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Our planet is capable of
unleashing extreme chaos.
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Volcanoes, earthquakes,
hurricanes, and floods
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can cause untold devastation.
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We may think we've seen
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the worst Mother Nature can
throw at us,
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but scientists struggling
to understand these disasters
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are discovering evidence
that even more extreme events
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have struck in the past.
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JEAN CHRISTOPHE KOMOROWSKI:
So this is about 13 times
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more powerful
than the Pompeii eruption.
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NARRATOR:
They're uncovering clues
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that the worst
catastrophes in history
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could strike again.
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Nearly 1,000 years ago,
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a disaster shook the world.
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KOMOROWSKI:
This is one of
the largest eruptions
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in the last 10,000 years.
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NARRATOR:
A volcano so powerful
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it chilled the entire planet.
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But where was it?
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No one knew the source
of the eruption.
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NARRATOR:
The clues are here, buried and
hidden all around the world.
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Now, scientists come together
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to scour our volatile Earth,
to solve the mystery
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of killer volcanoes.
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Right now, on NOVA.
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NARRATOR:
Of all the forces of nature,
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volcanoes are among
the most dangerous.
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They have the power
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to kill millions and disrupt
the fabric of modern life.
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Volcanoes can have
a global impact.
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NARRATOR:
Today, there are more than 1,500
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active volcanoes on Earth.
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About 50 erupt every year.
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Many are well known,
like Vesuvius in Italy,
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and Mount St. Helens
in Washington State.
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But could there be
other slumbering giants
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that we have never heard of?
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Volcanoes that were once
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even more powerful
and destructive
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than today's monsters?
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That's what a series of clues
is suggesting.
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Scientists working
across the world
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have begun to find evidence
of a cataclysmic event,
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a mysterious eruption
that could have been
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one of the largest
in human history.
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And the trail starts
in a very unexpected place.
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Here, in the heart of London,
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archaeologists
uncover a surprise.
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While excavating
a medieval cemetery,
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they happened upon
a series of mass graves
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on the edges
of the burial ground.
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Over 4,000
men, women and children,
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packed into large pits.
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The cause of death
was not obvious.
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So what killed so many people,
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and why were they all
buried together?
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DON WALKER:
When we find mass burial pits,
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we know that
there's been a lot of people
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dying very quickly, and
something has gone very wrong.
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NARRATOR:
As a first step
to identifying the killer,
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archaeologist Don Walker
and his team conducted
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radiocarbon tests, to find out
how long ago they died.
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The hope was that
they could tie their deaths
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to some historical event.
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But what they found
merely deepened the mystery.
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The victims all died
around 1250 in the Common Era.
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That ruled out
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one of the most notorious
mass killers of the past,
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the Black Death,
which ravaged Europe
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about a century later, in 1348.
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So what could have caused
this mass killing?
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Don Walker heads
to the British Library
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to consult ancient historical
records from the period.
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This manuscript
is a history of England.
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Over 750 years old,
it was written in Latin
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by a monk named Matthew Paris.
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Among these chronicles,
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one account stands out--
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a description of bitterly
cold weather around London
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in the spring and
early summer of 1258
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that kills crops and livestock
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and leads to a deadly famine.
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WALKER:
It says owing to
the scarcity of wheat,
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a large number
of poor people died,
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and dead bodies
were found in all directions,
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swollen and livid.
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NARRATOR:
Then Walker discovers
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a description that
seems to match the discovery
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of the mass graves.
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When several corpses were found,
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large and spacious holes
were dug in the cemeteries,
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and a great many bodies
were laid in them together.
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And of course, as soon as I
saw that, I got very excited,
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because it's exactly
the kind of thing that we found
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at St. Mary Spital, where they
were digging these huge pits.
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NARRATOR:
According to this text,
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the famine killed
over 15,000 people in London.
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That's 30% of the city's
population at the time.
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WALKER:
You're talking about something
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that was perhaps nearly as
deadly as the Black Death.
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NARRATOR:
And possibly as widespread too.
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Other sources reveal
the far-reaching impact
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of the extreme weather and its
disastrous effect on crops.
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CLIVE OPPENHEIMER:
There are various records
from this period--
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1258, 1259, 1260,
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in various parts of Europe
and as far as Japan,
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that do attest
to extreme impacts
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in terms of famine,
in particular.
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NARRATOR:
Something devastating
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was plunging much
of the Northern Hemisphere
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into a pattern of bitter winters
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and summers blighted
by torrential rain.
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We thought perhaps
this was something to do
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with some catastrophic event.
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NARRATOR:
Only one type
of natural disaster
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could have such a widespread
impact on the climate--
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a massive volcanic eruption.
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But which volcano
was the culprit?
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The closest volcanoes are a
thousand miles away in Iceland.
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In 2010, when a volcano
known as Eyja erupted,
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it sent an ash cloud over Europe
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that disrupted air travel
for weeks,
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stranding people
all over the world.
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And historical records
reveal that in 1783,
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eruptions from the Laki volcano
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caused mass deaths
across Europe.
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It seems like
an Icelandic volcano
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could be to blame for the
mysterious 13th century event,
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but Walker came across
another possibility.
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He became intrigued by one of
the most massive eruptions
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in recorded history,
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even though it occurred
just 200 years ago
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and was located
much farther away--
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Mount Tambora in Indonesia.
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In April 1815,
eyewitness accounts record
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that Mount Tambora
erupted explosively.
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KOMOROWSKI:
And this is one of
the largest eruptions
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of the last 10,000 years.
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NARRATOR:
It's estimated
over 60,000 people died
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in the shadow of this volcano.
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But the eruption had an
even more far-reaching impact.
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In northern Europe
and North America,
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the year after the eruption,
1816, is known as
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the year without a summer.
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In New York State,
it snowed in June.
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In Europe, cold weather led to
the worst famine for a century.
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The climate change
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caused agricultural failures,
poor harvests,
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it pushed up grain prices,
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with many people perishing
from malnourishment.
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NARRATOR:
So perhaps another
powerful eruption
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could have caused the year
without a summer in 1258.
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We began to think that perhaps
this might be something to do
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with what had happened
back in the 13th century.
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Perhaps this was
why the people starved.
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NARRATOR:
But to pinpoint the location
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of the mysterious volcano,
they needed to know more
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about its size
and type of eruption.
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They look at one of
the largest volcanic events
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in recent memory...
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the 1991 eruption of Mount
Pinatubo in the Philippines.
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Unlike volcanoes that erupt
by pouring out rivers
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of molten lava
over a long period of time,
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Pinatubo erupted
suddenly and violently...
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...when water and gases
trapped inside the magma
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exploded with tremendous force,
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shattering the rock into
millions of tiny particles
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and sending them
high into the atmosphere.
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Explosive eruptions like this
are the most dangerous of all.
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Pinatubo killed
847 people locally,
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and left over 200,000 homeless.
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But as with the other
big Indonesian volcano,
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Mount Tambora, this eruption
also had far-reaching effects.
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NASA's satellites were able
to monitor the eruption.
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Pinatubo blasted out one
cubic mile of superheated ash,
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but it also ejected
hundreds of millions of tons
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of volcanic gases
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in a plume 22 miles high.
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KOMOROWSKI:
The ash and the gases
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are dispersed through
the atmosphere by the wind,
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and they can travel
thousands of kilometers,
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tens of thousands of kilometers.
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NARRATOR:
But unlike heavy ash
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that soon falls
out of the atmosphere,
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the lightweight gases
persist for much longer.
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The most impactful gases
are the sulphur-rich gases.
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And those gases will form little
droplets of sulphuric acid
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in a large cloud.
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NARRATOR:
The tiny drops of sulphuric acid
are called aerosols.
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And in a large cloud,
high in the upper atmosphere,
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these aerosols caused enough
sunlight to reflect
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out into space
to cool the planet.
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00:12:06,326 --> 00:12:10,261
The satellite data revealed
that this sulphuric acid mist
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had a much more dramatic impact
than the ash.
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It blocked enough sunlight
to cool the entire planet
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by one degree Fahrenheit
for two years.
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That doesn't sound very much,
but it actually masks
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much stronger
regional variations.
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00:12:27,047 --> 00:12:30,181
And that translates into
real impact on the ground
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in terms of crop yields.
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NARRATOR:
In 1258, the temperature drop
was much greater
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than caused by Pinatubo.
