All language subtitles for The Power Of Volcanoes Series 1 1of2 Years Without Summer 1080p HDTV MVGroup

Volcanoes are sleeping giants,

woe betide us, should they awake.

Millions of people live in their shadows,

and very close to a looming catastrophe.

But, even giants, far
away and long forgotten,

can suddenly come alive.

Looking at history,

we come to understand that active volcanoes

also need to be reckoned
with in the future.

Volcanologists, climate
researchers, geologists,

they all want to learn
from previous catastrophes

in order to save lives in the future.

In a way, they're like
Beauty and the Beast.

Can we protect ourselves from this danger?

We can't always predict these events.

People will die.

Istanbul is Europe's largest metropolis.

More than 14 million people live here.

But, few of them know that
the eruption of a volcano

has shaped this city's destiny.

History shows what's in store

for many cities around the world.

Because, no matter how far
away the volcanoes are,

no one's truly safe.

In the year 541 AD, Istanbul is
still called Constantinople.

A foreign plague decimates the population

of the Byzantine capital.

Millions of people die.

Emperor Justinian, and the entire country,

are desperate.

An invisible foe has taken over the empire.

Your Majesty, the air we breathe is so bad,

the pestilence has spread to the city.

What do you plan to do?

Those who are righteous
have nothing to fear.

Then, ask the heavens what we've done.

The city is full of corpses.

What is the true reason?

The answer to this riddle

might be found one and a
half millennia later,

and more than 3,000
kilometers further north.

A small international team of researchers

has put up their tents
in eastern Greenland.

They are here to research
the climate of the past.

Johannes Freitag, of the
Alfred Wegener Institute,

hopes to retrieve information from the ice

on how the climate has changed

over the last millennia.

Good to see you.

Good to see you.

He is in search of sudden climate changes.

Greenland is an inhospitable place.

Even in summer, the temperatures cool down

to minus 18 degrees Celsius.

But here, far from civilization,

is the perfect place for ice core drilling.

Because the ice here is very thin,

100,000 years of climate
history are deep frozen

in only half a kilometer depth.

The exact location of the
drilling site is key.

If there are any anomalies
in the upper layers,

it needs to be relocated.

It goes down until this layer.

Here you can see the melted layer.

It's refrozen melt water from last summer.

And so, below here, there's massive ice.

The fine layers are like growth rings.

It's important not to destroy
them during the retrieval.

An annual layer measures
about half a centimeter.

So, the researchers are
slowly stepping back in time.

But, the work has to be broken
off every now and then.

The drill can't heat up,
or it would melt the ice.

The layers have been reached,

from around the time of the plague.

Does the ice give any
indications about the trigger

of the disease?

30.

50.

The electrical conductivity

of the drilling core
confirms the suspicion.

In the sixth century AD,

the ice suddenly points to a shift.

There was a sudden increase

in the atmosphere's sulfur content.

Very clear.

That's rare.

This mus be a volcanic peak.

It is quite high,

and present in 10 centimeters of the ice.

That equals about two years.

We don't know the time
period for sure right now,

because we don't have
the exact determination

of the age of the ice.

Volcanoes are fed by the hot inner core

of the Earth.

Driven by this heat,

magma rises out of the Earth's
mantle in slow currents,

and accumulates under its thin crust.

The molten rock also transports a whole mix

of poisonous gases to the top.

Could the mysterious epidemic
stand in close relation

to the eruption of a volcano?

Before the city was struck
by the unknown disease,

the sky darkened.

There are precise accounts,

dating back to the year 536 AD.

For months, the sun has been weak,

in summer as in winter.

Everyone fears it might never come back.

The wine is sour, the harvest is lean.

There is so much snow
that the birds are dying.

It is as though Hell had crept

out of the depths of the Earth.

Historian, Mischa Meier, of
the University of Tübingen,

has analyzed the accounts
to understand what exactly

happened back then.

During the sixth century AD,

the population is already
very wary of anything it sees

as abnormal.

This is due to a fatalistic
view of the world

that was quite popular back then.

It was sort of, waiting for
the world to end attitude

that fostered any thoughts
of the coming doom.

Any sign would do.

