All language subtitles for D D S02E06 Volcanoes 1080p AMZN WEB-DL DD2 0 H 264-playWEB_track3_[eng]

Volcanoes are
a spectacular display

of nature’s power,

with eruptions
which are awesome to behold

yet utterly deadly.

These infernos of nature

can unleash cataclysmic
destruction in their wake...

from explosive blasts capable
of scorching vegetation

and landscape for kilometers...

That’s very deadly,
very fast moving and that will--

You’ve got no chance
to escape from it.

...to towering toxic ash clouds

able to rise tens of thousands
of meters into the air

and kill animals and humans
by suffocation.

And if you see an ash cloud
rolling towards you,

you’ve probably not got time
to escape.

Volcanic blasts are so powerful

they have even been known
to change the world’s climate.

Since the 1500s, over
a quarter of a million people

have been killed by volcanoes.

And since the millennium,

over 2000
have lost their lives.

It is estimated
that volcanic eruptions result

in over a billion dollars

in global property damage
annually.

The ruminative force of
volcanoes can seem boundless,

yet these dragons of nature
also provide great benefits.

These include the creation
of extremely fertile soil,

essential for agriculture
and farming communities,

as well as stunning landscapes.

These features have attracted
human settlements

around volcanic regions
throughout history.

But such close cohabitation

with one of nature’s deadliest
forces comes at a price.

Suddenly there was
a blanket of dark ash,

came down and covered me.

It was so dark

that I just couldn’t see,
I couldn’t breathe.

With fascinating
expert insights

and firsthand accounts
from survivors,

in this episode,
we will be looking at volcanoes

and eruptions across different
parts of the world,

including the deadly disasters
on Mount Sinabung in Indonesia,

Mount Etna in Italy

and Mount Nyiragongo

in the Democratic
Republic of Congo.

Volcanoes are vents

on the surface
of a planet or moon

from which
extremely hot materials

such as molten rock
and hot gases

escape from the interior,
causing an eruption.

A volcano is a site
where there is molten rock

from within the earth
that rises towards the surface.

Now, the molten rock
can leak out

and give you lava flows,
and molten rock can explode

and give you
an explosive eruption,

or the molten rock can
interact with steam

and not actually reach
the surface itself

but give you
a steam-driven eruption.

So anywhere where stuff
from inside the earth

gets forced out onto the surface
usually builds a mountain,

sometimes blasts a hole.

But the term "volcano"

doesn’t only refer to the vents
from which hot lava erupts.

It also designates
the massive landforms

that have emerged over time

as a result
of volcanic activity.

These mountains,
birthed from the rocks, ash

and other solidified volcanic
debris around the volcano vent,

grow into towering peaks
and slopes.

The resulting volcanoes
are classified

according to
their shape and size.

Most significantly,

they are classified according
to their eruptive patterns,

a feature that plays
a significant role

in volcano monitoring.

There are a number of ways

of categorizing
different types of volcanoes.

So we can think of a volcano
as a very morphological thing.

So the shape of a volcano.

The picture-postcard volcano is
the one which is cone shaped,

the Mount Fuji-style volcano.

And then we get
our more classical

shield-type volcanoes,
or upturned dishes.

And we get variations of that
in between.

So a volcano is really
anywhere on the surface

that we see the product
of volcanic activity.

And that volcanic activity
is the result

of the generation
of heat at depth

and the rising of
molten magma to the surface.

And eventually we see
that erupted product,

and that creates the fantastic
shapes and activity

that we see
on the surface today.

One of the most crucial parts
of volcano classification

is assigning one
of three statuses:

Active, dormant or extinct.

If a volcano is labeled
as active,

it is currently erupting

or exhibiting signs
of a foreseeable eruption.

If it is described
as extinct,

it is not showing any activity
and probably never will.

A dormant volcano is one
that hasn’t erupted

for a significant amount
of time,

although that may change
in the near or far future.

However, just because a volcano
is labeled as dormant

doesn’t mean it is
necessarily any safer

than its active counterpart.

Mount Sinabung in Indonesia

was a volcano that,
right up to 2010,

had not erupted for 400 years
and was labeled as dormant.

But since then,
the mount has experienced

a series of deadly eruptions

that have taken numerous lives
and left thousands displaced.

