Original subtitles

Narrator: Iceland.

The world's largest volcanic island.

Formed by fire.

Home to some of the world's fiercest volcanoes.

>> for many, many years it was actually a place

That people feared.

Considered being the gateway to hell.

Narrator: A volcanic hotbed.

Where steam escapes.

Water explodes.

And new ground is born every day.

From deep inside the earth's blazing core.

>> the geology is alive here.

We have volcanic eruptions. You can watch the lava moving.

You can watch the plumes come up and so, it seems to be alive.

Narrator: Here, in one of the world's most beautiful

And volatile places, fire and ice collide.

>> many of the volcanoes are underneath glaciers,

So when they erupt we have this spectacular display

Of fire actually coming out of the ice.

Narrator: It is an epic struggle that makes iceland

The most geologically powerful island on earth.

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April, 2010.

Eyjafjallajokull, an 800,000-year-old volcano in the

Southern reaches of iceland, unleashes its terrible power.

For 39 days, eyjafjallajokull spews ash toward the sky,

Creating a plume.

That soars more than six miles into the atmosphere.

The mammoth cloud of ash creeps across europe,

Bringing global air travel to its knees.

Steffensen: Eyjafjallajokull is by now our most famous volcano,

And mainly of course, because of the problems that it caused

During its eruption in 2010, when people were

Sitting in airports all over the world cursing this mountain.

Narrator: Billions of dollars are lost.

Technology is no match for the most violent extremes of nature.

Steffensen: Looking at it was-- it was scary.

The mountain itself is big, and you could clearly

Hear the explosions and the rumble from this massive thing.

And the plume of ash, even though the mountain was big,

It was dwarfing the mountain underneath.

Looking at something so large, and there's absolutely nothing

You can do about it, is not a good feeling.

When nature takes over, you just have to sit and wait.

Narrator: The eruption causes flooding and destroys roads.

Farms are damaged.

Domestic animals poisoned by the ash fall.

The cloud of ash that turned air traffic on its head

Was the result of strong winds and the titanic collision

Between fire and ice.

In icelandic, eyjafjallajokull means

'the island's mountain glacier'.

Steffensen: Many of the volcanoes that we have or places that erupt are

Underneath glaciers, underneath thick sheets of ice.

So when they erupt, there is kind of a battle where the heat

From the fire underneath is melting its way through the ice.

Sometimes eventually making it all the way through, and we have

This spectacular display of fire actually coming out of the ice.

Narrator: This spectacular display, the potent interaction of magma

And the overlying ice cap, transformed eyjafjallajokull

Into an international hazard.

Steffensen: When it started erupting, the first thing that happened

Was the heat from the magma

And the eruption started melting the ice.

And most of the water went flowing down the northern side

Of the mountain, but a lot of it actually filled up the crater

Where the magma was coming out.

So the first thing that happened when this red, glowing magma

Came out of the earth was that it got in contact with water

And kind of exploded into these tiny particles

That were so light that they were projected all the way up

To the jet stream and all over the world more or less.

Narrator: But by icelandic terms,

Eyjafjallajokull was not a major eruption.

Nor was it the first time that one of iceland's volcanoes

Wrought havoc on the planet.

More than 200 years ago

A major eruption devastated iceland.

The terrible effects of which were also felt

Far beyond these shores.

It is a disaster that would leave thousands dead

In its trail.

At laki, in south-central iceland, lava, forced out

From a massive tear in the earth and now solidified ,

Stretches as far as the eye can see.

Now blanketed in thick, spongy moss, this seemingly endless

Lava field is the result of a colossal fissure eruption.

A disastrous volcanic event that had catastrophic effects

Around the world.

The laki eruption began on June 8, 1783

And lasted continuously for more than eight months.

As the earth repeatedly ripped open,

Terrifying amounts of lava bubbled up through the crust.

So much, that it would have buried dallas, texas

In more than 100 feet of molten rock.

It is the second-greatest lava flood on earth

In the last 1,000 years.

Steffensen: The laki eruptions, which occurred in 1783, were massive.

The ground split open, there was a crack that opened

That was about 25 kilometers long.

And the amount of lava and ash coming out of that

Was unbelievable.

The area that the lava ended up covering by the time

It finally stopped was about 600 square kilometers.

It's difficult to comprehend the size.

You basically have to see it from the air

To realize how big it is.

The laki eruption also sent more than 100 million tons

Of poisonous sulfur dioxide into the atmosphere.

