, a growing community

on the island's remote eastern shore.

JULIE BEARDSLEY: We fell in love.

It was so beautiful.

It was pretty remote, but the weather was perfect,

and there was the Black Sands Beach.

Among her neighbors are Todd Dressler and his family.

TODD DRESSLER: Everybody was so close and so friendly.

I never even had keys to my house.

NARRATOR: But living in paradise comes with a price.

DAVID OGLESBY: The entire Hawaiian island chain

is made up of lava flows.

Every single rock you see on those islands is volcanic.

NARRATOR: One of these volcanoes is none other

than the previously mentioned Kilauea.

Wit its caldera looming above Kalapana Gardens,

it's impossible for the residents to ignore it.

TODD DRESSLER: There had been a recent flow a few years before,

but it stopped far from the town.

So it really didn't bother me at all.

JULIE BEARDSLEY: Everyone from the neighborhood

thought, well, it's pretty inconceivable that it's ever

going to come all the way down here.

NARRATOR: In early 1990, magma surfaces through a vent

on a ridge almost two miles away and collects in a huge lava

lake, directly upslope from Kalapana.

When that lake level rises above the rim of the basin,

it overflows and heads downslope.

On the surface, it will harden and create

lava tubes, which are completely enclosed with hardened lava.

So lava flows through that tube as water flowing

through a pipe.

NARRATOR: Now armed with a highly efficient tube,

mother nature sends the flowing magma downhill

towards Kalapana.

JULIE BEARDSLEY: That's when the level of tension

really ratcheted up.

It came down into the subdivision

and started burning houses, one by one.

Are you a resident here?

NARRATOR: Authorities issue evacuation orders.

The last load.

JOHN OSTERAAS: The lava would cut off roads and destroy

houses.

Then it would move somewhere else.

It was a very slow motion destruction.

You no longer have utilities.

So you don't have electricity or county water.

JULIE BEARDSLEY: There was a lot of smoke

from all the plants burning.

It smelled like hell.

And the lava just kept on coming.

JOHN OSTERAAS: Lava actually doesn't even

have to touch the building.

Just getting close to the building,

the radiant heat from the lava is enough to set a wood

building aflame.

[explosions]

MARY DRESSLER: Sometimes it just whooshes through,

and rushes up the street, and you see all this fire.

And then, the next day, it slows down.

You just never really know.

It's the most unpredictable thing I've ever experienced

in my whole life.

NARRATOR: Then the volcano sets its sights on Julie's home.

JULIE BEARDSLEY: All this red hot lava

poured into the backyard.

I thought my house was going to be next.

Then it sort of hesitated, like it was playing with me.

NARRATOR: Instead, the lava goes after her neighbor

Todd's house.

Should I lock it up?

No.

TODD DRESSLER: It came out of a crack right next to my house,

oozed on over to the front porch.

And boy, did it go.

It was incredible fire, hundreds of feet high.

A lot of memories.

There she goes.

Yeah, it's a lot of memories.

NARRATOR: A few days later, Julie's dream house

also goes up in flames.

JULIE BEARDSLEY: Lava came to where it ignited

the side of the house.

And, poof, it went.

[crackling]

NARRATOR: In the months that follow,

nature lays waste to the entire city.

The fiery assault continues until it reaches

the final, untouched jewel of Kalapana, the black sand

beach Kaimu Bay.

When the lava came into Kaimu Bay,

people were just openly weeping.

It was one of the most special places that I've ever been,

and it was gone now.

It was really unimaginable.

NARRATOR: The picturesque coastline is eventually

buried under 50 feet of lava.

Today, the once vibrant community of Kalapana

has been wiped off the map, buried under lava flows that

added 170 acres to the Big Island.

JULIE BEARDSLEY: The truth was, all you could do

is get out of the way.

Because there was stuff going on that

was way bigger than you were.

[bubbling]

NARRATOR: When it comes to volcanic activity

around the globe, nothing compares to the Ring of Fire.

The Ring of Fire is one of the most extensive zones

of volcanic fury on the planet.

It encompasses hundreds of volcanoes that line the shores

of the Pacific Ocean.

They form an arc which extends 25,000 miles,

from South America, along America's Northwest coast,

to Alaska, and then down through Russia, Japan, and Southeast

Asia, all the way to New Zealand.

Three quarters of Earth's volcanoes are situated there,

and 90% of all earthquakes occur along this line.

One of the most notorious volcanic eruptions

in the Ring of Fire was also one of the world's biggest,

Krakatoa.

[explosion]

It was this colossal phenomenon that

created one of the most spectacular natural disasters

in history.

[rubble colliding]

Ground zero was one of a group of volcanic islands

that lies halfway between Asia and Australia

in present day Indonesia.

