All language subtitles for D D S01E08 Volcanoes 1080p AMZN WEB-DL DD2 0 H 264-playWEB_track3_[eng]

Volcanoes hold a special place
in our consciousness.

Stories of the destruction

of the ancient Roman city of
Pompeii continue to fascinate,

while terrifying visions of
explosive fire and molten rock

play a key part
in our nightmares.

But less well known are the
horrors of pyroclastic flows:

avalanches of hot volcanic
gases, ash and lava bombs

which can descend
from steep volcanoes

at blistering speeds of
up to 700 kilometers per hour,

vaporizing anything
in their path.

A volcanic eruption
is one of the most dangerous

and awe-inspiring
natural disasters.

When a volcano erupts,
it spews out clouds of ash,

lava...

and even volcanic bombs.

These are formed of molten rock

that has been blasted
into the air

before hardening
into solid lumps

of more than 64 millimeters
in diameter

and falling back to earth.

The molten rock
that emerges from a volcano

is called lava.

The liquid rock below
the surface of the earth

is called magma.

When lava flows,
it usually moves quite slowly

but still poses
a serious danger

to property and human life.

There are four different types
of volcano.

The simplest kind of volcano
is called the scoria cone,

also known as
the cinder volcano.

They can appear very suddenly

when gases propel lava
high into the air,

where it breaks apart into
small fragments, or cinders.

As they drop,
the particles cool

and fall around the single vent
to form conical hills.

Over time, the sides
of a cinder cone volcano

can become very steep,

but they rarely grow larger

than about 300 meters tall.

Many cinder volcanoes
are monogenetic,

meaning they will only erupt
once before becoming dormant.

Famous examples
of the cinder cone volcano

are Sunset Crater in Arizona,

a volcano
that is 305 meters high

which first erupted
around 1065,

and Paricutin, one of the
youngest volcanoes on earth,

which appeared suddenly
out of a cornfield

in West-Central Mexico
in 1943.

The second type of volcano
is called the stratovolcano,

also known
as the composite volcano.

So there are very different
shapes of volcanoes,

and that’s because
of the different ways

in which they erupt,

and they build up
material differently.

So a stratovolcano is the one
that we associate

with the most explosive
types of eruption.

And they’re capable of
a very wide range of behavior.

But they build up
those classic cone shapes

that we might associate
with something

like Mount Fuji
or Mount St. Helens.

These are the most violent

and dangerous kind
of volcanoes.

They can be massive,
sometimes reaching heights

of up to 3 kilometers.

The slopes
of the composite volcano

tend to rise slowly at first,

and then become very steep
with a narrow vent at the top.

They have a system of conduits
that channel the molten magma

from deep within the earth
to the surface.

Because they can deliver
so much magma to the surface,

they can grow
thousands of meters tall.

The stratovolcano can explode
with extreme violence,

and then go dormant for tens
or even hundreds of years

before coming
back to life again.

A famous example
is Mount St. Helens

in the Pacific Northwest
region of the United States.

This stratovolcano
last erupted in 1980,

killing 57 people

in what was the deadliest
eruption in American history.

Before Mount St. Helens,

it was a reasonable assumption
to make

that the big eruptions from
volcanoes come out the top.

But Mount St. Helens taught us

that sometimes
that’s not the case.

It blew a giant hole
out the side.

We’re still analyzing data
from Mount St. Helens,

because it’s still
valuable to science

and there’s so much more
to learn.

What’s special
about Mount St. Helens

is that we’ve seen
the beginning,

during and after effects
of the eruption,

which means that we can piece
together warning signals

and the effects
of the eruption itself.

Because it’s fairly
well studied,

we have a mass of data
and understanding

and knowledge to then ask
advanced questions upon.

And it’s these
advanced questions,

with a context of what we do
know about Mount St. Helens,

that allows us to make more
progress elsewhere.

The third type of volcano
is the shield volcano.

These are broad,
dome-like structures,

and when viewed from the air,
look like shields,

hence the name.

Mauna Loa and Kilauea in Hawaii

are both examples
of shield volcanoes.

The largest volcano known to
humanity is a shield volcano,

estimated to be the size

of the entire
Hawaiian Island chain.

Fortunately for us,
it is not on this planet.

It is a dormant shield volcano
found on Mars,

called Olympus Mons.

Its peak is more than twice
the height of Mount Everest,

making it the tallest mountain
in the entire solar system.

