Could We Survive a Mega-Tsunami?

For all our technological wonders,

mankind is vulnerable to a far greater power.

The wrath and fury that only our planet can unleash.

Volcanoes...

earthquakes...

and silent assassins, unseen until it's too late.

Tsunamis that bring death and devastation from the sea.

On Boxing Day 2004,

nearly a quarter of a million people were killed in southern Asia.

On March 11, 2011, Japan

and destruction that came within a whisker of nuclear catastrophe.

But scientists believe

that something even more destructive lies in wait.

Something that will one day strike us in the West.

A wave so many times bigger than any conventional tsunami,

it's been dubbed a mega-tsunami.

Now, using the very latest science, powerful computer models

and the terrible evidence of all to recent events,

this is the story of how some experts believe the greatest

natural disaster in human history might one day unfold.

The biggest wave ever seen...

threatening cataclysmic destruction

of some of the world's greatest cities...

..death and devastation on an unprecedented scale

and economic fallout that could reshape the future

of the entire world.

It will all begin on one of Britain's most popular

tourist resorts...

the Canary Islands,

with an event that last occurred in 1971

and, before that, in 1949.

A volcanic eruption.

'The Canary Islands' volcano of La Palma

'erupted for the first time in two centuries.

'Menacing the population

'and is turning night into day with blazing rivers of molten lava.'

People think of volcanoes of being, sort of, cone shaped

with a little hole in the top

and those are what we called stratovolcanoes,

they are the traditional volcano shape,

but this is very different, this is an elongate structure.

La Palma is one of a chain of volcanic islands,

lying off the coast of West Africa,

that includes Gran Canaria and Tenerife.

Its most active region is a high mountain ridge

called La Cumbre Vieja.

The Cumbre Vieja occupies the southernmost part of the island

and it forms this north-south lined ridge.

The whole ridge is, sort of, pockmarked craters and holes,

and then you have lava flows heading off in both directions,

to the west and east, from these particular craters.

In 1949, quite a small eruption, in terms of volume of lava,

the volume of magma, erupted but during the eruption

there had been a series of very strong earthquakes

and a fault line had developed along the crest of the volcano.

A giant gash had opened up along the island's ridge,

four kilometres long and up to four metres wide.

Part of the west flank dropped a couple of metres towards the sea

and then stopped, and that's really what tells us that something

other than just magma coming up was going on during that eruption.

That geological rift is the reason why this volcano

could one day trigger a mega-tsunami.

Because ever since 1949,

the peaceful island of La Palma has been a time bomb...

and some scientists believe that today another eruption

could send 500 cubic kilometres of it crashing into the sea.

A colossal landslide with enough energy

to generate the biggest wave humanity will have ever seen.

Unleashed not upon the Pacific but the Atlantic and heading for us...

..the first mega-tsunami in recorded history.

The terrible human cost of the recent Pacific tsunamis

came from underwater earthquakes.

But recent history has already shown that the collapse of a volcano

could unleash even greater devastation.

Most people think of volcanoes as these are unchanging sentinels

of solid rock that persists for many millions of years

and, really, just go on getting bigger,

but they are better viewed, really, as unstable piles of rubble.

It was the Mount St Helens eruption in 1980 that really provided us

with that first visual proof that volcanoes did collapse.

'This is the CBS Evening News with Dan Rather.'

It is an event that defies superlatives.

One geologist said today, "There is no record today, in geology,

"in the last 4,000 years, of anything like this happening before.

"The tremendous lateral blast is unprecedented."

This is the only photographic evidence that we have

for a volcano lateral collapse actually happening.

'This sequence of photos was taken during the first 60 seconds

'of the mountain's eruption,

'beginning shortly after 8.30 on Sunday morning.'

It was really an iconic moment, which taught us that volcanoes

did things that we didn't think they did before, and that is that

instead of just erupting upwards they can also erupt sideways.

You can see the bulge dislodging,

forming this landslide which heads off northwards.

And then this massive column of ash, which heads up into the atmosphere,

and ultimately covers the entire region.