The 8070-foot Mount Sinabung

on the Indonesian island
of Sumatra

is home to more
than 150,000 people.

The communities living along
the volcano’s slope

take advantage
of the fertile soil conditions

to grow a range of crops
and produce.

The mount has been a staple
and stable feature

on their landscape
for centuries,

and they are dependent on it
for their livelihoods.

But in 2010,
all that rapidly changed

when the volcano erupted,

killing two people
and displacing 30,000 more.

This sudden reanimation came
as a complete surprise.

And according to experts,

Mount Sinabung had been
monitored less

than its more active
counterparts.

But the violent eruptions

that would ensue
in 2014 and 2015

would cement the status of
Sinabung as an active volcano

and forever change the lives
of the inhabitants

who had made
their home around it

for so many generations.

On the 1st of February, 2014,

the mount erupted again,

spewing out a plume of hot ash,
gas and rocks

that reached up to 3000 meters
into the sky.

The deadly blast killed
at least 14 people,

including three schoolchildren
and a teacher.

The deaths were caused

by fast-moving, toxic,
pyroclastic ash clouds,

which engulfed
surrounding villages.

These deadly clouds,
termed pyroclastic flows,

made the eruption
of Mount Sinabung

particularly violent.

Pyroclastic flows are the most
dangerous and deadly elements

in an explosive volcanic blast.

Capable of moving at speeds of
up to 720 kilometers per hour

and at temperatures known
to reach 700 degrees,

they incinerate
everything in their path.

It was a pyroclastic flow

that destroyed the Roman city
of Pompeii in A.D. 79

and which claimed
nearly 30,000 lives

on the Caribbean island
of Martinique in 1902.

A pyroclastic flow is
an avalanche

of lava blocks and volcanic ash,

finely fragmented volcanic
material and volcanic gases

that cascade
down the side of a volcano

like an avalanche does,
like a snow avalanche
does almost.

It’s also accompanied by a big
sort of turbulent ash cloud

that rolls over the top
of the dense basal avalanche

at the base of the flow.

So when you’re looking
at these pyroclastic flows

from a distance, hopefully,

you see these
sort of boiling ash clouds.

The bit that you don’t see is
at the base of these currents,

sort of thick accumulations
of coarse material

that can be very destructive.

They can burn people
that get trapped in them,

they can destroy houses
and infrastructure

because there’s a lot of coarse
material in them as well.

So they essentially just
bulldoze buildings over.

And they can bury buildings
and towns as well.

It’s hot and it’s fast-moving,

you know, moving at
80, 90 kilometers an hour.

You can’t get out of the way.

And if you’re caught in
a blast of hot ash and hot air,

you basically burn to death.

The ferocity and scorching heat
of these pyroclastic flows

meant that rescue workers
had to wait

and could not get close
to Mount Sinabung immediately.

When they were finally able
to approach the volcanic peaks,

they were faced with bodies
buried deep in ash.

The disaster had
a severe effect on the economy

as farmers lost their crops,

resulting in
increased food prices.

Sadly, this would not be

the only volcanic disaster

to bring the region
to its knees.

In June 2015,

just a year
after the deadly eruption,

the Mount Sinabung volcano
exploded once again.

A series of violent eruptions

lasting over the course
of a few days

rocked the region.

On the first day,

the volcano erupted three times

in only a few hours.

Volcanic ash blanketed
parts of Medan,

the provincial capital
of North Sumatra,

about 50 kilometers
from the volcano.

Residents were forced
to wear masks

as winds carried smoke
towards the city.

Authorities raised the alert
status of Mount Sinabung

to the highest level.

Sinabung spewed out
rocks and hot gas

over a distance of
three kilometers incessantly.

Dense ash that was up
to two millimeters thick

covered roads and homes
located 15 kilometers away.

Eyewitnesses described
an almost apocalyptic scene

of a dark cloud of smoke
covering the entire sun.

Up to 28 pyroclastic flows
were observed in one day.

The Center for Volcanology and
Geological Hazard Mitigation

declared all areas
within a minimum radius

of three kilometers from
the summit of Mount Sinabung

a danger zone.

As a response to the severity
of the situation,

authorities initiated
the immediate evacuation

of the region.

Eyewitnesses described scenes

of several thousands of people,

including women
with infants in slings,

transported down the mountain
in police trucks.