The final type of volcano
is called the lava dome.

A lava dome
is when you have a type of magma

that comes out as lava,

that’s very, very slow
and stiff.

And so instead of flowing
away from the volcano top,

it piles up
at the top of the volcano

and creates these big features

that are as tall
as they are wide.

To a sort of
untrained observer,

going up to a lava dome might
be slightly disappointing,

because it can look
a little bit

like a giant
gray mass of rubble.

But when you fly over it,

you can see cracks
into the interior.

So only a few
tens of centimeters down,

it’s glowing red, and you can
see steam coming off it.

And when they collapse,
they generate things

called pyroclastic flows.

So they feel powerful,
lava domes.

So it’s a pretty
intense experience

going that close to one.

And the thing
about lava dome eruptions

is that they can suddenly
change their behavior.

So if you’re quite close
to them,

there’s always this sense
of approaching menace,

and we have to be really careful
about how we approach them

and make sure that the people
who are further away

and monitoring the volcano
are in contact with us.

A good example
of a lava dome volcano

is Mount Pelée,
an active volcano

on the Caribbean island
of Martinique.

Its last major eruption
was in 1902,

when it destroyed the port
of Saint-Pierre

and killed 30,000 people,

some 15 percent
of the island’s population.

There are over 500 volcanoes
in the world

that have erupted
at least once.

Fifty of them
are in North America.

An index was devised in 1982

to measure the force
of an eruption

so that different events
could be compared.

Called the Volcanic
Explosivity Index, or VEI,

it is determined
using a range of factors,

including the amount of material

vented from the volcano,

the height
of the eruption cloud

and how long
the eruption lasts.

This is expressed
on a scale of zero to eight,

with each number representing
a tenfold increase

in the explosive power
of the eruption.

One of the most terrifying and
deadly phases of an eruption

is undoubtedly
the pyroclastic flow.

Sometimes referred to
as a "glowing avalanche,"

the pyroclastic flow is formed
of many different components.

There are rock fragments

following the volcanic explosion,

particles of lava and magma
that are mixed with air,

water and gas
from the eruption,

as well as water vapor
from melted snow and ice.

This extremely hot
fluidized mixture

can reach temperatures
of 1000 degrees Celsius

and surge down the slopes
of the volcano

at astonishing speeds
of up to 200 meters per second.

A pyroclastic flow will
instantly incinerate

anything in its path.

And when you consider
the heat of the flow,

its speed and its reach,

it is one of Mother Nature’s
most terrifying

and deadly forces.

Another deadly event resulting
from volcanic eruptions

is the ash landslide
called a lahar.

Lahars are a hot or cold
combination

of volcanic debris and water

which advance
down the slopes of a volcano,

often moving
down a river valley.

They tend to occur
on or near stratovolcanoes.

While its initial flow
may be quite small,

a lahar can quickly grow
in volume

as it sweeps up soil,
trees and rocks,

even bridges and buildings.

Lahars can easily grow

to more than 10 times
their initial size

as they roar downhill.

In steep areas,
lahars can travel

faster than 200 kilometers
per hour.

Pyroclastic flows
can trigger lahars

when super-hot rock debris
melts snow and ice

as it rushes
down the volcano’s flanks.

Torrential rain during
or after an eruption

can mix with the fine particles
of ash and other debris

on the volcano’s slopes
and quickly turn

into a dangerous
and fast-moving lahar.

Rain can cause lahars

a long time
after an eruption,

especially if vegetation
has not managed

to consolidate the deposits
on the slopes of the volcano.

There are many volcanoes
in the world

that have not erupted
in years,

while others are in
a very active phase,

perhaps not erupting violently,

but with smoke, steam,

ash and lava
constantly venting.

It’s the simplicity
of the characterization

of extinct, dormant and active
that holds value,

because they have different
issues with each state.

If you have an active volcano
in your back garden,

you need to pay attention to it
all the time.

If you have a dormant volcano
in your back garden,

maybe you should be
keeping it in mind,

but it might not change

the day-to-day activities
that you have.

If you have an extinct volcano
in your back garden,

then you’re pretty happy
that it’s not going to erupt.

And if an eruption happens,
it won’t be from that point.

But as we learn more
about volcanoes,

and particularly as we apply
new technology,

more sensitive technology,
more sophisticated technology,

the line between
dormant and active

is becoming a little blurred.

And that’s because the new
technology can hear things

that we couldn’t before.

