Original subtitles

>> Earth, a 4.5 billion year

old planet, still evolving.

As continents shift and clash,

volcanoes erupt, and glaciers

grow and recede, the Earth's

crust is carved in numerous

and fascinating ways, leaving

a trail of geological

mysteries behind. In this

episode, Iceland, the world's

largest volcanic island, is

explored. This barren and

alien landscape generates one

third of the world's lava.

Steam billows from the ground

and boiling water is thrust

into the air.

It's a land of violent

extremes where fire meets its

nemesis, ice, and where

clues to understanding

Iceland's formation also

provide a window into the

formation of the Earth itself.

S01x11 Iceland Volcano Original Air Date on April 28, 2009

-- Sync, corrected by elderman -- -- for www.MY-SUBS.com --

In the middle of the north

Atlantic Ocean lies Iceland, a

lone island, only 300 miles

wide. A volcanic hotbed, it

holds some of the most diverse

geological wonders known to

mankind. To understand how it

formed and the dynamic forces

that are shaping this land,

scientists are scouring the

strange landscape for clues.

And the investigation starts

here, in the southwest of

Iceland - the Thingvillir

plain. This broad inland

valley runs through the center

of Iceland. Giant cracks scar

the valley floor, leaving this

unusual landscape behind.

Geologist Mike Poland believes

they're a major clue in the

mystery of Iceland's

formation.

>> I'm standing in a really

spectacular place.

There's evidence for volcanic

activity all around. This

valley is covered in lava and

the plain is being ripped

apart. Everywhere I look,

there's massive tears in the

ground, like this one right

here.

This crack is getting bigger

and bigger every year.

In fact, this entire valley is

spreading apart at about the

same rate that fingernails

grow. Now, imagine the forces

that must be involved to rip

the land apart like this.

>> Something powerful is

spreading this valley at a

rate of one inch a year.

A force so immense, it's

pulling the entire country

apart.

But what force on Earth

could have such power?

In 1912, German climatologist

Alfred Wegener found an

essential clue. Browsing

through maps, he noticed that

the great land masses of the

Americas and Eurasia appeared

to fit together. This

observation led Wegener

to propose a radical new

theory, that these great

continents had once been

joined together. So some

unseen force must have

pushed them apart, allowing

water to rush into the space

between them, creating the

Atlantic Ocean.

It was inspired detective work

and a major step forward in

the search for what was

pulling Iceland apart.

But with no method to prove

such a force existed,

Wegener's theory was ignored

for the next 40 years.

Then, in 1946, new evidence

was discovered to support

Wegener's ideas.

The US Navy, using a

technology called sonar

imaging, mapped the Atlantic

Ocean floor for the first

time. The pictures revealed a

10,000-mile network of

underwater mountains,

separated by a giant tear

which passes through the

center of the Atlantic.

Scientists call this the

Mid-Atlantic Ridge.

This huge tear through the

Earth's crust is the boundary

between the American and

Eurasian plates, and the tear

runs right through the center

of Iceland.

>> I'm actually standing on

what's essentially the ocean

floor where the Mid-Atlantic

Ridge comes onto land.

And it splits the North

American plate on this side

from the Eurasian plate on

this side. And the

Mid-Atlantic Ridge starts way

south down by Antarctica,

comes all the way up through

the Atlantic and splits this

country right in two.

>> Scientists suspected this

was pushing the continents,

and Iceland, apart.

They came up with a theory.

Deep below the ocean,

convection currents of molten

rock tear open the Earth's

crust, allowing magma to seep

up and push the continents

apart. But there was a

problem. It was so deep,

scientists had no way of

proving whether magma was

seeping through the crust at

the center of the ridge.

Until, in 1974, Alvin, a

human-operated submersible,

was launched by the Woods Hole

Oceanographic Institute.

With its ability to withstand

deep sea pressures, scientists

could finally travel down to

the depths needed to reach the

Mid-Atlantic Ridge.