The deadly haze caused iceland's harvest to fail,

Killed three-quarters of its livestock, and plunged

The island into a bitter famine that killed one in five people.

The thick fog that choked iceland spread east over europe,

Creating a lingering haze that blocked out the sun.

Steffensen: They actually believe that this eruption was one of the reasons

For the french revolution, because there was so much ash

Coming out of the laki craters that it ended up destroying

The crops in europe, so people ended up rising up

And fighting their oppressors.

Narrator: Scientists believe the lethal effects of laki

Were felt as far away as india and japan.

An estimated two million people died in its terrible aftermath.

The eruption at laki is one of the deadliest in human history.

The wrath of iceland's volcanoes

Has been felt outside its borders.

But this is a country that was built by volcanoes,

And to this day volcanoes continue to shape the land.

Without volcanoes, there would be no iceland.

Iceland lies in the middle of the north atlantic ocean, about

200 miles east of greenland on the edge of the arctic circle.

Mighty waterfalls carve the savage landscape.

Stunning cliffs define 3,000 miles of jagged coastline.

At the ragged edge of the world,

It is an island of extremes.

Just one-fifth of this hostile, alien land

Is inhabited by humans.

Iceland is roughly the size of cuba, but contains

Less than one-thirtieth of its population.

It is one of the least-inhabited countries on earth.

Despite the geothermal heat boiling under its crust,

11 per cent of iceland's landmass

Is covered by glaciers,

Including the world's third-largest ice-cap:

Vatnajokull.

Rising above this icy world, iceland's 30 active volcanoes

Generate one-third of the world's terrestrial lava.

This frozen island is on fire.

But what makes this rugged island, just 300 miles wide,

Such a frightening volcanic force?

What inflames this lonely outpost in the north atlantic?

Geological clues are everywhere.

At thingvellir plain in the south-west of iceland,

A giant gash in the valley floor bears witness

To the intense violence that has shaped the island.

Saemundsen: We are standing within a fault

That has been slowly moving apart in the last 9,000 years.

This is a basaltic lava wall that's been torn apart

From this one.

Some 9,000 years ago they were together and as all the years

Have passed they are slowly moving apart.

You think about the powers

That are needed to tear apart this landscape.

That is mind-boggling sometimes.

Narrator: Iceland is tearing apart at the rate of one inch per year,

About the same speed that fingernails grow.

The island is getting larger.

Here, in this cracked valley, something powerful is at work.

A geological juggernaut that runs right through

The middle of the island: The mid-atlantic ridge.

It's one of earth's longest mountain chains,

Yet it's almost entirely hidden beneath the sea.

The mid-atlantic ridge starts roughly midway

Between south america and africa

In the frigid south atlantic ocean and extends north

For about 10,000 miles to the arctic ocean.

In the north atlantic, it's the boundary between north america

And eurasia: Two plates of land that were once joined together.

Driven by forces deep within the earth,

The continental plates tear apart moving east and west,

Leaving a giant gash in the earth's crust.

Magma surges up and spews out onto the ocean floor.

As it cools, it forms new oceanic crust,

Forcing the older crust away inch by inch.

About 20 million years ago, lava erupting from the

Mid-atlantic ridge emerged above the waves

To create a new landform: Iceland.

This otherworldly landscape is essentially the sea floor

Pushed high above the ocean surface.

Iceland straddles the dividing line between the two plates.

It too is tearing apart.

The rift that splits iceland in two

Runs from the southwest to the northeast.

On the left, the western part of the island

Belongs to the north american plate,

The eastern part to the eurasian plate.

Saemundsen: Here, you have part of the north american continent

That is drifting slowly to the west and then, further out here,

We have the eurasian plate that is slowly drifting to the east.

What you're looking into here

Is basically the side of north america.

It's probably one of the few places in the world

Where you can look into the side of it.

Narrator: Iceland will continue to grow, east to west,

As the plates spread apart.

On the blackened lava plains of the reykjanes peninsula,

A 50-foot steel footbridge spans a broad fissure.

The bridge, named for the icelandic explorer leif erikson,

Allows visitors to symbolically walk the distance

From eurasia to north america.

For more adventurous explorers there are places in iceland

Where the edges of the north american and eurasian continents

Are within touching distance.

The silfra tectonic fissure, on the rim of thingvellir lake,

Provides a unique opportunity for underwater explorers

To float between continents.