And, this unusual weather
obviously fit in quite nicely.

Scholars had predicted the end of the world

to occur at the beginning
of the sixth century.

And, every change in the
environment was seen

as a sign of the coming last judgement.

And, indeed, change was coming,

but much different than
people back then expected.

They are testimonies of an
almost forgotten catastrophe.

Its cause, a seemingly insolvable mystery.

The Earth itself keeps destroying life

on its own surface,

because volcanoes spew out, not only ashes,

into the Earth's atmosphere,

but sulfuric gases as well.

During massive eruptions,
they catapult sulfur

as high as one kilometer into the air.

Once there, the sulfur mixes with water.

This creates a layer of clouds,
made up of sulfuric acid,

that barely lets in any sunlight.

A more recent example shows
the effects this can have.

In 1815, in Indonesia, the
Tambora volcano awakes.

Its actual eruption only
lasts for three hours.

In this short time, ashes and ash flows

kill about 10,000 inhabitants.

But, its cloud claims many
more deaths around the world.

By this time, the world had
already grown so close

that the word about the
catastrophe has spread to Europe.

Shortly afterwards, the
sulfur reaches our continent.

The clouds color the sky a deep red.

There are breathtaking sunsets,

that have been captured by William Turner,

and are preserved until today.

But this beauty, is the
harbinger of a catastrophe.

What follows, are cold
spells, bad harvests,

and the biggest famine of the 19th century.

The number of victims of
Tambora's sulfur clouds

can only be estimated.

On a global scale, the volcano
probably cost 10 times

the amount of lives than
the eruption in Indonesia.

In Germany, many people are
forced to flee their home.

The ice cores from Greenland are analyzed

in the Alfred Wegener
Institute in Bremerhaven.

Will the suspicion of a volcanic eruption

in the sixth century, the century
of the mysterious disease,

be confirmed?

There are hundreds of samples
stored in cold chambers.

It is one of the largest ice
core storages in the world.

Until now, the volcano
that poisoned the climate

in the sixth century hasn't yet been found.

We want to reconstruct the climate

on the entire planet to
piece together the puzzle.

That is why we have ice cores
from all over the world.

The analysis of the core from Greenland

confirms it.

The traces of sulfur actually do stem

from the sixth century.

At the same time the cold
spell reached Constantinople,

a previously unknown volcano
covers the northern hemisphere

with a cloud of sulfur.

But, the scientists have a suspicion.

Could it be that, within a few years,

there wasn't just one, but
in fact two eruptions?

And indeed, the laboratory analyses show

that a few centimeters further
there is another indication

of sulfur.

A second volcano had poisoned the climate

just a few years after the first.

And, the epidemic follows this eruption.

The eruption left traces on
the North and the South Pole.

The volcano that spit them out,

must therefore be found in the
middle, close to the Equator.

In El Salvador, hidden away
from the world until now,

lies the Ilopango.

The traces of its last eruption

have long since been overgrown
by the tropical rain forest.

Robert Dull, of the
University of Austin Texas,

has specialized in the
study of past ecosystems.

He is convinced that the
Ilopango is responsible

for the climate chaos in the sixth century.

And, he is looking for
evidence to prove his theory.

The volcano is, basically, the lake.

What you see here, is an
outline of the entire area

that was erupted, all at once,
when this volcano erupted

15 hundred years ago.

So, instead of just having a single vent,

where lava would come up
through a single vent,

we have many vents,

and all of that material was
expelled explosively at once.

The eruption must have been immense.

It buried the entire area under

a several meter high layer of ashes.

Volcanic ash doesn't have a lot
in common with regular ash.

It is finely scattered rock.

The force of the explosion ripped apart

huge amounts of lava, and
turned it into dust.

We find an ash that's
light in color like this,

it's very exciting for someone like me,

because what it tells us

is that it's both high in silica

and that it was erupted explosively
in a geologic instant.

Might have been a day,
might have been two days,

but a huge amount of material
was erupted all at once,

which tells us of the
strength, and magnitude,

and shear immensity.

Robert Dull tries to reconstruct

exactly what happened during the eruption.

He interprets the geological traces

that are invisible to most people.