It was by examining the tear

that runs through the center

of this ridge that they

spotted the evidence they'd

been looking for - hot

volcanic gases billowing into

the ocean. Finding this told

them that the Mid-Atlantic Ridge

was highly volcanic and, like

a giant wedge, was capable of

spreading great land masses

apart.

Iceland's cracked Thingvillir

valley is a continuation of

the Mid-Atlantic Ridge.

The same process that's

pushing America further away

from Europe is happening here

on land.

Finally, here was a force

powerful enough to explain why

the cracks are getting wider,

and Iceland is getting bigger.

As the ridge continues to spread

it's going to add, more and more

land to Iceland.

So, in a way Iceland

will start getting longer and longer

uh, in an east-west sense

as the plates spread

apart from one another.

So in a way, Iceland

is not getting torn apart

so much as it's getting built.

The investigation into how

Iceland is growing

has revealed

cracks on the Thingvillir Plain

are widening at a rate of

1 inch a year.

And hot gases prove

that this spreading force

is volcanic.

forming the Mid-Atlantic Ridge

which cuts right through Iceland.

Scientists concluded it's this

that's widening the country.

Convection currents of hot

rock pull the Mid-Atlantic

Ridge apart. Magma surges up

to fill the cracks and, as it

approaches the surface, it

cools, hardens and forms new

land. Like a conveyor belt, it

continually pushes Iceland

apart.

But something didn't add up.

Why wasn't Iceland at the

bottom of the ocean like the

rest of the Mid-Atlantic

Ridge? There's something

strange about the amount of

volcanic activity on this

island.

>> This is not a normal section

of the Mid-Atlantic Ridge.

There's a tremendous amount

of volcanism that's happening

in this part of the ridge.

as opposed to the ridge

that's off in the Atlantic Ocean.

>> The hunt is now on to

discover how Iceland rose a

mile and a half off the ocean

floor and became the biggest

volcanic island in the world.

Iceland. There are more active

volcanoes concentrated here

than anywhere else on the

planet.

Geologists are searching for

what has helped push Iceland

off the ocean floor and lights

the fiery volcanoes that rage

across this barren land.

On the hunt for clues, the

investigation heads to one of

Iceland's most active

volcanoes, Hekla, known

locally as the Gateway to

Hell. Like all active

volcanoes in Iceland, Hekla

sits alongside the

Mid-Atlantic Ridge.

Volcanologist Dr.

Pete La Femina is taking a

high-resolution scan of the

volcano to see if its geology

hides any clues about its

inner workings.

>> This is a terrestrial laser

scanner, and the laser

produces a 3-D image of the

Earth's surface, and that

allows us to see parts of

Hekla volcano here that we

can't see with the naked eye.

>> His scan reveals a giant

crack, or fissure, running

right through the center of

the volcano, similar to those

found in the Thingvillir

valley.

But this fissure doesn't just

span the width of the volcano,

it extends either side, along

a five-mile tear in the Earth.

It's this tear that's key to

understanding how Iceland's

volcanoes erupt.

When Hekla erupted in the year

2000, it wasn't just the

volcanic cone that exploded.

The earth actually ripped open

along the entire five-mile

length of the fissure, a

weakness created by the

stretching along the

Mid-Atlantic Ridge.

In the geological world, these

are known as fissure

eruptions. Forced open by the

sheer volume of magma pushing

up from below, the tear spewed

out a terrifying 750 million

cubic feet of molten rock an

hour, flooding the land with

lava. These fissure eruptions

are so huge they can change

the landscape drastically in a

matter of days, leaving behind

mountains like these.

>> You can see to the north

here where the Earth's surface

actually opened up during the

fissure eruption and lava

erupted out. This fissure

starts to the north and

extends eight kilometers

through Hekla volcano here.

