Volcanos Fierce Earth

You hear that noise, you see that smoke?

That's the sight of the earth actually coming alive.

And we've travelled a long way to get here by plane, by boat,

it's been a good four hours' hike up the mountain and we're here

to get face-to-face with one of the awesome forces on our planet,

an erupting volcano.

On today's explosive Fierce Earth special,

we're travelling to Italy to witness the awesome power

of two of the world's most spectacular volcanoes,

Etna and Stromboli.

We're going inside secret lava tubes...

..outside with children who live on a volcano...

and climbing all the way to the red-hot top!

That is fantastic!

What happens when the ground shakes,

the seas rise up and the air tears itself apart?

The Fierce Earth team move in,

taking on the most powerful forces on the planet.

Get ready for Fierce Earth. The earth, and how to survive it.

Volcanoes are planet earth's spectacular, and terrifying,

fireworks display. Living mountains that erupt molten rocks

from deep within the earth.

There are more than 500 active volcanoes in the world today

and right now about 20 will be erupting.

Volcanoes can lie dormant for years, perhaps centuries, and then, boom!

They explode, releasing seemingly endless rivers

of super-hot molten rock that destroy everything in their path.

I've travelled the world for many years,

chasing and observing these natural wonders.

I love volcanoes. I fear volcanoes. My mates call me Doctor Volcano.

Volcanoes are a reminder that the very ground humans walk upon

is ever-changing, and that the planet, not far below our feet,

is a violent furnace.

Today I'm on a mission to get right up close to an erupting volcano

and discover just where they get their awesome power.

So I'm heading straight for Europe's biggest,

Mount Etna on the island of Sicily, in Italy.

This cut-open peach is a great example of what the earth

might look like if we cut it with a really big knife.

On the outside is the thin, cold crust, that's where we live.

But inside it's thousands of degrees centigrade right to the eye

and core in the middle.

Now, this area here is known as the mantle

and that's where magma gets generated,

and, if cracks can be made in the earth's crust,

that magma can escape and form volcanoes.

So why do those cracks appear?

It's all down to plate tectonics. The earth's outer layer is made up

of giant tectonic plates that lock together like a huge jigsaw puzzle.

The plates float around on top of the sticky,

toffee-like mantle beneath.

The plates move very slowly, just centimetres a year,

but as they pull apart or push together,

the movement helps generate and release magma.

A volcano is born.

Etna is where the African Plate meets the European Plate,

with volcanic consequences. Just look at this lava flow.

This has come barrelling from the top of the mountain,

Mount Etna in the cloud there, all the way down, burning trees,

killing everything in its path.

Now, this would have been red-hot molten rock, a lava flow,

which people often fear the most. But sometimes it's the volcanoes,

the active ones that don't erupt lava, which are the most dangerous.

Let me show you why.

Take two mini volcanoes, tins for magma chambers

and coloured milk for the magma itself.

Both identical, but for one crucial difference

that will make one of them deadly.

So we've created two very simple homemade volcanoes here, OK?

We've put magma in both of them and I am just going to do

two very simple eruptions to explain the point.

I'm going to add these effervescent tablets to trigger the eruption.

Let's start with volcano number one, see what happens.

The fizzy tablets set off a reaction that simulates lava

leaving a volcano when flowing freely.

Beautiful, look at that.

A great lava flow now, it's starting to flow down the side

of our makeshift mountain, fantastic.

Etna erupts like this every few years

and the Sicilians are used to dealing with it.

Roads and houses often have to be rebuilt.

Although it's dangerous,

lava on the slopes here tends to be relatively slow-moving.

If it's heading in your direction,

you usually have time to get out of the way.

These lava flows will destroy everything in its wake,

just like what you see behind me.

But you will survive.

What happens, though, if the magma can't escape so easily,

if the gases can't release so easily?

So what we're going to do with volcano number two,

we've got the effervescent tablets,

but this time we're going to put a lid on.

Let's pile some rocks up. Look at that, a few rocks on top.

Now then, I'll just get out the way a bit.

We sit back and wait to see what happens.

You can see the pressure building now,

you see the rocks starting to move? There's real pressure building,

I can feel it... Oh! Look at that!

Wow! Now, you don't want to be around when that happens.

Sadly, that's exactly what did happen in the north west of the USA

in 1980. Sticky magma and tons of rock had combined

to keep Mount St Helens quiet for centuries.

But when it did finally erupt

they were the very things that made it so deadly.

The sudden release of pressure blew the entire top

and side of the volcano completely off.

A crater was left a kilometre and a half wide

and 57 people lost their lives.

Up on the slopes of Mount Etna, it's clear that there have been

huge amounts of volcanic activity over the years.

But, luckily, very few catastrophic explosions.

Look at this.