Others made their way down

the charred slopes
on motorcycles

with faces smothered in ash.

At least 10,000 people
were evacuated.

Many were housed
in temporary shelters

already under pressure
due to the 20,000 people

already displaced
from the volcanic eruption

of the previous year.

These refugee camps faced
huge humanitarian pressures,

with urgent need for beddings,

toiletries, clothing,
food, water tanks

and psychologists
for trauma healing.

However, many of the villagers
on Mount Sinabung

were reluctant to abandon
the fertile soil

of the volcanic slopes which
provides their livelihoods.

The volcano slope had been
a key economic source,

helping the community grow
diverse cash crops

such as chilies, oranges,
cocoa and coffee.

Some people have no choice
about living near volcanoes.

If you’re in a part of the world

where you’ve got subduction
going on,

one plate going below another,

there’s going to be
a line of volcanoes.

And volcanic land is
often quite fertile

because you’re bringing
fresh minerals to the surface.

So when it’s mature enough
to start growing crops on,

you can get a good yield.

So volcanic land is,

can be quite good for farming,

but it comes with the risk that
there’ll be another eruption.

For days,

authorities had pleaded
with villagers

in the main danger zone
to evacuate.

But according to the local
disaster mitigation agency,

only 10,000
of about 33,000 people

living within the danger zone
had moved a safe distance away

into tent camps
or government buildings.

Luckily, unlike in 2014,

no injuries were recorded
from the disaster.

But the cost and toll
of this latest volcanic event,

following so quickly
on the heels

of the previous year’s
eruption,

was a serious blow
for a community

already on its knees.

So, what exactly triggered
these explosive eruptions

on a volcano
that had stood dormant

for the past four centuries?

The answer seems to lie
in the location itself

of Mount Sinabung
on the Ring of Fire.

The Ring of Fire is essentially
a geographical feature

whereby you have lots of
different active volcanoes

in a very ring-shaped pattern.

Indonesia is positioned
on the Ring of Fire,

an arc of fault lines
in the Pacific Ocean

that frequently experiences
volcanic activity.

Mount Sinabung is among
about the 130 active volcanoes

in the country.

Most volcanoes are
in seismically active

parts of the world

because the process
that produces earthquakes

is often the same process

that causes molten rock
to be generated.

The formation of magma
is deeper down

as the rocks are dragged
into the earth

and they encounter conditions
which cause melting to occur.

Or they release seawater
into the rocks above,

and that melts them.

The melt generation process

is a slow, ongoing process

and you need a large amount
of molten rock magma

to approach the surface to give
you a volcanic eruption.

The magma rising towards
the surface under a volcano

doesn’t move smoothly.

It can vibrate the rock
as it moves,

so you get volcanic
earthquakes as well,

tiny earth tremors which,
if it’s close to the surface,

sometimes local people
can feel.

We can certainly detect it
instrumentally.

So you look for
these volcanic earthquakes

as the rock fractures
or the magma moves

or the gas moves through
the rock, vibrating it,

and if those signals
get closer to the surface,

that’s a very good warning sign

that an eruption
might be imminent.

So volcanoes
are often seismically,

earth-tremorly alive
before anything starts erupting.

And that’s a good sign
that something’s happening.

White Island is a volcano

situated in the Bay of Plenty
in New Zealand.

Most of the volcanic edifice
is submerged underwater,

but the main crater
is above sea level,

jutting out majestically
in the bay.

It is one of the most active
volcanoes in New Zealand

and has seen multiple eruptions
between 1998 and 2001.

However, this hasn’t deterred
the booming tourism industry

that had sprung up around it.

Being at a volcano

is one of the most
awe-inspiring things you can do.

Being at an erupting volcano,

one which is possible to see
the activity glowing at night,

for example,
is just simply awe-inspiring.

It’s a bit of a rush
as you’re up there

watching this activity
progress through time.

The privately owned island
was a major tourist destination

with boat tours to the volcanic
land mass happening daily.

As part of these expeditions,

tourists could go to the island

and actually walk inside

the main active
volcano’s crater.

However, with popular routine
visits to active volcanoes

like White Island,
comes the risk

of tour operators and tourists
being lulled

into a false sense of security.

So some of these tourists are,
you know, adventure tourists.

They are going for the thrill,

just as people
might go climbing

or doing some other
very dangerous sport.