The question we all asked ourselves at the time was,

"What would've happened if that collapse had occurred into water?"

What would happen would be the conversion

of a vast amount of energy into an ocean-going wave...

..starting off up to one kilometre high

and with the power to cross oceans at the speed of a jet aircraft...

..ready to make landfall with potentially apocalyptic results.

Startlingly, it wouldn't be the first time that a landslide

has called a tsunami on the Canary Islands.

One marine geologist thinks he's found evidence of a past event...

..not on La Palma but nearby on Gran Canaria

at a site called Agaete.

What we have here are tiny pieces of shell - that's about two centimetres.

That's a mollusc, it comes from the sea.

What is strange about finding them here

is that they are 50 metres above...

the level in the sea at which they usually live.

Shells like these can be found three kilometres inland

and 200 metres above the sea -

too far to have been carried there by any storm.

And, without evidence of changes in sea level,

there can be only one explanation.

If they weren't laid down by a high sea level,

if they weren't laid down by a storm, then what was the source?

We need something to have created a wave 200 metres high.

Dave Tappin's wave on Gran Canaria was far too big

to have been made by an earthquake.

The only answer, in my estimation, is the collapse of a volcano.

It's unlikely to have been Gran Canaria but the nearest island,

100 kilometres away, just over there, where I'm pointing, is Tenerife.

On the coastline, facing Gran Canaria, there is a major collapse

and that collapse is called Guimar.

The area where we are now, in the Guimar Valley, in Tenerife,

it's around about ten kilometres wide along the coast,

extends several kilometres inland, so it's a big feature.

Where now there is this broad, flat-floored valley,

there would have originally been a steep sided volcanic cone.

So, the area that collapsed is over to our right

and on the left we can see the lavas that formed the old volcano.

And between the two we have this enormous cliff.

But originally that would have been the sidewall of the landslide.

Over in the distance, from here,

we can see the tops of the mountains of Gran Canaria,

round about 100 kilometres away, so it's very easy to imagine

that the Guimar landside, as it went down into the ocean,

would have generated a tsunami that spread across the ocean

to Gran Canaria and produced the tsunami deposits at Agaete.

This tsunami would drive across the ocean,

between Tenerife and Gran Canaria,

and strike in this particular location,

could easily build up after it hit the coastline,

travel inland to heights above sea level of hundreds of metres.

But even Tappin's tsunami would pale alongside the wave

that would be created by a collapse of the entire mountain flank

of La Cumbre Vieja.

Not everyone agrees, but many experts think that such an event

would have consequences of global proportions.

It's not surprising that this tiny volcano has become

so intensely studied.

This is the story of a scientific model

of a volcanic collapse of La Palma projected into the near future.

By using reconstructions...

Tens of thousands of people are feared dead and hundreds of thousands

are still missing following the worst natural disaster in history.

..real archive footage from previous natural disasters

and graphical representations of what such a wave would do...

..we can plot out the possible unfolding of events

that one day could really happen.

Our scenario begins

one ordinary day on the island of La Palma itself.

No-one knows it yet,

but it's just five days before disaster will strike.

Seismic monitoring will register a sudden increase in activity.

Higher! Let's go, come up.

But, since earthquakes here are common,

no-one will take too much notice...

..but then local wildlife will begin to die,

succumbing to carbon monoxide fumes emanating from the ground.

A harbinger that something more dangerous is afoot.

An event that no-one can ignore.

La Palma's La Cumbre Vieja is erupting once more.

In one instant, a whole section of the island is dislodged.

Breaking up as it falls, an entire mountainside plunges into the sea...

at the speed of an express train.

We see the landslide first generating an enormous wave.

Within seconds, the surrounding ocean is distorted.

At first it forms a huge dome of water...

..and then a giant wall...

..on a scale that is almost unimaginable.

A mega-tsunami.

That wave could be as much as a kilometre high.

In terms of the height, you're talking about

more than two Empire State Buildings on top of one another

or three of London's Shard piled on top of one another.

This is an immense mass of water.

Not just fast, but fast.

Travelling at up to 800 miles an hour,

the giant wave surges out in all directions.

