Can scientists predict where and when volcanoes will erupt?
we follw the volcano doctors they use their tools and expertise to protect those who live in the path of the Earth's fire.
PEOPLE OF THE VOLCANOES (narrator) When a volcano erupts, it's a reminder of the terrifying, destructive power nature still has over man.
Yet in the 21st century, people expect answers.
They expect to be warned and protected from the consequences.
So all over the world, a new breed of scientists put themselves in the line of fire, to try to prevent the next tragedy and answer the impossible question: when and where will the next volcano strike?
VOLCANO DOCTORS (narrator) Wherever the great continental plates collide, the ground splits open, releasing boiling liquid and burning fires from the earth's belly.
Despite the danger, over 500 million people live in the shadow of an active volcano.
As scientists toil to prevent the next disaster, their greatest challenge is not to prevent the physical destruction of crops or houses.
Nor even to grapple with the different personalities of different volcanoes.
Their toughest challenge is human nature and the stubbornness of people for whom the land beneath the volcano is home.
In the northern Andes, in Colombia, the slopes of Nevado del Huila are rich and fertile, but at its crown, a glacial ice cap acts like a cork, bottling in the volcano's anger.
For centuries, small communities of indigenous people have lived beneath this danger.
(cock crows) It would only take a small tremor to knock out the ice cap and send an unstoppable torrent of water, mud and broken trees cascading down the valley straight through the village of Belalcazar.
In 1994, a tremor set off an avalanche which buried over 1,000 people in mud.
(man speaks Spanish over radio) (woman speaks Spanish over radio) (narrator) This shocking tragedy was a warning.
The glacier didn't collapse.
It still teeters on the edge, a menace to every living person in the valley.
Fast forward 15 years and the nearest large town is full of volcano doctors, monitoring the seismic tremors, the mini-quakes set off when the earth begins to crack open, the heartbeat of the mountain.
Adriana Restrepo makes the diagnosis.
The beat is irregular, the tremors running closer together.
The volcano doctors are on red alert, all leave cancelled.
Instead of fleeing, Adriana and her team must travel closer to the danger zone to check the instruments in the volcano's path.
The valley is so remote that the journey takes two days.
On the final stretch, there are no roads, only precarious bridges... ..crossing the very path that the torrent from the glacier could flood down.
MUDSLIDE DETECTOR FOR SCIENTIFIC USE.
DO NOT TOUCH.
(Adriana speaks Spanish) (translator) These stations have sensors, which monitor the vibrations produced by an avalanche.
They also have an alarm system that would let people know that an avalanche is on its way.
So they can react and find safe sites that have been identified previously.
(narrator) Because the population is so isolated, the mudslide alarms are essential.
But they only sound once the avalanche has begun and by then for many communities it would be too late.
The volcano doctors want to do better than that.
They're determined to warn the scattered population to move to safety before their mountain explodes and their rivers turn to mud.
(in Spanish over loudspeaker) (translator) Please pay attention.
Possible eruption of the volcano Nevado del Huila.
According to the Ingeominas report, there is a crack in the back, which could break up the ice and cause an avalanche.
This announcement affects the whole Inza community and everyone who lives in the Paez valley.
(narrator) Mountain communities have their own warning system.
Traditionally, they revere the volcano as a mother.
One of the last village shamans believes the volcano is angry because their ancient ways are dying out.
- (man speaks Paez language) - (translator) She is angry.
And then we think the danger has passed.
But she will get angrier and make whole villages disappear.
Nevado is thirsty too, but nobody remembers.
So she explodes to remind us that she exists.
The white people don't realize what will happen because they don't know the Paez language.
They only know how to look in their books and computers.
But they feel nothing in their bodies.
(narrator) The scientists do know that the tremors in the volcano are increasing and the heat rising from the fires burning in its heart could explode the ice cap any day now.
At the eleventh hour they're faced with a new crisis.
Once again Adriana has to send a team into the danger zone and beg for more resources.
(speaks Spanish) (translator) Mr Mayor, we have a problem at our relay station.
A team needs to go there with equipment to make repairs.