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00:12:39,459 --> 00:12:43,094
This suggests that whatever
triggered this medieval disaster
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could have been much bigger.
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00:12:50,036 --> 00:12:53,171
That indicated that a big event
occurred somewhere in the world.
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But there was no record of
a massive volcanic eruption.
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OPPENHEIMER:
For volcanologists,
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it was
the biggest mystery for us.
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NARRATOR:
So where could
the culprit volcano have been?
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And after more than 750 years,
could this killer volcano
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be found?
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It seemed the trail
had gone cold,
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until a clue appeared,
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frozen in the polar ice.
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About 1,000 miles
from the North Pole...
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00:13:34,614 --> 00:13:37,749
...researchers for the
Greenland Ice Sheet Project
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00:13:37,784 --> 00:13:42,153
are taking core samples
from deep in the ice.
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00:13:47,894 --> 00:13:51,162
This ice sheet was built
layer by layer
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00:13:51,197 --> 00:13:56,167
as snowfall accumulated
over 130,000 years.
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00:13:57,604 --> 00:14:01,639
The deeper into the ice
the scientists drill,
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00:14:01,674 --> 00:14:04,342
the farther back in time
they can look.
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00:14:07,414 --> 00:14:11,249
The samples arrive for analysis
at the Desert Research Institute
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00:14:11,284 --> 00:14:12,383
in Nevada.
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00:14:16,056 --> 00:14:20,425
Geochemist Nelia Dunbar
and glaciologist Joe McConnell
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00:14:20,460 --> 00:14:23,928
are preparing to analyze
an Arctic ice core sample
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00:14:23,963 --> 00:14:27,331
that contains snowfall
from the mid 13th century.
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00:14:27,367 --> 00:14:30,668
The core comes from 1,000 feet
below the surface
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00:14:30,703 --> 00:14:32,470
of the ice sheet.
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00:14:32,505 --> 00:14:35,773
They will be looking
for sulphuric acid--
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00:14:35,809 --> 00:14:37,742
evidence of an intense eruption.
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00:14:37,777 --> 00:14:40,578
NELIA DUNBAR:
If there were
a big volcanic eruption
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00:14:40,613 --> 00:14:41,879
that produced a lot of sulphur,
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00:14:41,915 --> 00:14:44,715
that sulphur should be
preserved in this ice.
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00:14:44,751 --> 00:14:46,584
And that's what
we're interested in studying.
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00:14:46,619 --> 00:14:49,120
Where is this from,
and what's the age of it?
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00:14:49,155 --> 00:14:52,657
McCONNELL:
So this piece is
from around 1250, 1255 AD.
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00:14:52,692 --> 00:14:56,661
This represents
about three years.
239
00:14:56,696 --> 00:14:58,262
So this is roughly one year,
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00:14:58,298 --> 00:15:00,398
roughly one year,
and roughly one year.
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00:15:03,636 --> 00:15:05,436
These ice cores hold
an incredible record
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00:15:05,472 --> 00:15:07,138
of past climate.
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00:15:07,173 --> 00:15:10,608
In between the snow crystals are
little pockets of atmosphere
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00:15:10,643 --> 00:15:13,311
that are little time capsules
that represent
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00:15:13,346 --> 00:15:14,979
the composition
of the atmosphere
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00:15:15,014 --> 00:15:18,015
at the time the snow fell.
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00:15:18,051 --> 00:15:20,384
Over time, more snow
will fall on the ice sheet,
248
00:15:20,420 --> 00:15:22,220
and that record is locked in.
249
00:15:24,157 --> 00:15:26,424
Up to the right
and then up to the top.
250
00:15:26,459 --> 00:15:29,093
NARRATOR:
But to unlock the record,
251
00:15:29,129 --> 00:15:33,531
scientists have to destroy it
inch by inch.
252
00:15:33,566 --> 00:15:36,300
Okay, so now we're ready
to start the analysis.
253
00:15:36,336 --> 00:15:38,202
Okay.
254
00:15:40,106 --> 00:15:43,107
NARRATOR:
As each layer of ice melts down,
255
00:15:43,143 --> 00:15:46,544
the melt water passes through
a mass spectrometer.
256
00:15:46,579 --> 00:15:49,747
It's like a time machine
257
00:15:49,782 --> 00:15:51,549
that reads out the chemicals
258
00:15:51,584 --> 00:15:54,552
that were in the atmosphere
hundreds of years ago.
259
00:15:57,290 --> 00:15:59,423
The results start
to come through.
260
00:16:02,562 --> 00:16:05,730
And the team immediately
sees a telltale spike.
261
00:16:05,765 --> 00:16:07,899
McCONNELL:
So we're seeing the responses
262
00:16:07,934 --> 00:16:09,767
come up on all the various
instruments right now.
263
00:16:09,802 --> 00:16:14,338
So this would be 1258,
and you can see the acid now
264
00:16:14,374 --> 00:16:15,606
has just skyrocketed,
265
00:16:15,642 --> 00:16:18,676
a huge increase in sulphur.
266
00:16:18,711 --> 00:16:20,077
So it's certainly
pointing to volcanism.
267
00:16:20,113 --> 00:16:22,380
Okay, so that must have been
a really big volcanic event.
268
00:16:22,415 --> 00:16:24,015
McCONNELL:
Yeah, absolutely huge.
269
00:16:24,050 --> 00:16:26,517
NARRATOR:
The sulphur locked inside
270
00:16:26,553 --> 00:16:29,053
the 1258 ice layer
tells the story
271
00:16:29,088 --> 00:16:31,322
of a powerful volcanic eruption.
272
00:16:33,726 --> 00:16:37,328
And though the sulphur
was washed out of the atmosphere
273
00:16:37,363 --> 00:16:41,265
in rain and snow in 1258,
274
00:16:41,301 --> 00:16:45,903
the eruption itself likely
occurred the year before.
275
00:16:47,607 --> 00:16:49,006
Now, keep in mind
276
00:16:49,042 --> 00:16:50,942
that it takes a while
for the sulphur to make it
277
00:16:50,977 --> 00:16:52,343
from the volcano
through the atmosphere
278
00:16:52,378 --> 00:16:53,744
and be deposited
on the ice sheet.
279
00:16:53,780 --> 00:16:55,146
DUNBAR:
Mm-hmm.
280
00:16:55,181 --> 00:16:56,914
And so this event,
it probably occurred in maybe
281
00:16:56,950 --> 00:16:57,882
mid to late 1257.
282
00:16:59,619 --> 00:17:02,453
NARRATOR:
And the amount of sulphur
ejected by this eruption
283
00:17:02,488 --> 00:17:06,891
was vast by comparison
with that produced
284
00:17:06,926 --> 00:17:09,293
by the other known eruptions
captured in the ice cores.
285
00:17:09,329 --> 00:17:12,496
Here's the 1257 of that
that we just measured again
286
00:17:12,532 --> 00:17:14,799
in this new ice core.
287
00:17:14,834 --> 00:17:16,434
We can see that it's huge.
288
00:17:16,469 --> 00:17:19,537
When you compare it to Tambora,
here in 1815, it's, you know,
289
00:17:19,572 --> 00:17:22,039
something like
more than twice as big.
290
00:17:22,075 --> 00:17:24,108
So this is a really,
really big event.
291
00:17:24,143 --> 00:17:25,610
And at least in this composite
it's the biggest event
292
00:17:25,645 --> 00:17:28,879
of the last 2,000 years,
very clearly.
293
00:17:30,316 --> 00:17:33,718
NARRATOR:
So this eruption
seems to have been large enough
294
00:17:33,753 --> 00:17:35,353
to account for the
freak climate disaster
295
00:17:35,388 --> 00:17:38,623
across the Northern Hemisphere
in 1258,
296
00:17:38,658 --> 00:17:41,259
including London's
deadly famine.
297
00:17:41,294 --> 00:17:44,762
OPPENHEIMER:
It was hard to really pin down
one event and say,
298
00:17:44,797 --> 00:17:47,331
"This was the result
of a volcanic eruption."
299
00:17:47,367 --> 00:17:50,368
But I think in this case
the evidence is quite strong.
300
00:17:52,205 --> 00:17:54,338
You can imagine
living in medieval London.
301
00:17:54,374 --> 00:17:56,374
You know that you haven't
got enough food to live,
302
00:17:56,409 --> 00:18:00,177
your crops are failing,
the weather's very bad,
303
00:18:00,213 --> 00:18:05,049
but you'd have no idea the true
cause of what was going on.