Immediately in its path, the highly populated island of Tenerife,

less than 100 miles away.

In less than ten minutes the wave makes landfall.

Locals and holidaymakers alike do all they can to outrun it.

Within minutes, the wave has claimed its first victims.

I don't think there's any doubt that,

however big the collapse of the west flank of Cumbre Vieja,

the initial wave will be very catastrophic

for the islands themselves.

So, you're talking about thousands of people dead and destruction

on a scale that we've never seen in this part of the world before.

With less than ten minutes to react,

it's hard to see many of the two and a half million locals

and visitors to the Canary Islands escaping with their lives.

But even as the wave devastates neighbouring islands,

La Palma continues to erupt.

The mountain of La Cumbre Vieja is still collapsing...

..releasing yet more energy into the sea.

Our mega-tsunami's journey of destruction has only just begun.

Within 20 or 30 minutes, all of the waves have spread out from La Palma

and they've started this long journey out across the Atlantic Ocean.

There's been no time to raise the alarm.

Within 60 minutes, 90 metre waves will strike

the coast of West Africa.

Over the following hours, these waves will devastate

the coastlines of Europe.

While across the Atlantic Ocean, millions of Americans lie sleeping.

Nothing can stop a wave this size.

Only landfall and the coastal cities that lie in its path.

It could be the costliest natural catastrophe

in the history of our planet.

While geologists have studied how a landslide tsunami could be caused,

wave experts like Nils Kerpin are working out

just how a mega-tsunami would travel once unleashed.

A miniature Cumbre Vieja

reveals exactly how fast waves would radiate out from La Palma.

See that the wave that occurs due to the landslide will propagate

and encircle around the island.

Using physical modelling,

Nils can analyse the very anatomy of the giant wave.

Here we see the beginning of some landslides

and we can see air bubbles that are rushing back

and running up the slope of the remaining island.

From the very moment it's first formed

to its height and its speed as it spreads.

The faster this landslides occurs,

the more energy will be induced into the water body.

Fluid science can model not only the wave itself

but exactly how its journey progresses.

Northwards towards Europe

and unchecked across the open Atlantic.

That science can help us to chart what will happen in our scenario

in the hours to come.

It's 80 minutes after the initial landslide

and, to the east, the wave, still up to 60 metres high,

is minutes from its first major cities...

..Casablanca, in Morocco, and its capital Rabat.

A combined population of six million.

It is estimated that two thirds of them

will not survive the wave's impact.

Only now are the first reports of the unfolding disaster

beginning to emerge.

It's likely that, before any news agencies begin to report,

Twitter, Facebook and mobile calls will carry the first images

of unfolding disaster to the world.

In London, the Prime Minister becomes aware of events.

When a disaster happens that dominates everything,

the whole diary's cleared.

The PM summons the relevant government departments

and representatives of the emergency services

to the Cobra response room.

Cobra's that kind of high-tech room with lots of links to police,

the fire services, etc, round the country.

But they have little time to plan.

Just 30 minutes after Casablanca, the wave reaches Europe.

It is still the height of a two-storey house.

The coastal capital of Lisbon is devastated.

Back in Westminster, the Cobra meeting room

is now a centre of intense activity.

So, the first thing we want to know

is, "Just how big is this? What's actually happening?"

Often, if you've got a TV screen on,

you'll know as much as the person in the centre of Whitehall.

As likely as not they'll have Sky and BBC 24-hour,

and they'd be following Twitter and social media.

There is always, always a period where there is a kind of fog of uncertainty.

I think the key point is to alert the emergency services,

so that they are prepared for it to happen.

After hitting Lisbon, the emergency services have just three hours

before the wave strikes Britain.

The Environment Agency issues flood warnings to the south coast.

Fire, ambulance and rescue units are put on standby.

Police clear the streets of southern coastal towns,

evacuating schools and vulnerable communities.

Back in Whitehall, the Government has two work out what to say

and how to deal with increasing public panic

as awareness of the scale of unfolding events spreads.

A giant tsunami is spreading throughout the Atlantic basin.

