Journeys into the Ring of Fire_1of4_Indonesia
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00:00In this series, I'm travelling around the Pacific Rim to visit some of the most volatile
00:19places on Earth and discover how the rocks beneath our feet are fundamental to the history
00:24of life on our planet.
00:30My journey includes the hostile peaks of the Peruvian Andes, the geological booby traps
00:37of California and the magnificent mountains of Japan.
00:45But in this episode, I'm exploring exotic Indonesia.
00:50To a geologist like me, this is the land of the Holy Grail.
00:56It has the most awesome range of volcanoes anywhere in the world.
01:00It's at 490 degrees there.
01:04Yeah, yeah.
01:05It's just above 50.
01:07For thousands of years, these volcanoes have had a huge impact on the lives of those who
01:12live here, destroying whole civilizations.
01:19And these fiery peaks have shaped the history of the whole planet.
01:40As a geologist, I'm fascinated to discover how the volcanoes of Indonesia have transformed
01:45civilizations not just locally, but all over the world.
01:52Indonesia has more active volcanoes than anywhere else and is home to many different religions.
01:58It's an archipelago of 17,000 islands, but my journey starts with one of the lesser known,
02:05Sumbawa.
02:08One volcano here had an extraordinary effect on art, literature and even technology, 9,000
02:15kilometres away in Europe.
02:19I'm going to show you how this bizarre sequence of events was triggered by the rocks beneath
02:24our feet.
02:44It all took place in 1815, when a volcano called Tambora blew its top in a ferocious
02:51surge of power.
02:57It was the largest known eruption of the last millennium.
03:12In the nearest town, I would need to trek for five gruelling days to reach Tambora,
03:18and I'm not one to shirk a hike.
03:20But taking a helicopter is the best way to see the top of this volcano.
03:34The massive eruption left this crater eight kilometres wide and over a kilometre deep.
03:46Known as a caldera, this is what remains when a volcano collapses in on itself.
03:51It's only from up here that you get a hint of Tambora's devastating power when it blew
04:01nearly two centuries ago.
04:07To get an idea of the impact, don't just think of the spewing rivers of molten lava, it was
04:12much more than that.
04:29The eruption blasted 50 cubic kilometres of rock high into the atmosphere.
04:36Carried by the winds, it began to spread, with terrible consequences.
04:41There are plenty of clues as to the devastation wrought by that ejected rock and dust.
04:50Beneath my feet, there's this deep layer of ash, it's characteristically dark and powdery,
04:55and in these parts, over a metre thick.
05:01When it falls, this ash is terrible stuff.
05:04It adheres to the leaves of plants.
05:08Even a thin coating is enough to stop the leaf from photosynthesising, from turning
05:11the sun's rays into usable energy.
05:14It kills a plant.
05:17It meant that in 1815, after Tambora blew, there was massive crop failure and widespread
05:24starvation.
05:28The effect could be felt in Europe and America, thousands of kilometres away.
05:39The debris blown into the atmosphere included particles of sulphur.
05:44This layer was thick enough to reflect the sun's rays back into space, and it actually
05:49caused the planet to cool.
05:51The results were catastrophic.
05:541816, the year after the blast, was so unusually cold in places that it became known as the
06:02year without a summer.
06:07The Big Chill left countries in the northern hemisphere suffering from severe famine.
06:14On farms across Europe and America, crops failed to germinate.
06:18In all, 200,000 people died worldwide, making it one of the worst volcanic disasters in
06:24history.
06:29The catastrophe had surprising reverberations across European culture.
06:38At around that time, the British artist Turner painted spectacular sunsets.
06:44These fiery skies are believed to have been caused by particles in the atmosphere from
06:48the Tambora eruption.
06:52The freakishly cold winter of 1816 was said to have inspired Mary Shelley in Europe to
06:58write this book, her classic story of Frankenstein.
07:03The lack of food during the year without a summer inspired new technology too.
07:07It's said to have prompted a German inventor to devise a new form of transport that didn't
07:12require a horse, because beasts of burden required feeding.
07:17Known as a running machine, it was a predecessor to the modern day bicycle.
07:25Indonesia is situated in what is known as the Ring of Fire.
07:29This extends northwards from South America, arching across Alaska, and goes south past
07:34Japan.
07:36It's dotted with volcanoes, but the largest number of active ones can be found right here
07:41in Indonesia.
07:49Worldwide, two thirds of deaths caused by eruptions over the last couple of centuries
07:54have happened on these islands.
08:07With volcanoes so entwined in the destiny of Indonesians, I want to find out how they've
08:13shaped people's fundamental beliefs about their gods.
08:19Indonesia is a melting pot of religions.
08:21It's home to Hindus, Muslims, Buddhists and Christians, but I've been told there's a local
08:26uniqueness to these faiths, thanks to the perilous geology here.
08:33To discover this relationship between rocks and religion, I'm heading 150km west of Tambora
08:39to Bali, where I'll be visiting one of the most extraordinary temples in the world.