It doesn’t necessarily
appeal to all of us,

but I guess in my mind
it’s okay

if people are
absolutely informed

about what the risks are.

And I think
that’s the question.

Did those people understand
the risk

that they may have been
putting themselves at

by going to those places?

For the White Island tours,

people were given
protective equipment

like gas masks and helmets
when exploring the crater.

But these precautions
proved defenseless

in the face of
the volcanic disaster in 2019.

On the 9th of December, 2019,

at the start of
the Christmas festive period,

a tourist tour group
was engulfed

in a volcanic disaster.

White Island erupted
in two explosions

following on
in quick succession.

The series of violent blasts

flung ash over 3600 meters
into the sky,

showering the volcano’s floor
with hot debris.

If you’re caught underneath
a very big eruption,

the sky can go black.

If you’ve got a big cloud
of ash above

and ash starts raining down,

you’re in darkness.

And your car headlights,

if you’re trying to flee, don’t
penetrate through the murk

because you’ve got ash falling

and you’re ingesting ash
into the engines

and trying to flee.

If you’re in that situation,
it’s too late.

Probably the best thing
you can do

is get undercover and stay there

and hope the roof over
your head doesn’t collapse.

It’s horrible to be caught

in a really big
volcanic eruption.

In Whakatane town,
50 kilometers across the ocean,

smoke could be seen rising
from White Island.

Forty-seven people had
been on the island

when the blast went off.

We know that reunification

won’t ease
that sense of loss or grief,

because I don’t think
anything can.

But we felt an enormous
duty of care

as New Zealanders

to make sure that we brought
their family members back.

Of the 47,

20 people were killed

and 27 were injured
with serious burns.

Casualties came
from all over the world,

including the U.K., U.S.,
China, Malaysia,

Australia and New Zealand.

Rescue operations proved
extremely difficult

in such volatile
volcanic conditions.

The New Zealand Police
dive team,

supported by
the Defense Force personnel,

deployed today. Um...

They haven’t found anybody
as yet.

Although in the immediate
aftermath of the disaster

some survivors were rescued
by boat and helicopter,

hazardous situations meant
that further rescue operations

had to be put on hold.

Of course I’m worried.

I would be inhuman
if I did not worry.

I have to emphasize
that the risk has not gone.

The risk remains present.

But reconnaissance flights that
did get close to the volcano

initially detected
no signs of life there.

Prior to the eruption,

the volcano had been
well monitored.

Scientists had been
keeping a steady watch

to try and spot any signs
or indications

of an impending explosion,
but nothing major was detected.

This is attributed

to the complex submarine
structure type of the volcano.

According to experts,

the volcano
is highly ebullient,

engaging in a variety
of eruption styles.

This makes it a complex brew

that is difficult to predict.

These eruptions are driven
by superheated steam and ash

rather than lava being shot out
of the magma chamber,

which can make them
difficult to predict.

White Island is
a submarine volcano

with only this summit crater
exposed to the surface.

So if we had an eruption
which was driven by magma,

so a magmatic eruption,

there are a number of things
we can look for

which can
tell us a little bit

about the state
of that volcanic system.

So if we can think about
measuring the gases

that are coming out
the top of the volcano,

is there an increase
of these before an eruption

or is there a decrease?

We can think about looking
at the seismic signals

that volcano
is producing through time.

We can also think about
how that volcano is deforming,

so inflating or deflating
or tilting, if you like.

At White Island,
the difficulty comes

because none of these
precursory events may happen

leading up to an eruption,

so it becomes very difficult
to understand

what may happen
through time.

Phreatic steam type eruptions

can happen so fast that there
is no time to react to events.

The deadly combination
of falling rocks,

wet debris jets
and scorching air

can also cause
life-threatening harm.

Questions are still being asked

about the White Island disaster

and why tourists were allowed
to approach

New Zealand’s
most active volcano.

With these volcanoes that tend
to be quite persistently active

and sometimes heavily visited
by tourists,

the problem, of course,

is when those volcanoes
do something

that they don’t normally do

or they do something
just every once in a while,

maybe every few months
or maybe every few years.

It would be interesting
to know, for example,

if the tourists
on White Island were aware

that some of the places that
they might visit on their tour

are places that
volcanologists

who work for the institutions

responsible for monitoring
the same volcano

would not go to
because it would be deemed

too high risk for them.