They were situated in a narrow passageway called the Sunda

Strait, between the two main islands of Java and Sumatra.

Today, the island chain is called Krakatau.

But history remembers it as Krakatoa

Krakatoa, suddenly annihilated itself‐‐ an enormous explosion,

basically.

You were left with a large hole in the sea f floor, an island

two thirds gone, vanished.

It was a global event, it was an exotic event,

and it was a big event.

NARRATOR: In 1883, Krakatoa was 2.5 miles

long and 5.6 miles wide.

It had three large volcanic vents or cones.

The largest was called Rakata.

In the middle was the Danan cone.

And at the far end, Preboewatan.

Experts agree that the location of Krakatoa

is the primary reason that to this day

it is one of the most dangerous volcanoes on Earth.

It lies in the center of Indonesia's

volatile volcanic arc.

STEPHEN SPARKS: The indonesian volcanic arc

is one of the most active in the world.

It has about 130 volcanoes spread over about 700 miles.

NARRATOR: The volcanic arc stretches the length

of Indonesia and into the Pacific,

along the edge of two, ever‐shifting continental

plates.

STEPHEN SPARKS: One of the great tectonic plates of the earth

is pushing underneath another of the great tectonic plates.

And where there's one plate pushes underneath the other,

you get volcanoes formed.

NARRATOR: This geophysical process is known as subduction.

The reason you get volcanoes is really quite simple.

The floor of the ocean on one of the tectonic plates

is soaked in water‐‐ the rocks are wet.

And when those wet rocks are pushed, perhaps 100‐150

kilometers deep into the earth, that water makes the hot rocks

in the Earth's interior melt. And those melts then come up,

they rise up, and they form volcanoes.

NARRATOR: Some of the biggest volcanoes on Earth

are situated in this hazardous region, including Toba

and Tambora, which last erupted in 1815.

Fortunately, both these mighty mountains

were located in remote and sparsely populated areas.

That was not the case with Krakatoa.

The famous volcano lay only 30 miles from the coast

of Java and Sumatra.

In 1883, about 500,000 people lived there.

The first clue of the impending, massive disaster

came on May 9th, 1883, when an earthquake was reported

by a lighthouse keeper.

He was at the First Point lighthouse

on the west end of Java, approximately 45 miles

southwest of the volcano.

SIMON WINCHESTER: He felt, in the middle of the night,

the ground shake.

And then there was a brief what he called an earthquake

in the air.

It was as if a brief sort of wind, which knocked him

backward briefly.

NARRATOR: After the first movements in May,

it would take Krakatoa a month to build enough force

to violently explode.

STEPHEN SPARKS: Now, it's quite likely

that some very hot molten magma from even deeper in the earth

started to rise up underneath the volcano

and actually came into this magma chamber.

And this magma chamber then increased in pressure.

This would start to force the rocks part.

NARRATOR: By August 26th, after weeks and months of explosions

and ejections, Krakatoa was ready to rip.

STEPHEN SPARKS: When that molten rock forces its way close

to the Earth's surface, it's like taking a cap off

of fizzy drink.

The pressure goes down and the gas forms bubbles,

but forms bubbles very violently, so that the magma

essentially explodes itself.

NARRATOR: Just after 1:00 PM, the volcano

let out an almighty bang.

A thick column of black smoke, steam, ash, and debris

shot 17 miles, more than twice the height of Everest,

into the sky.

SIMON WINCHESTER: But no one gave any thought to the idea

that this was merely the precursor to something truly

massive.

NARRATOR: Krakatoa had just entered what scientists call

the cataclysmic eruption phase.

The big one was about to hit.

NARRATOR: On the morning of August 27th, 1883,

the sky was filled with smoke for 40 or more miles

around Krakatoa.

A cloud of ash blanketed the Sunda Strait and the sun

was barely visible.

Krakatoa had entered its death throes.

[explosions]

GERARD FRYER: : There probably were substantial evacuations,

because people were scared about the volcano.

But they'd also sort of been seduced into staying,

because the eruption grew slowly.

NARRATOR: The eruption culminated that morning

in a series of huge, very loud, and cataclysmic explosions.

STEPHEN SELF: When there's a particularly vigorous explosion

or a particularly vigorous pulse of magma,

then it sends a great cloud up in the atmosphere.

And as that cloud gets into the higher levels

of the atmosphere, it becomes supersonic,

and it generates an explosive noise.

[explosion]

NARRATOR: The first mega blast was recorded by chance.

At the Batavia Gasworks, 90 miles to the east,

it appeared as a pressure spike on their barometer

at precisely 5:30 AM.

A massive column of volcanic ash, rocks, and pumice

shot 20 miles into the sky.

Another larger explosion hit at precisely 6:42 AM.

Then another, an hour and 38 minutes later.