The sheer volume of magma

produced can be seen very well

here at Hekla volcano,

especially with these lava

flows that have draped the

land's surface. And, to me,

this is really exciting

because you can see very large

volumes of eruptive material

produced over very short

amounts of time. And Hekla

is--is a beautiful place to

study that.

>> But what is creating the

vast quantities of lava that

are forced out during these

eruptions? For many years, the

answer remained elusive, until

geologists found incriminating

evidence locked inside the

rocks.

>> The composition of the

rocks here in Iceland is quite

different than we see in

other places. By taking this

rock back to the lab, we can

get a very good idea of under

what conditions it formed,

whether it formed deep within

the Earth or--or near the

surface.

>> This rock was once molten

lava which erupted from one of

Iceland's volcanoes.

Analysis of the chemicals in

the rock revealed unusually

high concentrations of rare

Earth elements lanthanum and

cesium, chemicals which are

only found in magma with a

very deep origin.

It's the breakthrough

scientists had been searching

for. It was evidence that

another, much deeper, heat

source was combining with the

Mid-Atlantic Ridge to power

the volcanoes of Iceland.

The rock evidence suggested

this second force lay hidden

from view, deep beneath

Iceland's surface, but it is

possible to get a glimpse of

what's happening down there.

Scientists monitor the seismic

waves triggered by earthquakes

all over the world.

As the Earth's plates move,

they release shockwaves

called seismic waves that pass

through the Earth's crust.

These travel at a steady

speed, unless they hit a

region of hot rock, then they

slow down.

>> POLAND: Now, as seismic

waves arrive in Iceland,

they're traveling very slowly

through the subsurface, and

this is somewhat unique to

Iceland and a few other places

in the world. It tells us that

there's a very hot column of

rock, perhaps even some--some

molten material beneath the

surface.

>> These massive columns, or

plumes, are known as hotspots,

and are not unique to Iceland.

They are found beneath certain

volcanic areas in the world,

like Hawaii and Yellowstone.

>> Hotspots are these

unwavering plumes of--of hot

material, including molten

rock, magma, that stream up to

the surface from deep within

the Earth.

>> The scientists finally had

a snapshot of the second force

that was helping to create

Iceland. The hotspot that lies

beneath the island is almost

100 miles wide and 400 miles

deep. It channels rock slowly

upwards at temperatures over

1,700 degrees Fahrenheit.

It pushes against the crust,

heating the land from below

and forcing magma up onto the

surface as lava.

The investigation has

identified the two colossal

forces that built Iceland -

the Mid-Atlantic Ridge and the

deeper Icelandic hotspot.

Millions of years ago, the

Mid-Atlantic Ridge drifted

eastwards, creeping towards

the fixed Icelandic hotspot.

Finally, they met and have

been locked together in a

deadly partnership ever since.

The result, a truly formidable

volcanic beast, capable of

creating magma on a monumental

scale.

>> As the mid-ocean ridge

pulls apart, there's

decompression of the material

underneath it and that creates

melting. Decompression is

simply removing the pressure

from a pile of rock. It's much

like opening a can of soda or

popping the cork off of a--

a champagne bottle.

>> The removal of so much

pressure makes the rock melt

into liquid magma.

>> The hotspot is transporting

heat directly from the

interior of the Earth to the

surface, which also creates

melting. So this combination

of decompression of existing

rock beneath the surface and

the direct transport of heat

from the center of the Earth

create a huge amount of magma.

>> This incredible meeting of

the Mid-Atlantic Ridge and

hotspot began to build the

island beneath the waves,

pushing it upwards and giving

birth to Iceland.

Scientists have dated the

island's emergence to 20

million years ago, but could

only imagine what this might

have looked like. But on

November 14th 1963, off the

south coast of Iceland, the

world watched an action

replay of Iceland's

spectacular birth.

A column of rock and ash

blasted out of the ocean,

18,000 feet into the sky, so

high it could be seen 70 miles

away in Iceland's capital

city, Reykjavik.

A new island was forming right

in front of the world's eyes.