So if we deploy
this technology

and we get signals
from a dormant volcano,

is it waking up
or was it never truly asleep?

According to the
definition of "extinct,"

it means no activity
in the last 10,000 years.

Now, 10,000 years is a long
time, even for a volcano.

Normally, they erupt
more frequently than that.

So if you go to the volcano

and measure the age
of the youngest rock

and that’s more 10,000 years,

then it’s declared extinct.

When experts assess

which volcanoes are the most
dangerous in the world,

they take several things
into consideration:

How many people live nearby,

the types of magma
that emerge during eruptions

and each volcano’s
eruption history.

A volcano that has laid dormant
for a long time

can pose a higher risk

because of the mounting
pressure inside it.

Taking all this into account
means that Mount Vesuvius,

a stratovolcano located just
14 kilometers away from Napoli,

is also
one of the most dangerous.

While experts disagree

on the precise number
of incidents,

it is clear that Vesuvius
has erupted at least 30 times

since its iconic eruption
in 79 A.D.

The last eruption occurred
in 1944

when 26 people were killed.

For the Romans,
there wouldn’t really have been

a living memory of it
as an erupting volcano.

But in Italy,
there are other volcanoes

that erupt pretty frequently,

so probably they knew
it wasn’t entirely benign.

And in the run up
to the eruption,

we do know
there were known signals

that things weren’t
quite right down below.

There was a big earthquake,

and then we think
there were sequences

of these smaller,
little earthquakes

as that magma’s trying to make
its way up towards the surface

in the run-up to the eruption.

And the Romans would have
felt those,

and they would have been
fairly intense, I would imagine,

in the few days leading up
to the eruption itself.

There are plans in place
to evacuate 600,000 people

should Vesuvius show
signs of erupting again.

Active volcanoes
in densely populated areas

obviously pose
the biggest threat to life.

In other places
around the world,

there are volcanoes
that erupt very frequently.

So the big contrast
from Vesuvius is Stromboli,

which the Romans called

the Lighthouse
of the Mediterranean.

And that’s a little island
that had a little eruption

that happens every
10, 15 minutes.

It erupts extremely regularly.

So the populations who live
with those sorts of volcanoes

tend to live with it
in a different way.

The Volcano de Fuego,

a stratovolcano situated
less than 44 kilometers

from Guatemala City,

the capital of Guatemala
in Central America...

has erupted 600 times
since 1542,

including the last
explosive eruption in 2012

that forced 11,000 people
to flee the area

but luckily did not result
in any loss of life.

For many people living
in the shadow of the volcano,

it was
an uncomfortable reminder

of the awesome power
of the Volcán de Fuego

sitting right
at their doorstep.

But when the volcano
suddenly exploded

just before midday on
the 3rd of June, 2018,

many of them
had no time to evacuate.

It spewed a cloud
of ash and lava

10 kilometers into the air.

The explosion caused the rocky
surface of the volcano

to shatter into dust.

It mixed with ash
and superheated gas

into a pyroclastic
cloud of death

that engulfed the villages

of San Miguel Los Lotes

and El Rodeo,

instantly killing
more than a hundred people.

The 3700-meter-high volcano

continued to erupt
for more than 16 hours.

After the initial explosion,

a stream of lava spewed down
the side of the mountain.

Guatemala’s coast was also hit
by an earthquake,

though there were
no reports of damage.

Hundreds of emergency
and military personnel

faced appalling conditions to
retrieve bodies from the lava.

The ash and lava
was still so hot

that the soles
of some firefighters’ boots

were melted away.

The firefighters were
unable to reach people

they knew were trapped
in villages

on the slopes of the volcano,

because roads
leading to the area

were cut off
by pyroclastic flows.

It suddenly dawned on them

that the volcano’s activity

had started to increase again
after the initial blast.

Gas, mud and ash flowed
down the slopes of the volcano.

As stones hailed down on them,

darkness fell
as the sun became obscured

by more ash clouds
spewing into the air.

Emergency personnel were forced
to retreat from the villages

until early the next morning.

Guatemalan President
Jimmy Morales

declared a state
of emergency

and ordered the population

to heed warnings
from emergency officials.

He also declared three days
of national mourning.

Rescuers that reached
the town of El Rodeo

reported that it
had been buried in heavy ash

which could have
reached temperatures

of up to 700 degrees Celsius.