Waves of up to 40 metres high have already devastated

the coasts of Portugal, North Africa and Spain.

Scientists estimate that the wave is travelling at approximately 500mph.

It's expected to move across the Atlantic...

You're still building up information as well as trying to move people.

That'll be the time that the media are saying,

"What are you doing about it? What's happening?"

The key test of the Government will be to show they're responding,

to outline the measures they're taking.

But the measures they're taking

are in the time when they really don't know how serious it is.

Just three hours after the first UK warnings,

a wave up to 25 metres high makes its first landfall in Britain...

..on Cornwall.

In the immediate aftermath, say two or three hours after it's hit,

they'll still be confusion.

I mean, we're probably talking about a very, very wide area of hundreds of miles.

So, finding out what's happening in a cove in Devon or Cornwall,

I mean, you know, how is that going to get back?

I mean, you could well have communities wiped out.

We can get some idea of the impact of a seven to ten metre wave,

on the UK south coast,

by looking at what happened in the Indian Ocean in 2004,

in places like Sri Lanka and Thailand.

The level of destruction was immense

and the death toll was in the tens of thousands.

You could say that the population of the south coast of the UK

is probably quite a bit higher,

so that sort of wave would be immensely destructive in the UK.

From Cornwall, the wave surges through into the Irish Sea

and through the English Channel,

engulfing much of Britain's south coast.

The aspect that makes a tsunami so devastating is its wavelength

and how long it is.

A storm wave might be ten, 20, 30 metres long, 40 metres long,

50 metres long.

In the case of a tsunami,

we have a wave that is 200 or 300 kilometres long.

Unlike a storm wave, a tsunami just keeps on coming -

mile after mile of it.

Seawater floods our southern cities

and penetrates low-lying farmland for miles inland.

It not only runs up the coastline and inundates the land,

but it continues to flow inland, as if it's a river flowing over

the land and scouring out, and removing things in its path.

So, it's the inundation, it's the wavelength,

that actually makes these events so dangerous.

Models differ on what the wave might do to our southern cities

as it works its way east.

Towns such as Brighton would probably survive,

but would suffer serious disruption.

In our scenario, London, our capital,

tucked in from the North Sea, is safely sheltered.

Britain, it seems, will survive the worst calamities seen elsewhere.

The wave, however, as well as travelling east to Africa

and north to Europe is also heading west, across the Atlantic.

And there is a whole new nation is waking up - America.

'Good morning, New York. It's a beautiful day out there in the city

'but here's a word of advice, enjoy it while you can.

'The weathermen says there's going to be some rain this afternoon

'and temperatures could drop dramatically by the end of the day.'

It's 7am. As the tsunami is devastating southern Britain,

it's three hours away from New York.

1,500 miles off the coast, the wave hurtles west at incredible speed.

The deeper the water, the faster the wave moves.

So, in five kilometres of water

the wave will move at 800 kilometres an hour.

It's travelling at the speed of a jet plane.

Bear in mind, it's not the water that is moving.

So, you can't imagine water moving at 800 kilometres an hour,

it's the energy of the wave.

The particles of water are pushing against each other

and so, if you like, each is knocking against the next

and it's moving the energy across the oceans.

For evidence of how tsunami waves can travel between continents,

scientists, once again, only need to look to the past.

In particular, evidence of

an earthquake generated tsunami that began in Chile in 1960.

'Devastation untold, a death toll close on 5,000,

'is part of the reckoning that staggers Chile. In Concepcion, city of...'

The earthquake itself caused lots of damage, significant damage

but it also created a very large tsunami.

That tsunami did cause damage in Chile itself,

but what was interesting about that one was that the damage it caused

further afield was also significant.

'Incredibly, Hawaii, 6,000 miles away in mid-Pacific,

'was struck by four gigantic tidal waves.

'On surged the terrifying walls of water as far as the Japanese coast

'9,000 miles from Chile.'

And that really brought home the fact that a tsunami happening

one side of the ocean can have a dramatic impact

the other side of the ocean.

The wrath of volcanoes and earthquakes is all too evident,

but often their violence is geographically limited.