Scientists called it Surtsey,

after the Norse god of fire,

Surtr.

Located 20 miles off the

mainland, the small island of

Surtsey is now a magnet for

geologists. It offers a wealth

of forensic evidence for Dr.

La Femina, who is

investigating how Iceland

first formed.

It's amazing to see Surtsey

for the first time.

I've seen pictures.

I've seen aerial photographs.

But to actually be here

and a chance to, uh

go out and see it

up close and actually

look at the geology

it's just, awe inspiring.

This type of eruption that

formed Surtsey has now been

named after Surtsey, we call

them Surtseyan eruptions, and

they're very, very explosive.

The interaction of hot magma

or lava with the ocean causes

these very steam-rich and

highly explosive eruptions of

ash and water.

>> When scientists first

stepped foot on the island in

the summer of '64, they found

it hard to believe that this

was an island whose age was

measured in months, not

mimillennia.

>> In about nine and a half

months, this whole volcanic

cone built up. In addition,

lava flows came out of the

volcanic center here, and

we're seeing those, these nice

black cliffs in front of us.

>> Now geologists had an

insight into how early Iceland

might have formed. In only 20

million years, Iceland grew

from a tiny island into a

40,000 square mile land mass

as big as the state of

Kentucky. The forces that

power Iceland's volcanoes have

been revealed. Cracks along

Hekla volcano unleash gigantic

fissure eruptions. And rare

chemicals in the rock prove

that these eruptions were

fueled by two separate forces,

the Mid-Atlantic Ridge and the

hotspot. Iceland grew to

become the world's largest

volcanic island. But volcanism

alone doesn't explain how the

land of Iceland was formed.

The investigation will unearth

another, equally dramatic,

force that sculpted the

distinctive shape of the

Iceland we know today.

A force which would challenge

the might of Iceland's

volcanoes.

If Iceland was formed by fire

alone, it should look like

other volcanic islands such as

Hawaii or Tahiti, but

something else was at work

here to transform this island

into the distinctive shape it

is today. Its shape is another

clue to Iceland's formation.

An extraordinary force

indented Iceland's northern

coastline, burrowing deep

fjords which extended far

inland. But what colossal

force could cause such a

dramatic change to Iceland's

volcanic landscape? There's an

obvious suspect that's found

scattered across the island -

ice. As its name suggests,

Iceland has a long history of

being covered in ice

like this.

Today it covers ten percent

of the island, all year

round. And in the middle of

the country lies Europe's

biggest icecap, the mighty

Vatnajökull. Over 3,000 square

miles in size, Vatnajökull is

so large it even has its own

climatic conditions.

Up to two thirds of a mile

thick, it squashes the land

like a giant slab of rock, and

at its edges, great tongues of

ice flow out through deep

valleys.

Glacier expert Dr. Matthew

Roberts is investigating how

ice can gouge out solid rock,

and discover the role it has

played in Iceland's past.

>> This is a GPS receiver,

just like in car satellite

navigation. It's used here to

measure glacier movement.

This will be left on the ice

surface for a few days and

then I'll come back and I'll

analyze the data and discover

just how far the glacier has

moved.

>> Dr. Roberts' data reveals

that this whole glacier is

sliding forward at an

astounding rate of two feet

per day.

>> This is an amazing,

ever-changing environment. The

ice around me is like an icy

sea that's been frozen in

place. As the ice flows out of

the confines of the valley, it

expands and spreads to occupy

a greater area. Now, as it

expands, crevasses form, and

large depressions just like

the one here. Here's a smaller

crevasse that's formed.

Occasionally, when these

crevasses open, as they begin

to open, sounds can be heard.

Also, the glacier occasionally

makes a groaning sound. This

is all signs that the glacier

is alive and moving forward

very slowly.

>> Vatnajökull is one of the

largest icecaps in the

northern hemisphere.