They poked metal rods
into the ground,

releasing clouds of smoke
into the air,

showing that temperatures
below the surface

were still extremely hot.

Two days after
the initial explosion,

volcanologists reported
that the eruptions

seemed to have ended
for the moment.

Soldiers and firefighters
continued searching

for those missing, but the
death toll had climbed to 69.

By now,
the ash from the eruption

was covering a radius
of 19 kilometers

around the volcano.

Satellite footage of Fuego
revealed

that the massive dark-gray
cloud from the eruption

was visible from space.

By Wednesday,
the death toll had climbed

to 75 people, and a further
200 were still missing.

Officials were worried
that a downpour

of additional rock and debris
could destabilize the slopes,

sending lethal lahar flows
of water

mixed with volcanic ash
and debris

hurtling down the volcano.

They called everyone
off the mountain,

halting the recovery effort
for a whole day.

Some relatives of the missing
defied police roadblocks

and went
to their family’s houses.

They tried to dig through
the rapidly hardening ash,

which they feared
had buried their relatives,

using whatever tools
they could get their hands on.

There were concerns
that the government’s focus

seemed to be
on getting the highway cleared

and not recovering
the bodies of the dead.

By the time the authorities
could get

heavy digging machinery
to the buried towns,

it became clear how little
chance of survival

there had been for anyone
trapped in the path

of the pyroclastic flows.

Amid scenes
of apocalyptic devastation,

the death toll reached 112,

with 197 still missing.

Many people didn’t accept

the government’s
official death toll.

They were convinced
that the scale of fatalities

was being underreported.

It emerged that scientists

at the National Institute
of Seismology, Volcanology,

Meteorology and Hydrology
had warned officials

in the early morning
on the day of the eruption.

But despite these warnings,

the national coordinator
for disaster reduction

did not issue a red alert
and evacuate communities.

Even though
nearly 200 people died there,

the area around the volcano
will continue to be inhabited.

The deaths
in the Fuego eruption

were mainly attributed

to the lightning-quick
pyroclastic flows

typical of the stratovolcano.

And although it brought death
and destruction to a wide area,

Fuego’s reach was
not nearly as far

as an event that occurred
in April 2010,

when a volcano in Iceland
suddenly erupted,

spewing a vast plume of ash

that spread across
much of Europe.

The eruption of
Eyjafjallajökull

became an international event,

as around 20 countries
closed their airspace

and forced flight cancellations

that affected
10 million travelers

as well as thousands
of businesses

that relied on air freight.

The volcano Eyjafjallajökull

had been dormant
for nearly 200 years

when it burst into life
in March.

Although relatively small,

at a rating of one on
the Volcanic Explosivity Index,

it was a mere suggestion
of the violent activity

that was to come.

On the 14th of April, 2010,
earth tremors were reported

under the summit of
the Eyjafjallajökull glacier,

in the south of Iceland.

In the lead-up to the eruption,

one of things that you’re
gonna be most aware of

is that space problem
the magma’s creating.

So it will generate
lots of earthquakes and shaking,

there’s maybe bulging.

But that kind of slow run,

the slow time scale
of volcanoes erupting,

becomes really fast once
the volcano starts to erupt.

So if it’s an explosion,

there will be a sudden change.

And you will start to see
a huge pulse

of gas, ash,

and bits of solid magma

flying out of that volcano.

And there’s been
slow-motion footage taken

that’s shown
there’s even a sound wave

that comes out ahead of this
because this happens so quickly.

The force
of the volcanic eruption

under the Eyjafjallajökull
glacier

sent a plume of ash
8.5 kilometers into the air.

Heavy ash fell
over the areas to the south,

with police reporting
that visibility

had been severely reduced,
in some places down to zero.

Icelandic air-traffic control
received two reports

from commercial aircraft

of steam plumes
rising from the glacier.

But because the glacier
remained covered in cloud,

it was impossible to see the
extent of the volcanic activity

occurring on the ground.

But there were alarming clues

about the severity
of the eruption.

The water level
in two nearby rivers

had suddenly risen
by over half a meter,

showing that there had been
substantial melting

of the volcano’s glacier.

Concern grew
about the ash plume,

which by now was engulfing
much of Northern Europe.

It contained large amounts

of microscopic abrasive
particles of silicates,

or glass fibers, capable
of clogging jet engines.

Once ingested,
the particles can melt,

causing the engine
to flame out and stall.