As long as the giant is asleep,

nothing tells of the danger lying beneath.

Even back then, the volcano
was a crater lake.

Its magma chamber lies underneath.

The pressure in it slowly increases

until it reaches a critical point.

The gases that are freed in the molten rock

start to ascend.

Steam, created by the heat
of the magma chamber,

settles over the landscape, like fog.

Until suddenly, the roof
of the chamber flies up

like the cork of a bottle of champagne.

As the eruption column
falls back into itself,

pyroclastic streams flow over the earth.

The ash clouds, as hot
as 700 degrees Celsius,

destroy everything in their way.

Not only do they flow over
the edge in huge sheets,

but they flow through the
valleys and up mountainsides,

and there's some estimates that they flowed

as high as 15 hundred
meters in some places,

up hillsides, according to
geologists working in this area.

So, you can't outrun these events.

You cannot outrun a pyroclastic flow.

You can't hide from a pyroclastic flow.

You die in a pyroclastic flow.

It's unlikely that anyone in a radius

of 1,000 square kilometers
survived this inferno.

Today, only the ashes show
just how big the eruption was.

The size of the eruption,
by measuring the thickness,

not only right by the crater itself,

but as we get further and further away,

the more measurements we have

the more accurately we
can estimate the size

of the eruption itself.

In order to discover the
world's biggest volcanoes,

one can't solely rely
on the search on land.

The ship, Bedeor,

carries a team from the Kiel
Research Institute GEOMAR,

that will examine the ocean
floor around Cape Verde.

There is a steel pipe

on the underside of the two ton weight,

which is supposed to be
jammed into the sea bed.

That way, it is possible
to extract a drilling core

of about nine meters,

but only if it doesn't
hit a spot on the ground

that is too hard.

The gravity core has to sink down

to about three and half kilometers,

until it reaches the seabed.

At a speed of one meter per second,

this can take up to an hour.

Time and again, sediment
coring continues to unveil

previously unknown volcanic eruptions.

Important information,
in order to understand

the impact of volcanoes on
the history of the Earth.

The actual success of
the team was uncertain,

but at eight in the morning,

hope turns to certainty.

The drilling has succeeded.

The drill sleeve contains everything

that has swept over the
ocean floor for centuries,

even volcanic ash.

Volcanologist, Steffen
Kutterolf, collects samples

of this ash from all over the world.

He is eager to discover the frequency

of big volcanic eruptions.

Once we find 10 layers of ash in a core,

we examine in what
direction the ashes flew.

Only with the information
of dissemination at hand,

is one able to make other predictions,

like the volume that came
out of this eruption.

The sediment cores have a big advantage.

Other than sulfur, ash can be traced back

to a particular volcano.

It is like a fingerprint.

Every volcano, and every
eruption is unique.

In the GEOMAR Institute in Kiel,

there are samples from
all around the world.

The ashes of the ocean
floor can, therefore,

be traced back exactly to
a particular eruption.

Steffen Kutterolf has brought
in several sediment samples

of the Pacific Ocean floor,

close to Central America's coast.

The type of crystals in the ashes alone,

can reveal their possible origin.

The volcanologist has a suspicion.

The mineral is typical for
the last big eruption

of the Ilopango Volcano.

The exact composition reveals
that the ashes are indeed

from El Salvador.

Even though he has found
them hundreds of kilometers

further away on the Pacific Ocean floor.

By doing so,

we could place the marine
ash layers that we found

and had previously been undiscovered

in correlation with the
eruption of the Ilopango.

Now, we have a result of an expansion

of 1.2 million square kilometers,

which is about four times
the size of Germany.

This proves that the
eruption of the Ilopango

catapulted more ash and
gas into the atmosphere

than any other volcano has,
in the last 2,000 years.

Today, buildings cover
the ash in many places.

As a matter of fact, the
capital of San Salvador

was built on it,

16 kilometers away from
the, still, active volcano.

No one is prepared for a possible
eruption of the volcano,

especially not on the scale
of the amount of ash

a previous eruption suggests.

The country has other,
more pressing, problems.

There are, however, 6 million people

living in a radius of 100
kilometers around the volcano.

Anywhere between North
America, Central America,

and South America,

no country is more densely
populated than El Salvador.

