Forces Of Nature

Planet Earth, four and a half billion years ago.

A blazing sphere formed by colliding cosmic matter...

a violent world, covered by a sea of molten lava.

Over time, the surface cooled into a rocky crust.

Great clouds of watervapor rose...

then rained down, forming a vast ocean.

The crust fractured into huge, moving plates

that shifted the emerging continents...

producing the face of the planet we know.

But the forces that created Earth still rule it.

Around the globe sweeps a volatile atmosphere...

and within, a fiery world still burns.

Floating on this semi-molten interior,

the plates of the crust are forever in motion.

Only in a thin layer between the inner heat and the atmosphere

could life arise and thrive...

yet always at the mercy of these colossal forces...

erupting from the depths...

shaking the solid ground...

descending from the sky.

We cannot control such power.

But we can use our human powers of invention and discovery--

to learn, to understand...

and to survive.

There are places where primal forces are still on display,

where lava streams freely from the earth's interior.

Yet these same forces can also erupt suddenly, unpredictably...

with terrible consequences.

For hundreds of years, a volcano called Souf riere Hills

on the Caribbean island of Montserrat was dormant.

But in 1995, some 12,000 islanders discovered they were living on a time bomb.

RADlO ANNOUNCERS: The situation has escalated.

This followed a major ash fall at just after 8:00 this morning.

The scientists have told us that they can no longer guarantee six hours notice.

All incoming data are being processed on a near real-time basis

because the volcano can just go off with litle or no warning.

Deadly cascades of ash, gas, and lava rocks called pyroclastic flows

raced down the mountain at temperatures as hot as 1,000 degrees.

The eruptions continued, burying the capital of Plymouth under ash,

but there was time to evacuate the population of about 4,000...

and no lives were lost here.

Yet outside the city,

pyroclastic flows killed 19 people who had ignored the warnings.

For scientists, this place has become a kind of living laboratory.

At the Montserrat Volcano Observatory,

Dr. Marie Edmonds is part of a team from the British Geological Survey.

I became a volcanologist

because we know so litle about these dangerous mountains...

and I saw that studying them could mean better forecasts of eruptions,

which could save many lives.

l sometimes feel like the volcano is almost a living thing.

lt grows, it breathes, it even has a kind of pulse.

l grew up wanting to be an astronaut or a spy--

but living alongside an active volcano is just as exciting.

Right now, there are signs the mountain is building towards another big event .

We feel a great weight of responsibility on ourshoulders.

But it's difficult trying to figure out

what might be happening miles below in the crust of the earth.

Montserrat is actually the peak of an undersea volcano

which was built up by a collision between two plates of the earth's crust.

As the heavier plate plunges beneath the other,

intense heat and pressures melt the leading edge into magma.

The magma rises into a chamber and then heads towards the surface.

lf it reaches the surface quickly, it can generate enough gas to explode.

Smaller explosions continued here,

and during the last couple of years

thick magma has built a 500-megaton mountain above the vent--

a huge lava dome.

We believe it will collapse,

and that it will trigger more explosions and potentially dangerous pyroclastic flows.

NARRATOR The first hint of danger comes

when seismic instruments show increasing swarms of earthquakes--

a sign that magma is rising, causing tremors within the volcano.

Routine monitoring takes on a new urgency.

They need to check the instruments designed by Marie

that constantly monitor gases rising from the volcano.

We've discovered that if the volcano suddenly exhales more gas,

it can mean that the activity is ramping up to an eruption.

So today the volume is up, and that's a worrisome sign.

Next we have to fly as close as possible to the crater of the volcano

to get more data and to evaluate the situation.

This is one of those times when the research we conduct is a bit risky...

especially for my partner Richard Herd.

One of his jobs is to install a laser reflector,

which can measure even a few millimeters of ground deformation.

That can tell us if magma is filling the chamber below

and causing the ground to swell.

We avoid dangerous situations unless it's absolutely necessary.

Too many researchers have died in recent years because eruptions surprised them.

All of the evidence suggests that the dome is increasingly unstable.

The collapse seems imminent.

Warnings from the scientists convince the government to begin evacuations.

On a July night, it happens.

Violent eruptions send ash clouds rocketing ten miles high.

Because of the warnings, not a single life is lost.

Ash still falls occasionally, but most have learned to live with it.

Most likely the eruptions will pause for a while,

then begin a new eruptive cycle.

But as long as we continue to monitor the volcano,

as long as we continue to unravel its secrets,

there's no reason for anyone else on Montserrat to be harmed or to lose their life...

and that in itself is reason for celebration.

What scientists learn in Montserrat

could help reduce risk for millions of people living near volcanoes around the world...

but there is another kind of event caused by forces below

that is even harder to predict, and far more dangerous.

Among the places at greatest risk is a heavily populated part of Turkey,

where shifting plates of Earth's crust meet along a 1,000-mile seam.

lt's called the North Anatolian Fault, and it can produce a sudden catastrophe--

one of the deadliest of all natural disasters--

an earthquake.

lf we could pull the plates apart...

and descend within...

we'd see that 10 or 15 miles down

they begin turning into extremely hot, putty-like rock,

sliding in opposite directions

atop the semi-molten interior farther below.

Somewhere along the fault, the plates lock together,

and over long periods of time, enormous pressure builds.

Eventually they break loose and rip past one another,

unleashing powerful waves of energy that race through the crust,

shaking the surface above.

Nearly atop the fault

lies one of the world's great cities-- lstanbul, Turkey--

which has been jolted by earthquakes across recorded history.

ln the heart of the city, one remarkable structure

has remained standing through 14 centuries of quakes...

The Hagia Sophia is an enduring marvel of art and architecture.

But for one man, it's also a treasure-house of geologic history.

Geophysicist Dr. Ross Stein has spent more than a decade

studying earthquakes in Turkey,

trying to find ways of forecasting when and where they will strike.

Here, he found a critical piece of the puzzle.

STElN: When l first learned that since ancient times,

the clerics of Hagia Sophia kept records of their earthquake repairs,

l was tremendously excited.

Because with such a chronology of quake dates and damage--

combined with other data--

we might discover a pattern that could help us forecast quakes.

Such a discovery is every scientist's dream.

And in some ways it came true.

lt turned out that 11 major quakes in the last 60 years

had occurred in a largely westward progression.

And l kept asking myself why.

We went out to take a look at each quake site,

and we began to form an idea

about how built-up stress where the plates are locked

suddenly gets moved during an earthquake.

We turned our data into a computer model of stress being transferred by a quake...

with red showing where stress increased along the fault ,

and blue where stress was relieved.

Suddenly, the puzzle pieces fit together.

With each quake, stress didn't just dissipate...

but moved down the fault , where it concent rated again.

And in most cases, a major quake struck in the red zone where stress had increased.

Our model suggested the next great quake

might strike lzmit, a city of more than 200,000 people.

And on August 17, 1999, disaster did strike.

The lzmit earthquake was a magnitude 7.4 and lasted 45 seconds--

an eternity to those who suffered through it.

Local news crews captured the aftermath,

as rescuers searched for thousands of people trapped under the rubble.

20,000 buildings were destroyed...

half a million people left homeless.

Some believe the death toll reached as high as 25,000.

The real toll may never be known.

The loss of life was caused in large part by substandard construction.

ln many places, cheaply built modern structures