I am asking for your help to provide us with several horses.
(narrator) The terrain is so steep that halfway up, even the horses have to be abandoned.
The relay station is crucial, because from its high vantage point it transmits information all over the valley.
Only when they see it do they understand the problem.
Unbelievably, a mobile phone company has built a new shed which is blocking the sun.
(translator) At the moment the sun is halfway up, so the transmitter needs to stay more or less there.
Before these Comcel installations were built, the equipment worked without any problems.
We work with solar energy.
The wall they've built casts a shadow over the solar panels.
So at times we lose power, depending on the position of the sun or the time of year.
The sun rises there and sets over there.
(narrator) This is more than a repair.
It'll take at least a day to move and rebuild the station.
Perhaps the shaman was right to mistrust modern technology.
Meanwhile Nevado waits for no man.
It could erupt any minute or remain idle for weeks.
Scientists could predict far more accurately when a volcano will erupt if they could examine the molten rock or magma deep inside its underground chamber.
In Hawaii they can do the next best thing, because, although Kilauea is the most active volcano in the world, it's also one of the safest.
As a rule its eruptions don't send explosions of molten rock high into the air.
Instead it creates rivers of liquid lava.
The gradual flow of these rivers down to the sea allows easy access to the molten lava.
And the scientists have a great view of the volcano mouth, because the observatory has been built right on the edge of the crater.
So this station is a natural laboratory, a classroom, where every form of monitoring from basic photography to remote sensing can be tried and tested against live explosions and then the instruments improved.
Working so close to an active volcano, using modern satellite techniques, allows specialists like Mike Poland to measure miniscule changes in the earth's surface as the magma forces its way up.
I'm trying to get it centered as close as I can to the center of the mark.
So this white disc here is the GPS antenna.
It's what actually receiving the signals from the orbiting satellites.
It sends that signal down to this receiver right here.
We'll leave this unit out here for a few days and let it collect enough data so we get a really good position, take the data back to the lab and process it.
We'll get the position of this particular receiver, this antenna, down to within just a few millimeters.
And by doing this repeatedly over time, we can see how this benchmark is moving.
And when you relate that to all the other benchmarks out here at Kilauea, you can get a very good idea of how the surface of the volcano is deforming and we can relate back to where the magma is beneath the volcano, how much there is, and whether or not the volcano's likely to erupt.
(narrator) And when it erupts, the damage caused depends on what the magma is like.
The Hawaiian lava is quite runny, so the gas escapes safely and eventually the lava solidifies.
But if the magma is thick and sticky like toffee, the gas bubbles can't escape, so the pressure builds up until the magma explodes furiously like a bomb.
The more gas, the bigger the explosion.
So instruments which can test the amount of gases like sulfur dioxide in the chamber are essential for saving lives.
Most volcano doctors can't get this close to trouble, so they're developing new instruments which can transmit their readings to monitors sited at a safer distance from the crater.
(coughs) (narrator) These techniques can then be used at far more dangerous volcanoes around the world.
In the Philippines, the perfect symmetry of the Mayon volcano attracts tourists, and the fertile ash fields lure farmers to grow crops, despite its volatile history.
The magma in this crater is highly explosive, so the people could face the most lethal type of eruption.
A deadly avalanche of burning gas and scalding ash, propelled faster and faster by the steep slopes, reaching over 60 miles per hour, asphyxiating everything in its path.
In 1993, a suffocating cloud tore through Veronika Perez's village.
She was the only survivor.
The air came first, very hot air.
Then lava came down, lava rolling down.
I said, "What's that?"
Because the noise was like an airplane.
I think airplane.
I look up and see trees falling down.
After five minutes, maybe five minutes, here... this was falling off...
Then I sat down on the ground.
And I said to myself, "I want to live.
I want to live."
"I want to live."
(narrator) Despite the tragedy, people have returned to farm.
And this time the scientists are determined to give them more warning.
It's December 2009 and for weeks now, Mayon has been belching smoke.
The locals try to continue life as normal.