In the narrowest reaches of the fissure, divers can touch

Both north america and eurasia at once.

Vita: This is the only place in the world where you can stand

In the north atlantic dorsal rift.

It's a ridge that goes from north to south through the whole

Atlantic ocean and it only rises to the surface here in iceland.

So actually it's quite unique because we are in between

Two tectonic plates and we are standing.

Normally, you have to be 4,000 meters depth in the ocean

To stand in a place like this.

Narrator: The water in silfra is among the clearest and cleanest

In the world, the result of a remarkable

Natural filtration process.

Water trickles underground from a melting glacier

30 miles north of the dive site.

The glacial melt water percolates down through

Porous lava rock before it wells up from underground springs

Directly into silfra, a process that can take

Between 30 and 50 years.

This naturally filtered, crystal-clear water

Has made silfra one of the world's top dive sites.

But with temperatures that hover at 35 degrees year-round,

It's not for the faint-of-heart.

Vita: Diving in silfra is not easy at all.

It's quite cold and it's quite demanding.

Your body needs to burn a lot of energy to stay warm.

More than one hour is not recommended, not even with

The best of the suits, because you lose your heat very fast.

It's very cold and it can be dangerous.

Besides the cold and the dry suit, it's a fissure which is

Very narrow, so it can be a little bit claustrophobic.

You need a lot of gear, a lot of weight,

So it's not the easiest dive in the world, to be honest.

But once you put your face in the water and you get to see

How clear the water is, everything is worth it.

Everything makes sense.

Narrator: At grjotagja, in the north of iceland,

Another clear sign that the earth is being ripped apart.

But deep inside this dark abyss

Is a surprisingly inviting natural wonder.

It's a world away from the frigid waters

Of the silfra fissure.

An alluring hot spring beckons,

Heated by magma deep within the earth.

Water in this shimmering cave pool

Simmers at more than 120 degrees, too hot for bathing.

Hot springs like this are pivotal to understanding

How the island formed.

Iceland is an on-shore continuation

Of the mid-atlantic ridge, one of the few places

Where this drowned mountain chain reaches the surface.

But what caused it, and the island as a whole,

To rise more than a mile above the ocean floor?

The answer lies with a second geological force

As indestructible as the rift that tears iceland in two:

Its inner fires, fueled by a hot spot deep within the earth.

There are more active volcanoes in iceland

Than anywhere else on earth.

On average, the country experiences

A major eruption every five years.

The most forbidding of iceland's volcanoes, hekla,

Towers 5000 feet over a landscape lain bare by lava.

Steffensen: Hekla is special in a way because --

Because of the frequency of the eruptions there.

And since the settlement, we've had about 20 eruptions there.

Some of the eruptions have been absolutely enormous,

Creating just catastrophic situations around it,

Killing people and burying farms in ash and pumice.

So, for many, many years it was actually a place

That people feared.

It was considered being the gateway to hell

And no one wanted to go close to it.

Narrator: Hekla lies alongside the mid-atlantic ridge.

A massive fissure similar to the fractures found in

Thingvellir valley tears through the centre of the volcano.

When hekla erupted in the year 2000,

The earth unzipped along the fissure, unleashing

A flow of lava more than four miles long.

The lava formed mountains,

Each of which has its origins deep underground.

Iceland sits on what's known as a hot spot: A plume of scorching

Molten rock believed to be 100 miles wide and 400 miles deep.

Lava erupting from the hot spot cooled

And accumulated to build the island above the sea.

Over 20 million years, iceland has grown from a tiny seamount

Into the world's largest volcanic island.

Thordarson: We have an unusual amount of volcanic activity in iceland.

So the volcanoes are producing more magma, molten rock,

Than in most other places.

Therefore, it's piling up more material.

And that all helps keep iceland above sea level.

If we wouldn't have this,

Iceland would be 2000 meters under the sea.

Narrator: The volcanic process that built iceland continues today.

As volcanoes erupt, and magma from deep within the earth

Rises to the surface to create new land,

Iceland is forever being reborn.

On the snaefellsnes peninsula,

The most westerly point of iceland, a volcanic cave

Traces the path of a lava flow more than 100 feet underground.

Lava-tube caves like this form

When the surface of flowing lava cools.

Molten rock solidifies along the sides of the lava river

And a hard crust forms on top.

Hot lava flows through this pipeline,

Streaming up from deep in the earth.

