Hello from Iceland.

I am so lucky to be here right now with this amazing volcano erupting, and this is just, it's just unbelievable.

♪ Doug, voice-over: Iceland is a place where a volcano erupts every 3 to 6 years or so.

In this show, we'll see how Iceland's volcanoes are unique in the types of lava that they produce.

We'll also explore Iceland's many other geologic treasures.

This is an island where geology dominates the scenery and the attention of all who live and visit here.

This is "Doug's Geology Journal."

We're in Iceland.

Let's go explore this amazing island.

♪ ♪ Announcer: Funding for this program was provided by the National Science Foundation.

♪ Doug, voice-over: Iceland just touches the Arctic Circle, halfway between Greenland and Norway.

It's not particularly big.

It's about the size of the state of Indiana, where I was born, or the country of South Korea.

But Iceland has more of one thing than most other places of comparable size--lava, which hardens into a rock called basalt.

Around 90% of the rocks in Iceland are this hardened lava.

Basalt.

Aha!

Ah, another basalt.

So, this rock is a-- guess what kind of rock it is.

Wait.

This one's a basalt.

Every single rock here is this same thing.

There's not too many places in the world where you can go where every rock you pick up is the same thing.

But here in Iceland, it's all lava.

Doug, voice-over: The lava originally came from various volcanoes that have been erupting here over the past 16 million years.

Everywhere you drive in Iceland, you see big cliffs with horizontal ridges of old lava flows.

So, you see all kind of different shapes of cliffs and mountains in Iceland but they're all basically lava, hardened lava.

Doug, voice-over: There are a few rare exceptions to the one-rock-type landscape in Iceland, and one of those exceptions is a famous mountain called Kirkjufell.

It looks like a pile of lava flows, but some of the layers are actually eroded sediments.

It must be said, though, that here in Iceland, hardened lava in the form of basalt is king.

There's basalt everywhere in Iceland, but in terms of its chemical makeup, it is very rare on Earth.

So, any geology-minded person would love to come and see it, especially when it is erupting out of a volcano as lava.

That includes me, and finally, here I am.

We just got here.

We flew for 10 or 11 hours to get here from San Francisco and we're on the trail on the way to the volcano.

It's unbelievable.

So, here we go.

So, volcanoes just start erupting and scientists don't know how long eruptions are, so, they could just be going and going and going and suddenly stop.

It could be years, it could be days, it could be months.

So far, it's been months.

Doug, voice-over: This eruption ended up lasting for 6 months and we hit it just at its prime.

Incredible.

Took about an hour and a half to get up here, but... Wow.

That's-- that's definitely the coolest thing I've ever seen.

Doug, voice-over: This volcano, called Fagradalsfjall, erupted in an isolated volcanic area, which turned out to be conveniently close to Iceland's capital Reykjavik.

The volcano is only 30 miles away from the big city in Iceland--Reykjavik.

So, everybody here is going to see the volcano at least once and usually a lot more than that.

An erupting volcano is normally very difficult to visit, very dangerous, and there's a lot of ash involved, but this particular eruption has no ash fall and it's quite safe to get pretty close to it.

So, it's really a very, very popular volcano.

Doug, voice-over: I am in heaven, or maybe it's more like hell, being so close to an erupting volcano and its surreal lava flows.

The surface of the newly hardened lava is cool, but it is still on the move.

This is the edge of the lava flow.

This is about probably a quarter-mile away from the crater and this lava is making-- it sounds like the crinkling of a fire but in a big scale.

[Crackling] So, every once in a while, a huge piece of lava will just break off... [Cracking] like that.

Ha!

That's so cool.

Oh!

Doug, voice-over: Iceland's eruptions are stunning for sure, but there are other volcanoes around the world that look like this.

It's where the lava comes from and what it contains that sets it apart from the others.

The lavas that erupt out of the volcanoes in Iceland are really, really rare.

In fact, some of the lavas are bringing up materials from the deepest part of the Earth that have not changed since the Earth was created.