08:52The Balinese have been Hindu for thousands of years, but their faith is different from
08:57the original Indian Hinduism, having absorbed many animistic beliefs.
09:03I'm meeting Gusaji, who will become a Hindu high priest next year.
09:07How are you?
09:08I'm fine.
09:09And what's this then?
09:10This is sarong.
09:11This is a Balinese custom.
09:12Yeah.
09:13It must be worn by someone who wants to attend a ceremony, who wants to come to a temple.
09:18So what is the difference between Hinduism in Bali and Hinduism in, say, India?
09:22The most important difference that we have in Bali, we have volcanoes.
09:26Volcanoes, yeah.
09:27Yeah, volcanoes that give us life and bring us to death.
09:32There's not any volcanoes in India, right?
09:34No, no, there's not.
09:35That makes a difference to us, yeah.
09:39Gusaji and his family live in the shadow of Gunung Agung, a volcano they and many Balinese
09:45hold to be sacred.
09:48So do you believe that gods live in the volcano?
09:50Yes, we believe it very much.
09:52Agung is the home of the gods of the mountain.
09:55Are the gods good gods or bad gods?
09:57Do they destroy or do they protect?
09:59We believe good.
10:00We expect him to protect us here in Bali.
10:03But sometimes he doesn't always protect.
10:05Yes, sometimes he doesn't protect us, you know.
10:10So we try to make him heavy.
10:16Perched on the slopes of Agung is Bisaki, the great mother temple of Bali.
10:23It's here the islanders perform ceremonies to assuage Vishnu and the other gods of the
10:27mountain.
10:29The Balinese believe rituals must be performed absolutely correctly.
10:34Many remember one time when they got it wrong.
10:41An important ceremony held once every hundred years and known as the Eka Desa Rudra was
10:47due to get underway at Bisaki on March the 8th, 1963.
10:54The Indonesian president wanted the delegates of a huge tourism conference to see the wonders
10:59of Balinese culture.
11:02So he demanded that the timing of the ceremony should coincide with the conference.
11:07Just ten minutes after the start of the rituals, smoke began to pour from Mount Agung.
11:17These pictures show the volcano erupting.
11:24In that time I was still young, maybe nine years old.
11:29I could see the explosion, the fire, the ashes covered all of the Bali island and also small
11:37stones also come down from the sky.
11:43Many worshippers at the temple of Bisaki decided to stay and pray rather than flee, even though
11:50a massive lava flow was heading straight for them.
11:55The lava flow on the south part of the mountain destroyed everything but avoided the temple.
12:02It avoided this temple?
12:03Yeah, it avoided this temple.
12:04You think it avoided it deliberately?
12:06Yeah, I think so.
12:07I think so.
12:08Agung had laid dormant for hundreds of years.
12:12Many Balinese believe the eruption was no coincidence.
12:16So why do you think the eruption happened?
12:19Because the ceremony was held on the wrong day, I think the god of the mountain was angry
12:24in that time.
12:27It's not surprising that today the Balinese go to great lengths to please their gods.
12:41Today hundreds of worshippers bring offerings from all over the island.
12:51They're hoping to entice the gods down from their volcanic home.
13:07Today I'm a special guest at the ceremony.
13:10The priest arrives and starts to pray with mantras to the gods.
13:18The priest says in his mantra, Oh God, please come down from the mountain.
13:24We are ready to worship you here.
13:26You are the creator, you are the protector, we are ready with all kinds of offerings for
13:31you.
13:32So bless us here and then protect us forever.
13:42Once the gods are lured down to the temple, worshippers will try to keep them here.
13:47The longer they stay, the greater the good fortune bestowed on the assembled company.
13:58Entertainment is laid on to persuade the gods to dally among the mortals.
14:04This is the sacred dance of the virgins.
14:17They're followed by the warriors.
14:24The warriors are ready to welcome him, to entertain him as well.
14:29And they'll protect the god if he comes down?
14:31Yeah, to set him exactly, to protect him.
14:40The ceremonies last all day.
14:43And when they're over, the gods return to their mountain.
14:46So do you think it was successful?
14:49It's very, very successful.
14:51And then we think that the gods are very, very happy in the ceremony.
14:55Good.
14:56It's very successful, I think.
14:57Good, I'm glad they're pleased.
14:58Yeah, that's good, yeah.
15:07Volcanoes are fundamental to the beliefs of people on this island.
15:11Thanks to geology, Bali has its own brand of Hinduism,
15:14a faith inextricably woven into this volatile landscape.
15:27I'm travelling 600 kilometres to Java, which is the next island west of Bali.
15:33It's one of the most densely populated parts of Indonesia.
15:42If a reliable warning system for eruptions is needed anywhere, it's here.
15:53Thousands of people live here in the shadow of Mount Merapi,
15:56one of the most dangerous volcanoes in Indonesia.
16:00It erupts every year, and every six years, there's a big one.
16:09These pictures from Merapi show the cause of most human casualties.
16:15Pyroclastic flows, extremely hot blasts of ash and debris
16:21which hurtle down at speeds of up to 100 miles an hour.