One defense has been the idea

of freedom of choice
and freedom of access.

Geological hazard monitors
GeoNet

relayed data and information
around volcanic activity

to tour operators
and the police,

but some say that the decision
to visit or not

ultimately lies with tourists.

The interaction
between volcanoes

and the tourism industry is
a difficult and fraught one.

The dangers of having people
in such close proximity

to active volcanic sites,
as evidenced by White Island,

cannot be underestimated.

But it can be difficult
to navigate this relationship

in lower-income countries
who are increasingly dependent

on the economic boost
of a tourism industry

around their volcanic sites.

Mount Nyiragongo in the
Democratic Republic of Congo

is one such example.

The mount, respectfully known
by the local community

as General Nyiragongo,

is an active 3470-meter peak
north of the town of Goma,

near Congo’s border
with Rwanda,

a region that has experienced

a series
of conflicts and unrest.

Nyiragongo has the largest
lava lake in the world

and is one of
the most volatile volcanoes.

But in recent years,

it has become
a popular tourist destination.

Volcanoes, because they are
often mountainous

and are in mountainous parts
of the world,

the scenery’s beautiful.

So people just go and hike
and enjoy the scenery.

And if it’s a volcano
that’s recently been active,

there’s usually interesting
rock formations to see,

there’s a sulfurous smell,
maybe hot springs

or maybe some small eruptions
going on,

which usually are
quite safe to watch

from a range
of a few hundred meters,

so they attract people.

The trouble is
that just now and then

there’s a bigger than
expected eruption,

and that’s what can kill people

who have gone there
to experience it

and they just get unlucky.

Virunga,

Africa’s oldest national park,

started offering tours
to the volcanic region in 2014.

Since then,
the volcanic tour has become

one of the park’s
most popular attractions

and is set to increase
exponentially

as more foreign operators
add the tour to their packages.

For a region still recovering

from the effects
of past conflicts,

this influx of tourism
and potential investment

is a much needed and
sought after economic boost.

But despite
the increased prosperity

that Mount Nyiragongo
may attract to the Congo,

it still remains
one of the world’s
most dangerous peaks.

In 1977, it experienced
a sizable eruption

that killed 400 people
and left 400 homes

and 10 kilometers
of roads destroyed.

On the morning
of January the 17th, 2002,

the great mountain would erupt
once again

with devastating consequences
for the local community.

That morning,
rivers of liquid lava

came spewing down
the sides of the volcano.

One of these rivers
spilled into the town of Goma,

burning swathes of jungle
and properties in its path.

Large smoke plumes created
by the eruption

similarly endangered
the region’s famed wildlife,

including its mountain gorillas

living in the nearby peaks
of Mount Nyamuragira.

The mountain gorillas are
critically endangered,

and over half
of the population

reside in the Virunga Mountains.

The disaster also caused

substantial socioeconomic disruption.

Thirteen percent of Goma city
was ravaged.

There are about 150,000 people

that did not leave
the town of Goma.

An additional 250,000
left to Rwanda,

and 100,000 people

went a bit west
in a place called Sake.

The World Health Organization

estimated that close
to 15,000 homes were destroyed

and 400,000 people were
displaced by the disaster.

Most of the locals
who were displaced

are still unable to rebuild
homes on the original sites,

as these have been buried
underneath the lava field.

For a country with
an already struggling economy,

the volcanic eruption
was a major blow,

creating a huge depression
for businesses in the region

and leading to mass
unemployment at the time.

Whether a volcano
is dangerous or not

depends a lot
about what’s happened

at that individual volcano.

So volcanic activity
and volcanoes in particular,

they have
their own characteristics.

So I like to think of volcanoes
as having their own personality.

Each one behaves differently
through time.

So about understanding the risk
that individual volcano poses

is about understanding what
that volcano does through time,

which is very different
at each volcano.

So whilst one volcano
may be very safe to visit,

it hasn’t had an eruption in
hundreds or thousands of years

or by "less safe,"
I mean there’s less probability

of an eruption occurring,

there might be others
which have more frequent,

more risky activities
which will be higher probability

of getting caught up
in something dangerous.

Different volcano
monitoring strategies,

which are better able
to predict

these changing
eruptive patterns,

will have to be put in place

in order to safeguard
the local community

and the increasing visitors
to the mount

from future disasters.