304
00:18:09,689 --> 00:18:10,755
NARRATOR:
The true cause
305
00:18:10,790 --> 00:18:14,025
was that somewhere
on the planet, in 1257,
306
00:18:14,060 --> 00:18:17,728
a volcano exploded
and blasted its contents,
307
00:18:17,764 --> 00:18:21,299
including poisonous gas and ash,
high into the atmosphere,
308
00:18:21,334 --> 00:18:24,869
where it dimmed the sun
for months, if not years.
309
00:18:29,275 --> 00:18:32,009
But where was this killer?
310
00:18:32,045 --> 00:18:35,012
The mystery that remains
is what was the volcano
311
00:18:35,048 --> 00:18:38,149
that was responsible for
this big volcanic eruption?
312
00:18:40,019 --> 00:18:42,420
NARRATOR:
More than 1,500 volcanoes
313
00:18:42,455 --> 00:18:45,089
have been active
in the last 10,000 years,
314
00:18:45,124 --> 00:18:48,426
so pinpointing which
of these caused
315
00:18:48,461 --> 00:18:54,665
such a massive disruption
in 1258 is a huge challenge.
316
00:18:54,701 --> 00:18:59,270
The first place to look
is a string of volcanoes
317
00:18:59,305 --> 00:19:01,439
known as the
Pacific Ring of Fire.
318
00:19:03,242 --> 00:19:05,409
The continents we live on
319
00:19:05,445 --> 00:19:10,181
ride atop giant tectonic plates
made of rock.
320
00:19:10,216 --> 00:19:13,417
Where plates collide
or slide under each other
321
00:19:13,453 --> 00:19:16,253
gives rise to volcanoes,
322
00:19:16,289 --> 00:19:20,191
making this one of the most
geologically active regions
323
00:19:20,226 --> 00:19:22,526
of the world.
324
00:19:22,562 --> 00:19:27,465
But the Ring of Fire
extends for thousands of miles.
325
00:19:27,500 --> 00:19:31,902
How can scientists work out
which volcano is the culprit?
326
00:19:36,442 --> 00:19:40,177
In her lab at the
New Mexico Bureau of Geology,
327
00:19:40,213 --> 00:19:43,347
Nelia Dunbar examines
some distinctively shaped
328
00:19:43,383 --> 00:19:46,283
mineral particles lodged
in a section of ice
329
00:19:46,319 --> 00:19:48,285
from a different
Greenland ice core.
330
00:19:48,321 --> 00:19:52,390
The particles also date to 1258,
331
00:19:52,425 --> 00:19:56,127
when the sulphur concentrations
are highest.
332
00:19:58,131 --> 00:20:00,464
Could these particles
be possible clues
333
00:20:00,500 --> 00:20:03,601
to the volcano's identity?
334
00:20:05,171 --> 00:20:08,139
At 50,000 times magnification,
335
00:20:08,174 --> 00:20:10,241
it's clear that
the mineral particles
336
00:20:10,276 --> 00:20:13,411
are actually microscopic
pieces of volcanic ash.
337
00:20:13,446 --> 00:20:17,715
DUNBAR:
These particles are smaller
than a human hair.
338
00:20:20,052 --> 00:20:21,419
NARRATOR:
The ash particles
339
00:20:21,454 --> 00:20:23,921
are fragments
of shattered pumice,
340
00:20:23,956 --> 00:20:28,359
produced when magma cools
rapidly during an eruption.
341
00:20:28,394 --> 00:20:30,194
And their chemical composition
342
00:20:30,229 --> 00:20:35,766
is unique to each
volcanic eruption.
343
00:20:35,802 --> 00:20:37,902
Just like a human fingerprint
allows a suspect
344
00:20:37,937 --> 00:20:41,505
to be identified, the chemical
composition of an ash layer
345
00:20:41,541 --> 00:20:44,341
allows the source volcano
to be identified.
346
00:20:44,377 --> 00:20:50,881
NARRATOR:
This unique signature didn't
match any known volcano.
347
00:20:54,654 --> 00:20:59,223
But it did show up
in one other surprising place...
348
00:21:01,761 --> 00:21:05,429
...at the exact opposite
end of the world,
349
00:21:05,465 --> 00:21:08,933
in ice cores
taken from the South Pole.
350
00:21:10,837 --> 00:21:14,405
These cores also contained
a significant spike
351
00:21:14,440 --> 00:21:17,107
in sulphuric acid,
352
00:21:17,143 --> 00:21:19,610
corresponding to the eruption
in 1257.
353
00:21:19,645 --> 00:21:23,614
This means that
the monster darkened not only
354
00:21:23,649 --> 00:21:28,652
the Northern Hemisphere, but
the Southern Hemisphere as well,
355
00:21:28,688 --> 00:21:33,791
smothering the entire world
in a blanket of sulphuric acid.
356
00:21:37,530 --> 00:21:39,897
Climatologist Michael Mills
357
00:21:39,932 --> 00:21:42,967
believes the size
of this global cloud
358
00:21:43,002 --> 00:21:46,237
can help pinpoint the place
where the volcano erupted.
359
00:21:48,441 --> 00:21:50,074
He uses satellite data
360
00:21:50,109 --> 00:21:53,344
to map how clouds of sulphuric
acid aerosols
361
00:21:53,379 --> 00:21:55,179
disperse around the world.
362
00:21:57,517 --> 00:21:58,983
Let's look at what happens
when you have an eruption
363
00:21:59,018 --> 00:22:01,151
in the Northern Hemisphere.
364
00:22:01,187 --> 00:22:04,622
In 2008, we had
several eruptions,
365
00:22:04,657 --> 00:22:08,459
and the aerosol stays
in the Northern Hemisphere.
366
00:22:08,494 --> 00:22:10,895
Now look at what happens
367
00:22:10,930 --> 00:22:13,497
when you have an eruption
in the Southern Hemisphere.
368
00:22:13,533 --> 00:22:16,667
The aerosol spreads,
and will remain
369
00:22:16,702 --> 00:22:19,436
in the Southern Hemisphere.
370
00:22:19,472 --> 00:22:23,140
NARRATOR:
But how could an aerosol cloud
reach both hemispheres?
371
00:22:23,175 --> 00:22:28,612
For that, an eruption has to
occur within a narrow band
372
00:22:28,648 --> 00:22:30,881
around the middle of the globe.
373
00:22:32,818 --> 00:22:35,819
This is Pinatubo
in June of 1991,
374
00:22:35,855 --> 00:22:37,521
in the Philippines.
375
00:22:37,557 --> 00:22:40,624
It starts spreading
throughout the tropics,
376
00:22:40,660 --> 00:22:43,561
and from there, it spreads
377
00:22:43,596 --> 00:22:47,898
into the Northern Hemisphere
and to the Southern Hemisphere.
378
00:22:47,934 --> 00:22:50,167
Within a year
after the eruption,
379
00:22:50,202 --> 00:22:53,837
the aerosol has covered the
globe from pole to pole,
380
00:22:53,873 --> 00:22:55,806
affecting temperatures globally.
381
00:22:57,176 --> 00:23:00,844
NARRATOR:
The mystery eruption of 1257
382
00:23:00,880 --> 00:23:05,416
also spread a cloud of
sulphuric acid over both poles.
383
00:23:05,451 --> 00:23:11,956
So it too must have erupted
near the equator.
384
00:23:11,991 --> 00:23:16,460
But that still leaves over 700
possible volcanoes as suspects,
385
00:23:16,495 --> 00:23:20,698
like Mount Tambora, that led
to the year without a summer,
386
00:23:20,733 --> 00:23:26,303
Krakatoa, that also erupted
in Indonesia in 1883,
387
00:23:26,339 --> 00:23:31,008
and El Chichon in Mexico,
that erupted in 1982.
388
00:23:31,043 --> 00:23:34,111
Any one of hundreds
of tropical volcanoes
389
00:23:34,146 --> 00:23:36,080
could have caused
thousands of deaths
390
00:23:36,115 --> 00:23:38,949
on the other side of the planet,
but which one,
391
00:23:38,985 --> 00:23:40,784
and could it strike again?