What does that mean?

There's land scarcity,
there's not enough room

for all these people to live.

So, to think of moving an
entire city, like San Salvador,

even to ask people to move
off the flanks of a volcano

that we know is active,
is very very difficult,

because that's all they have.

Therefore, it is even more important

to examine the early
eruptions of the Ilopango.

Robert Dull wants to get an impression

of the area around the crater lake.

He hopes to find regional indications

of the last big eruption of the volcano,

because the dispersion of the ashes

reveal which areas might be
in danger in the future.

Generations have settled in this area

without even knowing about
the volcano's existence.

The giant has been dormant
for several centuries,

and no one remembers the big eruption.

Was it really a trace of sulfur from here

that was found in the ice cores?

If you look across this valley now,

you can see it's a broad,
relatively flat valley

that's quite rich with all
the volcanic materials

it's fallen over thousands
of years of development

in rich agricultural soils.

So, you can see why people
were attracted to this region

in the first place.

Agriculture has erased the traces

of the eruption even further.

This makes it almost impossible
to determine the exact time

of the eruption.

Volcanic ash is made up
of inorganic material,

like stone or fragments of glass.

Their age is indeterminable.

Robert Dull has to rely on
the remains of living beings

that died during the eruption.

Wood is a great help here.

It was carbonized in the scorching ash,

but didn't burn up completely,

due to the lack of oxygen.

That is how it is possible to
narrow down the exact time

of the eruption.

It's a time capsule.

It's a precise moment in time

that's captured in this ash.

So, when we dig these pieces of wood out,

the smallest pieces that we find,

the big tree trunks that we find,

any piece of wood that we're able to pull

out of this ash,

can then directly be
associated with the time

of the eruption.

These are rare moments of joy

for Robert Dull and his colleagues.

Because the carbonized wood
has chemical substances

that steadily decompose over the years,

the tree's time of death can be determined

by measuring the decomposition
in the laboratory.

These samples have helped
us narrow the dating range

from 120 years down to more like 20 years.

And, we've really been able to pinpoint,

and say, yes, Ilopango was not
a fifth century eruption,

it happened in the early sixth century AD.

Following the eruption,

there was a cold spell of 15 years

that reached all the way to Constantinople.

Once there, the unknown
disease spreads further.

In desperation, people turn to religion.

Emperor Justinian even
mandates forced baptisms

to appease the alleged wrath of God.

But, to no avail.

More and more residents fall sick and die.

The disease spreads from Asia,

all the way through the east
Roman Empire and Europe.

It's trace goes all the way to Munich,

and the suburb Ascheim.

So many people died within a short period,

that several bodies had to
be put into the same grave.

But here, time has erased
almost all traces.

The only surviving evidence
could possibly be found

in the people's teeth.

Holger Scholz, of the

Institute for Microbiology
of the German Armed Forces,

hopes to solve the riddle
by using forensic methods.

Special suits protect the
samples against contamination,

because one skin flake,
alone, is all it takes

to soil the last DNA samples
before their analysis.

The scientists manage to
isolate the genetic substance.

It belongs to a bacteria

that caused the deadliest
infectious disease

in the history of human kind,

Yersinia pestis, or the plague.

The cooling off that happened back then,

left a further weakening of the population.

There were extreme famines,

and that meant that people
didn't have enough to eat.

Even rodents, that are an important factor

for the transmission of the plague,

retreated to the cities

where there was still some food left,

and that is obviously how
humans came into more contact

with the pathogens.

The plague's bacterium actually feeds

off the blood of rodents.

The connection to humans
is created by fleas.

Once the flea changes its host,

it transmits the pathogen,

and the risk of an infection increases

with every animal a human has contact with.

There was terrible hygiene.

The immune system was severely weakened.

And all that, furthered the
expansion of the pathogen,

which in turn cost the lives
of millions of people.

Far away, the Ilopango in El Salvador

changes the climate.

Famine ensues.

The population becomes more
vulnerable to the plague.

The disease can strike anyone.

It blurs the lines between
the rich and the poor.

Panic and chaos ensues.

There is no more food.

The emperor cannot uphold law and order.