Because of the danger
of catastrophic failure

of any aircraft
flying into the ash

and to ensure
the safety of passengers,

aircraft were left idle
on the tarmac

of some of Europe’s
busiest airports.

Practically all flights

over mid, north
and Eastern Europe

were canceled
until further notice.

It’s really a bit strange
to think

that a volcano would
affect a flight.

But, yeah, so...

It’s not something
you expect to happen.

Other flights were either
rerouted north over Greenland

or south over Spain
to avoid the cloud,

which now stretched
1930 kilometers

from Iceland
to Northern Spain.

The plume of ash
was further carried along

by Atlantic winds
and later forced the closure

of 15 airports
in northern Spain,

and was expected to expand
into parts of France.

More than 100 flights
were canceled

at Portugal’s three
international airports.

It was the most
serious disruption

of European air traffic
since the Second World War.

As the eruption continued,

meltwater from the summit
of Vatnajökull,

one of the largest glaciers
in Europe,

increased dramatically.

It was estimated
that the volcano was ejecting

about 750 tons of magma
every second,

much of it through a fissure

that was already
2 kilometers long.

Tuesday, the 20th of April,

most of the ice in the crater
appeared to have melted.

But it was another month
until the eruption had subsided

to the point that no further
lava or ash was being produced.

Finally, in October 2010,

scientists monitoring
the volcano declared

that the eruption
had officially ended,

although the area was still
geothermally active

and might erupt again.

The explosive activity might
drop down for a period time,

but then we will have, over
an extensive period of time...

Months to even years.

...intermittent
explosive eruptions.

Taking stock of the devastation
caused by the eruption,

experts estimated that at least
55 million cubic meters of ice

melted during the eruption.

It’s a scientist’s job
to report the facts

and explain what would happen
if there were an eruption,

and then recommend
a course of action

that will provide more
information to decision makers.

Now governments will invest
more in monitoring

and volcanology in general

because the risk to society
is growing.

Our world is more
interconnected now.

Look at what happened
in Eyjafjallajökull.

If that happened 200 years ago,

it wouldn’t have had
nearly the same impact

as it did on the world economy,

through airlines,
et cetera.

So now disruption,

indirect disruption
from volcanoes,

has a large impact.

And that just underscores

that we need to urgently
understand what happens

before a volcano erupts

so we can put in place plans

to mitigate
against those hazards.

Every volcanic eruption
is different.

Eyjafjallajökull caused mayhem
because of its ash cloud,

and Fuego with its terrifying
pyroclastic flows.

But when Kilauea,

a shield volcano
on the island of Hawaii,

erupted in May 2018,

it demonstrated a very
different kind of behavior.

Kilauea is the youngest volcano
on the island of Hawaii

and looks like a bulge
on the side of Mauna Loa,

a much bigger volcano.

It rises 1227 meters
above sea level

and makes up about 14 percent

of the land area
of the Big Island.

Legend supposes that
the lava lake at its summit

is home to Pele, the Hawaiian
goddess of volcanoes,

indicating the significance
of Kilauea

to the people of Hawaii.

It provides us a window
of a deeper level than usual,

because it hasn’t been modified
on its way to the surface.

The fact that it’s coming up
so rapidly means

that’s it preserving
the information

that it carries from depth.

Although it had been erupting
continually since 1983,

the people on Big Island

had learned
to live with the volcano.

In fact, it was seen
in a very positive light,

attracting tourists
eager to see

such a dangerous
force of nature close up.

Obviously the geothermal energy
around volcanoes

is a wonderful benefit
that they bring,

with an infinite supply
of power and hot water.

But also,
for many populations,

these geothermal areas are
fantastic tourist attractions.

In places, people could get
so close to the lava

that it became a tradition
to take postcards

and burn one corner in the flow
before sending them off.

But that all changed
when a magnitude 5 earthquake

struck the Big Island

and triggered a violent
and dramatic eruption,

turning the tourist volcano

into a dangerous threat
to life and property.

The day before, on Wednesday,
the 2nd of May,

seismologists had noticed
significant volcanic activity

coming from Kilauea.

As the volcano blasted
solid and molten rock fragments

and gases into the air,

the authorities
immediately told residents

in the surrounding area
to make preparations to leave.

So at 1:30, after we all kind of
got up and said, "Okay, well,"

I opened the door to see
if I could see anything.

And, of course, I could see
the orange glow

coming through the forest.

And, um, I said, "Wow!"