392
00:23:40,820 --> 00:23:42,987
OPPENHEIMER:
It's still a needle
in a haystack
393
00:23:43,022 --> 00:23:46,256
to find the one volcano,
the one eruption
394
00:23:46,292 --> 00:23:48,492
that triggered all of this,
because there are
395
00:23:48,527 --> 00:23:51,729
so many volcanoes, even if you
narrow it down to the tropics,
396
00:23:51,764 --> 00:23:53,263
where do you start?
397
00:23:55,401 --> 00:23:58,402
NARRATOR:
It seemed an impossible mystery
to solve.
398
00:24:02,108 --> 00:24:03,540
But then a French geographer
399
00:24:03,576 --> 00:24:06,510
named Franck Lavigne
decided to take it on.
400
00:24:08,814 --> 00:24:10,447
LAVIGNE:
For me it looks
401
00:24:10,483 --> 00:24:14,184
a bit strange that nobody found
this eruption.
402
00:24:14,220 --> 00:24:16,987
So I decided
to take up the challenge.
403
00:24:17,023 --> 00:24:21,325
NARRATOR:
He approaches it as a detective.
404
00:24:21,360 --> 00:24:25,062
LAVIGNE:
Trying to find the identity
of this mystery volcano
405
00:24:25,097 --> 00:24:27,398
was like a crime scene.
406
00:24:27,433 --> 00:24:28,899
So we needed to investigate,
407
00:24:28,934 --> 00:24:31,902
to look for culprits,
to look for clues.
408
00:24:31,937 --> 00:24:35,439
NARRATOR:
Volcanologist
Jean-Christophe Komorowski
409
00:24:35,474 --> 00:24:38,809
joins the investigation.
410
00:24:38,844 --> 00:24:40,544
KOMOROWSKI:
It's a very large eruption.
411
00:24:40,579 --> 00:24:43,447
It's an unknown eruption,
so it has to be in a country
412
00:24:43,482 --> 00:24:46,750
where there are
many, many volcanoes,
413
00:24:46,786 --> 00:24:49,286
most of them perhaps
have not been studied.
414
00:24:49,321 --> 00:24:52,990
NARRATOR:
The team focuses on one
particularly active region
415
00:24:53,025 --> 00:24:55,526
of the Pacific Ring of Fire--
416
00:24:55,561 --> 00:25:00,698
Indonesia, home of
the once deadly Mount Tambora,
417
00:25:00,733 --> 00:25:04,268
that last erupted in 1815.
418
00:25:04,303 --> 00:25:08,439
With 129 active volcanoes spread
over 3,000 miles,
419
00:25:08,474 --> 00:25:14,211
Indonesia is the most volcanic
country in the tropics.
420
00:25:14,246 --> 00:25:19,550
It is also one of the most
unstudied and mysterious.
421
00:25:19,585 --> 00:25:21,218
KOMOROWSKI:
Indonesia has
422
00:25:21,253 --> 00:25:23,487
the second largest number of
active volcanoes in the world.
423
00:25:23,522 --> 00:25:27,758
NARRATOR:
Indonesia marks the place
424
00:25:27,793 --> 00:25:31,495
where two giant
tectonic plates collide.
425
00:25:31,530 --> 00:25:34,798
Here, one plate
dives under the other
426
00:25:34,834 --> 00:25:37,534
in a process called subduction.
427
00:25:37,570 --> 00:25:40,971
At depth,
the diving plate releases water,
428
00:25:41,006 --> 00:25:44,808
which lowers the melting point
of the hot rock above.
429
00:25:44,844 --> 00:25:49,646
The rock melts, forming giant
bubbles of magma that rise up,
430
00:25:49,682 --> 00:25:52,282
forcing their way
through the Earth's crust,
431
00:25:52,318 --> 00:25:54,284
until the magma erupts
432
00:25:54,320 --> 00:25:55,853
at the surface.
433
00:26:00,426 --> 00:26:03,560
Today, the most dangerous
Indonesian volcano
434
00:26:03,596 --> 00:26:06,530
is Mount Merapi
on the island of Java.
435
00:26:06,565 --> 00:26:12,102
This volcano erupts explosively
every few years...
436
00:26:16,208 --> 00:26:18,208
...threatening hundreds
of thousands of people
437
00:26:18,244 --> 00:26:19,510
who live in its shadow.
438
00:26:24,416 --> 00:26:27,384
AGUS BUDI SANTOSO:
Merapi volcano is considered
439
00:26:27,419 --> 00:26:29,953
to be one of the most active
volcanoes in the world.
440
00:26:33,192 --> 00:26:35,259
NARRATOR:
The last major eruption
441
00:26:35,294 --> 00:26:38,362
was in 2010.
442
00:26:38,397 --> 00:26:41,598
400,000 people evacuated.
443
00:26:41,634 --> 00:26:45,936
Even so, more than 200 died
in the avalanches
444
00:26:45,971 --> 00:26:47,738
of superheated ash and rock,
445
00:26:47,773 --> 00:26:52,342
called pyroclastic flows.
446
00:26:52,378 --> 00:26:56,947
20,000 were left without homes.
447
00:27:01,587 --> 00:27:03,987
The ash produced by Merapi
448
00:27:04,023 --> 00:27:05,689
does not match
the chemical fingerprint
449
00:27:05,724 --> 00:27:08,392
of the ash in the ice cores.
450
00:27:08,427 --> 00:27:11,929
But understanding the forces
that make this volcano
451
00:27:11,964 --> 00:27:17,501
so dangerous sheds light on all
of Indonesia's active volcanoes.
452
00:27:17,536 --> 00:27:23,841
So which one exploded so
catastrophically in 1257?
453
00:27:23,876 --> 00:27:26,743
Geographer Lavigne
454
00:27:26,779 --> 00:27:30,514
hunts through satellite images
for large volcanic craters
455
00:27:30,549 --> 00:27:34,818
and other telltale signs.
456
00:27:34,854 --> 00:27:36,486
And one of these clues
is a large volume of pumice
457
00:27:36,522 --> 00:27:38,822
all around the volcano.
458
00:27:38,858 --> 00:27:43,827
NARRATOR:
Pumice, a rough textured rock,
is solidified magma,
459
00:27:43,863 --> 00:27:48,232
blasted out during
explosive eruptions.
460
00:27:51,136 --> 00:27:53,737
When you suddenly depressurize
461
00:27:53,772 --> 00:27:56,974
and cool magma that was
very rich in gas,
462
00:27:57,009 --> 00:27:58,609
it forms this very lightweight,
463
00:27:58,644 --> 00:28:01,578
foamy rock, which is pumice.
464
00:28:01,614 --> 00:28:07,084
NARRATOR:
It can be a deadly material.
465
00:28:07,119 --> 00:28:12,022
When Mount Vesuvius erupted
in Italy in 79 the Common Era,
466
00:28:12,057 --> 00:28:15,893
it entombed the town
and the people of Pompeii
467
00:28:15,928 --> 00:28:19,763
in layers of pumice
16 feet deep.
468
00:28:19,798 --> 00:28:25,535
Throughout Indonesia today,
pumice mines dig out
469
00:28:25,571 --> 00:28:27,704
this volcanic material,
primarily for use
470
00:28:27,740 --> 00:28:29,539
in the construction industry.
471
00:28:29,575 --> 00:28:34,578
And the scars left by the
quarrying work are so extensive
472
00:28:34,613 --> 00:28:38,515
that they're visible from space,
making it easy for scientists
473
00:28:38,550 --> 00:28:42,185
to pinpoint locations
for further investigation.
474
00:28:42,221 --> 00:28:45,255
Journeying to Indonesia,
475
00:28:45,291 --> 00:28:47,858
Lavigne works with partners
from the government's
476
00:28:47,893 --> 00:28:51,361
geological agency
and Indonesian universities.
477
00:28:51,397 --> 00:28:57,067
They visit several volcanoes,
with no success.
478
00:28:57,102 --> 00:29:00,804
At each site, the pumice
is compacted and hard,
479
00:29:00,839 --> 00:29:03,206
likely too ancient
to have been created
480
00:29:03,242 --> 00:29:06,777
during the 1257 eruption.
481
00:29:06,812 --> 00:29:08,478
(translated):
It seemed older
482
00:29:08,514 --> 00:29:13,150
than we had predicted, so older
than the 13th century.
483
00:29:15,254 --> 00:29:18,488
NARRATOR:
Then the team
sees something intriguing
484
00:29:18,524 --> 00:29:21,558
in the satellite images,
and decides to narrow its search
485
00:29:21,593 --> 00:29:24,628
to the island of Lombok,
just east of Bali.