KEN WOHLETZ: Volcanoes that have this type of behavior

often are compared to many nuclear bombs exploding

all at once.

That's their power.

NARRATOR: At exactly 10:02 AM, the biggest explosion of all

struck.

SIMON WINCHESTER: The sound was undeniably the loudest noise

ever generated on the surface of this planet, at least

since humankind has been around to hear it.

Sailors that were maybe 10 miles away,

they took the full brunt of it, and nearly all of them

had their eardrums punctured and went deaf.

NARRATOR: The sound of the fourth explosion

traveled a radius of about 3,000 miles.

SIMON WINCHESTER: It was as if there was an enormous explosion

in New York, which was heard with perfect clarity

over in San Francisco.

An unimaginable thought, but Krakatoa was up big.

NARRATOR: The biggest explosion ever heard on earth

was measured 100 miles away to be a record shattering 180

decibels.

Ash from the explosions fell on Singapore, more than 500 miles

to the north, and the Cocos Islands, over 700 miles

to the southwest.

At the same time, through these explosions,

there is an enormous push into the atmosphere.

It's the atmospheric tsunami.

This is the example of this pressure wave

that then goes out and it actually traveled

around the world several times.

NARRATOR: The massive blast blew dust, debris, and molten rocks

more than 20 miles into the stratosphere.

GERARD FRYER: Once the eruption was really going full bore,

you have this immense amount of material

that's basically suspended, dynamically in the air,

and forms a big cloud up at about 30,000 feet or so.

STEPHEN SELF: Parts of the eruption column

are simply too heavy to be taken up into the atmosphere,

and it falls out‐‐ it sort of cascades out

like a fountain collapsing.

And ash and hot gases flow down the outside of the eruption

column, down the outside of the volcano, and hit the sea.

STEPHEN SPARKS: When the pyroclastic

flows into the water, they're like very rapidly moving

avalanches.

They push the water away, and these can create waves which

are essentially tsunamis.

HERMANN FRITZ: It's kind of like on a superheated cushion.

Water is vaporized at the interface and kind of lifts

the lighter part of the pyroclastic flow

across the surface.

NARRATOR: An estimated 4,500 were killed

by pyroclastic flows alone.

Experts agree, they probably perished in seconds.

BILL MCGUIRE: Pyroclastic flows travel extremely quickly,

so you can't outrun them.

They're also extremely hot‐‐ several degrees centigrade.

So they will, if you're caught in the middle of one,

incinerate you instantly.

GERARD FRYER: It truly is biblical.

Out of nowhere comes these massive great waves,

and no one really knows what's going on‐‐

just completely terrifying.

BILL MCGUIRE: And most people die not because of 100% burns,

but because they inhale the gases, which

are so hot that they just destroy the air passage

in their lungs instantly.

And so after two breaths, they're dead.

NARRATOR: Each massive Krakatoa explosion triggered

bigger and bigger waves.

Some were said to be over 100 feet tall.

SIMON WINCHESTER: There were lighthouses where they were

concrete harbors, all of them wrecked.

A huge masonry lighthouse, 150 feet tall,

was just ripped off its foundation.

Locomotives, weighing scores of tons,

being just tossed off the lines and smashed into the ocean.

STEPHEN SELF: The waves push inland, float everything ahead

of them, drown people, and then suck everything back out

to sea again.

And this happened four or five times,

with major tsunami hitting Java and Sumatra.

NARRATOR: The Krakatoa eruption had a stunning finale,

a fifth enormous explosion came at 10L55 AM.

In a complex chain of geophysical events,

known as a caldera collapse, Krakatoa's three cones

caved in and fell into the chamber vacated

by the once erupting magma.

SIMON WINCHESTER: The island essentially disappeared.

And for a few seconds there was an almighty crater

torn in the sea.

NARRATOR: Two thirds of the island

collapsed, slid into the ocean, and triggered more killer

waves.

Less than two hours after the final explosion, a wall

of black water hit Batavia on the mainland of Java,

90 miles away.

The giant wave had lost much of its awesome height and power,

but still caused chaos and deadly destruction in the city,

and dozens died.

CASPAR AMMANN: These waves continued far out.

They went through the Indian Ocean.

They made it around South Africa and were even measured

all the way up into the North Atlantic and into Liverpool.

NARRATOR: When Krakatoa was done erupting,

the toll could be counted.

Some 165 Indonesian coastal villages and towns

were devastated and at least 36,000 people were killed.

Every village on either side was destroyed.

NARRATOR: The news of the cataclysmic eruption

of Krakatoa and the catastrophe it

caused shocked the whole world.

ALAN ROBOCK: It was the first large disaster that took place

after telegraphs had been invented.

And so, instantly, within a day, everybody around the world

knew about it.