This ropey texture,

that's typical of lava flows.

Unlike explosive volcanoes,

the magma here is less sticky

and it flows down the side of the mountain.

But it's the hidden treasures that lie beneath this

is what I've come to see today.

And that's what I'm going to need this for.

Sometimes, rather than looking up at a volcano,

it pays to look down.

Under the slopes are secret tunnels built by the volcano itself.

The walls, ceiling and floor are all made of lava.

These lava tubes are all over Etna,

sometimes miles from the crater

where the lava first started flowing.

Lava tubes are formed when the top layer of lava hardens.

The rock roof keeps everything inside from cooling,

a bit like the insulation on a hot-water pipe.

The hot lava inside carries on flowing and, when the eruption ends,

it leaves behind this amazing network of tubes.

Tunnels like this are the real hidden wonder of the volcano.

The magma would have started up at this level

and it drained rapidly to start forming a lava tube.

You can see the drips of lava it left behind as it drained.

And just here you can see there's a tide mark.

This is where the river of lava once was.

If I was in this tunnel now when that lava was flowing,

it would be around sort of waist high here, chest high.

I'd be sort of wading against a river of lava

which is cascading down the mountain

and feeding lava flows maybe... maybe miles away from the vent.

It drained even further.

It cooled and formed the top crust of the final lava flow,

the final resting place.

Now, if I was in this tube when that lava was flowing,

I'd be burnt alive.

All volcanoes are named after Vulcan, the Roman god of fire.

It was Vulcan's job to make weapons for the other gods

and the Romans believed the glow of the lava

was from Vulcan's furnaces as he worked away under the earth.

Around three quarters of the world's volcanoes

are found around the edge of the Pacific Ocean.

Because of this, the area is known as the Ring of Fire.

Volcanoes are always changing,

and an active one may suddenly go quiet and become dormant.

Others are very reliable and have been erupting for decades

or even centuries.

Here are three of the most active volcanoes on the planet.

The US state of Hawaii

is a chain of volcanic islands in the Pacific Ocean.

The main volcano, Kilauea, has been erupting on its flank since 1983.

It's generally not explosive

but it's thought to release more lava

than any other volcano in the world.

At two is Stromboli,

off the coast of Sicily in Italy.

This tiny island is pretty much all volcano

and has been providing amazing firework displays without a break

for the last 2,000 years.

Number-one most long-standing active volcano

is Etna on Sicily in Italy.

Estimated to have been erupting on and off

for an incredible 3,500 years,

it's the biggest volcano in Europe and, despite all this activity,

over a million people, a quarter of all Sicilians,

live on its slopes.

Around 500 million people live on or near volcanoes.

Why would so many people choose to live

so close to such dangerous mountains?

Well, it's all down to our old friend lava.

It's full of minerals that make the land around volcanoes

incredibly fertile - great for growing food,

and the reason why people first started living around volcanoes.

To find out what that's like, I am off to number two in our chart,

Etna's little brother, Stromboli.

The Mediterranean Sea.

The water here is full of fish

and the coast is green and fertile.

Because of this, the area has been home

to generations of farmers and fishermen.

But this particular home happens to be...

a real volcano.

Stromboli is the tiny volcanic island

that makes a very big impression.

It's been erupting so regularly, and for so long,

that the Romans called it the Lighthouse of the Mediterranean.

Around 800 people live on the island,

in two villages clinging to the edge of the volcano.

There's only one school, with less than 50 children.

Instead of playing fields out the back, there's a live volcano.

Playing in the shadow of Stromboli looks scary.

So, what do the kids think of their volcano?

CHILDREN SPEAK ITALIAN

TRANSLATION: In reality, you ought to be scared of Stromboli

but once you've got used to living here a while

you no longer have all this fear.

-TRANSLATION:

-I have always liked the volcano

because in the evening

I hear it do things.

"Voom, voom, voom!" is the noise it makes.

-TRANSLATION:

-We can see the theatre of fire.

Also, if there are any flares

they are beautiful because you can see real things close up.

TRANSLATION: Even from my house.

-TRANSLATION:

-I'm never scared of the volcano

because the lava has never come down this far,

so we don't need to be scared.

We can rest easy with no worries.

The two villages on Stromboli are on the other side of the island

from the main danger zone.

But that doesn't mean there's no risk.

In 2003, a series of major eruptions nearly caused Stromboli

to be evacuated.

There were no deaths, even though boulders ejected from the crater

left houses in ruins.

For this reason, emergency plans are in place.

-TRANSLATION:

-If there IS an enormous eruption,

then we can evacuate the island by boat.

Because of the 2003 eruption,

a volcano monitoring station was put in place

and is manned 24 hours a day, all year round,

watching over the safety of the children below.

