How the Earth Was Made

>> Earth, a 4.5 billion year old

Planet, still evolving.

As continents shift and clash,

volcanoes erupt, glaciers grow

and recede, the Earth's crust is

carved in countless, fascinating

ways, leaving a trail of

geological mysteries behind.

This is the story of Hawaii, a

mountain chain over 80 million

years old and home to the

most active volcano in the

world.

In this exquisite, volatile

landscape, scientists hunt for

clues to the islands'

origins - clues that may shed

new light on the formation of

the Earth itself. S01x12 Hawaii Original Air Date on May 5, 2009

Hawaii. The most isolated group

of islands on Earth, stretching

1,500 miles across the middle of

the Pacific Ocean.

These eight tropical islands are

one of the youngest geological

formations on the planet.

With stunning beaches, huge

canyons and the biggest

volcanoes on Earth, this is

where paradise meets hell.

The investigation into how

Hawaii was formed began in 1934.

Dutch geophysicist Felix Meinesz

invented the gravimeter, an

incredible machine which enabled

scientists to accurately measure

gravity for the first time.

With his cutting-edge

technology, Meinesz was able to

calculate the gravitational

forces at work on the Big Island

and, using this data, determine

its size.

His results revealed that the

Big Island was like a gigantic

iceberg. Only its tip was

visible above the ocean. But

drain away the water and its

true size is remarkable. The

island is twice the height of

Everest, and so massive that

Everest could fit inside it 140

times.

Geologist Mike Poland heads to

the top of the mountain Mauna

Kea, the highest point on the

Big Island, to get a sense of

its true enormity.

>> We're standing at the top of

Mauna Kea volcano, which is the

tallest mountain in the world.

It's 13,796 feet above sea

level, but it goes all the way

down to the ocean floor and

ends up being about 56,000 feet

high.

>> This giant island is the

largest in the United States and

bigger than all the other

Hawaiian Islands put together.

Intrigued, scientists set out to

discover what could have created

such a huge land mass.

10,000 feet below the peak of

Mauna Kea and 70 miles to the

south, the prime suspect is

plain to see - the awesome

Kilauea volcano.

>> (Poland) We like to call

Kilauea the most active volcano

in the world because it's been

erupting continuously since

1983. And it's been going every

day, almost nonstop, since that

time. Since early 2008, it's

been even more active, 'cause

now we have this summit

eruption as well, so now

Kilauea's perhaps by two times

the most active volcano in the

world.

>> But this volcano is not

predictable. Although the summit

is no longer spewing out lava,

12 miles down on the south flank

of the volcano is an active

vent.

For the last 25 years, lava has

been gushing out of the side of

the volcano from this vent,

with no signs of stopping.

Homes, towns and forests are

swallowed up by scorching hot

lava. With each new flow, layer

upon layer of black crust

builds, covering the island in

volcanic rock.

Could this huge island have been

built entirely by lava?

Experts needed to figure out

exactly how much lava Kilauea

produces. Their first clue can

be found all over the volcano.

Clinging to the rocks are yellow

crystals. These are sulfur

crystals and tell scntists

that Kilauea volcano is

releasing vast amounts of

sulfur dioxide gas.

To determine just how much the

volcano is producing,

researchers take regular

measurements.

>> The amount of sulfur dioxide

that effervesces from the magma

is tied directly to the amount

of magma that's coming out of

the ground, the amount of lava

that's erupted. So by measuring

the amount of sulfur dioxide,

we can use that number to

calculate how much lava is being

erupted.

>> These samples reveal

staggering results.

Kilauea could be producing 100

million cubic yards of lava a

year, more than any volcano on

Earth. But there isn't this much

lava flowing across the surface.

So where does the rest of it go?

Geologists ventured below the

surface, into the guts of the

volcano, to investigate.

Stretching 400 feet into the

dark is a strange tunnel, just

like a subway tunnel. But it's

not a manmade structure. It's

part of a vast network of tubes

that hold the key to how much

lava moves around the island.

>> We're standing in Thurston

lava tube in Hawaii Volcanoes

National Park, and this lava

tube was one of the main

conduits for lava that was

flowing from Kilauea summit

to the sea in an eruption that

occurred about 500 years ago.

So once this tube system has

been established, you

essentially have an underground

river of lava. So these tube

systems can be very long-lived

and very efficient delivery

systems for lava.

>> The lava is so hot it burns a

channel into the rocks beneath

it.

This incredible time-lapse

footage shows that, because the

top of the flow is still exposed

to the air, it cools and crusts

over. Below this crust, a tunnel

forms, through which the lava

continues to flow.

But how much lava can these

tubes carry?

Back on the surface, Dr. Ken Hon

is carefully inspecting the lava

fields to find an active tube.

Only inches beneath his feet

could be a tunnel full of 2,000

degree lava.

Dr. Hon is on the look out for a

skylight, a window in the

ceiling of a tube. They can come

and go within days and are a

sure sign of an active lava

tube.

>> You can see the lava glowing

inside the lava tube. This one's

about ten to 15 feet wide and

probably about five feet deep.

And it's about 2,000 degrees

Fahrenheit, and it glows like

the sun.

>> These hidden tunnels keep the

lava insulated and hot,

preventing it from cooling and