There’s no such thing
as a typical volcanic eruption.

I’ve stood next to lava flows.

You feel the heat
if you’re close,

but they will trundle by you

and you can see
the rock pleating over,

and it’s beautiful,
it’s fascinating.

And there’ll be a smell.

There’s usually
a sulfurous smell

and you can hear
little cracky, poppy noises

as the surface chills to glass

and the glass flakes
plink away.

It’s great to be near
an eruption like that.

But an explosive eruption
that’s roaring out of a vent,

you’ve got a sound
like a jet engine...

and you’ve got bangs
as individual explosions occur,

which are big bubbles bursting,

but you don’t to be too close
to that kind of thing,

because there could be
brick-sized lumps of rock

flying through the air.

And even if you’ve got
a hard hat on,

one of those hits you, you’ve
got a serious head injury.

And if an ash column gets
too dense to support itself

and collapses
back to the ground,

it doesn’t just sit there,
it rushes downhill,

and you get what’s called
the pyroclastic flow.

Since the eruption,

the number of seismographs
in the region has increased.

This vital technology,

which is able to signal
impending eruptions,

will hopefully allow scientists
in the region

to be able to warn the public
in advance.

So an earthquake
at its most fundamental

is caused by rocks breaking
and moving past each other.

So in the example
where you have a volcano,

you might have a magma chamber
under the ground

that’s underneath the kind of
main volcanic cone.

And if magma
from the magma chamber

starts moving
towards the surface,

that’s going to cause
small earthquakes to occur

as it moves up
through the volcano.

So you can actually track
the movement of magma

through volcanoes
by using earthquakes

and using kind of
dense networks of seismometers

that measure the ground motion
from earthquakes in a volcano

to try and forecast

when a volcanic eruption
is going to occur.

Volcanoes are one of the most
mercurial elements of nature.

And as we’ve seen, when we add
human interactions to the mix,

the results are deadly.

Volcanic monitoring is
at an advanced stage,

with seismographs and super
computers in some instances

able to offer early predictions
to facilitate evacuations.

However, as we’ve seen
in various parts of the world,

the geological benefits
and stunning sights

that volcanoes provide can make
them hard for us to resist.

We do not always heed
the warnings.

And human complacency
in the face

of such a devastating force
is deadly.

The tourism industry

and its interaction
around volcanic sites

is something that will need
to be re-evaluated

in the future

if we hope to prevent disasters

such as the one witnessed
in New Zealand.

Yellowstone is one such site

where there has been
speculation and discussions

around tourism monitoring.

Yellowstone National Park

is one of the most popular
natural reserves in the world.

Four million people travel
to the park every year

to view untrammeled vistas,

glimpse untamed animal life

and get close
to hot, gushing geysers

and simmering thermal springs.

Yellowstone also houses

approximately 10,000 geysers,
hot springs and mud spots.

It is a unique
geothermal hotspot.

However,
the stunning natural reserve

that attracts so many

also comes with its hazards
for unwary visitors.

Apart from the obvious dangers

of its wildlife
and famed grizzly bears,

its unique geothermal features
also pose serious risks.

Through the years,
a number of scalding accidents

have been reported,
often a result of visitors

getting too close
to geyser basins.

But perhaps
the biggest threat of all

is one
that has not yet happened

and lies beneath Yellowstone.

The National Park sits
atop a supervolcano.

Supervolcanoes are described
as volcanic centers

that have had eruptions

covering more than
1000 cubic kilometers.

Yellowstone has had
three major eruption events

in the past
2.1 million years

that have led to the creation
of large volcanic craters.

When this volcano last erupted
630,000 years ago,

it had a massive eruption
that formed a giant caldera.

A caldera is a large
circular or oval depression

caused by the collapse
of the surface

following magma removal.

The last one, formed
by Yellowstone’s eruption,

measured approximately
45 by 76 kilometers in size.

But although Yellowstone has
not erupted for so many years

and may seem extinct,

evidence of an active
volcanic state

can be witnessed
in hydrothermal activity

in the area.

Geothermal features
and hot springs

are one of the key elements
of volcanic activity.

They are the products
of interaction

of groundwater with magma
at shallow depths.

Volcanoes are
really, really deadly

if you’re close to one
when it erupts.