And I can hear crackling,

and we’re all kind of just
going, "Whoa."

I said, "Well, we’re not leaving
until we hear the siren."

And the moment I finish
the sentence,

the siren went "whoop!"

We all looked at each other
and says,

"Yep, everybody in the car."

And out we went.

When the volcano started
to spew lava

into residential subdivisions

in the Puna district
of the Big Island,

compulsory evacuation orders
were released.

The volcano became
increasingly active.

There were quakes,
with hundreds of tremors

of magnitude 2.5 or higher.

But shortly after midday,

a quake measuring 6.9
knocked out power

to thousands of islanders,

causing sea-level fluctuations
which terrified residents,

fearful that it would
generate a tsunami.

Fortunately, the sea
remained relatively calm,

but lava flowed
down the sides of the volcano

and gases spewed
into the air.

Homes were destroyed
as eruptions increased.

During the 2018 eruption,

the magma moved
and created pressure

that then resulted
in the opening of new vents

for that magma to pour out of

during the course
of its eruption,

sometimes right
in the middle of a road.

On a volcano like that
in the Big Island in Hawaii,

there’s an almost
continuous supply of magma

coming into the base.

But what-- It’s one of
the best monitored volcanoes

in the world, if not thebest
monitored volcano in the world,

and what they picked up
were signs

that new magma was coming
into the system,

causing pressurization and
causing the ground to move up.

As news of the eruption

and dramatic footage
showing houses being engulfed

by red-hot flows of molten lava
was beamed around the world,

people began to wonder
why anyone would choose

to live near
an active volcano.

Volcanoes and their
immediate environment

offer a lot of benefits
to people who live around them.

So they create soil
that can be more fertile

than surrounding area.

There’s a lot of volcanoes
in the tropics,

and they are a little bit
of higher land

that’s a little bit
more pleasant to live in.

They provide geothermal energy

and soil and rock resources
as well.

And when you think about how
often volcanoes erupt, it’s--

In the grand scheme of things,
it’s not very often.

So I think often people live
around volcanoes

because it’s worth enjoying
all of those benefits

for the small but finite risk

that it’s going to erupt
during their lifetime.

One of the things
that’s very challenging

about volcanic eruptions

is that they aren’t
just instantaneous.

A volcano can be in eruption

for many days and weeks
and months.

And so sometimes
what we’re doing

is we’re asking people
to move away permanently

or for very long periods
of time,

and that’s a difficult thing
to do.

People are attached
to where they live,

but also in many volcanoes
around the world,

people are dependent on that
area for their livelihoods.

Once a volcano’s erupted,

it obviously creates
a lot of damage,

and people may want to build

quite close to where
that damage was created.

And I think one of the things

that we are doing now
as volcanologists

is we’re recognizing
we have to work in partnership

with the communities
who are impacted,

to try and work out the
best way to choose the place

that it’s going to be
the safest to build back

and try to ensure
that they’re ready,

as much as they can be,
for future eruptions.

A week after
the first new eruption,

12 more fissures opened up
in Leilani Estates

on Hawaii’s Big Island.

The new points of lava flow

showed that the eruption
of Kilauea was ongoing.

There were now
major disruptions

to life on the island,
with more evacuations needed.

On Wednesday, the 9th of May,

Kilauea volcano erupted again

as two new vents released toxic
gases into the atmosphere.

The Civil Defense Agency
ordered

the immediate evacuation
of residents

from Lanipuna Gardens

on the east side
of the Big Island.

Scientists noticed a drop
in the lava lake

at the summit of the volcano.

They warned that this might
create conditions

for an explosion
that could send ash

and refrigerator-sized boulders
shooting into the air.

The following day,
the authorities warned

that mass evacuations
might be required.

Levels of sulfur dioxide
reached dangerous levels,

which could prove fatal
if inhaled,

and residents were at risk

from magma bursting
out of the ground.

People who are frail
or who have underlying COPD,

that’s chronic lung disease,

we worry about them
quite a lot.

That can be made much worse
by spikes in sulfur dioxide.

So checking people’s lungs,

making sure they have
medications,

making sure we evacuate them
further away if they’re bad.

By the following weekend,

there were now 17 open fissures

since the lava flows began
on the 3rd of May.

On Wednesday, the 16th of May,

following the rise
of an ash plume

several thousand meters
into the air,

the Hawaiian Volcano
Observatory issued a code red,

warning residents
that additional activity

could be expected.