GERARD FRYER: It was the modern world's first big disaster,

in that it was the first public disaster.

NARRATOR: The global impact of the modern world's

first massive disaster had just begun.

ALAN ROBOCK: A few months later, red and yellow skies

appeared around the world.

In London, there was this beautiful volcanic sunset

that appeared.

They said, this came from the other side of the world.

And they could actually see, with their eyes,

at sunset, the effect of this eruption.

NARRATOR: The vast volcanic clouds

laced with sulfuric acid caused startling atmospheric

aberrations across the planet.

A pale green moon was seen in Madras, India,

more than 2,000 miles away, on September 12th, 1883.

Sun glows reported in Yuma, Arizona, in October.

But since then, scientists from all over the world

sifted through the ruins in the remains of Krakatoa,

as well as the historical records,

to find clues as to what happened and why.

What they discovered about the modern world's

first massive disaster changed science forever.

STEPHEN SELF: A whole number of sciences made big leaps,

because they could associate the phenomena that were observed

in the sea, and the atmosphere, and on land,

with a natural volcanic event.

NARRATOR: For decades after the 1883 catastrophic eruption,

the world believed that Krakatoa would once again sleep

for thousands of years.

But then, on January 26, 1928, a small volcanic mound

emerged from the sea where Krakatoa once stood.

The most deadly and dangerous volcano on earth was back.

[wind blowing]

NARRATOR: On June 29th, 1927, Indonesian fishermen

were sailing between the three islands left

by the fearsome 1883 eruption of Krakatoa.

They were trolling the fertile waters

around the most famous volcano, when they noticed gas bubbles

rising from the sea.

SIMON WINCHESTER: Suddenly, out of the sea itself,

came a huge eruption of smoke, and steam, and flames.

I mean, the idea of flames coming out of the sea

is sort of hellish.

This went on for quite a while.

The eruption stopped, and there was a thin cusp of black land

above the surface of the water.

It was washed away by the waves and the currents.

NARRATOR: Within six months, an island measuring 10‐feet high

and 600‐feet long had appeared above the water.

STEPHEN SELF: Obviously, a new volcano

had been growing on the sea flow,

and had taken that long, from 1883 to the 1920s,

to become first emergent, and then established itself

as a permanent island in 1929.

And since then, it's erupted regularly, it's grown,

and it now occupies a good chunk of the caldera floor.

NARRATOR: In the intervening years,

volcanologists, mindful of its violent past,

have closely monitored the growth of the new island

that the locals call Anak Krakatau, or Son of Krakatoa.

Quiet periods have been punctuated

with occasional large explosions and eruptions.

Fresh and steady lava flows have contributed

to the relentless growth of the new volcano,

adding 25 feet to its height every year.

A lot of the Anak Krakatau activity that we now witnessed

today is actually almost a continuation

of the volcanic activity that took place back in 1883.

We could have another eruption here on the scale of the 1883

eruption of Krakatoa.

NARRATOR: Experts reason that a massive eruption of Anak

Krakatau is only a matter of time.

This is the new Krakatoa.

If ever there is another event, it

will occur in and around this extremely dangerous

little volcano.

[traffic sounds]

NARRATOR: December 22ND, 2018 saw a preview of Anak

Krakatau's might, as an eruption caused

a 158‐acre chunk of the volcano to slide into the ocean.

The landslide created a deadly tsunami

that hit coastal Java and Sumatra, claiming more than 400

lives.

The collapse reduced the volcanic cone

from 1,100 feet above sea level to a mere 360 feet.

However, baby Krakatau is nothing if not ambitious.

Subsequent eruptions have continued,

helping the young fire mountain to rapidly form

new land and new height.

Most scientists agree that it will likely take thousands

of years for Anak Krakatau to build up

enough volume or repressed magma to generate a supereruption.

But an eruption the size of the one

that destroyed Krakatoa in 1883 is still

a terrifying possibility.

Meanwhile, it was a different fire mountain

in the region that gave residents a devastating taste

of its fury not so long ago.

[dramatic music playing]

Java, Indonesia, a densely populated Pacific island

paradise, forged by one of nature's most powerful forces,

volcanoes.

Indonesia is the country but has more active volcanoes

than any other.

And out of all those active volcanoes,

the most active one of all is Mt.

Marapi.

NARRATOR: In past centuries, Marapi

has killed thousands who dare to live and work on its flanks.

But more recent eruptions have done little damage,

giving the half million people living in its shadow

a deadly sense of complacency.

People keep coming back and colonizing the same area,

despite the death and destruction,

because volcanic soils are rich.

They're great for agriculture.

So they move right up into the throat of that volcano,

right into the deadly zone.

NARRATOR: Now, the mighty giant is stirring once again.

