A Timewatch Guide

Natural disasters unleash forces

that are, literally, earth-shattering.

Whether it be an earthquake, a volcanic eruption, a tidal wave,

each is terrifying.

But fascinating too.

Hollywood disaster movies make for a thrilling spectacle,

but what about disaster documentaries?

Surely we look to them to provide answers, not just entertainment.

But to do that, programmes need to keep pace

with science that advances every day.

So, I've searched the archives

of the ground-breaking history series Timewatch

and 60 years of BBC documentaries,

to see how film-makers have dealt with disaster,

providing an extraordinary insight

into one of the fastest-moving branches of knowledge.

I'll see how rival theories keep emerging

on the destruction of ancient Atlantis...

It's normal, as a scientist that you guess, essentially,

what might have happened, say, in Atlantis,

based on the evidence at the time.

...how there's still much to learn

about history's most famous volcanic eruption at Pompeii...

Science, if it's healthy, is a constant state of doubt.

...how film-makers explore theories

that sometimes sound barely believable.

Was this killer wave of 400 years ago a British tsunami?

These films do show that historians and scientists have made

incredible advances in the study of historical disasters.

Best of all, we can share that thrill of discovery

and a new understanding of some of history's greatest calamities.

As an engineer, I'm fascinated to discover how things work.

But, as I've studied the film archive on disasters,

I've realised we're still learning how the Earth itself works.

The experts in this field keep turning up

fresh evidence and new theories.

What they thought was true just a few years ago

may no longer seem certain today.

But there's still something in me

that wants to ask what actually happened to cause such and such?

Was it X or was it Y? Surely somebody knows.

For me, searching the film archive offers

a unique opportunity to see how theories develop over time.

I know that definite answers will be hard to find.

For instance, this beach I'm on in south Wales was hit

by a giant wave 400 years ago, causing huge loss of life.

Some researchers say it was a massive storm surge.

Much more controversially, others believe it was a tsunami,

caused by an earthquake out at sea.

I'll come back to that later,

but it's just one example of how researchers,

and the film-makers who document their work,

are forever seeking new explanations

for some of the greatest calamities to ever strike our planet.

Since the dawn of time,

we humans have been trying to understand how the Earth works.

Specifically, the earthquakes and volcanic eruptions

which can wipe out whole cities in moments -

events so cataclysmic, they're still often simply called acts of God.

Before we consider the disasters themselves,

we need to look at the science behind them.

The realisation that the Earth has a constantly moving crust

is really very recent

and it's completely changed our understanding of disasters.

This has only really been an accepted theory

since as late as the 1960s.

Earthquake science is really quite novel and quite new

and the last 30 years or so have shown incredible developments.

And so, when this film appeared 45 years ago,

it was proclaiming nothing less than a revolution.

Nearly all earthquakes occur at the boundaries

between the great plates of the Earth's outer shell.

In the Middle East and the Mediterranean,

the home of many ancient civilisations,

there's an extraordinary jumble of large and small plates.

Dan McKenzie of Cambridge University

is one of the young revolutionaries of the Earth sciences.

He played a pioneering part in first telling

how the first great plates move as rigid units about the globe.

Most of the worst earthquakes in the Mediterranean occur

because Greece and Turkey are moving really quite rapidly westwards,

at about 5cm a year.

This means they've moved about 100 yards since the time of Socrates.

This pair of scissors and a bobbin show what's happening.

The bottom of the scissors is Africa and the top is Europe.

Bobbin is Turkey.

As Africa comes towards Europe, Turkey is squeezed out of the way.

In this village, three-quarters of the population perished.

An earthquake struck at 2.15 in the afternoon of 31st August, 1968.

It killed 10,000 villagers and some of the bodies were never found.

When the heavily-built roof of this communal wash house

fell on them, 28 women died.

The energy let loose in this earthquake was equivalent

to an H-bomb of several megatons.

The film shows how this new theory,

that pieces of the Earth's crust collide

and grind against each other,

allowed scientists to understand even very recent disasters

in a completely new way.

Right across the world, in California,

the San Fernando earthquake of 1971 awoke old faults

that hadn't moved for thousands of years.