The fact that the emperor, himself,

was struck with the plague,

obviously increased the
insecurity immensely.

And, if one is seeing this
as one of God's plans,

it was clear that the
emperor is being punished,

and therefore was losing the
grounds of his legitimate rule.

Even the emperor,

who was godlike in the
eyes of the population,

is struck by the plague.

In view of the span of a human life,

volcanic eruptions that
trigger climate chaos

are comparatively rare.

So rare in fact, that the
risk is often forgotten.

But they have, nevertheless,

been present throughout history.

In 2014, danger came very close.

The Bárdarbunga volcano in Iceland

had been belching out
lava for several months.

And, it still pumps about 35,000 tons

of sulfur dioxide into the air.

No one knows, yet, how the
eruption will develop,

and when it is going to come to a halt.

The volcano is located under
Europe's largest glacier.

Once the lava comes too close to the ice,

there's a possibility of
a hydrogen explosion.

If this were to happen,
the gases would rise up,

even higher.

And, Iceland is close to western Europe.

The sulfur could make it
all the way to Germany,

even without such an explosion.

One look into history reveals
the possible consequences.

The winter of 1784 was
one of the hardest ever

to hit central Europe.

In the following spring,

melt water and ice flooded down the rivers.

The flood breaks bridges,

causing many stretches
of land to disappear.

There are severe floods in
Würzburg and other cities.

Cologne reports a water
level of almost 14 meters,

the highest water level ever measured.

Even at the start of the eruption,

volcanic gases drift to western Europe.

John Grattan, a geographer
at the University of Wales,

has assembled accounts of
contemporary witnesses.

On the 23rd of June, 1783,
people across western Europe

woke up to a changed world.

Forests being stripped of their leaves,

and there's an intense smell
of sulfur in the air.

The cause of the disaster

was the Icelandic volcano, Laki,

a giant gap in the earth,

that produces more than
6,000 cubic meters of lava

per second.

Within eight months,

it releases approximately 120 million tons

of sulfur dioxide, which
travels to western Europe

and changes the local climate.

There are very clear descriptions

of people struggling to breathe,

of an uncomfortable pressure

palpitated through their hearts,

of mysterious agues and fevers,

of outbreaks of terrible
diarrhea of the bloody flocks.

There are theories that imply

that the Laki eruption is co-responsible

for the French Revolution.

Ever since then, Laki has been dormant.

But, what would happen if
the giant awakens again?

Today, the atmosphere
is a lot more polluted

than during the eruption of Laki.

Calculations show, that today,

430,000 people die prematurely,

due to the effects of dust particles.

Industrial plants and traffic
pollute the environment,

not only through emissions
of carbon dioxide,

but also through very small
particles in the air.

Volcanic gases would burn the
atmosphere even further.

Scientists have calculated

that if this were to happen,

there would be 140,000
more deaths per year.

The purpose of the

Federal Office of Citizen
Protection and Disaster Assistance

in Bonn,

is to organize quick aid
in times of crisis.

Christoph Unger is in
charge of the institution.

He and his co-workers develop strategies

to prepare for multiple
instances of crisis.

Are we prepared for a volcanic eruption

happening far away?

At the moment we are not preparing

for gases or dust particles in the air

that might reach Germany.

But the consequences of a volcanic winter

are comparable to today's weather extremes.

The onset of a cold spell could
have far reaching effects,

as the example of the Münsterland shows.

In 2005 there is a snow storm,

leaving up to half a meter of snow.

Power poles fall over under the weight.

And, there are entire stretches of land

that are plunged into darkness.

250,000 people are without electricity.

Some, even for several days.

And that, was relatively harmless.

A blackout of a larger
area would be disastrous.

No radio, no TV, no computers.

There's hardly any cash left,

so you can't buy anything.

Gas stations need electricity
to pump gasoline.

Security systems wouldn't work.

It would have a huge
impact on our social life.

In the last years,

Germany has repeatedly had
to fight with cold weather

and high water levels,

but not to the extent as
after the Laki eruption

in the 17th century.

In such a catastrophic case,

the danger of infectious
diseases would increase.

What would happen if 30% of
the population fell sick?