Flowing down the valleys, the

great mass of ice bears down

with the weight of 100 tons

per square foot. Dr. Roberts

believes this moving giant is

a force capable of eroding

solid rock, and he's found

crucial evidence to prove it.

>> This is an excellent

example of the power of

glacial erosion. This boulder

would have been trapped

beneath the base of the ice,

and as the ice flowed over the

surface of it, it would have

progressively eroded the

surface of the boulder to

produce these very distinctive

marks called striations in its

surface. We can even tell the

direction in which the ice was

flowing. If I take a rock, I

can illustrate this. Imagine

this is the base of the--of

the ice and material trapped

inside the ice is being

dragged across as the glacier

moved to produce these

very distinctive marks in the

surface. This is just like

sandpaper over wood. The same

erosive effect.

>> The erosive process that's

happening on this boulder is

the same process that's

happening on a much larger

scale along the surface of

these valleys.

>> ROBERTS: The glacier is

responsible for literally

carving the landscape,

producing very distinctive

troughs and basins which were

formerly infilled with solid

rock. This really testifies to

the--the erosive power of--of

a glacier.

>> The ancient fjords on the

north coast are the same deep

basin shape, which means they

must once have been filled

with ice.

Scientists now know that,

around one and a hf million

years ago, changes in the

Earth's orbit, and the tilt of

its axis, began to cool the

planet. An enormous ice sheet

descended from the north and

shrouded Iceland in a cloak of

ice. As the ice advanced and

retreated, it carved out deep

fjords and indented Iceland's

northern coastline. Ice was a

formidable force in Iceland,

and many volcanoes lay

entombed beneath it. Fire and

ice were now locked in a

titanic battle of supremacy.

Would the giant ice sheets

that cbrved the fjords put out

the fires that created

Iceland?

The first clue lies in this

ancient valley, five miles

west of the glacier.

The valley floor is strewn

with hundreds of giant

boulders, but it's how they

got here that interests Dr.

Roberts.

>> These boulders provide a

lot of insight into how this

landscape was formed.

The boulders are clustered

together and, interestingly,

these boulders are rounded,

which shows that they've been

rolling. Now, the boulders

have been brought together by

some dynamical force. You can

also see smaller boulders

trapped in the center. And

It's quite clear that flowing

water is the cause of this.

But this wouldn't have been

water in the stream that we

see in the background.

This would have been water

produced by a much larger,

faster flow that would have

inundated this entire valley.

>> Dr. Roberts has an

extraordinary theory about

what happened here. In ancient

times, a cataclysmic flood 100

feet high cut through this

valley. It was so powerful

that it rolled these giant

boulders like pebbles in a

stream, before dumping them on

the landscape.

But what could create such a

colossal flow of water?

Dr. Roberts suspects the flood

came from the mighty

Vatnajökull glacier and is

hunting for clues.

With such a huge area to

cover, Dr. Roberts takes to

the air.

His investigation leads him to

a crucial piece of evidence -

this strange bowl-like

depression on the surface of

the ice.

>> This is an amazing

location. This giant

depression in the--in the ice

has been formed as a pocket of

water has drained from beneath

the base of the icecap. The

beautiful concentric crevasses

that you see on the ice

surface have formed as the ice

has slowly crept into the

hollow that's been created as

the water has drained away.

>> Beneath the ice, a dynamic

process is happeni. Hot

magma and steam are melting

the glacier from underneath.

The meltwater collects in a

huge ice basin, at the top of

the volcano. The basin slowly

fills, but as it does, the

surrounding ice becomes

unstable. Cracks appear in the

ice basin and, as the hot

water drains away, it forms a

tunnel which channels the

water to the edge of the

glacier. This would suggest

that volcanic eruptions still

happen, even under the

enormous weight of ice.