486
00:29:26,732 --> 00:29:29,132
This island is
quite a big island,
487
00:29:29,168 --> 00:29:31,969
with a very big crater.
488
00:29:37,309 --> 00:29:40,110
NARRATOR:
Stretching four miles across
489
00:29:40,145 --> 00:29:42,946
and over two and a half
thousand feet deep,
490
00:29:42,982 --> 00:29:46,049
this giant crater
is called a caldera.
491
00:29:46,085 --> 00:29:51,288
It's what remains of a volcanic
system known as Mount Rinjani.
492
00:29:51,323 --> 00:29:54,925
When you have a very large
explosive eruption,
493
00:29:54,960 --> 00:29:58,595
you're left at the end of the
eruption with a huge hole.
494
00:29:58,630 --> 00:30:02,432
NARRATOR:
To the team's expert eyes,
it looks like there were
495
00:30:02,468 --> 00:30:08,205
not one, but two giant volcanic
peaks here in the past--
496
00:30:08,240 --> 00:30:13,410
Mount Rinjani itself,
and a second peak that once rose
497
00:30:13,445 --> 00:30:15,979
above the main part
of the caldera.
498
00:30:16,015 --> 00:30:21,118
Today, inside this caldera
is now a small volcanic cone--
499
00:30:21,153 --> 00:30:22,819
Mount Barujari.
500
00:30:24,289 --> 00:30:27,591
Surrounded by a rainwater lake,
501
00:30:27,626 --> 00:30:30,193
Mount Barujari is the part
of the volcanic system
502
00:30:30,229 --> 00:30:31,828
that is still active.
503
00:30:39,872 --> 00:30:42,706
In 2015 and 2016,
504
00:30:42,741 --> 00:30:45,776
this small cone erupted
with enough force
505
00:30:45,811 --> 00:30:50,013
to send plumes of ash thousands
of feet into the atmosphere,
506
00:30:50,049 --> 00:30:52,983
disrupting international flights
in the area.
507
00:30:55,220 --> 00:31:02,859
It's far too small to be the
source of the mystery eruption,
508
00:31:02,895 --> 00:31:06,430
but the caldera it sits in
is large enough
509
00:31:06,465 --> 00:31:09,699
to have been created during
a much more powerful eruption.
510
00:31:14,406 --> 00:31:17,641
And all around the
Mount Rinjani volcanic system
511
00:31:17,676 --> 00:31:20,510
are pumice quarries.
512
00:31:20,546 --> 00:31:22,546
Everywhere in the island
513
00:31:22,581 --> 00:31:26,316
you can find a pumice quarry.
514
00:31:26,351 --> 00:31:28,785
NARRATOR:
Could the pumice in these
quarries be dated
515
00:31:28,821 --> 00:31:30,887
to help in their investigation?
516
00:31:35,461 --> 00:31:39,830
The team travels to Lombok.
517
00:31:42,801 --> 00:31:46,503
And the hunt starts in the
shadow of Mount Rinjani...
518
00:31:50,409 --> 00:31:55,479
...a peak that soars
12,000 feet high.
519
00:32:01,286 --> 00:32:04,187
On the island, they join forces
with more Indonesian experts.
520
00:32:09,361 --> 00:32:11,128
They head for the quarries
521
00:32:11,163 --> 00:32:15,765
identified in
the satellite images.
522
00:32:19,204 --> 00:32:23,840
And as soon as they arrive, they
discover something remarkable.
523
00:32:23,876 --> 00:32:30,714
The volcanic pumice deposits
are at least 120 feet deep.
524
00:32:37,356 --> 00:32:39,322
LAVIGNE:
Here we are,
525
00:32:39,358 --> 00:32:41,458
looking at
the huge volcanic deposit.
526
00:32:41,493 --> 00:32:45,228
And that's very rare,
527
00:32:45,264 --> 00:32:46,863
to find so thick deposit
528
00:32:46,899 --> 00:32:51,468
very far away from
the summit of the volcano.
529
00:32:51,503 --> 00:32:55,539
NARRATOR:
Pompeii, just over five miles
530
00:32:55,574 --> 00:32:57,774
from the erupting
Mount Vesuvius, was buried
531
00:32:57,809 --> 00:33:00,110
under 16 feet of pumice.
532
00:33:00,145 --> 00:33:05,549
Here, the deposits of pumice
and ash are at least
533
00:33:05,584 --> 00:33:08,919
six times thicker,
and they are much farther away
534
00:33:08,954 --> 00:33:13,857
from Mount Rinjani than Pompeii
was from Mount Vesuvius.
535
00:33:13,892 --> 00:33:18,161
It's a sign of a giant eruption.
536
00:33:18,197 --> 00:33:21,064
KOMOROWSKI:
You're dealing with
a very massive eruption.
537
00:33:21,099 --> 00:33:22,832
Much larger than
the Pompeii eruption,
538
00:33:22,868 --> 00:33:26,069
and probably also much larger
than the Pinatubo eruption
539
00:33:26,104 --> 00:33:27,237
in 1991.
540
00:33:31,910 --> 00:33:35,045
NARRATOR:
And it looks to them
as though the ash and pumice
541
00:33:35,080 --> 00:33:39,816
flowed down from the volcano
in vast avalanches.
542
00:33:43,255 --> 00:33:45,655
KOMOROWSKI:
You can see it's very rich
in finer material.
543
00:33:45,691 --> 00:33:48,959
It's not pumice falling
from a column, raining down.
544
00:33:48,994 --> 00:33:51,595
It's an avalanche
of incandescent,
545
00:33:51,630 --> 00:33:53,430
hot volcanic rocks
mixed with gases.
546
00:33:56,602 --> 00:33:57,667
My first impression,
547
00:33:57,703 --> 00:33:59,936
when I saw such a huge deposit,
548
00:33:59,972 --> 00:34:02,739
was that we have here
a very serious candidate
549
00:34:02,774 --> 00:34:03,840
for the mystery eruption.
550
00:34:09,081 --> 00:34:10,413
NARRATOR:
But is all this pumice
551
00:34:10,449 --> 00:34:16,086
from the mystery eruption
of 1257?
552
00:34:16,121 --> 00:34:19,656
KOMOROWSKI:
To confirm that this eruption
is the 1257 eruption,
553
00:34:19,691 --> 00:34:24,194
we need to try to find charcoal,
wood logs that were burned
554
00:34:24,229 --> 00:34:27,697
by this eruption, carried by
the pyroclastic flow,
555
00:34:27,733 --> 00:34:30,267
and settling here,
and we need to date those.
556
00:34:32,537 --> 00:34:36,439
NARRATOR:
If they can find burned wood,
they can radiocarbon-date it,
557
00:34:36,475 --> 00:34:39,976
since, unlike pumice,
wood contains carbon
558
00:34:40,012 --> 00:34:42,012
absorbed from the atmosphere.
559
00:34:42,047 --> 00:34:44,614
And by taking samples
of the pumice itself,
560
00:34:44,650 --> 00:34:48,385
the team hopes
to compare its chemistry
561
00:34:48,420 --> 00:34:53,156
with the fragments of volcanic
ash from the polar ice cores.
562
00:34:55,727 --> 00:34:59,296
But Lavigne still needs
more evidence, so he decides
563
00:34:59,331 --> 00:35:01,164
to investigate Lombok's past
564
00:35:01,199 --> 00:35:06,069
to see if he can find records
of historic eruptions.
565
00:35:11,043 --> 00:35:12,575
Under lock and key in the museum
566
00:35:12,611 --> 00:35:15,011
of Lombok's capital city,
Mataram,
567
00:35:15,047 --> 00:35:17,847
is an original text,
568
00:35:17,883 --> 00:35:20,650
written on dried palm leaves,
569
00:35:20,686 --> 00:35:23,320
in an old Javanese script.
570
00:35:27,326 --> 00:35:30,760
Called the Babad Lombok,
571
00:35:30,796 --> 00:35:35,732
this text is a rare account
of Lombok's history.
572
00:35:35,767 --> 00:35:37,734
(translated):
It chronicles the story
573
00:35:37,769 --> 00:35:41,438
of Lombok, from prehistoric
times to historic times.
574
00:35:41,473 --> 00:35:45,241
NARRATOR:
And hidden in this document
575
00:35:45,277 --> 00:35:48,044
is a remarkable account
that historians have dated
576
00:35:48,080 --> 00:35:50,180
to the 13th century.