We have a problem with supply.

Because, the supply chains would break.

There'd be very different
kinds of problems in security

in vulnerable institutions,

where there wouldn't be
enough personnel at hand,

and there's even the question of

who would be vaccinated, when.

Who will receive the very
short supplies of vaccines?

This would lead to an
immense impact on all areas

in society, as a whole.

The residents of Constantinople

don't fare any different.

And not knowing the cause of the disease,

makes them even more afraid.

More and more,

the city is overwhelmed with the plague.

It isn't just the people that fall sick,

but the system itself that
is beginning to fail.

Panic ensues.

Civilization unravels.

There simply wasn't enough population

and military capacity

to protect these regions and these cities,

because the plague had
decimated too many of them.

And it isn't just the effects

on the people's health.

The plague kills soldiers and taxpayers.

Trust in the power of the state
has been gravely damaged.

Even after 100 years, the empire
cannot defeat the onslaught

of the Arabs.

And that is how the
eruption of the Ilopango

might have also heralded the
end of antiquity itself.

Since the time of Emperor Justinian,

the world population has grown
to over 7 billion people.

And, more than half of them live in cities,

and depend on transport,
trade, and telecommunication.

Can you protect all these people
against a volcanic eruption

with a global effect?

There are about 15 hundred
active volcanoes worldwide,

but only 100 of them are
under local surveillance

by observatories,

and the last eruption
of the other volcanoes

isn't even known.

But, even if the volcanoes
are well monitored,

an eruption is still hard to predict.

Even experienced scientists
can make horrendous mistakes.

In 1993, an international
team of researchers

perform measurements on the
peak of the Colombian volcano,

Galeras.

They are in good spirits.

Nobody seems to be bothered by the mist

that covers the view on the crater.

Suddenly, the volcanologists
are taken aback

by a hydrogen explosion.

Rocks and small particles
fly up in the air.

One part of the group is still
on the inside of the crater.

There is no hope for these nine people.

Others are severely injured.

A joyous trip has turned into a nightmare.

Only two months later, the
volcano erupts again.

This time, it also hits the
scientists' research station

that was seen as secure, at the
time of the first eruption.

So, even in modern times,

even in the developed
world and rich countries,

the level of preparedness is not adequate

to handle such a large, sudden event.

And, no matter how many instruments we have

measuring small earthquakes and
measuring Earth's elevation

as it rises, in anticipation
of an earthquake,

we can't always predict these events.

So, even if scientists know

that a volcanic eruption
is about to happen,

do they know the course of the eruption?

In 1980, Mt. St. Helens
announced another eruption

through several small earthquakes.

It is located on the west coast of the USA,

close to the major cities
of Portland and Seattle.

Richard Waitt, of the US Geological Survey,

witnessed the eruption.

As so many others, he was
convinced that he knew

what was going to happen.

By late March, this word, bulge,

was on everybody's lips.

So, it got big enough that,
and the volcano steep enough

that many people suspected,

at some point it's gonna start landsliding.

What was expected, though, is that there be

a series of small landslides

and that would be a warning

and people could get out.

The eruption was announced in the media,

and drew more and more
onlookers to the area.

But then, Mt. St. Helens erupts
in a totally unexpected way.

An earthquake let's the entire
north slope slide down.

The mountain explodes, due
the the loss of pressure.

Mud and small stones
rush down the hillside.

No, that was not anticipated.

It went over one ridge, down into a valley,

over the next ridge,

and just kept going out and out,

20 kilometers, 30 kilometers maybe.

I don't even know how far it went.

But, way out.

And, nobody anticipated anything like that.

Ash, clouds, and mudslides overrun

the fleeing people.

57 people died.

Among them, are scientists
that miscalculated the impact

of the eruption.

The surrounding area is covered in dust.

540 million tons of
volcanic ash are dispersed

over an area larger than the Netherlands.

Only weeks later, the
immensity becomes clear.

There is a huge hole in the volcanic cone.

The desertificated area,
in front of the opening,

is over 600 square kilometers large.

As a comparison,

the eruption of the Ilopango, in 540 AD,

was about 10 times as large.

So, we do know that modern
science can help us

predict, somewhat, when
these events will occur.