Is this process the key to

explaining the ancient

cataclysmic flood? To answer

this we must go to one of

Iceland's largest volcanoes,

Grimsvotn. Lying entombed

beneath the ice in the heart

of Vatnajökull, this massive

volcano violently erupts every

ten years. Here, fire and ice

spectacularly collide, with

Iceland's volcanoes emerging

victorious. Ice cannot

suppress the invincible power

of Iceland's volcanoes, which

have now found a new way to

vent their anger. During a

huge eruption like this,

Grimsvotn can melt enough ice

to fill America's largest

man-made reservoir, Lake Mead.

But this vast volume of water

cannot be held back by the ice

for long and leads inevitably

to a massive glacial flood.

Such a force of nature struck

Iceland in 1996, with

devastating consequences, the

floodwater taking out

everything in its path.

Bridges were torn down and

swept away, and the highway

was submerged under water.

>> The flood itself reached

a--a peak discharge of over

1.8 million cubic feet per

second, that's a remarkable

discharge, equivalent to the

summertime discharge of the

River Amazon. Imagine that

sort of condition over a

relatively small area.

>> The sheer force of the

water carried icebergs the

size of four-storey buildings.

It's floods like these that

can change the landscape in a

matter of days.

>> The erosive power of the

flowing water can result in

tremendous amounts of--of rock

being eroded, literally being

fractured away by the high

water pressure that's being

created. So, literally, a

landscape can form before your

eyes during a very severe

glacial flood.

>> The story of Iceland's

bizarre landscape is taking

shape. Striations on rock

prove that ice is a formidable

force that carved out

Iceland's unique coastline.

Boulders strewn in an empty

valley reveal cataclysmic

floods of the past.

And depressions in the ice

confirm that Iceland's

volcanoes could not be

suppressed. But 12,000 years

ago, the great ice sheets

retreated, and Iceland was

liberated from their wintry

grip. Now, the effects of

Iceland's volcanoes would be

felt on a global scale.

For thousands of years,

Iceland's volcanoes were

locked in a titanic battle

with ice, but then, 12,000

years ago, the giant ice

sheets finally retreated.

This would open a new chapter

in Iceland's volcanic history,

as they were now free to wreak

havoc. But what effect would

this have on Iceland and its

surroundings? One of the most

dramatic effects can be found

in the south central region of

the island. This alien

landscape is known as Laki.

A row of strange craters and

solidified lava flows that

have bubbled up from a huge

tear in the earth. A massive

fissure eruption, it stretches

for an astounding 16 miles

across the landscape.

Volcanologist Dr. Thor

Thordarson is investigating

Laki, the site of one of the

greatest eruptions in recent

history, one which would have

devastating effects worldwide.

>> The Laki fissures which

extend from here in the

southwest continue here

through the landscape as a row

of cones, up here, through

Mount Laki, which was split

into two during the eruption,

and continue further to the

northeast all the way to the

margins of the glaciers here.

>> Eyewitness accounts

accurately date the eruption

to 1783. This was one of the

most disastrous years in

Icelandic history. Fallout

from the eruption caused

harvests all over the island

to fail and 75 percent of the

livestock died, plunging

Iceland into a great famine

which killed ten thousand

people. But mysteriously, at

the same time, the rest of the

northern hemisphere reported

freakishly cold weather.

Averaging 2.3 degrees

Fahrenheit below normal, the

northern hemisphere froze

over.

>> THORDARSON: The North Sea

along the coast of Holland

froze, so people skated

between villages along the

coast. There was ice on the

Mississippi down by New

Orleans in that winter.

>> For many years, it was

thought the Laki eruption and

these climatic ents were

unrelated, but advances in

geology found it wasn't just a

bizarre coincidence.

Comparing eyewitness accounts

with the geological remains,

Dr. Thordarson has

reconstructed what happened.