It's Monday morning, over 500 volcanic earthquakes

have been recorded over the weekend,

alerting authorities that Marapi is about to blow.

Local officials issue evacuation orders for anyone

within four miles of the summit.

Convinced of their own invincibility,

some villagers ignore those warnings.

[explosions]

That afternoon, Marapi awakens with a series of explosions,

sending lava down its southern slope.

JAMES REYNOLDS: It's Thursday the 28th of October,

and I'm just in the village of Selo, which is on the north

side of Merapi Volcano.

NARRATOR: Videographer James Reynolds positions himself

on the back side of the mountain,

just 2 and 1/2 miles from the crater, hoping to capture

the smoldering danger up close.

The authorities have raised the alert level

to four, which is the maximum level in Indonesia.

It's a volcanic crisis.

NARRATOR: As light falls, refugees

wait out the coming volcanic fury

in camps on the edge of the evacuation radius,

six miles from the peak.

JAMES REYNOLDS: You think you're safe.

You think you're well outside the danger zone.

But then, Merapi doesn't play by the rules.

[thundering explosion]

[sirens]

[non‐english speech]

JAMES REYNOLDS: In the middle of the night,

just all hell breaks loose.

Merapi Volcano just undergone a major eruption.

NARRATOR: Merapi unleashes its most horrifying wake‐up call

in 140 years.

JAMES REYNOLDS: It's a massive, unprecedented eruption.

One of the most jaw dropping sites I've ever seen.

[explosions]

[sirens]

There are sirens, horns, motorbikes, trucks,

just flying in all directions.

Villagers are fleeing for their lives.

[non‐english speech]

[rumbling explosions]

NARRATOR: Morning brings Merapi's apocalyptic power

into stark view.

While the village of Selo has been spared,

everything within a 19‐mile radius

is smothered in a choking blanket of ash.

JAMES REYNOLDS: It was total destruction of villages.

It just made it look like an apocalypse.

I've never seen anything like it.

NARRATOR: Unfortunately, Merapi's deadly tirade has just

begun.

[explosions]

DAVID OGLESBY: Mount Merapi continues

to erupt for a number of days.

JAMES REYNOLDS: Pyroclastic flow takes place, which

sweeps 12 kilometers down a riverbed

and kills 100 people in a refugee center.

Jogjakarta City, one of Indonesia's largest cities,

is just blanketed in choking volcanic ash.

If you breathe it in, it will just rip your lungs to shreds.

NARRATOR: Making matters worse, seasonal storms rain down

a whole new round of misery.

KYLE HUNTER: We're just starting in the rainy season.

The volcanic ash and all the pyroclastic material

combines with the rain to produce a lahar‐‐ a mudflow.

NARRATOR: A mixture of mud, ash, and water

combine to form deadly lahars, which chased nearly

9,000 people from their homes.

[explosion]

Finally, after 35 days of hellish eruptions,

Merapi grows weary, and nature's killing machine finally

goes back to sleep.

This was the largest eruption since 1872

of this stratovolcano.

Luckily, it was very well forecast.

Scientists did a superb job of almost predicting exactly when,

down to the minute, when this thing was going to erupt.

PATRICK ABBOTT: In this series of eruptions of Mt.

Merapi, 341 people died.

Were it not for the warnings, the death toll

would have been in the thousands.

JAMES REYNOLDS: We humans, we may think,

you know, we're grand and mighty,

but coming face to face with nature,

we don't stand a chance.

[rumbling explosion]

This was the biggest eruption for that volcano

since modern volcanology has existed,

and Merapi just showed a real display of who's boss.

on to the Mediterranean, where,

Italy is home to a number of the world's most active volcanoes,

including the deadly and notorious Mount Vesuvius.

[traffic sounds and chatter]

[horns honking]

Every day, thousands of tourists crowd the streets of Naples,

basking in the history of this centuries old Italian city.

But just down the road lies a sleeping monster.

At nearly 4,200 feet, Mt.

Vesuvius dominates the landscape.

It has erupted at least 100 times in the past 10,000 years.

FREDERICK SCATENA: The whole area, the whole Bay of Naples,

is very volcanically active, and it will remain so

for a long time.

The oldest rocks in the area immediately around Vesuvius

are 300,000 years old.

And there's been a continuous sequence of volcanoes

and activity since that time.

NARRATOR: 2,000 years ago, Vesuvius destroyed

a city whose name has become synonymous with disaster,

Pompeii.

Vesuvius is part of the Campanian Volcanic Arc, which

includes other famous Italian volcanoes, such as Stromboli

and Etna.

They were formed as the result of Earth's

constant tectonic activity.

MICHAEL SHERIDAN: In the area between the African continent

and the European continent, two plates are squeezing together.

And these plates have caused the formation of the Mediterranean

Sea on one side, the Adriatic Sea and the other,

and the Italian peninsula is squeezed up.