It killed more than 60 people and gave warning

of what more severe earthquakes might do to Californian cities.

Earthquakes are part of a systematic remodelling of the Earth.

That's the doctrine of a new generation of Earth scientists,

like Tanya Atwater.

She worked out how movements of the ocean floor have affected the land

and so explain afresh much of the scenery of the western USA.

When I was in school, I was taught that the Earth makes its mountains

by a complicated sort of sinking and bobbing action,

first down and then up again.

That doesn't seem to be the case at all.

Most mountains seem to be made

by one piece of the Earth's outer crust

pushing sideways against another.

This is some of the damage from the recent San Fernando earthquake.

The buckling here is just the latest step

in the buckling of the Earth that made the mountains behind.

Here, great plates are grinding.

The coastal strip of California is edging

past the rest of North America.

This is three feet of mountain that was thrown up

in the recent earthquake, just like the sidewalk was.

It doesn't look like much, but you have to think about this happening

over and over again, maybe once a century for thousands of centuries.

If you look at the documentaries in the early '70s,

they were still explaining plate tectonics to the audience.

Now, if you look at more recent documentaries,

plate tectonics is very broadly understood by the viewing public,

I think, so they're starting from a different point.

Once you know how recently the nature of the Earth's crust

was still a mystery, it's easier to understand

how theories are still being revised and refined.

I'm going to look first at how this rapidly developing knowledge

actually posed problems for film-makers.

I've been looking at a series of films tackling the same subject,

with each of them drawing a different conclusion.

One of the most enduring, most romantic mysteries of all

is the search for the fabled island of Atlantis.

Historians have argued whether the story of a lost civilisation,

first told by the Greek philosopher Plato, around 350 BC,

has a basis in fact, or whether it's merely a legend.

Finally, in 1972,

archaeologists discovered startling new evidence

that Atlantis may have truly existed

but was wiped out in a natural disaster.

This is how Plato had described it.

"In this island of Atlantis,

"there was the fairest and noblest race of men that ever lived.

"But they fell from grace"

"and were punished by the Earth shaker Poseidon."

"And afterwards, there occurred violent earthquakes"

"and floods and, in one terrible day and night,"

"the island of Atlantis disappeared in the depths of the sea."

The new evidence suggested

that the disaster struck in the eastern Mediterranean

on an island now crowded with tourists ever year,

but which, in 1972, was a sleepy backwater -

Santorini, sometimes known as Thera.

A land of grapes and wine,

one of the most enchanting of all the Greek islands of the Aegean,

a picturesque, idyllic island on the surface but, underneath,

there lurks a threat of terrible natural violence.

For Santorini is an area of alarming geological instability.

These cliffs are the walls of a caldera,

a vast crater that formed when the erupting volcano collapsed,

leaving a gaping hole to be filled by the sea.

It was a Greek philosopher, Plato,

who first wrote of the legend in the fourth century BC.

It told of an ancient island civilisation.

They became greedy and were punished by the gods

and their land sank beneath the sea.

What the archaeologists had just discovered was an entire city

buried beneath tonnes of volcanic ash.

And, remarkably, it seemed to match Plato's description

of a wealthy, civilised society,

with a taste for artistic expression.

Perhaps the most exciting discoveries are the frescos,

and we arrived at the site

just as completely new wall painting was being uncovered.

Skin divers and fishermen at work. One goes down with a hook.

One might be collecting sponges.

And, as the divers pick their way through the coral on the seabed,

on the surface, a convoy of ships is on the move,

led by a 50-oared galley.

What's more, the eruption on Santorini also appeared

to neatly solve another long-standing historical mystery.

Experts already knew that, at almost the same time,

sudden disaster had overcome the island of Crete,

60 miles to the south.

The wealthy and highly developed civilisation there,

the Minoan kingdom, disappeared almost overnight,

and for no obvious reason.

But, armed with their new knowledge of the Earth sciences,

archaeologists imagined that the volcano on Santorini

had sent out a tidal wave big enough

to cause wholesale destruction on Crete.

Tidal waves of appalling violence, perhaps some 600 feet high,

came raging in over the exposed northern coasts of Crete.