He discovered that the

eruption started with a bang

on the morning of June 8th

1783. It sent rocks flying

high into the air and ripped

the earth open along a

one-mile tear. But this was

just the beginning. Three days

later, a second eruption

ripped open, then a third,

fourth, fifth. In total, the

earth unzipped along ten vast

tears in the crust, erupting

lava continuously, for over

eight months. The mammoth

amounts of lava that poured

out of the ground here would

have buried Manhattan to a

depth of 830 feet. But how an

eruption on this small, remote

island could cause climatic

chaos thousands of miles away

remained a mystery.

The evidence that would link

Laki with this worldwide

catastrophe was locked inside

these boulders.

>> The story is in the rocks.

This rock here is part of the

material, the magma that came

out during the eruption. These

holes are called bubbles.

And they form as the magma

rises from deep within the

ground and approaches the

surface, and it really starts

to boil. The gas which is

dissolved in the magma at

depth goes into the bubbles,

then it escapes into the

atmosphere.

>> When this "bubble rock"

erupted onto the surface, it

would have poured gas out into

the Icelandic atmosphere.

Could this gas have caused

climatic chaos across the

globe?

The identity of this gas can

be found in the microscopic

structure of the rock.

>> If you look closely at this

rock, you can see a lot of

white specks. These little

white specks are crystals who

grow in the magma at depth.

Sometimes these crystals, as

they grow, they will

encapsulate pristine magma and

bring it up to the surface.

>> Like time capsules, the

white crystals contain

untouched magma from deep in

the Earth, locked away since

1783. Dr. Thordarson has

analyzed this magma and found

it to contain poisonous

sulphur dioxide. And because

there was so much lava here,

it would have released

enormous amounts. A staggering

100 million tons of sulphur

dioxide gas was pumped into

the atmosphere.

But how could gases released

from Laki cause bitterly cold

weather across the globe?

The answer lay in accounts of

a thick red fog reported over

Iceland in June 1783. Within a

few weeks, it had been blown

over London and Paris, and by

July it had dispersed across

the entire northern

hemisphere. Scientists now

know that the red fog was

caused by the sulphur dioxide

which rose high into the air.

Mixing with water, it created

a sulphuric acid haze. The

haze blocked out the sun and

it sent temperatures

plummeting. As a result, the

northern hemisphere endured

three bitterly cold winters,

which brought spring floods,

famine and widespread poverty

to Europe. Some historians

have long believed that these

climatic conditions triggered

social and political unrest

which le!d to the French

Revolution in 1789. But

scientists now suspect Laki

had ramifications even further

afield. The cold temperatures

in the north changed air

currents in the south, causing

dramatic climate changes.

India was hit by a terrible

drought.

>> People say that more than

half a million people died

from the drought in India.

Also, this change in

atmospheric circulation caused

a very cold summer in Japan.

It was cold and wet, the rice

harvest failed and the result

was the greatest famine in

Japanese history.

>> It is estimated that Laki

killed over two million people

worldwide and was one of the

most devastating volcanic

eruptions in the history of

mankind.

The evidence has proven that

Iceland's recent volcanic

history has had a devastating

effect on the island, and the

rest of the world. Enormous

lava fields reveal that Laki

was a gigantic eruption.

Bubbles in the rock indicate

that huge volumes of gas were

released from Laki. The white

crystals reveal that this gas

was poisonous sulphur dioxide.

Evidence that Iceland's

volcanoes caused climatic

mayhem across the globe.

But eruptions like Laki may

not be confined to the past.

Some believe that the balance

between fire and ice is

shifting and has the potential

to propel Iceland into another

hell on Earth.

The evidence is mounting that

Iceland has the potential to

be the most lethal island on

the planet. A fearsome

volcanic force lies beneath

it, creating powerful

volcanoes capable of

generating gigantic lava flows

and altering global climates.

Yet many of Iceland's

volcanoes are covered in

glaciers. Fire and ice are

held in a delicate balance.

Scientists fear if this

balance were tipped in the

volcanoes' favor, Iceland

could become even deadlier.

If the remaining ice were to

melt, what effect would it

have on the activity of

Iceland's volcanoes? The first

clue in the investigation lies

in these innocuous looking

piles of rock and rubble.