They cautioned
that at any time,

activity could become
more explosive,

producing ballistic
projectiles near the vents.

The following day,
another 2000 people

were forced
to abandon their homes.

Several schools closed
because of the risk

from high levels
of sulfur dioxide.

I, uh-- I’ve already
evacuated everything.

I just came down to say,
um, goodbye to my neighborhood

one last time.

There were also earthquakes
around the volcano

which damaged many roads,
including Highway 11

near the entrance of the
Hawaii Volcanoes National Park.

Fast-moving lava spewed
into a region

southwest of Leilani Estates,

cutting off about 40 homes
in a remote region.

Hawaii’s County Civil Defense
warned

that brushfires caused
by the burning lava

were threatening homes in
the Malama-Ki Forest Reserve.

Residents were
immediately evacuated.

Then scientists noted something
worrying.

The lava spattering
out of fissures in lower Puna

seemed to be different.

It was coming out faster
and more dramatically.

That contrasted with the first
two weeks of the eruption,

when activity was
largely a slow oozing

of a very thick, pasty lava
that wasn’t moving very far.

Scientists explained
that the lava

of the first two weeks
was probably from magma

stored underground making
its way onto the surface

as a result of the fresh magma

pressing down
from Kilauea’s summit.

The lava now coming out of the
latest fissures was different.

Scientists braved noxious fumes
and spattering lava

to gather samples that
would be crucial for research.

One of the most important
things for volcanologists

in these sorts of situations
is really teamwork.

So it’s making sure
that there’s people

who have their eyes
on the instruments

and that you are not doing
anything that is too risky

and that you think about it
very carefully in advance.

And so when something
like that happens,

what you’re really thinking is,
"This is quite scary,"

but you have to have
strong trust and reliance

in the team
that are around you

so that you’re going
to get out in time.

A chemical analysis
of the samples showed

that the fresh,
more violent magma

had come down
from the summit of Pu’u O’o,

a volcanic cone situated in the
eastern rift zone of Kilauea.

This was fresher
and hotter magma

with the potential
to produce lava flows

that moved with greater ease

and therefore covered
a wider area.

A wall of lava blocked
part of a coastal road,

cutting off a key escape route
for residents

and hampering evacuations.

Fresh lava flows
overwhelmed more houses

while the ash plume continued
to ground flights in the area.

The situation for residents
on Big Island

was steadily worsening.

Lava flows forced the shutdown
of a geothermal energy plant

that normally provides
about a quarter

of the island’s electricity.

By now, the lava had reached
Big Island’s south coast.

As the lava plunged
into the ocean,

it caused some
of the 1000-degree-Celsius

molten rock
to explode into lava bombs

that shot hundreds of meters
into the air.

The lava also reacted
with the salt water

to produce poisonous gases,

and triggered further
safety warnings.

When the lava flows
reached the Pacific,

it created thick hazardous
clouds known as laze,

which is a kind of hot
and corrosive gas mixture.

The clouds contain
hydrochloric acid

and glass particles,
which can cause irritation

and breathing difficulties.

Even the wispy edges
of the clouds

can be enough
to cause irritation.

Residents were told to stay
away from any ocean plume,

since they traveled on wind

that was liable to change
direction without warning.

But they need to really pay
attention to what’s happening,

because anything can happen.

Mother Nature, Madame Pele,
can come out at anytime.

But we don’t wanna cause panic.

We want them to just be
well informed.

So volcanology’s a very exciting
and dynamic science,

because volcanoes throw
all sorts of challenges at us.

They’re capable of erupting
in all sorts of different ways,

and they can change
how they erupt

during the course
of even one eruption,

and also what they can do
is erupt for long times.

And that’s what
we are trying to face:

the challenge of figuring out
how to forecast that,

and forecast those changes

during the course
of an eruption.

And all of these mean
that there’s all sorts

of new understanding
and techniques

that improve
how we do that all the time.

The lava flow
continued unabated.

A huge river of molten rock

crept several kilometers
across the landscape

towards the eastern tip
of the island.

It swallowed two entire
seaside housing estates.

It took just a matter of days

for a relentless wave of lava

over 4 meters high
and 800 meters across

to bury hundreds of homes.

It even vaporized the island’s
largest freshwater lake.

Within four hours,
the 400-year-old Green Lake,

which was about 60 meters deep

and had been
a popular swimming spot,

completely disappeared
under a mass of molten rock.