When the eruption stops, the lava ceases to flow,

Leaving behind a hollow tube.

Different colors on the walls of the cave record the history

Of eruptions: Layers of lava piled one on top of the other

Over thousands of years.

Thordarson: The geology is alive here.

We have volcanic eruptions. You can watch the lava moving.

You can watch the plumes come up, and so it seems to be alive.

Narrator: Nowhere is this living breathing earth more evident

Than here, in the southern lowlands

Where the earth's inner fires boil over.

Strokkur, a powerful fountain cast from deep within the earth,

Soars into the icelandic twilight.

In this pool, geysir, the first natural geyser known to

Europeans, now lies dormant on this geothermal plain.

In icelandic, the word 'geysa' means 'to gush'.

It is from this place that the world's geysers take their name.

Strokkur is far more active,

Erupting every eight to 10 minutes.

The geyser explodes from vents in the earth's surface

That run deep into the crust.

These hydrothermal eruptions are the result of cold rainwater

Seeping down through fractured bedrock onto hot volcanic rock.

The water trapped underground is super-heated

And converts to vapor that would normally fill

1,600 times more space than the original volume of water.

But it remains trapped under intense pressure.

The steam explodes from this subterranean furnace,

Passing through liquid groundwater near the surface,

Jetting more than 60 feet into the air.

On the flank of an active volcano,

Steaming fumaroles hiss into the cold atlantic sky.

Fumaroles are vents in the earth's crust,

Similar to geysers, yet they only emit steam, not water,

And volcanic gases such as hydrogen sulfide.

Superheated to temperatures as high as 280 degrees,

The cool groundwater deep within this system

Has entirely transformed to vapor.

Hydrogen sulfide rising through surface water

Produces sulfuric acid, strong enough to dissolve

The surrounding rock and soil to create boiling mudpots.

Sulfurous steam clouds and colorful minerals

In the ground paint the geothermal field

With an almost extraterrestrial beauty.

But there's real danger here.

Visitors who venture too close risk breaking through

The fragile mineral crust and scalding themselves

In the boiling pools.

Sulfur is one of the elements

Often found deposited at hot springs.

In previous centuries,

The sulfur was mined in iceland to make gunpowder.

Today, icelanders harness natural resources

For their own needs: Boring into the ground for the steam

That spins turbines to generate geothermal power.

Steffensen: The geothermal power plants that we have

Produce about 30 percent of the energy that we have in iceland.

Of course it's brilliant to be able to produce energy

In a green way like that.

There's no, or hardly any pollution and it's a very

Green way to keep life in iceland going.

There's always the downside that in order to create those

Power plants you have to build structures and you have to

Drill and you have to have pipes on the surface.

So there are mixed emotions when it comes to these power plants.

Narrator: Iceland's two mighty geological powers,

The mid-atlantic ridge and the deep icelandic hotspot,

Create a dangerous volcanic force capable of generating

More land-based lava than any place else on earth.

Saemundsen: We are on the mid-atlantic ridge, but it's above water

Because the hot mantle plume is pushing it above the sea level.

So, all of iceland in a way, when you drive around iceland,

You see mountains and hills.

They're all the result of some volcanic activity

At some point in time.

So, iceland is one big volcano.

Narrator: South-central iceland is the site of the greatest lava flood

Of the last 1,000 years.

Cutting through the lava field is eldgja,

The largest volcanic canyon on the planet.

Five miles long.

1300 feet wide.

500 feet deep.

The canyon's flat bottom confirms

That it isn't a valley carved by water.

It was formed by a more fiery power.

In icelandic, eldgja means 'canyon of fire'.

It's part of an eruptive fissure that stretches for 45 miles.

The canyon appeared in 934 ad

During an extremely violent eruption.

Far more powerful than the laki lava flow in 1783

That killed 20 per cent of iceland's population.

But this lava didn't erupt from a circular crater.

Instead, fountains of basalt lava spewed from a thin fissure

In the earth's crust nearly 20 miles long,

An unusual but natural phenomenon found along

The entire underwater stretch of the mid-atlantic ridge.

The eruption likely lasted for years.

More than three cubic miles of basalt lava

Oozed from the fissure, spreading across a lava field

That covers more than 250 square miles.

The largest lava field the earth has known since the ice age.

In iceland, large eruptions like laki and eldgja

Occur every few hundred years.

The chances of another catastrophic volcanic event

Are highly likely.