NARRATOR: In a process known as subduction,

the African plate is actually sliding

under the European plate.

The friction causes crust material

to turn into magma or molten rock.

This magma rises, finding weak points on the Earth's surface

to break through and form volcanoes.

Vesuvius began life inside of another volcano called Somma.

But Somma collapsed 18,000 years ago,

making Vesuvius the dominant structure.

Together, they're known as the Somma‐Vesuvius Complex.

GEORGE MYER: The end result is that this makes this volcano

terrain really quite complex to study,

because you've got the older events that are in the vicinity

of the newer events.

[explosion]

NARRATOR: In predicting what may be brewing beneath the surface

of Vesuvius, scientists have an important ally, history.

The firsthand accounts of activity at Vesuvius

are some of the planet's oldest and most extensive.

In fact, volcanolgy, the study of volcanoes,

began with a description of the eruption in 79 AD

by the Roman statesman and philosopher, Pliny the Younger.

The city of Pompeii was considered large for the time

and even more cosmopolitan than Rome.

Vesuvius had been silent for 800 years,

and residents thought little of its potential danger.

GEORGE MYER: The remarkable thing

about the volcanic eruption in 79 AD, which we refer to

as the Pompeii eruption, is that we

had a witness for this event.

And Pliny the Younger literally wrote down everything

that he could see during this eruption,

because it was so fierce, it was so frightening.

NARRATOR: The eruption was foreshadowed

by a series of earthquakes that hit

the area in June and through the next few months.

And then, on August 24th, the mountain suddenly came to life.

Pliny, a naturalist, produced the first scientific recording

of a complete volcanic sequence.

He writes, "A cloud was forming.

Its appearance and shape would best

be expressed as being that of an umbrella pine."

Similar to this large tree I have behind me.

"Synched, stretched upward like an extremely tall trunk,

it then spread out like branches."

FREDERICK SCATENA: By midday on the 24th,

the volcano has ejected this large column of debris that

went up almost 20 kilometers into the atmosphere, spread

out, and started to rain volcanic

ash and material, mostly of the size of up to about a

centimeter in diameter.

This episode lasted for about eight hours,

and the deposit was about 10‐feet thick.

[screams of panic]

NARRATOR: The ash column shooting up from Mount Vesuvius

gradually increased in weight, until the atmosphere

around the volcano could no longer support it.

The plume cloud collapsed suddenly,

triggering several deadly avalanches called

pyroclastic surges.

This flood of searing hot ash, toxic gas, and rock

raced down the mountain at 150 miles per hour,

with temperatures more than 1,000 degrees Fahrenheit.

It incinerated everything and everyone in its path instantly.

DOUGAL JERRAM: At the early stages of the eruption here at

Herculaneum, you'd have seen a big, eruptive cloud coming out

of Vesuvius, heading off up into the atmosphere.

Just imagine how scared you would have been,

watching this cloud suddenly turn around,

and the black cloud starts heading towards Herculaneum.

This cloud of hot material‐‐

hot, boiling, bubbling pyroclastic material‐‐ starts

to enter the city streets, starts

enveloping you, and heading off down towards the port.

And that was it.

The pyroclastic flows had hit Herculaneum.

NARRATOR: A second pyroclastic surge

followed a few hours later, burying what

was left in 20 feet of ash.

In just 18 hours, Vesuvius spewed out more than 10 billion

tons of rock.

[explosions]

Pompeii was literally erased from the map

until it was accidentally rediscovered in 1594

at a construction site.

The final surge of ash had turned Pompeii into a time

capsule, preserving temples, shops, and houses exactly

as they were in 79 AD.

Although only fragmentary skeletal remains

were found there, hollow spaces within the hardened volcanic

debris defined the shapes of many bodies frozen in death.

Plaster casts made from these forms

reveal the final moments of their lives.

We see a picture of people struggling to breathe,

like this body here, which is curled up with their hands

close to their face, essentially recording

the last final breaths of the people

as they filled up with ash and hot fiery dust

from the volcano.

MICHAEL SHERIDAN: When the pyroclastic flow started

to come down, they were choked.

And we can see then, in the archeological sites, the casts

of people that were preserved in this ash that

resulted from the pyroclastic flow and surge.

NARRATOR: The disaster of 79 AD covered areas eight miles away.

But Pompeii is only part of a long, destructive history.

Far from extinct, Vesuvius has continued to have

deadly eruptions ever since.

s]

Vesuvius has erupted 30 times since 79 AD.

Sometimes the mountain has been explosive, other times

it has peacefully effused lava.

The volcano's erratic behavior makes

it difficult to forecast what the next eruption might

be like.

FREDERICK SCATENA: Understanding the past

is a key to the future, but it's not necessarily the future.