577
00:35:51,383 --> 00:35:54,184
(translated):
Mount Rinjani avalanched,
578
00:35:54,219 --> 00:35:57,053
and Mount Samalas collapsed.
579
00:35:57,089 --> 00:35:59,589
Rocks flooded down in rows.
580
00:36:03,428 --> 00:36:06,129
LAVIGNE:
It describes a huge
volcanic eruption
581
00:36:06,164 --> 00:36:07,797
that occurred in Lombok.
582
00:36:09,534 --> 00:36:11,868
NARRATOR:
Lavigne is familiar
with Mount Rinjani,
583
00:36:11,903 --> 00:36:17,741
mentioned in the text, but
not the name of the volcano
584
00:36:17,776 --> 00:36:22,178
that's described as collapsing--
Mount Samalas.
585
00:36:22,214 --> 00:36:24,581
This description
is absolutely fantastic,
586
00:36:24,616 --> 00:36:29,853
because it mentions the name of
a new volcano, Mount Samalas.
587
00:36:29,888 --> 00:36:32,088
I never heard about this before.
588
00:36:33,558 --> 00:36:37,260
NARRATOR:
This remarkable discovery
raises a new question--
589
00:36:37,295 --> 00:36:42,665
could the giant caldera
the team saw on satellite images
590
00:36:42,701 --> 00:36:46,302
belong to the unknown
Mount Samalas?
591
00:36:46,338 --> 00:36:52,809
The text also reveals the scale
of the human catastrophe.
592
00:36:52,844 --> 00:36:54,577
LAVIGNE:
The text in the Babad
593
00:36:54,613 --> 00:36:59,048
says these flows destroyed the
seat of the kingdom, Pamatan.
594
00:36:59,084 --> 00:37:02,685
All houses were destroyed
and swept away,
595
00:37:02,721 --> 00:37:05,588
floating on the sea,
and many people die.
596
00:37:05,624 --> 00:37:08,691
There is a strong possibility
of the remains of this capital
597
00:37:08,727 --> 00:37:13,763
still lie preserved beneath
the pumice, just like Pompeii.
598
00:37:13,799 --> 00:37:16,499
NARRATOR:
The text is a tantalizing clue,
599
00:37:16,535 --> 00:37:20,970
but could it just be a myth?
600
00:37:21,006 --> 00:37:25,341
LAVIGNE:
It made this volcano our chief
suspect in our investigations,
601
00:37:25,377 --> 00:37:29,946
but to confirm it was the one,
we needed scientific proof.
602
00:37:34,052 --> 00:37:36,753
NARRATOR:
So the team decides
to mount an expedition.
603
00:37:41,760 --> 00:37:45,762
To trek into the mountains
and hunt for hard evidence
604
00:37:45,797 --> 00:37:50,633
at an altitude of 9,000 feet.
605
00:37:59,878 --> 00:38:03,480
NARRATOR:
From up here, the team can
assess the landscape and geology
606
00:38:03,515 --> 00:38:06,249
in a way that's impossible
from satellite images alone.
607
00:38:14,893 --> 00:38:18,027
Exposed in the cliffs
are geological layers
608
00:38:18,063 --> 00:38:19,963
that allow
Jean-Christophe Komorowski
609
00:38:19,998 --> 00:38:23,566
to work out the sequence
of events that led
610
00:38:23,602 --> 00:38:25,001
to what we see today...
611
00:38:27,606 --> 00:38:29,305
...the giant caldera.
612
00:38:31,776 --> 00:38:34,944
These cliffs are the remains
of a very massive volcano.
613
00:38:37,582 --> 00:38:40,216
NARRATOR:
And towering over the east side,
614
00:38:40,252 --> 00:38:46,389
the remains of Mount Rinjani.
615
00:38:46,424 --> 00:38:47,490
You can see the slopes
616
00:38:47,526 --> 00:38:51,861
of Mount Rinjani volcano
rising to 3,700 meters.
617
00:38:51,897 --> 00:38:54,330
And it was much higher before.
618
00:38:54,366 --> 00:38:56,432
NARRATOR:
The scars in the cliffs
619
00:38:56,468 --> 00:38:59,602
suggest to Komorowski
that half of Mount Rinjani
620
00:38:59,638 --> 00:39:03,406
avalanched into the caldera
after it formed.
621
00:39:03,441 --> 00:39:06,543
KOMOROWSKI:
The formation
of the Samalas caldera
622
00:39:06,578 --> 00:39:08,144
destabilized Mount Rinjani,
623
00:39:08,179 --> 00:39:11,014
which collapsed
into the caldera,
624
00:39:11,049 --> 00:39:13,816
and this formed this
massive sheer cliff here.
625
00:39:16,721 --> 00:39:20,723
NARRATOR:
To the experts, it looks like
Mount Samalas once stood
626
00:39:20,759 --> 00:39:22,258
next to Mount Rinjani,
627
00:39:22,294 --> 00:39:30,066
just as the ancient text
describes.
628
00:39:30,101 --> 00:39:32,802
(translated):
In fact, the latest
research found that there was
629
00:39:32,837 --> 00:39:34,737
a volcanic mountain
called Mount Samalas,
630
00:39:34,773 --> 00:39:38,775
which in the end is different
than Mount Rinjani.
631
00:39:43,315 --> 00:39:46,482
NARRATOR:
By extending the existing slopes
of the volcano,
632
00:39:46,518 --> 00:39:50,720
experts have reconstructed
what Mount Samalas looked like.
633
00:39:54,893 --> 00:39:56,826
KOMOROWSKI:
Imagine that,
before the eruption
634
00:39:56,861 --> 00:39:58,728
you had a huge conical volcano
635
00:39:58,763 --> 00:40:03,066
rising 1.6 kilometer above
the rim of this giant hole.
636
00:40:03,101 --> 00:40:08,237
NARRATOR:
That's an extra mile in height
of volcanic mountain.
637
00:40:08,273 --> 00:40:11,474
So how did several cubic miles
of rock disappear
638
00:40:11,509 --> 00:40:14,677
and leave an enormous caldera
in its place?
639
00:40:14,713 --> 00:40:19,115
It all begins
with a giant eruption.
640
00:40:19,150 --> 00:40:20,550
KOMOROWSKI:
And in order to form a caldera,
641
00:40:20,585 --> 00:40:23,786
you have to have first a very
massive explosive eruption.
642
00:40:26,091 --> 00:40:27,657
NARRATOR:
In a magma chamber
643
00:40:27,692 --> 00:40:30,660
far beneath the volcano,
the pressure rises,
644
00:40:30,695 --> 00:40:33,763
and finally cracks open
the rock above.
645
00:40:33,798 --> 00:40:36,799
Magma blasts upwards.
646
00:40:36,835 --> 00:40:41,904
As this chamber empties,
it becomes unstable.
647
00:40:41,940 --> 00:40:44,741
This destabilizes
the whole volcano on top.
648
00:40:46,344 --> 00:40:48,978
NARRATOR:
The roof of this
partially empty chamber
649
00:40:49,014 --> 00:40:52,548
now cracks under the weight.
650
00:40:52,584 --> 00:40:53,983
And it collapses.
651
00:40:54,019 --> 00:40:58,354
NARRATOR:
The entire top of the volcano
caves in.
652
00:41:01,860 --> 00:41:05,328
Billions of tons of rock
disappear as it falls
653
00:41:05,363 --> 00:41:09,465
thousands of feet down
into the magma chamber below,
654
00:41:09,501 --> 00:41:11,501
forming a giant crater above...
655
00:41:14,172 --> 00:41:17,106
...the enormous caldera.
656
00:41:18,410 --> 00:41:22,078
But that's not the end.
657
00:41:22,113 --> 00:41:24,047
KOMOROWSKI:
As the volcano
collapses on itself,
658
00:41:24,082 --> 00:41:26,416
it forms a massive
explosive eruption,
659
00:41:26,451 --> 00:41:28,484
producing giant
pyroclastic flows
660
00:41:28,520 --> 00:41:30,653
that sweep down
the flanks of the volcano.
661
00:41:36,361 --> 00:41:38,494
NARRATOR:
This catastrophic event
662
00:41:38,530 --> 00:41:40,663
explains the depth
of the pumice deposits
663
00:41:40,699 --> 00:41:42,098
in the quarries,
664
00:41:42,133 --> 00:41:44,467
and closely aligns
with the ancient story
665
00:41:44,502 --> 00:41:46,502
in the Babad Lombok.