Doug, voice-over: And that was 4.6 billion years ago.

Iceland is sitting right over a thing called a mantle plume, and what a plume is is a very hot part of the Earth.

It's like a cylinder of hot rock coming up from the very core of the Earth, which is 2,000 miles below my feet, and the lavas here that come out of the volcanoes in Iceland are actually starting their journey down there at that part of the Earth.

So, the plume is coming up through the mantle of the Earth and hitting the crust of the Earth and then it melts, turns into lava, which shoots out of the volcanoes here on Iceland and ends up here in my hand.

Doug, voice-over: The volcanic rocks that make up Iceland are most unusual in another way.

They're actually a part of a geologic feature that mostly resides on the floor of the Atlantic Ocean.

This right here is the boundary between two huge tectonic plates, and most of the boundary is underwater.

It's under the Atlantic Ocean, splits the Atlantic Ocean right down the middle all the way down the globe.

Doug, voice-over: This boundary where the plates meet is called the Mid-Atlantic Ridge.

The plates on either side are the North American, the African, and the Eurasian plates.

So, that's the North American Plate over there and that's the Eurasian plate.

So, now I'm in Europe.

Uhh.

Now I'm in North America.

Doug, voice-over: The parting plates are etching a dramatic geologic signature right down the heart of the island, marking the Mid-Atlantic Ridge.

Nowhere else on Earth can you so easily see the effect of two tectonic plates pulling apart than in Iceland, and that includes volcanic activity.

Geologically, Iceland's rocks are similar chemically to those of the rest of the Mid-Atlantic Ridge, and, so, the island is technically part of the ocean floor.

Then why does it rise above sea level?

So, that's because the mantle plume is feeding so much magma and lava up to the surface that it created this island.

Otherwise, this would be thousands of feet underwater right now.

We'd need a submersible to be able to go along the ground right here.

Doug, voice-over: This particular mantle plume is among the strongest plumes on the planet.

Put that under the boundary, where two tectonic plates are pulling apart, and it's no wonder Iceland explodes so often with volcanic power and might... and why gashes reveal the tectonic movement tearing at the island's surface.

But these gashes don't happen overnight.

The tectonic plates are pulling apart extremely slowly, just a couple of centimeters per year.

So, there's plenty of time left before the island is split in two, which is great because there's so much geology to explore here.

So, let's go.

Two minutes till 11 p.m. Sun's still up but it will go down... but only for a few hours.

Makes for a long day.

Doug, voice-over: During the day, if there's no volcano erupting in Iceland, you can always glimpse a similar geologic phenomenon at one of Iceland's most popular tourist sites.

Be prepared to wait, though.

[Pretending to snore] It still hasn't gone off.

This is the original geyser.

Where the word "geyser" came from was right here.

But you don't want to stand here and wait for it to go off 'cause it won't.

It used to go off but it stopped a long time ago.

So, it's now inactive.

But there is one that does go off.

OK, if it goes off exactly every 3 minutes, it's gonna go off any second.

Here it goes.

So, it doesn't go off exactly the same every time.

Here it goes, maybe.

Any second.

Aww.

Here we go.

Ohh.

If I have it timed right, it's gonna go off any second.

Oh, there it goes.

See?

I told you.

Ha ha!

Doug, voice-over: Geysers work on a similar principle as volcanoes in that extremely hot magma underground heats groundwater, and as it rises through the Earth's crust, pressure is reduced and it begins to bubble.

When gases build up high enough to explode the water above them, you get a geyser.

Doug, voice-over: So, what happens when huge quantities of water mix together with lava, as often happens in Iceland?

You get ash, huge amounts of it.

This type of eruption is totally different from the oozing lava kind, and it is common in Iceland.

That's because this is Ice Land.

There's so much ice in so many volcanoes going off here that the two cannot avoid each other.

In fact, you can't even see Iceland's biggest volcanoes.

Each one is hidden under a dome-like cap of snow and ice.

So, that ice cap can be up to 3,000 feet thick.