But if you don't understand the past

and understand what the sequences are, how

the volcanoes change through time,

there's no way that you can actually predict the future.

NARRATOR: Each subsequent outbreaks in 79 AD

has had its own unique characteristics.

An eruption in the third century created a blast that could

be easily heard 25 miles away.

Eruptions in 472 and 512 turned day to night and spread dust

over many parts of Europe.

And three separate explosions at the end of the 10th century

spewed out heavy lava flow.

At Vesuvius there are actually three types of behavior.

I relate this to human personality.

So Vesuvius has three sorts of personalities.

NARRATOR: The first and most destructive

type was named for the man who gave such a detailed account

of the eruption that destroyed Pompeii.

The documentation that Pliny produced

was so impressive, that literally it allowed us,

in terms of the volcanology community,

to name this type of eruption a Plinian eruption, in honor

of Pliny the Younger.

In a Plinian eruption, generally it

starts with a big explosion that produces a column that

goes into the stratosphere, maybe 10 miles or 15 miles

above the volcano.

But if the eruption continues for a long time,

this column can collapse due to its weight

and travel down the sides of the volcano, producing

pyroclastic flows and pyroclastic surges, which

are very, very dangerous.

NARRATOR: The second type of eruption is called sub‐Plinian.

It is very similar to a Plinian eruption, but only

a tenth of the size.

It may be mildly explosive, such as an eruption that

occurred in 1631.

We call it mildly explosive, but it destroyed

most of their cities in the area around Vesuvius

that exist today.

NARRATOR: The blast was still strong enough

to kill more than 3,000 people from pyroclastic flows.

Following that event, the volcano

underwent 300 years of persistent activity,

with numerous eruptions, none more than seven years apart.

MICHAEL SHERIDAN: There are small but frequent eruptions,

such as those that occurred between 1631 and 1944,

and those types are called Strombolian.

In this case, there's a sort of fire fountaining.

It forms a cone of cinders above the event,

and then lavas appear.

NARRATOR: The 1944 eruption was recorded on film.

The eruption of 1944 was really a very small eruption.

It occurred during the Second World War.

But the eruption produced a lot of slow

and destroyed a local town called San Sebastiano.

NARRATOR: Since then, Vesuvius has been silent.

But by no means is the volcano extinct.

GEORGE MYER: In terms of the inactivity of volcanoes,

they may be quiet for thousands of years.

NARRATOR: If Vesuvius behaves like most volcanoes,

it will reawaken and have at least another 200,000 years

of deadly eruptions.

Vesuvius has averaged an eruption every 64 years

since 79 AD.

That means we could be due for another eruption any day now.

MICHAEL SHERIDAN: It's very difficult

to forecast when the next eruption of Vesuvius

will occur.

But what most people agree on is the longer the period of time

since the last eruption, the larger we

expect the next eruption to be.

NARRATOR: Why?

Because of the geology of Vesuvius.

In the years following 1944, hardened lava and rock

sealed the conduit that leads from the magma chambers

to the volcano's mouth.

The effect is similar to what happens when a bottle of soda

is shaken.

And if it ends up with a lot of pressurized gases

in this liquid, the bubbles will stay in the carbonated beverage

as long as the lids on.

And so now this becomes the real issue with the volcano.

The container, if it's also getting squeezed and jostled

a little bit by the way the plates are behaving,

you're getting it ready for something more cataclysmic.

And the image that you could get today is the‐‐ pshew!

Out comes this explosion, instantly.

That's why we're concerned about Vesuvius,

We're not really measuring the behavior of Vesuvius

today from 1944.

We're looking at it back to when did it really

behave as it did in 79 AD.

And it has been throwing out explosive volcanism,

over 1,000 to 3,000‐year cycle, a number of times.

In terms of the geologic history,

we know that it does repeat itself.

NARRATOR: The next eruption could not only be explosive,

it could be devastating.

FLAVIO DOBRAN: Large, Plinian eruptions

occur every few thousand years, and it is now past

more than 2,000 years since we had a major eruption.

MICHAEL SHERIDAN: I think there's general agreement

that the next eruption of Vesuvius

is going to be of a Plinian or something

little bit less than a Plinian type of event, one that may be

similar to what happened in 1631 at the volcano.

NARRATOR: That's 1631 eruption occurred

after 130 years of quiet.

At the time, large trees had grown over the cone,

and locals didn't remember it being a volcano.

Today, Naples may be facing a similar fate.

FLAVIO DOBRAN: It has been more than 50 years

since the eruption or 1944, and the grand majority of people

do not remember this eruption.

They do not perceive the volcano as being something menacing,

but they perceive it rather as a mountain, a very tranquil

mountain.

And this has produced a false sense of security

that essentially lets the population sleep.