In mid-July, a tiny island
less than 10 meters wide

suddenly appeared
off the coast of Big Island.

It wasn’t long before lava
filled in the gap

between the new island
and the shore,

and it became part
of the changing coastline

caused by Kilauea’s eruption.

It was a reminder of
how the Hawaiian Island chain

was first formed.

The Big Island of Hawaii
is around a million years old,

but it’s part of
a chain of volcanoes,

and the oldest chain of those
that stretch across the Pacific

is about 80 million years old.

And that observation that
the volcanoes seem to get older

as you go west
across the Pacific

is part of the evidence

to say that there’s a hot spot
in the mantle underneath

that is more or less fixed,

but as the tectonic plate
moves across

like a conveyor belt,

the volcanoes that are produced

start traveling off
towards the west.

Melt within the earth
travels upwards

until such time
that it hits the surface.

Now, that could be
the surface of a continent

or, in the case of Hawaii,

it’s the bottom
of the sea floor.

And it starts a small volcano.

And over time, it builds up
and builds up.

And if it builds up
fast enough,

it will reach
the top of the sea.

Throughout the eruption,

a remarkable transformation
had occurred

to the lava lake crater
at the top of Kilauea.

The Halema’uma’u crater
at the summit

had been rumbling nonstop

since the eruption
began in early May.

Then the lava lake began
to drain quite suddenly

as the reservoir of magma
beneath it

began dumping its contents
out of fissures

on the volcano’s slopes.

The United States
Geological Survey sent a drone

into the crater
to see the dramatic changes.

It showed that
the steep walls of the crater

were collapsing inwards,

with large chunks of the rim,

including a parking lot

which served the Hawaii
Volcanoes National Park

swallowed by
the crater’s collapse.

The powerful activity
was triggered

by the flow of magma
away from the summit crater

eastwards toward the rift zone.

As the crater got deeper,

the walls began
to collapse inwards,

which led to further
explosive releases

of gas, ash,
and other volcanic debris.

The lava lake
in the Halema’uma’u crater

in the volcano of Kilauea

started draining
from the inside.

And as each phase
of the draining happened,

the eruption site flared up.

And this is part of the evidence
to link the two phenomena

and suggest that this is
a linked plumbing system

in the lower
Eastern Rift Zone of Hawaii.

The magma is interconnected,

and as each cycle of
the volcano of Kilauea occurs,

it’s becoming
more and more evident

that the behavior
of the lava lake can be used

to understand
the eruption site itself.

On the 9th of August,

the lava flow
finally stopped expanding.

And with the lull in activity
on Kilauea continuing,

volcanologists are saying
that the eruptive period

which first began in 1983

and continued right through

to the recent
and most violent cycle

is over.

So one of the things that was
amazing about the eruption

that happened in 2018
is that it was exceptional.

There were huge amounts
of material,

we opened up new vents,

and that caused a shift
in the magma system.

So before that, it was erupting
continuously for decades.

It’s quite likely now

that it may remain quiet
for a few years.

That’s what happened
the last time it had

one of these
really big eruptions.

But what’s for sure
is there’s still magma

underneath the ground there,

and that the shift will probably
cause it to erupt again,

and probably
in the lifetime of the people

who live on the island.

If and when eruptive activity
does eventually return,

it will be classified
as an entirely new eruption.

A period of constant eruption
of Kilauea

lasting over 35 years
will have come to an end.

The simple answer is,
we don’t know

exactly what will happen
to the lava lake.

Will it refill?
Will it be a hole in the earth

for times to come?

But what we do know
about Kilauea

is that it has gone
through cycles

of repeated lava lake formation
and draining.

So one reasonable idea
about what might happen

is that the lava lake
will refill

and an eruption will happen
as it drains.

Volcanology is
a fairly new science

in that there’s
lots of different sciences

that are trying to
understand the same phenomena.

You can approach it from
a chemical point of view,

you can approach it from
an atmospheric point of view,

you can approach it from
a geophysical point of view.

And it’s as these fields
emerging

and is called volcanology,

that’s only happened
in recent decades

as a modern science
of volcanology.

One thing we do know

is that volcanoes will continue
to cause death and destruction

for as long
as there is life on Earth.

And whether it’s the horrors
of pyroclastic flows,

the choking gas,

or the molten lava,

volcanoes are truly
one of Mother Nature’s

most combustible killers.