666
00:41:48,273 --> 00:41:51,741
KOMOROWSKI:
It gives a name
to the volcano that existed
667
00:41:51,776 --> 00:41:53,976
at the beginning
of the eruption, Mount Samalas,
668
00:41:54,012 --> 00:41:59,382
and it describes how Mount
Samalas collapsed in on itself.
669
00:41:59,417 --> 00:42:02,518
Altogether, the description
in the Babad matches remarkably
670
00:42:02,554 --> 00:42:04,721
what we have found
in our field investigations.
671
00:42:06,825 --> 00:42:10,860
We now know that
Babad was not a legend,
672
00:42:10,895 --> 00:42:12,328
but eyewitness accounts.
673
00:42:16,334 --> 00:42:18,701
NARRATOR:
If the long-forgotten
Mount Samalas
674
00:42:18,737 --> 00:42:20,703
was the source of the giant
eruption on Lombok,
675
00:42:20,739 --> 00:42:24,540
as the evidence suggests,
could it also be
676
00:42:24,576 --> 00:42:28,177
the mystery eruption of 1257?
677
00:42:30,515 --> 00:42:32,448
To answer that definitively,
678
00:42:32,484 --> 00:42:37,820
the team still needs
more forensic evidence.
679
00:42:37,856 --> 00:42:40,389
OPPENHEIMER:
It's really critical
to get on the ground
680
00:42:40,425 --> 00:42:41,791
to look at the actual
rocks themselves.
681
00:42:46,698 --> 00:42:48,131
NARRATOR:
They take samples
682
00:42:48,166 --> 00:42:52,201
of pumice and ash
from over 100 different sites
683
00:42:52,237 --> 00:42:53,870
across Lombok
and on neighboring islands.
684
00:42:56,007 --> 00:42:58,241
They conduct geophysical surveys
685
00:42:58,276 --> 00:43:01,310
to measure the depth
of the volcanic deposits
686
00:43:01,346 --> 00:43:03,846
still buried beneath the ground.
687
00:43:03,882 --> 00:43:05,882
And they investigate whether
688
00:43:05,917 --> 00:43:09,118
gases from this eruption
could have reached high enough
689
00:43:09,154 --> 00:43:11,954
into the upper atmosphere
to spread globally.
690
00:43:14,559 --> 00:43:16,526
KOMOROWSKI:
To assess the scale
of the eruption,
691
00:43:16,561 --> 00:43:18,728
we looked at these
pumice fragments
692
00:43:18,763 --> 00:43:20,863
that were ejected
by the eruption column.
693
00:43:24,102 --> 00:43:25,968
And the idea is that
the further away
694
00:43:26,004 --> 00:43:28,704
you find big fragments,
it means that these fragments
695
00:43:28,740 --> 00:43:30,506
were ejected with
a lot of energy...
696
00:43:33,812 --> 00:43:34,844
...and that the eruption column
697
00:43:34,879 --> 00:43:36,946
reached very high
in the atmosphere.
698
00:43:39,818 --> 00:43:43,653
NARRATOR:
In this case, pumice fragments
two inches across
699
00:43:43,688 --> 00:43:48,291
were found 29 miles away on
the nearby island of Sumbawa,
700
00:43:48,326 --> 00:43:52,461
allowing the team to calculate
that the pumice likely ascended
701
00:43:52,497 --> 00:43:58,401
nearly 27 miles high--
more than ten miles higher
702
00:43:58,436 --> 00:44:00,703
than the Mount St. Helens
eruption of 1980.
703
00:44:02,874 --> 00:44:05,308
KOMOROWSKI:
This is one of
the highest column heights
704
00:44:05,343 --> 00:44:08,177
for explosive eruptions
in the last 10,000 years.
705
00:44:09,547 --> 00:44:11,848
NARRATOR:
The Mount Samalas eruption
706
00:44:11,883 --> 00:44:15,751
was certainly massive enough
to cool the entire world.
707
00:44:18,656 --> 00:44:21,891
But can scientific tests prove
that the pumice
708
00:44:21,926 --> 00:44:24,927
was from the mystery 1257
eruption?
709
00:44:28,032 --> 00:44:32,768
In Paris, French volcanologist
Celine Vidal goes through
710
00:44:32,804 --> 00:44:35,137
the samples taken
from Indonesia.
711
00:44:39,010 --> 00:44:41,110
First, she selects
pieces of carbonized wood
712
00:44:41,145 --> 00:44:47,116
found inside the pumice deposits
for radiocarbon dating.
713
00:44:47,151 --> 00:44:50,086
(translated):
We analyzed 20 pieces
of carbonized wood
714
00:44:50,121 --> 00:44:51,487
from sites all across
the volcano,
715
00:44:51,522 --> 00:44:55,258
and the carbon 14 dating
told us that the eruption
716
00:44:55,293 --> 00:44:57,126
dated to the second half
of the 13th century.
717
00:44:58,997 --> 00:45:00,963
LAVIGNE:
All the results were consistent
718
00:45:00,999 --> 00:45:03,699
with the mystery eruption.
719
00:45:03,735 --> 00:45:07,536
NARRATOR:
The dates are in range,
720
00:45:07,572 --> 00:45:09,538
but there is one final test.
721
00:45:09,574 --> 00:45:11,641
Will the chemical fingerprint
of this eruption
722
00:45:11,676 --> 00:45:15,778
match the fingerprint
in the polar ice cores?
723
00:45:19,250 --> 00:45:21,350
At high magnification,
724
00:45:21,386 --> 00:45:24,320
Vidal compares
the volcanic ash fragments,
725
00:45:24,355 --> 00:45:28,190
one from the Antarctic ice core
from 1257,
726
00:45:28,226 --> 00:45:35,097
and one from the pumice deposits
on Lombok.
727
00:45:35,133 --> 00:45:36,699
(translated):
You can see that the surfaces
728
00:45:36,734 --> 00:45:38,134
of the two different
particles of ash
729
00:45:38,169 --> 00:45:42,405
have the same texture, and that
their edges are very sharp.
730
00:45:42,440 --> 00:45:46,208
NARRATOR:
They appear very similar.
731
00:45:46,244 --> 00:45:50,379
But how closely do their
chemical fingerprints match?
732
00:45:50,415 --> 00:45:52,682
(translated):
I add now the chemical
composition of the ash
733
00:45:52,717 --> 00:45:56,218
from Samalas here in blue,
734
00:45:56,254 --> 00:46:01,090
and one sees that the peaks
correspond perfectly.
735
00:46:01,125 --> 00:46:02,758
They are comparable
to more than 99%,
736
00:46:02,794 --> 00:46:05,294
and that is really excellent.
737
00:46:05,330 --> 00:46:09,365
This allows us to conclude that
they are from the same origin.
738
00:46:09,400 --> 00:46:14,103
NARRATOR:
Now there is finally enough
evidence to remove all doubt--
739
00:46:14,138 --> 00:46:18,441
the mystery killer volcano
is here on Lombok,
740
00:46:18,476 --> 00:46:22,878
Mount Samalas, once known
and since forgotten.
741
00:46:22,914 --> 00:46:25,481
The team was very excited
by the result.
742
00:46:25,516 --> 00:46:30,720
KOMOROWSKI:
The source of the 1257 eruption
has been a mystery for 30 years,
743
00:46:30,755 --> 00:46:34,490
so we were quite excited
when we were able to prove
744
00:46:34,525 --> 00:46:38,361
that Mount Samalas
erupted in 1257.
745
00:46:38,396 --> 00:46:42,732
NARRATOR:
The mystery of the massive spike
of sulphuric acid
746
00:46:42,767 --> 00:46:45,501
in the polar ice cores,
the global volcanic winter
747
00:46:45,536 --> 00:46:48,971
caused by a cloud of aerosols
that blocked the sun,
748
00:46:49,007 --> 00:46:53,209
and likely, the thousands
of people killed in London
749
00:46:53,244 --> 00:46:58,014
in a catastrophic famine,
all have been answered.
750
00:46:58,049 --> 00:46:59,949
By combining these discoveries
751
00:46:59,984 --> 00:47:02,618
with the investigation
on the volcano,
752
00:47:02,653 --> 00:47:08,724
the team can now unpack
the eruption blow by blow.