But they're essentially sleeping on a time bomb,

and eventually this time bomb will go off.

MICHAEL SHERIDAN: When volcanic eruptions

are less frequent than a generation, which

will be 20 to 40 years, people living on volcanoes generally

feel that they're safe and it's not going to happen to them.

NARRATOR: The longer Vesuvius slumbers,

the more danger it poses for the Bay of Naples.

And the past indicates the threat may be

worse than previously thought.

NARRATOR: Though volcanology has made great strides

in recent years, scientists can't predict the exact day

when Vesuvius might next wreak havoc.

The forecast of a future eruption, of the next eruption,

of Vesuvius is very hard to do.

It could remain in this condition for centuries

or even erupt next year.

NARRATOR: But volcanoes do give warning signs

called precursors.

Scientists at the Vesuvius Observatory

use an array of high tech tools to keep watch for any trouble.

Vesuvius is one of the best‐monitored volcanoes

in the world.

So we have about all the types of instruments

on the volcano, which provide monitoring 24 hours a day.

NARRATOR: The most noticeable precursors of an eruption

are earthquakes.

Another warning sign is a buildup of volcanic gas.

Some of this can be gauged by looking at the many fumaroles

or steam‐releasing holes that surround the volcano.

The more steam that appears, the more that's

brewing beneath the surface.

GIUSEPPE MASTROLORENZO: So by using our monitoring system

at the Vesuvius Observatory, we are

sure that we will be able to detect

the sudden change of the volcano before an eruption.

NARRATOR: While still far from an exact science,

volcanology can help predict some eruptions weeks

beforehand.

FREDERICK SCATENA: The devil's always in the details.

We've gotten much better in our ability

to predict when eruptions will occur,

but predicting exactly where the damage will occur

and how big that damage will occur is much more difficult.

NARRATOR: To get an idea of how much damage the next eruption

may cause, volcanologists look at worst‐case scenarios.

The importance of using worst‐case scenario is to take

what has happened in the past and its worst incidents

and projected it‐‐ if that would happen today,

what kind of situation would we have to deal with?

NARRATOR: A group of geologists from Italy

and the University at Buffalo in New York focused on an eruption

that happened more than 1,800 years before the famous Pompeii

disaster.

It occurred during the Bronze Age in approximately 1780 BC.

MICHAEL SHERIDAN: If we compare the 1879 eruption

and the Bronze Age eruption, both of these eruptions

produced about the same amount of new material on the surface.

[explosion]

The big difference was the direction of dispersal.

NARRATOR: In the 79 AD eruption, winds pushed most the damage

to the south.

A similar event today would threaten more than 1 million

people who live directly around Vesuvius.

But a repeat of the Bronze Age eruption

could be far more deadly.

In that blast, winds forced most the damage

to go a different direction.

MICHAEL SHERIDAN: The pyroclastic flows and surges

were mainly dispersed towards the northwest.

In other words, in the direction of Naples.

NARRATOR: In fact, pyroclastic surges

reached as far as 15 miles, completely covering what is now

the city.

When we actually traced the thickness of the deposits

produced by the pyroclastic surges and flows

from the Bronze Age eruption, we found that the thickest

deposits were directed more towards the Northwest,

and a significant deposit existed

within the city of Naples.

Meaning that people in the Bronze Age

would not have survived an eruption of this scale.

NARRATOR: The ash deposits from this earlier bronze age

eruption are as much as 10‐feet deep in some parts of Naples.

MICHAEL SHERIDAN: Finding a deposit right in the center

of Naples has changed the way people think about their safety

from eruptions at Vesuvius, and people are now considering

that Vesuvius may truly represent

a risk to their safety.

CHRISTIAN RENSCHLER: We don't want to scare people,

but we want to make them aware.

As scientists, we have got an obligation

to facilitate this communication that has to take place

in a dangerous situation, like living around a volcano.

And it's important that the general public understands

these dangers and also acts responsibly

and try to do the best that they can to prevent being harmed

in such a situation.

[music playing]

NARRATOR: Vesuvius, Krakatoa, Yellowstone, and the islands

of Hawaii, these volcanoes are still active and dangerous.

And scientists warn that the devastating potential

within these fiery giants could prove to be

nothing less than apocalyptic.

DONALD THOMAS: I think everyone needs to recognize

that everything we've seen up to now is not the complete story,

that these systems can behave in ways that we've never seen

before and, clearly, in some ways that could potentially

be very dangerous.

My money would be on you've got to hope that you're wrong,

but you're expecting the worst.

To be alert is to be ahead of the game.

MICHAEL RAMPINO: Nothing you can do about a volcano.

If it's going to go off, it's going to go off.

And the effects on civilization are going to be drastic.

[rumbling explosions]