But tsunamis are different.

Fluid dynamics means that the ocean itself can carry the energy

of a tsunami over thousands of miles and in all directions.

30 minutes after the northern face of the wave first struck Cornwall,

its western edge is just 1,200 miles from a whole new nation.

In the US, 40 million people

live within 40 kilometres of the coastline.

And of those 40 million people,

something like 30 million of them

live within ten metres, vertically, of the shoreline.

If you're looking at these extreme events, like a tsunami,

that can put ten, 20, 30 metre waves at the shoreline,

that's an incredibly vulnerable population.

Atlantic City, Washington, Boston...

and New York.

Major cities along the coast all lie directly in its path.

-ALARM BEEPING

-'Short period alarm.'

'Short period alarm.'

America is equipped with systems

capable of detecting an inbound tsunami.

The first is a network of seismometers,

located around the world,

which feed real-time data to a monitoring station in Alaska.

This shows the signal from all the different seismometers

that come in to the centre. Coming in in what we call real-time.

If there's anything that significant, it will trigger an alarm

and that will bring the guys in to take a look at the event.

But this system is designed to detect tsunamis generated by earthquakes.

Not a distant landslide

like the collapse of La Cumbre Vieja on La Palma.

Landslide generated tsunamis are very hard for us to respond to.

They do not show up on our seismic networks in the same way that earthquakes do.

Much, much more challenging.

A second line of defence is a network of deep ocean sensors

called DARTs, designed to detect changes in water pressure

caused by passing waves.

If there was a tsunami generated in the Canary Islands,

we would see impacts on our DART in the central Atlantic Ocean.

The DART system would raise the alarm,

but just three to four hours before the waves hit the coast.

The likelihood, though, is that, for all their sophistication,

these technological detection measures would do well

to beat the speed of reports coming through social media.

For America, news of the mega-tsunami's impact in Africa and Europe

would throw their own fate into sharp relief.

New York City is 8.4 million people who live on 302 square miles.

That is three islands and a peninsula,

mostly about 50 feet above the waterline.

It is a world-class city with enormous strengths

and also significant vulnerabilities.

An example is the island of Manhattan,

which has a population of about 1.5 million.

That population doubles every business day

to about three million people.

For the city authorities, it's a question of how many people

you might be able to save.

New York's Office of Emergency Management is responsible

for coordinating the response to any natural disaster.

We have spent the last ten years analysing the roadway network

and the mass transit network, and the population,

and determining how long it would take to evacuate.

The city's rail network would be the primary means of escape.

And yet, for all the evacuation plans in place,

there's a terrible irony.

Even in the apparent knowledge that disaster is imminent,

studies have shown that whole populations can go into denial.

Refusing to accept that the danger is real.

So, if we can get people to think, "This IS going to happen to me,

"I AM at risk, my family is at risk,"

then we can get them to move. But the reality is that up to half

the people won't move, no matter what we say to them.

They don't believe that it's going to happen.

For many typical New Yorkers,

with the wave heading straight towards them,

this is just another day in the Big Apple.

Meanwhile, as American city dwellers try to decide whether to go or stay,

the wave is about to hit the islands of the Caribbean.

Here, it's another ordinary day of perfect sun and sea.

But, across all the islands,

40 million people live predominantly in coastal towns.

The Caribbean would be absolutely devastated by this kind of wave.

We would have ten to 20 metre waves sweeping across many of the islands.

Bermuda, the wave would probably sweep entirely over the island.

There would be nothing left.

It would actually be stripped to the foundations.

A lot of the islands are volcanic, so they have very steep shorelines.

If you could go half a mile inland you would be out of the way

but how do you get half a mile inland?

The road infrastructure parallels the coastline,

so you would literally have to run on foot

to get out of the wave in many areas.

So it's an extremely dangerous event for the Caribbean.

With the wave now just minutes away from both the financial

and political centres of the world's greatest superpower,

most experts believe that the major eastern cities

would still be packed.

But now even hardened New Yorkers have to take notice.

Evacuation plans have been activated, but it's chaos.