They're found all over

Iceland, and yet these rocks

don't come from a volcano.

They're moraines, the

geological term for rock piles

deposited at the mouth of a

glacier. These deposits are

evidence that the glaciers are

shrinking. Year by year, the

glacier has melted and

retreated back up the valley,

leaving a moraine like this

behind.

Dr. Roberts has studied the

Vatnajökull glacier for the

last ten years and has noticed

this dramatic trend.

>> The glacier has retreated

at a remarkable rate. Since

I've been visiting the area,

I've seen tremendous changes.

The ice has retreated annually

at a rate of about 200 feet

per year. This lake over here

used to be filled with ice.

I've seen the ice

progressively melt, this

moraine has formed and this

whole valley has become almost

bare. Maybe in the next 20

years, this whole glacier will

disappear and a lake will form

in the valley.

>> Iceland's glaciers are

melting at an unprecedented

rate. With five percent of

Iceland's icecaps melting in

the last 40 years, the

question that scientists are

keen to understand is what

effect this rapid melting will

have on the volcanoes that lie

beneath. The only other time

that glaciers have melted this

quickly is when Iceland came

out of the last Ice Age. But

what can past events tell us

about the future? Geologist

Professor Bill McGuire is

investigating how volcanic

activity changed at the end of

the last Ice Age, and he's

unearthed some surprising

results.

>> Around about 11 or 12,000

years ago, you--you started to

see quite rapid melting of

glaciers in Iceland and

elsewhere, and that triggered

a--a recognizable increase in

volcanic activity because you

were removing this large mass

of ice very, very quickly.

>> The rapid melting of ice

kick-starts volcanic eruptions

beneath.

>> Volcanic eruptions are

triggered by the gas in the

magma, which expands to form

bubbles, and the bubbles drive

the eruption. It's rather like

taking the cork out of a--a

bottle of champagne. Now, if

you have a very heavy weight

on top of a--a volcano, if

there's a heavy mass of water

or ice, that can help suppress

eruptive activity.

>> But when ice melts quickly,

this downward pressure is

suddenly released, and that's

when the trouble starts.

>> As the ice melts, so the

pressure on the magma

underneath is reduced, the gas

in the magma can form bubbles,

they can coalesce and they can

eventually drive the magma

upwards towards the surface

and trigger either explosive

eruptions or effusions of lava

that can spread out over huge

distances.

>> Iceland's glaciers are

melting rapidly. This has led

scientists to believe that a

devastating eruption on the

scale of Laki could happen

again.

>> The question is when. These

are things that we have to

think about and try to prepare

ourselves to deal with if they

happen in our lifetime. Is it

possible that we can get

another eruption like this in

Iceland? Definitely.

>> The investigation has

revealed how the vast and

violent island of Iceland was

formed. Cracks in the

Thingvillir Plain and traces

of chemicals in the rocks

revealed how the Mid-Atlantic

Ridge and hotspot joined

forces to create a colossal

volcanic force.

Massive fissure

eruptions ripped the land

open. Hemorrhaging millions

of tons of lava, Iceland

rapidly formed. Deep northern

fjords were evidence that a

giant ice sheet eroded the

land and entombed the

volcanoes, locking fire and

ice in a titanic battle.

Boulders, strewn in an ancient

valley, revealed how fire

emerged victorious, unleashing

cataclysmic floods. And specks

of sulphur in the rocks showed

how Iceland's volcanoes have

the potential to cause global

destruction. Now glaciers,

melting above some of the

world's most deadly volcanoes,

are increasing the threat of

future eruptions.

Over the last 20 million

years, Iceland's almighty

volcanic force has created a

vast, alien landscape.

Volatile and unpredictable, it

may one day unleash a massive

eruption which could devastate

both Iceland and the wider world beyond.

-- Sync, corrected by elderman -- -- for www.MY-SUBS.com --