But, we've never been tested
on the level of Ilopango.

We've never had a massive
eruption, of this size,

near a densely populated urban center.

Never.

So, what happens when this
happens near Seattle?

What happens when this happens in Naples?

Will our technology be good
enough to get everybody out?

There are more than 67 large cities,

worldwide, located close
to an active volcano.

That means there are
about 116 million people

living dangerously close to these giants.

There are already 37 million of them,

living in the area of Tokyo,

in the shadow of Mt. Fuji.

Its last big eruption happened
more than 300 years ago.

Geologically speaking, this
is the blink of an eye.

If it were to erupt, its
ashes would destroy

the entire infrastructure of the city.

The situation in Seattle isn't much better.

Scientists see Mt. Rainier as
one of the sleeping giants

that could erupt at any time.

Even in Europe, it's dangerous.

Mt. Vesuvius, alone, could
destroy Naples entirely.

But there's an even larger magma chamber

in the Bay of Naples.

The Soufriere Hills Volcano,
located close to Plymouth,

the capital of the Caribbean
island of Montserrat,

can provide a glimpse
into the possible effects

of an eruption happening close to a city.

Before the city was buried under its ashes,

several times, there were
4,000 people living here.

Hardly anyone has stayed.

Today, Plymouth is a ghost town.

Volcanic eruptions are a global threat.

But, their awakening also
offers new possibilities,

because with every one of these eruptions,

scientists learn more about them.

One such example is Mt. St. Helens.

Even if every giant is unique,

a few of the results taken from here

can be applied to other volcanoes as well.

This is a birthplace of modern volcanology

in many ways,

especially some of the
extraordinary events.

This landslide, there's
probably four or 500 volcanoes

around the world now,

that have had a landslide, we know of,

because of this.

I mean, this is what opened the
door to understanding that.

Only a few years ago,

a young geologist developed
a ground breaking method.

It enables us to predict
a volcanic eruption

more precisely.

Today, experts from the
US Geological Survey

fly to the top of the
mountain several times.

Down here, it's about 30
degrees in the shade.

But, on top, the scientists have to deal

with very cold temperatures.

Angela Diefenbach monitors
the volcano from the air.

The most important point for her,

is that the method is simple, flexible,

and affordable enough for
developing countries,

where a lot of volcanoes are not monitored

on a regular basis.

You can use a point and shoot camera,

or a smart phone camera.

You just want to make
sure you have good lens

characteristics.

So, you don't want,

like a GoPro camera wouldn't be that good

for this type of work,

because you have a lot
of radial distortion,

and that translates into your model.

Currently, there is a plug of cold lava

that keeps the volcano shut.

This so-called lava dome is dangerous,

because it stores pressure underneath it.

Any change in the surface could be a sign

of a possible eruption.

Angela Diefenbach shoots her photos

from a precisely chosen angle.

The brilliance of the idea is
that the photos form a basis

on which her computer generates
an exact 3-D replica

of the volcano.

If she, then, compares the
data to earlier flights,

the smallest changes become
visible immediately.

This method can even be
applied during an eruption,

because it is often in the last moment

that one can predict how the
giant is truly going to act.

This particular lava dome
doesn't pose much of a threat,

because it erupted very slowly
and it was relatively cool

when it erupted.

But, other lava domes, other volcanoes,

tend to collapse,

either from big explosions
or by gravitational forces.

And, when they collapse, they
produce pyroclastic flows,

which are very dangerous to people.

Mt. St. Helens is a very
well monitored volcano,

but there are many sleeping
giants all over the world

that can hardly be researched.

There is a huge, seething lava lake

in the Democratic Republic
of Congo, for example.

The Nyriagongo lies in
the middle of an area

that is torn apart by civil war.

And, even if the giants lie in
sparsely populated regions,

like the Tavurvur in Papua New Guinea,

their load of sulfur can reach
any corner of the world.

This is why Angela Diefenbach's
method is so beneficial.

It helps to assess the risks.

But scientists can nevertheless,
only warn in time.

They cannot stop an
eruption from happening.

In the midst of big cities,

life seems to be as safe as ever,

but history shows that some
things aren't as they seem.