Now, what do I mean by close?

It depends on how big
the eruption is.

The worst possible case

is an eruption of something
like Yellowstone.

They’re sometimes called
supervolcanoes,

a large caldera where
you’ve got a magma chamber

10 or more kilometers
across.

If that breaks through
to the surface

and all the gas escapes,

you can get a column of ash
rising into the sky

and pyroclastic flow
sweeping out

hundreds of kilometers
in all directions

and an ash cloud which will
spread around the world

and block out the sunlight.

And then you lose
your wheat crop

for two or three years.

That’s mass starvation,

that’s end-of-civilization
stuff potentially.

The total heat flux

from Yellowstone’s
geothermal features

is estimated to be around
a staggering 300 million watts.

This high geothermal activity
in the area

has led to researchers
investigating

when the supervolcano
might erupt once again.

An eruption is not expected
to happen anytime soon,

or at least not
in the next thousand years.

But according to research
from 2017,

the volcano’s transition
to active status

might happen faster
than we expect.

And given the unpredicted
eruptions at Mount Sinabung,

Mount Nyiragongo

and White Island,

we may have to pay
closer attention.

So, what might happen

if Yellowstone were
to erupt again?

If it did erupt, it could be
a devastating disaster

for the entire surrounding
regions in the U.S.

An eruption could lead
to a deadly pyroclastic flow

made up of molten lava

measuring more than 1000 degrees.

It could also lead
to the formation

of toxic ash clouds that would
expand over 800 kilometers.

This thick ash would also
likely cover the ground

and measure up
to 10 centimeters thick,

which could
potentially destroy crop growth

in the Midwest of America.

Along with the ash,

the supervolcano could release

a range of equally toxic gases,

including sulfur dioxide,

a gas that can lead to
acid rain and global cooling.

However, such an eruption,

although devastating
on a large scale,

especially for the western
region of the U.S.A.,

would be unlikely
to wipe out human life.

Another popular volcano

which is also being
very closely monitored

is the notoriously active
Mount Etna in Italy.

The volcano is situated
on active tectonic plates

and sits on the boundary
of the African plate

subducting underneath
the Eurasian plate.

This has made the volcano
a hotbed for volcanic activity

over its long history.

Etna, which means
"I burn" in Greek,

is the largest of the three
active volcanoes in Italy.

Standing at a colossal
3320 meters above sea level

and two and half times
the size of Vesuvius,

Mount Etna is the highest
active volcano in Europe.

Since ancient times,
Etna’s ebullient activity

has continued incessantly.

This constant volcanic activity
helped attract

some of the earliest
traveling geologists

and birthed
some of our first insights

into the origins of volcanoes.

Careful observations
by these early geologists

of ancient lava flow

helped develop
our understanding

of how solidified lava and ash

added to the construction
of stratovolcanoes over time.

But despite
its hyperactivity,

Mount Etna, like the other
volcanoes we’ve looked at,

continues to attract
a large human presence.

Its fertile volcanic soil
benefits

the extensive agricultural
activity on its lower slopes,

from vineyards and orchards

to olive groves
and citrus plantations.

Its lower slopes are also home

to several populous settlements
and communities,

including the city of Catania.

Approximately 25%
of Sicily’s population

lives on the slopes
of Mount Etna.

Its rich history
and stunning scenery

also attracts
its fair share of tourists,

with thousands flocking
to the volcano every year.

This human presence,

combined with Etna’s
high volcanic activity,

has led to a number
of deadly incidents

through the centuries.

In the 20th century,
Etna’s hyperactivity continued.

The 1920s saw
a series of eruptions,

including a major one in 1928.

In November of that year,
an explosive eruption

led to the destruction
of Mascali,

a town located on the eastern
flank of the volcano.

The next explosion that would
rock the volatile mount

would be in 1950.

In the festive month
of December that year,

disaster struck.

A titanic wall
of scorching molten lava

measuring nearly 10 meters high
surged down Mount Etna.

The incendiary landslide
blazed through villages

on the volcano’s
lower slopes,

torching houses in its path.

Inhabitants again were able
to evacuate successfully

and no loss of life
was recorded,

but they were left devastated

by the loss of their homes
and cherished farmlands.