TRANSLATION: There are explosions that are beautiful

because they light up everything. I like it a lot.

Far from being scared of the fire-breathing mountain

in their own back yard,

the children of Stromboli love the volcano

they call simply "iddu" - "him".

Stromboli can make life in a country with no volcano

seem a little boring

but there is volcanic action if you know where to look -

as Leo is about to find out in Edinburgh.

Edinburgh, in wet and windy Scotland.

It seems about as far as a volcano as you can possibly get

but even in the UK there is evidence of volcanic activity

if you know where to look.

Believe it or not, there are two here, but where are they hiding?

For this slightly unusual challenge,

I have chosen one of my favourite ways of getting around -

a mountain bike.

There is no better way to go urban-volcano hunting.

You just need to know the clues.

I have climbed enough mountains to know

that you need to look for a certain sort of volcanic rock.

It's the rock that will give away the location of volcanoes,

even millions of years after they were active.

My first sleeping giant is right under the noses

of all the tourists at Edinburgh Castle.

The castle is at the very heart of Edinburgh

and it's famous throughout the world,

but what I am interested in is what is underneath it - Castle Rock.

The rock that creates the spectacular setting of the castle

is actually the remains of an ancient volcano.

Over the millennia the earth's tectonic plates shifted

and the volcanoes became extinct.

The mud around the extinct volcanoes eroded

and all that was left of these once-fearsome mountains

was their central cores of tough volcanic rock.

So that's volcano number one,

but I want to show you another in Edinburgh

that is even more spectacular.

If you want to go ancient-volcano spotting yourself,

there are opportunities all over the UK -

the Giant's Causeway in Northern Ireland

and Fingal's Cave on the Isle of Staffa in Scotland

were both built from cooling lava.

And many of the peaks in Snowdonia in Wales

were originally volcanoes.

It's a shame we are a little too late to see them erupting -

about 60 million years too late.

With some hard pedalling, I make a two-mile loop of the city streets

in under ten minutes.

You can't miss what I have come for

and there it is, brooding over the city -

secret volcano number two, and it's a whopper.

That's Arthur's Seat,

the central core of a massive volcano

right in the middle of the city.

These are the clues that give the volcanic activity away.

Even today, you can clearly see layers of ancient lava and ash -

still visible despite millions of years of erosion -

all that's left of a once-great volcano.

There's no way I'm leaving Edinburgh without conquering

this mini-mountain.

I'm not going to scare Bradley Wiggins at this speed,

but I need to pick up the pace if I am to get to the top.

It's not my toughest challenge,

but it's made slightly harder by the fact

there's no cycling allowed on the ancient volcanic rocks.

There's nothing for it but for me to carry my bike.

But it's worth it.

It is incredible to think that this was once the centre

of a giant volcano that created this entire landscape.

Awesome.

360 million years of history.

40 km/h top speed.

Two ancient volcanoes.

Sorted.

The ancient volcanoes of Scotland are long extinct

but there are many around the world that are still very much alive.

Back in Italy, Dougal is preparing for a close encounter

with one of the most awe-inspiring.

Stromboli -

the tip of a massive volcano emerging from under the sea,

erupting pretty much continuously for the last 2,000 years.

Every year it gets a little bit bigger

as yet more layers of ash and lava are launched out of its crater.

If you want to get face to face with a volcano

this is my particular favourite one,

and today I'm going to go right to the top.

Even from sea level it's clear that Stromboli is very much alive.

They call this scree slope built from rocks ejected from the crater

the Sciara del Fuoco - the Stream of Fire.

Those rocks have bounced over 900 metres

from the top of the volcano

all the way down to the sea

and that's how far we've got to go to get up to the top.

It is going to be fantastic.

900 metres is over twice the height of the Empire State Building

in New York,

and all of it built from volcanic rock.

It's clear Stromboli is not to be messed with,

so before my climb I drop in on the monitoring station

that helps the islanders live safely side by side with their volcano.

So, here we're at the main monitoring hub of Stromboli volcano,

and these little diagrams here that have been

almost virtually printed out on the screen,

these record how the volcano shakes.

Devices on the slopes measure minute changes in the volcano -

rumblings that can predict when Stromboli may erupt dangerously.

This is a lovely graphic here.

You can see this is the April 2003 eruption.

You can get a real feel for the small normal background eruptions

and the big one.

Let's hope that doesn't go off when we're up there.

So, am I going to get what I came here for?

A face-to-face encounter with an erupting volcano?

It's time to head for the top of Stromboli and find out.

Climbing an active volcano can be dangerous,

so I'm travelling with local guide Antonio.

I ask him how many times he's climbed Stromboli.

Mille volte.

-A thousand times?

-Yes.

-A thousand times. That's incredible.