753
00:47:08,760 --> 00:47:12,695
The 1257 eruption
started with a very explosive,
754
00:47:12,730 --> 00:47:16,966
violent eruption
from Mount Samalas.
755
00:47:17,001 --> 00:47:19,502
NARRATOR:
At its peak,
the eruption blasted out
756
00:47:19,537 --> 00:47:24,507
one million tons
of material a second.
757
00:47:24,542 --> 00:47:26,876
And that produced
a very tall eruption column
758
00:47:26,911 --> 00:47:29,812
of ash and gases and pumice,
759
00:47:29,847 --> 00:47:33,049
rising 43 kilometers
in elevation.
760
00:47:33,084 --> 00:47:36,719
NARRATOR:
Nearly four cubic miles
of pumice and ash
761
00:47:36,754 --> 00:47:40,689
rise four times higher
than the operational altitude
762
00:47:40,725 --> 00:47:42,691
of a passenger jet.
763
00:47:42,727 --> 00:47:46,762
While the gases remain aloft,
most of the pumice and ash
764
00:47:46,798 --> 00:47:49,198
then falls back to Earth.
765
00:47:49,233 --> 00:47:54,637
And it produced a rain of pumice
over a very vast area.
766
00:47:54,672 --> 00:48:00,142
NARRATOR:
It covers an area at least
450 miles across.
767
00:48:00,178 --> 00:48:04,480
During the final collapse
of the volcano,
768
00:48:04,515 --> 00:48:06,816
six cubic miles
of pumice and ash
769
00:48:06,851 --> 00:48:09,785
form giant pyroclastic flows.
770
00:48:09,821 --> 00:48:15,458
Racing down, they reach speeds
of over 125 miles an hour,
771
00:48:15,493 --> 00:48:20,863
at temperatures
of 1,500 degrees Fahrenheit.
772
00:48:20,898 --> 00:48:22,698
They covered the entire
landscape of Lombok
773
00:48:22,733 --> 00:48:25,134
with thicknesses
of five to 50 meters,
774
00:48:25,169 --> 00:48:28,504
reaching the sea in many places.
775
00:48:30,141 --> 00:48:34,543
NARRATOR:
But even as the dust
settles on Lombok,
776
00:48:34,579 --> 00:48:40,616
the vast volcanic cloud starts
to envelop the entire world,
777
00:48:40,651 --> 00:48:43,319
even as far away
from the eruption
778
00:48:43,354 --> 00:48:46,489
as North America and Europe.
779
00:48:46,524 --> 00:48:50,025
WALKER:
The fact that we have
so many thousands of people
780
00:48:50,061 --> 00:48:53,462
buried in these mass pits
as a result
781
00:48:53,498 --> 00:48:54,997
of this volcanic eruption
782
00:48:55,032 --> 00:48:58,267
just shows us what
a global event it was.
783
00:49:02,807 --> 00:49:06,175
NARRATOR:
This was possibly the most
massive volcanic eruption
784
00:49:06,210 --> 00:49:08,210
in recorded history.
785
00:49:10,014 --> 00:49:12,248
And it raises
a troubling question.
786
00:49:12,283 --> 00:49:17,119
Could another eruption of this
magnitude happen again?
787
00:49:17,155 --> 00:49:25,461
It's been 750 years since the
giant eruption of Mount Samalas,
788
00:49:25,496 --> 00:49:28,864
yet inside its vast caldera,
eruptions from Mount Barujari
789
00:49:28,900 --> 00:49:34,203
reveal that the volcanic system
is still active.
790
00:49:38,976 --> 00:49:41,610
Two and a half thousand feet
below the caldera rim,
791
00:49:41,646 --> 00:49:47,216
Komorowski rejoins the team
of Indonesian volcanologists,
792
00:49:47,251 --> 00:49:49,985
monitoring the active heart
793
00:49:50,021 --> 00:49:52,488
of the Samalas/Rinjani
volcanic complex.
794
00:50:05,102 --> 00:50:09,905
Using thermal imagery
and making a risky trek
795
00:50:09,941 --> 00:50:11,840
to collect lava
from the latest eruptions,
796
00:50:11,876 --> 00:50:14,443
the Indonesian volcanologists
797
00:50:14,478 --> 00:50:17,479
are gaining an ever
more accurate picture
798
00:50:17,515 --> 00:50:22,051
of the volcano's activity
level today.
799
00:50:22,086 --> 00:50:25,454
And the most telling clue
to the volcano's activity
800
00:50:25,489 --> 00:50:27,022
is not the cone itself,
801
00:50:27,058 --> 00:50:31,193
but the rainwater lake
that surrounds it.
802
00:50:35,099 --> 00:50:38,067
Volcanologist
Devy Kamil Syahbana
803
00:50:38,102 --> 00:50:40,569
measures the water temperature.
804
00:50:42,573 --> 00:50:47,610
At an altitude 6,500 feet,
more than a mile high,
805
00:50:47,645 --> 00:50:50,212
this lake should
have a temperature
806
00:50:50,248 --> 00:50:53,816
of about 60 degrees Fahrenheit,
or 15 degrees Celsius.
807
00:50:53,851 --> 00:50:57,519
DEVY KAMIL SYAHBANA:
But here we have, like,
20 to 22 degrees Celsius,
808
00:50:57,555 --> 00:51:00,122
which is much hotter
than a normal lake,
809
00:51:00,157 --> 00:51:03,425
which indicates a very strong
magmatic activity
810
00:51:03,461 --> 00:51:06,128
beneath the caldera.
811
00:51:06,163 --> 00:51:09,298
NARRATOR:
The eruption of 1257
812
00:51:09,333 --> 00:51:13,535
likely left a lot of magma
behind, inside this chamber.
813
00:51:13,571 --> 00:51:15,938
The volcano is still
under pressure,
814
00:51:15,973 --> 00:51:18,207
and it is still unstable.
815
00:51:18,242 --> 00:51:20,242
NARRATOR:
The volcano remains active,
816
00:51:20,278 --> 00:51:21,810
but their analysis tells them
817
00:51:21,846 --> 00:51:24,346
that there is
insufficient pressure
818
00:51:24,382 --> 00:51:28,350
to power a 1257-scale eruption.
819
00:51:28,386 --> 00:51:32,488
But what about other volcanoes?
820
00:51:32,523 --> 00:51:37,660
According to the ice core
record, there have been at least
821
00:51:37,695 --> 00:51:40,496
seven explosive eruptions
on the scale of Pinatubo
822
00:51:40,531 --> 00:51:44,166
near the equator since 1257.
823
00:51:44,201 --> 00:51:46,602
It will happen again.
824
00:51:46,637 --> 00:51:49,838
The worry is, no one knows when.
825
00:51:49,874 --> 00:51:53,609
KOMOROWSKI:
If another major explosive
eruption were to happen
826
00:51:53,644 --> 00:51:55,344
today in the equatorial region,
827
00:51:55,379 --> 00:51:57,513
it would have
devastating consequences.
828
00:51:59,583 --> 00:52:01,050
There'll be huge disruption
829
00:52:01,085 --> 00:52:02,985
to global aviation.
830
00:52:03,020 --> 00:52:04,853
LAVIGNE:
The economic impact would be
831
00:52:04,889 --> 00:52:05,721
really catastrophic.
832
00:52:08,092 --> 00:52:09,558
These massive volcanic events
833
00:52:09,593 --> 00:52:12,895
really impact
on people globally.
834
00:52:12,930 --> 00:52:14,296
It affects their climate,
835
00:52:14,332 --> 00:52:16,265
food source, causes famine,
836
00:52:16,300 --> 00:52:20,202
and can cause catastrophic
numbers of deaths.
837
00:52:21,739 --> 00:52:24,573
NARRATOR:
750 years ago,
838
00:52:24,608 --> 00:52:28,610
an eruption on a small island
in Indonesia
839
00:52:28,646 --> 00:52:31,613
destroyed lives
on the other side of the world,
840
00:52:31,649 --> 00:52:39,288
reminding us again of the power
of our volatile Earth.
841
00:52:51,036 --> 00:52:53,703
This NOVA program
is available on DVD.
842
00:52:53,738 --> 00:52:59,108
To order, visit shopPBS.org,
or call 1-800-PLAY-PBS.
843
00:52:59,144 --> 00:53:01,277
NOVA is also available
for download on iTunes.
68796
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