You either go up high and risk becoming marooned

or take underground road and rail tunnels out of Manhattan,

and face the possibility of a gridlocked tomb.

By the time the warning network's been up, it's here.

So, we might have two or three hours notice at best.

The question is, what can you do in two or three hours?

And the answer is not much.

The ocean wave is now only 12 metres high,

but, as it approaches New York, it rears up again, becoming a monster.

The back of the wave is still moving at, say, 500 miles an hour.

The front of the wave is moving at, maybe, 40 miles an hour.

And so the wave piles up,

and that's where we go from a wave that is maybe a foot,

30 centimetres high, to a wave that can suddenly become 50 metres high.

And that's where the destruction occurs.

No-one knows exactly how great a mega-tsunami's impact would be,

but science points to one of mankind's greatest cities

being humbled by the power of nature.

What's worse is that studies have revealed that the landslide

will result in not one wave but several.

And the first will not be the biggest.

People think of it as being one tsunami.

There would be as many as ten waves sweeping across the coast.

The first wave would be maybe eight to ten metres.

The second wave would be as much as 25.

Only 12 hours earlier, it was just another normal day.

Now a geological collapse of a small volcano on a tiny island

has changed tens of millions of lives on three separate continents.

Tens of thousands of people are feared dead

and hundreds of thousands are still missing,

following the worst natural disaster in history.

By the time our tsunami strikes New York,

in Britain a nation is already coming to terms

with widespread loss.

The authorities say they are doing everything they can

and have appealed for calm.

A state of emergency has been declared.

But this tsunami itself would only be the beginning

of a whole new chain of events.

Disaster planners know that, following any catastrophe,

the biggest dangers come in the aftermath.

Rescuing the injured and identifying the dead...

..caring for a traumatised population and preventing disease...

..retaining law and order and the reins of civilisation.

In America, where our mega-tsunami has struck at the very heart

of the world's political and economic capitals,

the challenges are greatest of all.

When you talk about Manhattan,

virtually the entirety of Manhattan is below ten metres above sea level.

So, if you were in the New York City area, hopefully,

you evacuated up and didn't try to go out...

and you'd be trapped, basically, while the water receded.

You have this initial impact of the water, which is heavy,

but as it recedes you've got the same amount of water going back

into the ocean, taking with it a lot of debris.

It's taking trees, it's taking buildings, it's taking cars

and, so, all of a sudden, you have this water with a load

of battering rams going back through the population that it's just hit.

And as much damage is caused by the receding wave

as is often caused by that initial wave.

Taking the wave's progress to its final conclusion

and, with the help of experts in disaster planning,

we are able to continue our own scenario.

It takes days before calm finally returns to the sea.

Only now is the true scale of destruction becoming clear.

New York, Boston, Washington, Miami -

entire cities have been destroyed.

The number of casualties is really hard to get at

in something like this.

For the 25 metre scenario, with maybe three to four hours of warning,

we came up with roughly 4.5 million casualties.

After the wave, those living, like in Japan,

face a devastated homeland.

You'd be left with an unimaginable landscape.

Smaller structures would be destroyed and scattered,

so the debris would be piled probably five, six metres high in the streets.

Debris sits like a blanket across the city

and it prevents us from getting ambulances to people who need them,

and getting fire trucks to fires, and getting people to grocery stores

to get food, and so, debris is our biggest and worst problem.

The doctors, physicians, emergency responders,

they're going to have enough trouble dealing with things

they can see within 100 yards of their facility,

much less being able to actually go on emergency calls.

So, you can pretty much expect anyone that is injured

is going to be on their own for at least a week.

If it's any kind of a serious injury, without medical attention,

they are likely to expire.

Dealing with death on such a scale becomes a massive priority.

Kenyon International Emergency Services is a private company

that responds to disasters.

Disasters that typically involve the loss of human life.

We deal with mass fatalities that are catastrophic -

a quarter of a million dead.

This is a refrigeration unit, a portable refrigeration cabinet,

of which we have several that we use to hold the deceased.

The purpose of the morgue is where we examine the bodies

and collect that picture that we're going to use to identify them.