But in the observatory, the newly modernized instruments reveal to the director, Ed Laguerta, that it's serious.
The instruments are really important for forecasting an incoming eruption, because not all the time can the volcano be seen.
It can be cloud-covered and during the rainy season here in the Philippines, sometimes for months.
Then if we depended only on physical observations, it would be too late to evacuate people.
(narrator) The volcano doctors have a new tool, developed in Hawaii, which will work whatever the visibility and at a relatively safe distance, because it measures the amount of sulfur dioxide in the plume of smoke.
They find an increased concentration of gas which means the explosive mixture of sticky magma and gas has moved even closer to the surface.
Load percentage is still five percent.
What are the conditions?
(narrator) They return quickly to base, where the instruments are checked and counter-checked with increasing urgency.
It's a difficult decision to make.
If Ed misinterprets the data, then next time the locals will not trust the scientists and even more lives will be lost.
He makes the call.
The army moves in to try and evacuate 50,000 people.
But some are reluctant to abandon their homes.
Many are Christian and they don't want to spend Christmas in a refugee camp.
Villages are barricaded and guard posts set up to try and stop people returning.
(man speaks Spanish) (translator) Yes, there are more people.
We haven't evacuated everyone yet.
We are advising them to go to a safer area while the volcano is only half-awake.
(narrator) Despite the barriers and the warnings, some farmers slip back.
They have crops to tend and this is their only livelihood.
They're used to the volcano grumbling away, but the scientists and their predictions are new.
When we raised the alert status today from three to four, some people were still reluctant to evacuate, because of their experience in prior eruptions of Mayon.
They have already experienced a lot of eruptions of Mayon, and they are waiting for some physical observations before they would say that, really, Mayon is going to erupt and there will be some hazards to their community.
(narrator) On 20th December, only hours after Ed made his call, Mayon erupted in the middle of the night.
(shouting) (narrator) And only when they actually saw red-hot lava pouring down the mountain did the last of the village families flee and join the thousands forced to spend Christmas in the refugee centers.
There were already some ashes coming out and then we heard the volcano like broom, broom, broom, and there was a little bit of fire coming down.
So the captain ordered us to evacuate during that time.
The volcanologists already warned us to move but nobody moved until they can see that the volcano already has fire coming down.
(narrator) This time the lava solidified before it reached the larger villages and towns.
The volcano doctors made an accurate diagnosis and no one died.
Yet, perhaps because there was no tragedy, even before Mayon has finished venting its anger, people have returned, determined to defy the volcano any way they can.
At the other end of the split in the earth's crust, in Colombia, the volcanologists also made the correct diagnosis and in November 2008, under cover of darkness, Nevado del Huila exploded.
As they feared, hot gases burst through the ice cap and a huge avalanche of rocks and mud headed for the terrified villagers of Belalcazar.
(sirens) This time the heat melted the glacier, so the torrent of black water and the damage it wreaked was far greater than the 1993 mudslide, which killed over a thousand people.
By morning the town is flattened or entombed in mud, and in serious shock.
24 HOURS BEFORE THE ERUPTION 24 HOURS AFTER THE ERUPTION 24 HOURS BEFORE THE ERUPTION 24 HOURS AFTER THE ERUPTION In Belalcazar, nothing looks the same anymore... ..and the village is totally cut off from the outside world.
But happily the people are alive.
As the villagers begin the cleanup, at first they believe there are no casualties.
But gradually and unsurprisingly, given the scale of the floods and the strength of the torrent, reports of a few missing people filter through.
But several thousand people had an incredibly lucky escape.
And thanks to the warnings, the emergency services are quickly on the scene.
While civilians and soldiers work side by side, there's no rest for the sleep-deprived volcano doctors.
(speaks Spanish) (narrator) The mudslide has devastated over a hundred miles of river valley and the scientists have to scan every inch to try and understand exactly where the avalanche flowed.
They need to find and map safe areas where families might be able to shelter safely next time.
(men speak Spanish) (translator) Here there are little trees below the mark.
I don't think there's more than five or six meters.
Let's say six meters.
(translator) Over there.