And it's a really interesting thing when a volcano underneath it erupts.

So, let me show you how that works.

Doug, voice-over: When a volcano erupts under an ice cap, there's tons of ice sitting on top of the volcano.

So, when it erupts, the lava quickly melts a big hole up through the ice.

The melted ice pulverizes the lava into cinders and the resulting slurry bursts out of the ice cap and pours down its side in a massive flood.

When mixed with ice, the lava is reduced to a torrent of water, gravel, and ash.

This happened in an eruption in 1996.

And the flood from the eruption was many miles wide and it just wiped out the road, of course, and all the bridges in the way.

It's just unbelievable flood.

Doug, voice-over: In between eruptions, the ice caps obscured the resting giants below, but the ice caps themselves are not serene and stable everywhere.

Slipping off the lofty edges of those frozen domes are masses of creeping, splintering ice called glaciers.

Glaciers comes down all around this ice cap into the valleys here, and this part of Iceland has glacier after glacier after glacier.

It's just awesome to go around this eastern side of the island and see all these beautiful glaciers.

Doug, voice-over: Glaciers cover more than 10% of Iceland, but the area they cover has shrunk by 18% over the last 120 years.

So, this glacier that's coming down this cliff is shrinking.

And in fact, all the glaciers in Iceland are shrinking, and as a matter of fact, all the glaciers in the entire world are shrinking because of climate change, and it's pretty scary.

Doug, voice-over: Glaciers often shed their ice into lakes, where they float away like ships embarking on a voyage.

So, these icebergs aren't from the ocean.

They're from a glacier that's over that way, and it's a gigantic glacier that came right off the ice cap into this lagoon.

A lot of these icebergs are a gorgeous blue color and other ones are white, and that's because when the iceberg comes off the glacier, it's white on its top because that's where the snow accumulates on top of a glacier, and eventually the ice gets compressed really densely and that dense ice turns blue.

Doug, voice-over: Dense ice is mostly pure water, and water molecules mostly reflect blue light, which is what our eyes see, while absorbing the rest of the color spectrum, just like the ocean does, or a big, blue lake.

The glaciers are shrinking right now on Iceland, but during the ice ages, ice completely covered the island at various times.

It's hard to picture, but even the 1,500-foot-tall Kirkjufell Mountain, all but the very top was overrun by a slow-moving blanket of ice.

If that didn't happen, Kirkjufell would not exist, and would not be said to be the most photographed mountain in Iceland.

It was formed during the Ice Age when the huge glaciers that covered Iceland and all the rest of the northern hemisphere just moved slowly along and planed off this shape into a beautiful wedge and then, when it melted away, you had this gorgeous mountain.

Doug, voice-over: As ice sheets came and went through the ice ages, the climate also shifted dramatically, creating amazing geologic formations.

["Toccata and Fugue in D minor" by Bach playing] OK, this is not a pipe organ.

This is a columnar basalt.

So, these columns of basalt are the edge of a huge lava flow.

Doug, voice-over: To see a columnar basalt formation, like this famous one by the town of Vik, is not very common in Iceland.

The columns formed down below the surface of a hardening lava flow as the lava cooled.

When you see a lava flow, you don't see a bunch of these columnar basalts extending down from the surface, but sometimes, they're there.

They're underneath your feet.

If you walk over lava flow, you could be walking over columnar basalt.

Doug, voice-over: The only reason we see these columnar basalts is because sea level fluctuated by hundreds of feet as the climate shifted during the ice ages.

Dropping sea level exposed the lava flow and beautiful columnar basalts were laid bare in many forms on this beach by erosion.

Inside lava.

Doug, voice-over: The ancient lava flow towers over the beach, where it is destined to end up when erosion and time reduce it to sand and gravel.

This is a black sand beach.

Really nice here in Vik... the southernmost part of Iceland.

Beautiful black pebbles.

It's actually not sand right here.

This is all gravel.

So, it's more like a black gravel beach and some rocks.

Ha ha!