So, it's where the personal effects are collected...

where we take the fingerprints, get the dental x-ray,

make measurements of the body, record tattoos and scars.

In the case of a natural disaster,

where it's going to be some time before we can return the body,

doing the embalming, the restoration, and the preservation of the body.

So that it can be returned in a sanitary condition to the families.

But even if emergency facilities like these could be set up,

they would soon be overwhelmed.

It's possible that millions of dead

would be left to decay where they died

and that brings with it yet another threat.

It would be a horrific mix of debris and, unfortunately,

human remains, animal remains.

So, you can imagine, after a few hours,

you would have a biological nightmare.

Lack of shelter, food, water,

and diseases like dysentery all become killers.

We have identified 500 different locations

that we could activate as emergency shelters.

Those are primarily public schools

and some of our city university buildings and facilities.

The capacity of the system is 600,000 people.

We don't look forward to a job

where we would have to shelter 600,000 people,

but that is the capacity of the system today.

It's simply impossible to plan for such a scale of disaster.

All these provisions will feed only 70,000 people for seven days.

Just a tiny fraction of the possible numbers of displaced survivors

in Manhattan alone.

Our mega-tsunami has triggered not only death and destruction

in the American East,

but a humanitarian crisis that could affect the entire nation.

Think of losing every single east coast shipping port.

That's essentially what we're talking about with a mega-tsunami.

If you lose those ports, you have a huge problem,

believe it or not, into the Midwest of the US.

All the way to the Mississippi River because a lot of that infrastructure, those rail hubs,

come right to the coast.

So, even if people weren't directly impacted by the tsunami itself,

they wouldn't have food coming to their supermarkets.

Far inland, many hundreds of miles

from the direct effects of the mega-tsunami,

there could be mass food shortages.

Most cities only have a two or three day supply of food,

so you think about cities like Atlanta,

you think about Memphis, you think about those inland areas

that get a lot of their material coming from ports on the east coast

and that's suddenly gone for years, perhaps, to recover -

that's an enormous problem.

And, ultimately, the scale of disaster

won't just be measured in lives lost.

No-one can be sure,

but a mega-tsunami could deliver a financial shock so great

that it's impact could change the global economy,

politics and the balance of East-West power, perhaps forever.

You think about how much disruption was caused

by September 11, 2001, attacks

and how much that disrupted the world economy.

Well, they were back up and running four days later.

Imagine if they weren't able to be back up and running in 40 days or 40 months.

It could be that the world's economy would recover,

as capitalists moved electronic money to safer havens.

There is some evidence,

as was the case with the Kobe earthquake of 1995,

that's natural disasters can even trigger investment and renewal.

But it's hard to imagine the fragile global economy bouncing back

from such devastation as this.

The truth is, no-one really knows...

..and, hopefully, given that landslide events

are, fortunately, rare,

no-one soon will get the chance to find out.

In the long-term, we know these ocean island collapses occur.

Around the world, there may be one of these enormous events

maybe once every 20,000 years, maybe only once every 50,000 years.

We can't say when the collapse is going to occur...

..but the problem with the Cumbre Vieja

is that it seems to already be close to failure.

So, the crucial question is not a matter of "if" but of "when".

We aren't prepared in the UK, for a tsunami.

No measures have been put in place to mitigate tsunamis.

Now, I think we need to learn from events, like Japan,

that that really isn't the best policy.

I think the question, "Are you prepared for a tsunami?"

is almost the wrong question because, to an extent,

you can't prepare for them, as Japan very clearly illustrated.

The Japanese were ready,

they prepared themselves for the potential impact of a tsunami wave.

Those defences were still inadequate.

The consequences were 15,000 dead

and the costliest natural catastrophe in the history of our planet.

Can we prevent the same thing that happened in Japan happening in Britain?

No. Japan is probably one of the best equipped countries in the world

in defending itself against tsunamis.

If they can't get it right...we can't.

And it's not a question of them getting it wrong,

it's a question of there's a limit of what we can do

against the forces of nature.

Subtitles by Red Bee Media Ltd