And here it's a bit higher.
(narrator) Three days after the eruption, Hugo Mercia answers the difficult question.
How much did they get right this time?
(translator) In this case... We're talking about 2008.
Nothing is official yet.
But there were about a dozen deaths.
A death is always terrible, but I think a good job was done.
The Nevado del Huila will always be a threat.
It's important to have maps of the danger, maps of the vulnerable areas and the risks and to integrate all the information in order to avoid a tragedy like the one in Armero in 1985 or in Belalcazar in 1994.
(shaman speaks Paez language) If we, the shamans, continue to lose our memory, Nevado will never calm down.
And even if Nevado empties out all its lava, her daughters will wake up, and only after this awakening will she be quiet.
Only when she has buried enough people will she go back to sleep.
(narrator) Despite their different beliefs, the mystical shamans and the practical scientists agree that Nevado hasn't finished with them yet.
The shamans also remind us that every volcano is different.
Each has its own personality, its own mood.
So wherever they travel in the world, the challenge for the volcano doctor is always unique.
On an island off Papua New Guinea, a vast crater known as Rabaul has risen out of the sea.
Around its edge, several smaller volcanic cones have formed.
For more than 15 years, one of these cones, known to locals as the Hornets' Nest, has continually blasted the town with ash.
Under constant bombardment, Rabaul looks like a ghost town.
Yet a third of the original population has returned home.
For scientists here, it's an even tougher challenge to predict when the next cataclysmic eruption will occur, because all the early warning signs are hidden under the sea.
In September 1994, the Hornets' Nest erupted at the same time as another cone and together they destroyed half the town.
Like most volcanic towns, Rabaul has its own observatory packed with monitoring equipment.
But in the days leading up to the eruption, they revealed little out of the ordinary.
Luckily the scientists had also placed three tidal gauges out in the bay.
Normally these measure tidal height, but at Rabaul, with a bit of trickery, they measure the height of the sea floor.
The day before the eruption, the sea floor suddenly rose by more than 16 feet.
The alarm was sounded and 70,000 people were evacuated in the nick of time.
They only had six hours' warning of the volcano's fury and yet amazingly no one was killed.
Today it's John Bosco's job to make sure the life-saving tide gauges are still working.
- (high-pitched tone) - 16.8094.
So that's it transmitting.
You can hear it's changing in frequency.
When there's a wave coming in, it moves the sensor up and down and you should hear the tone changing in pitch, changing frequency.
(tone rises) (narrator) But John is powerless to stop the corrosive ash raining down on the people of Rabaul, wearing them down and threatening the sensitive volcanic instruments.
(John) With the situation here near to the ash, it's very corrosive, the gases and whatever is coming out of the volcano.
So we are always in need of money to do maintenance work.
(narrator) Against the odds, the scientists need to keep their instruments working.
The people here are resilient.
They've got used to living with the daily rumblings and the skies raining ash.
Ironically this puts even more pressure on the volcano doctors.
They need to predict the next big crisis accurately.
In the northern hemisphere, where the African and Eurasian continental plates collide, history records that the Italian volcano, Stromboli, has been exploding almost continuously for nearly 2,000 years.
Known as the Lighthouse of the Mediterranean, Stromboli is famous for its nightly firework display.
These spectacular explosions are so well documented that they are known as Strombolian eruptions and considered safe enough for scientists to work a few feet away.
Stromboli has been studied in more detail than any other volcano and the nearby town benefits from its popularity.
Yet despite the battery of instruments monitoring its every mood, Stromboli is sometimes dangerously unpredictable.
In December 2002, lava spilled from the volcano with very little warning.
This triggered a collapse and part of the mountain fell into the ocean, creating a giant tidal wave or tsunami.
Luckily it was the quiet winter season and no one was killed.
Today a French-Italian team, led by Anthony Finizola, is trying to solve the mystery of these unpredictable eruptions.
Because they can get so close to an active volcano, they're attempting something that has never been done before.
They will unroll six electric cables over Stromboli in an attempt to examine its very heart.
(translator 1) Three reels go over there at the entrance to the direct line.