So, of course, all this black is coming from lava.

Doug, voice-over: Lava is what makes up the cliffs that underpin Iceland's countless waterfalls.

There are several geologic forces at work, making so many incredible waterfalls.

I'm doing something you can't do every day.

It's walking behind a waterfall.

So, I'm back here behind the waterfall.

It's just amazing, the power of it.

This waterfall is falling 200 feet off a basalt cliff.

And actually, this waterfall used to fall into the ocean.

Now it's just falling into this huge, beautiful pool and flowing down to the ocean in a river.

Doug, voice-over: The rivers typically start their journey under glaciers high up on Iceland's volcanoes.

The river that's making this waterfall started way back up on the volcano and it flowed down over a lot of lava flows to get to this point.

I want to show you how this works with the lava flows and the waterfalls.

Doug, voice-over: The river comes out of the melting glacier and starts flowing over an ancient lava flow.

That lava flow ended on top of an older flow and made a cliff and a waterfall for the river.

Then that lava flow ended on top of an even older lava flow, so, the river goes over another cliff.

There might be lots of these waterfalls over lots of different lava flows, until the river reaches the last waterfall, which people are walking behind today.

Yet another geologic force creates one of the biggest waterfalls in Iceland.

That force is the tectonic splitting of the island, which creates linear cliffs across the land.

This is Gullfoss Waterfall, and what's happening is upstream of the waterfall, the river is actually following one of the ridges that was formed by the splitting of the two tectonic plates here, and it started following along the cliff side and gathered a lot of speed and started eroding into the lava flows that are piled up along the cliff walls here.

So, this whole area is a big lava flow.

The river just started eroding into that lava flow and now you've got this beautiful waterfall going down a really deep canyon.

It's awesome.

Doug, voice-over: Sometimes, rivers blast through thick, ancient lava flows surprisingly quickly, geologically speaking.

This river is cutting through a lava flow and the lava flow is a couple million years old, but the canyon was just formed after the last ice age ended about 9,000 years ago.

So, it's actually not that old, but it got pretty deep in that amount of time.

Doug, voice-over: And then there are lava flows that are not near any rivers, letting Iceland's odd vegetation take hold.

This moss is so cool.

When it rains like it has been doing all morning, it goes from a kind of a pale green to a real bright green 'cause it sprouts, and it's right now sprouting.

It's beautiful.

Doug, voice-over: Moss thrives on Iceland's hardened lava flows, but it never grows higher than a few inches or so.

The same goes for most other kinds of vegetation here.

The funny thing about Iceland is there are no trees in Iceland.

The only trees that are here are basically trees that people have planted.

And maybe there's some small birch trees that grow to about 20 feet tall, but other than that, most everywhere you go, there's just no trees, and the biggest vegetation that you see in Iceland almost everywhere you go is that tall.

Doug, voice-over: Meanwhile, the Icelandic people have incorporated their lava-covered, tectonically splitting world into every aspect of their lives, including shelter.

I'm really cold.

There's a house over here that's protected from the wind by this big basalt flow.

I'm gonna go in there and get warm.

The big advantage of living on the Mid-Atlantic Ridge, which is splitting apart and letting heat come up pretty close to the surface, is that you can drill down into the crust of the Earth where the rocks are super hot and tap the hot groundwater that's down there, bring it up, and create geothermal energy.

Geothermal energy in Iceland creates about a quarter of the electricity and it also creates nearly all of the heating for the buildings.

Doug, voice-over: The importance of geology to the people of this island is reflected in Reykjavik's prominent landmark.

When you go out to look at a lava flow and then you come back to Reykjavik and look at this church, you'll notice a similarity, and that's that the church has columnar basalts built into its design, and they're not real columnar basalts, but the architect was thinking about columnar basalts when he designed the church.

Doug, voice-over: In other words, you can't help but appreciate that everywhere you go in Iceland, you're in touch with and utterly dependent upon its awesome geologic forces in some form or shape.

♪ ♪ ♪ ♪