We are just about halfway up the volcano now

and you get this fantastic view over what we saw from the boat -

this scree slope of ejected bombs and debris.

Now, this stuff is ejecting out of the volcano

and just dropping to the ground

and the volcano builds

piece by piece, bit by bit, relentlessly out.

We're a good two hours into the climb now

and we spot something I'm not expecting.

Turns out humans aren't the only creatures

to make their home on the steep slopes of Stromboli.

As we get towards the rim of the volcano here

we are seeing more and more of this metalwork.

These solar panels and aerials and so on are housing seismographs,

there's a thermal camera there constantly monitoring the volcano

and they send this as messages, radio messages,

down from here all the way down to the observatory

where we were this morning.

And that's really how we can sort of listen

to the heartbeat of the volcano.

We're nearing the climax of our four-hour climb.

As we get closer to the crater,

the danger of approaching a live volcano becomes very clear.

Wow.

Things are starting to get a little interesting.

Believe it or not, this is a bomb.

This is a ballistic that's been thrown from the volcano

during one of its slightly more... aggressive phases, let's say.

There's lots of them, actually.

These small ones are the usual size of things that might fall.

So I think it's a good time we probably put our hard hats on.

Now, I'm not sure how a hard hat like this

is going help me when a rock like this falls out the sky,

but we've got to wear them from now on in anyway.

The last couple of hundred metres is tough going

with a loose surface that's difficult to walk on.

The rocks are called scoria.

Every single bit was once a chunk of hot lava,

rocks thrown out from the depths of the earth by this awesome volcano

as it built itself up, piece by piece, out of the sea.

Wow.

This... This is an incredible vantage point

We have got all four, five craters of the volcano at eye level.

-HE SNIFFS

-There is sulphur in the air.

You can see an eerie gas and fog drifting over the mountain.

We are right now close to the heart of Stromboli.

All we've got to do is wait here

and see if Stromboli is going to talk to us.

Turns out our timing is perfect,

and the view, just 150 metres from the live crater, is awesome.

Look, you can see the red blocks of lava now, drifting down.

It didn't take long for Stromboli to say hello.

It's so exciting to see a live volcano erupt.

Stromboli doesn't let us down.

But we haven't yet seen just how red hot the rocks really are.

I wait for it to get dark -

my favourite time to view an erupting volcano.

Between eruptions, it almost looks like

some of the land over there is quite safe.

You can only just see a little bit of the volcano

glowing in the background,

but when you bring a heat camera up and have a look,

you can actually see

every one of those craters over there

is glowing hot.

And you're getting spot heights

in excess of 100 degrees centigrade.

Now, water is going to flash to steam

at over 100 degrees centigrade,

so this is really, really hot stuff.

Imagine boiling your kettle and sticking your hand in it,

it's not a good idea at all.

So you wouldn't be able to walk over there -

it would start to melt your boots.

Stromboli often erupts like this several times an hour.

The explosions are so distinctive

that the mountain lends its name to the classic volcanic sight -

the Strombolian eruption.

Whoa, whoa! Look.

That is fantastic. Are you seeing that?

I am getting that on the thermal camera.

Wow. That is just what we've been waiting for.

150... It went up very quickly.

You can imagine.... Look at the scoria

just falling down the scree slope there.

Can you imagine tons and tons of that material

every day gets erupted from this volcano?

The road of fire is literally on fire now

and all of that is falling down to the sea.

Wow.

That's fantastic.

So. I've got exactly what I came for -

a close-up encounter with the planet's

most spectacular natural force.

When you have witnessed something

like Stromboli erupting in the flesh,

it is something that just keeps giving -

you want to keep coming back and seeing more and more.

Whoa, here we go!

Look at that!

Oh, beautiful!

Earth, raging earth!

This is the earth at its most active and its most violent...

..and yet it's so beautiful, you just can't stop watching.

Where there are volcanoes,

there will always be humans.

And, being humans, we've developed ways to survive alongside volcanoes.

Seismographs and other monitoring devices are used by scientists

to predict large eruptions.

Evacuation alerts are only issued in a real emergency, so act on them.

Remember, when it comes to danger, all volcanoes are not equal.

Extinct or dominant is your best bet.

When volcanoes are active, a shield shape is safer -

it means the lava can flow freely.

Domes are more dangerous -

pressure could be building deep beneath the earth

with lethal consequences.

If you are lucky enough to visit an active volcano,

you should only ever approach it with a professional guide,

check volcanic activity before your trip

and always travel with communication,

supplies and full safety gear.

This is how you maximise your chances of surviving...

the Fierce Earth.

Coming up next time...

The destructive force of the world's fastest winds...

..winds that tear buildings apart and leave destruction in their wake.

Join Fierce Earth for a spin inside the fury of the tornado.

HE LAUGHS

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