One will go to the first shelter and two go to the direct line.
(translator 2) So two go there and one here?
(translator 1) Yes, the one that goes over there is in my backpack.
(narrator) It works a bit like an MRI body scan.
The electrical readings will detect the presence of different types of rock or water, helping to construct a 3D map of the volcano.
(speaks French) (translator) Our objective is to study the structure of the volcano using electrical measurements.
So in other words we're trying to observe where groundwater is circulating.
(narrator) The team wants to map the movement of water because when water hits molten rock, it vaporizes immediately.
They believe water may be causing the sudden frenzied explosions.
(Anthony speaks French) (translator) So the goal is to understand the big events that happen on the island where blocks of lava fall all over the place, even onto the houses, and to understand better the dangers of the volcano and give more warning of these dangers using new surveillance equipment.
The volcanic shaft is very close to the area we are going to investigate.
To understand the interaction between the rainwater which filters in and which can create strong eruptions in the case of water and magma, it's a big advantage to be able to get close to active craters.
We can't do it in volcanoes that are more explosive.
Here we are crazily close to the volcanic shaft.
(explosion) (speaks French) (translator) There's a lot of logistics, so we don't know what will happen.
It takes a few days to install the 2.5 kilometers of cable from one side of the volcano to the other.
It's the first time we've tested this device on this scale.
No other teams on earth have such a long cable for deep investigation.
So it's high resolution.
We'll be able to do real geology, to understand the structure of the volcano down to a depth of 500 meters.
This is the last stage.
We connect the electrodes every 40 meters, so 64 electrodes from the summit to the sea.
And then we just have to switch on the power.
Stromboli is a good starting point because we know that there are magma-water interactions in the volcano.
We know that there are weak points and risks of destabilization.
That's what happened at the end of 2002.
So, in theory, we should be able to find something interesting.
And, obviously, from the moment the device works, it can be used at other volcanoes.
That's the goal.
(narrator) All over the world, where there are volcano doctors and monitoring stations, people stand a good chance of escaping an eruption.
But some volcanoes have been dormant for thousands of years, longer than recorded history.
In Chile, at the foot of the Andes, the Chaiten volcano had been asleep under thick forest for over 9,000 years, with no one watching over it and no shamans to pass on the ancient tales.
So when it erupted in May 2008, it caught the whole country by surprise.
Living beneath this ash storm, 7,000 people had to suddenly and unexpectedly flee their homes.
(news commentary in Spanish) (narrator) For days, ash rained down like snow, slowly burying their town.
The refugees were forbidden to return home to rebuild their shattered lives, because so little was known about this volcano and no one could predict what it would do next.
But new surveillance equipment has arrived in town.
The only people allowed in are the brave volcano doctors, this time the forensic scientists.
Their first job: a postmortem of the unfolding disaster.
They discover that only days after the town was evacuated, rain swept up the ash, building a gray avalanche, which tore down through the valley, uprooting trees, changing the course of the river and swamping half the town.
The cement-like paste flowed, as it still does today, out into the ocean, where it is gradually winning over the sea.
This is exactly how the foothills of the Andes have been built up over the years, how much of Chile was born.
And sadly the people who lived here may never be allowed to return, because on the summit a new, more terrifying menace is growing.
An international team of scientists is measuring the magnetic field, trying to assess the risk to the town.
(men speak French) (narrator) A giant new lava dome has risen like a cake to fill the entire crater.
It's just about set, holding in its bubbling liquid center, but the whole mountain is a time bomb waiting to explode.
If the dome rises any more, or collapses, it will send burning gases and hot ash racing towards the town, burning alive anyone in its path.
Once again they could face the most dangerous type of eruption, the same kind that burned and buried Pompeii almost 2,000 years ago.
Yet despite the threat, despite the dark skies and the devastation, just like they have in Colombia and the Philippines, families have returned to the danger zone to rebuild their lives.
As the world's population increases, even more people are taking the risk.
For too many of the world's poorer people, living in the shadow of an active volcano is better than living as a refugee.