The lava is reported to have
burned through the villages,

turning vegetation,
including chestnut groves,

apple orchards,
vineyards and trees,

into flaming torches.

Eruptions continued
through the following decades,

including the ’70s and ’80s.

In 1983,
a breakthrough was made

in the strategies used
to divert volcanic lava.

During an eruption in 1983,
Italian scientists managed

to persuade the government
at the time

that a direct intervention

to halt the volcanic process
was needed.

Explosives and earthen barriers
were used with some success

to divert
the oncoming lava flow.

This feat wasn’t recognized

as a resounding breakthrough
at the time,

but it would be the first
successful intervention

that would pave the way
for many more in future.

Eruptions continued
through the following decades,

including a series of violent
outbursts in the late ’90s.

Today, in the 21st century,

Mount Etna remains
as active as ever,

with recent activity
in 2017 and 2019.

In 2017,

after a few fairly quiet years,

the volcano experienced
a phreatic eruption.

At the time,
about 35 tourists

and their guides
had been visiting the mountain

when the explosion happened.

The eruption shot
lava and rocks

198 meters into the air

and did cause some harm,
leaving 10 injured.

In 2019,

more activity was witnessed
on the great mountain.

Italy’s National Institute
of Geophysics and Volcanology

tweeted about a series
of strombolian eruptions

that occurred on the volcano
in May.

Strombolian eruptions
are named

after the Stromboli volcano,

an active volcano
on the Aeolian Islands.

This type of eruption
can spurt jets of lava

tens or even hundreds
of meters high.

But in this event,

the eruptions were minor,

with some spluttering
of volcanic material

landing on the mount’s slopes.

What was significant
about this event

was the fact
that the eruption occurred

on the flank of the volcano
and not its summit.

A flank eruption on
the mountain the year before

had been the first
for a decade.

Explosive flank eruptions
pose a real threat,

as they lead
to lava floods, landslides

and potentially deadly
pyroclastic flows.

Although this recent flank-side
eruption was concerning,

there was some reassurance
in the fact

that Mount Etna is
constantly monitored.

Etna is one of the most
studied volcanoes in the world,

with a long history
of observation.

I’ve been on Etna when
it’s been erupting explosively,

with substantial ash column
rising from the vent

and stuff falling
on the ground

a few hundred yards
in front of me.

To be honest,
it’s exhilarating.

That’s fine when
it stays at that level,

but if the eruption
intensifies,

then I imagine it is terrifying,

because I would know
the consequences

that could be coming my way.

I’d hate to be
in that situation,

because there’s not a lot
you can do if you’re too close.

There are currently
three observatories

set up on its slopes

with Italy’s National Institute
of Geophysics and Volcanology

constantly keeping
a close watch.

There has also been significant
development in technology

around volcano detection
and monitoring

that has emerged around Etna.

The use of airborne volcano ash
trackers, for instance,

have helped aircrafts learn
to navigate around volcanoes

and avoid the disruption
of grounding planes

and shutting down airports
for extended periods

during volcanic activity.

New automated warning systems

also help predict
imminent volcanic eruptions.

Mount Etna,

with its long history
of volcanic activity,

has provided
great opportunities

for volcanic studies

and the development
of technology

around monitoring
and managing eruptions.

But despite the observations

and introduction
of volcanic monitoring devices,

Etna’s enigmatic
eruptive pattern

and myriad
of eruptive styles

makes it difficult
to rule out the future threat

of an unpredicted eruption.

The tragic events around
volcanoes in Indonesia,

Italy,

New Zealand and the Congo

prove that we cannot
be complacent

in the face of potential
volcanic eruption.

A dormant
or even extinct volcano

can reanimate at any time.

And a tourist tour
along a scenic route

could quickly turn into
a deadly eruption zone.

You can have intervals of repose

lasting several hundred years

between one eruption
and another.

And those are the worst
volcanoes to deal with

because if a volcano has done
nothing for hundreds of years,

the local people will
regard it as safe.

"My grandfather lived here.
He never had any problems.

Why should I move out?"

And even if there are
warning signs building up,

it’s very hard
to convince people.

Although technology is advanced

in volcano monitoring,

there is still a lot
for us to learn

in understanding
more complex volcanic patterns

so that seemingly invisible
signals are not missed.

Volcanoes are
terrifyingly awesome,

and we are drawn to them
like moths to a flame.