Icelanders still live under constant threat of eruptions,

Which occur on average every five years.

In the shadow of volcanoes, people have learned to adapt.

Most live on the edge of the island,

In coastal towns and cities.

Rural areas are largely uninhabited

Except for those where the land can be farmed.

Steffensen: The volcanoes are not close to cities or towns.

So the people living closest to them are usually farmers

And they and their families

Have been living there for generations.

They know that these things are there.

They know that they might erupt every now and then.

Narrator: Hekla, one of iceland's most-active volcanoes,

Erupts almost without warning.

Seismic activity at hekla was detected less than 90 minutes

Prior to four eruptions in the late 20th century.

Geologists monitor unrest in hekla,

Looking for telltale signs of a possible eruption.

Thordarson: We do monitor them and they monitor

The icelandic volcanoes very closely.

Basically, it measures the deformation of the ground.

As magma comes in, it will lift the ground up

And change its sort of orientation and deform it.

And so that's one way of detecting something happening

Underneath the volcano.

Steffensen: These volcanoes that are close to where people live

Are monitored quite carefully so that scientists

And the authorities can predict if something is going to happen

And they can issue warnings.

But usually when they do so, if they do issue warnings,

The farmers, they already know, because they can

Judge by the behavior of their animals.

They seem to sense this way before we do.

Narrator: In the southern highlands, the mountains of landmannalaugar

Form one of iceland's most striking and beautiful

Natural wonders.

The mountains were built from rhyolite, a lava rich in silica,

Which cools slowly after it erupts.

Rhyolite has the same mineral composition as granite,

Which cools deep within the earth.

Iron oxide in the rock creates these multicolored peaks.

Landmannalaugar rests on the edge of a rambling lava field

Formed by an eruption in the late 15th century.

It too glitters with rhyolite.

The caramel-colored mountains that surround the lava field

Are the starting point of an epic four-day trek

Through the highlands.

It's considered one of the world's finest hikes.

J.R.R. Tolkien,

Author of the hobbit and the lord of the rings,

Was fascinated by iceland.

These southern highlands are believed to have inspired

The landscape of middle earth.

In the northeast of iceland, the twisted rock towers

Of dimmuborgir rise like ruined citadels over a field of lava.

This remarkable, sinister domain,

Also reminiscent of tolkien, was sculpted by a volcanic eruption

More than 2,000 years ago.

Lava flowing from a large explosion to the east

Pooled over a small lake, trapping the water underneath.

The lake boiled as if on fire,

Sending columns of steam skyward.

Molten rock wrapped around the vapor plumes.

When the lava cooled and its top crust collapsed,

Only these hollow pillars of solidified lava remained.

These columns of mangled rock rise as high as 100 feet.

Church-like structures also formed around bubbles of vapor

Are large enough to harbor humans.

In icelandic, dimmuborgir means 'dark castles'.

The site was long believed to be the meeting point

Between earth and the netherworld.

According to nordic christian lore, satan landed here

After being cast from the heavens

And created these bulging 'catacombs of hell'.

But amid the tangled darkness there is simple beauty.

Dimmuborgir blooms with thickets,

Alpine plants and moss.

Each time the volcano wields its destructive power,

The ground heals and new life springs again.

Iceland's volcanoes blast.

Burn.

And melt.

Bringing to bear unthinkable chaos.

But occasionally, lava spills from the earth

To create formations so uniform, so ordered,

That they appear man-made.

At reynisfjara, iceland's southernmost beach,

Thousands of basalt columns stand tall,

300 feet above the slate-grey sand.

The question that has puzzled people for centuries:

How did a volcano produce such precise geometric structures?

The answer comes down to physics.

Thordarson: Columns form because

When the liquid lava cools down, it contracts.

And so, the solid lava is-- has a volume that's roughly

10 percent less than the liquid lava and so it accommodates

For this volume change by forming these joints

That are demarcated as columnar joints.

So they form the columns because of this contraction,

And they're usually hexagonal in form.

Narrator: These hexagonal basalt columns appear throughout the world:

In washington and wyoming in the united states,

And at the giant's causeway in northern ireland.

The process that forms columnar basalt

Is part of the ongoing creation of iceland,

A powerful island forever renewing itself through volcanic unrest.

The geological violence that built iceland

Is also tearing it apart.

The earth rips open.

The ground hisses.

And volcanoes explode.

And the power that burns deep within our planet

Continues its unrelenting drive to escape.

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