The ash clouds from the Chaiten volcano had another effect.
Sent high into the atmosphere, they disrupted South American airspace for several weeks.
This barely made the news.
But thanks to the infamous Icelandic volcano, ash clouds have piled new pressure on the volcano doctors.
As big business and those who can afford to fly demand answers, ash clouds have suddenly come under the microscope.
Volcanic dust contains tiny shards of rock, small enough to filter into a plane's engine.
At speed, the sharp edges act like a sandblaster, eating away at metal or stripping a plane window of its protective windshield.
Even more dangerous, the heat inside the engine melts the ash particles, causing them to stick to turbine blades and block the airflow.
We'd know very little of the dangers of ash clouds if not for Captain Eric Moody's dramatic story.
We were going from Kuala Lumpur to Perth, Western Australia, on an evening flight.
It was a very easy evening's work, we thought, and the engineer who sits between the two pilots said, "No.4 engine has failed."
So I looked in and yes, it had.
It was winding down very, very slowly.
And then he said in rapid succession, "No.2's gone.
Oh, we've lost the lot."
(narrator) The plane and its passengers plunged over 20,000 feet.
After 50 attempts to reboot the engines, minutes before impact, all four engines started again.
The strange thing was, the nearer we got to the city, at first it appeared through our windscreen that it was misty, then it appeared to be very foggy.
When we asked what the visibility was on the ground, they said it was unlimited.
We thought, "It's not up here.
What's going on?"
Something made me then look across, reach across and look out the edge of my windscreen and I could see clearly through that.
Obviously something had happened to the windscreen.
(narrator) The abrasive ash from an Indonesian volcano had stripped the plane's windscreen.
This was nearly 30 years ago and in the pilots' training manuals there was scant mention of ash clouds.
Or that the finest dust, as light as flour, can be carried by winds into the jet stream where, invisible to the naked eye, it travels at the same height that passenger planes fly.
Soon after this near miss, the International Airways Volcano Watch was set up to monitor these toxic clouds and warn airlines of the dangers.
They have a dazzling array of hi-tech sensors to measure the size and numbers of ash particles as they scatter light into different wavelengths, creating a unique signature that can be tracked across the skies.
They also measure cloud temperature, because to protect planes, they need to forecast the height at which the dangerous cloud layers will travel.
A tough question when scientists still struggle to forecast the weather accurately.
In 2010 this new science was put to the test by the notorious Eyjafjallajokull volcano.
When it first erupted in March, it caused a few local problems for the Icelanders, while the rest of the world ignored it.
But scientists and engineers went quickly to work.
Iceland's volcanoes are particularly dangerous for airplanes because they're covered in ice fields.
When hot lava meets ice, it cools instantaneously and smashes into millions of tiny shards.
Tons of water vapor are also ejected into the atmosphere.
So each cloud is a mix of toxic ash and harmless water.
The question no one knew the answer to was, how many ash particles can a plane's engine tolerate safely?
With the volcanologists predicting more eruptions and forecasters predicting westerly winds, time to answer the question was running out.
In April, a second eruption smashed through the ice field.
The amount of ash in these clouds was far greater than the agreed danger limit for planes and the heat sent them high into the atmosphere.
The winds picked up the ash clouds and carried them over Europe.
The airspace was closed and the chances are thousands of lives were saved.
At first the public and airline industry accepted the cancellations for their own good.
But as the days crept by, for those stranded around the world, there were countless untold personal dramas.
Airlines did their own test flights and, with millions of dollars lost by industry, pressure on experts and government increased and the anger turned red hot.
Finally, on the sixth day, the tolerance limit for ash particles was raised and aircraft were allowed to fly.
Yet the volcano continued to erupt.
Once again it's human nature, the need to take risks, the demand for accurate predictions that has given volcano doctors their toughest challenge.
But they know there's an even bigger challenge lying in wait.
Under the ice fields, not far away from the fiery Eyjafjallajokull, other more dangerous volcanoes lie sleeping.
And when they stir again, it'll fall to the volcano doctors to break the bad news.
Subtitles by Silverway Media