16:31In 1994, a deadly pyroclastic flow ripped right through this village.
16:36It measured incredible 400 degrees centigrade,
16:39and the houses were just incinerated.
16:4243 people died.
16:57Scientists are doing their best to predict eruptions here,
17:00but even with the latest technology, such forecasts can be notoriously vague.
17:10This is the Babatan Observatory on the flanks of Merapi.
17:14I'm meeting Dr Rudy Hadesantano, a fellow geologist
17:18who, like me, has been studying volcanoes for years.
17:22We have 69 volcanoes monitored throughout Indonesia.
17:29Rudy has invited me to join him in an expedition to the top of the mountain
17:33to collect crucial data for making predictions.
17:38We don't get a chance like this every day,
17:40but it's going to be a hard slog up the 3,000-metre-high peak.
17:45First, we need to find out whether the mountain is quiet enough for us to make the climb.
17:51So what exactly are you monitoring?
17:52We are monitoring the summit of the volcano, the growth of the dome of Merapi.
17:59By taking the picture day by day and week by week,
18:04if there is any change, it means that the dome is getting bigger.
18:08Right, so the dome is kind of getting steeper like that
18:11because of what, magma coming up, pushing through?
18:13Yes.
18:14And what can happen if that steepens? Why is that?
18:16It can collapse.
18:17It can fall off?
18:18Yes, it can fall off.
18:20And when the dome falls off, that's when deadly pyroclastic flows occur.
18:27I can show you what's happening with Merapi with this bottle of fizzy water.
18:30If I shake it up, the gas that's trapped inside the drink separates out.
18:36But it can't escape, so it builds up pressure.
18:39Under Merapi, gas is released from the molten rock,
18:42but it can't escape because it's underground.
18:44Eventually, though, the pressure builds up and it goes,
18:49taking lava, ash and dust with it.
18:52An explosive eruption.
18:56And gassy too.
18:57The scientists here have another, more immediate way of collecting data
19:02on the state of the volcano.
19:05So what are we monitoring here, Rudi?
19:06Here we have seismograph monitoring, detecting the earthquake of Merapi.
19:11Yeah, the significance here is that as the molten rock breaks its way to the surface,
19:15it creates earthquakes, and lots of earthquakes mean it could be about to erupt.
19:19So anything going?
19:20Yeah, we had an earthquake here, for example, yesterday.
19:23This is yesterday, is it?
19:24Yes, during the quiet time.
19:28Right. And what happens during an eruption?
19:30During an eruption, it has a different pattern.
19:33Look at this!
19:35It's quite crowded here.
19:36It's gone crazy.
19:37Really? Yeah.
19:38So that's an eruption about to happen.
19:41Wow.
19:42But the main thing for me is, what, it's quiet, is it?
19:45Yeah, it's quiet.
19:46It's nice.
19:47We have nothing.
19:49We're not waiting for that needle to start going, niggity-niggity.
19:51Just plain, yes, just plain paper.
19:54Good.
19:55These readings suggest that it's safe for us to climb Merapi
19:58and collect more data higher up.
20:00But the question is, how effective are these measurements
20:03for making predictions and saving lives?
20:06I guess we'll find out the answer to that tomorrow.
20:19So we have the gas sampling?
20:20He's gone to...
20:21After a few fitful hours sleep,
20:24I join Rudy's team of porters and technicians
20:27who are loading up, ready to make the ascent.
20:32We've got about a five-hour trek up the volcano to the summit.
20:35We've got about a 20-man team carrying equipment and water.
20:39These lamps are going to light our way.
20:41The path should be a bit muddy because we've had a lot of rain
20:44and it's been blowing a gale overnight.
20:45So we'll just see what we're going to get up there.
20:47Are we all ready? Yeah.
20:55We need to reach the top by dawn.
21:14The climb proves harder than I'd imagined.
21:172,000 metres up, the heavy wind and rain
21:21prevent me seeing more than a short distance ahead.
21:30We're at the halfway point.
21:32And, to be honest, it's more like West of Scotland than Indonesia.
21:36We're all pretty exhausted.
21:39HE BLOWS A RASPBERRY
21:51Finally, the night storm moves off,
21:54leaving us with a breathtaking view of the Great Peak
21:57towering above us.
21:59HE BLOWS A RASPBERRY
22:07Four hours gone and we're within sight of the summit.
22:10I can see the smoking fumaroles. It stinks.
22:13It's fantastic.
22:29HE BLOWS A RASPBERRY
23:00I can't believe it.
23:02I've just come up to the summit of Merapi.
23:05Here it is.
23:07Ahead of me is a dome-like plug of hardened lava.
23:11If that collapses, we're all in trouble.
23:14But it's here that we need to take our more accurate measurements
23:17to find out the state of the volcano.
23:30HE BLOWS A RASPBERRY
23:33Swirling around the pinnacle of Merapi
23:36are toxic sulphur and carbon dioxide gases,
23:39so we have to put on masks.
23:42On the gas field, we join Rudy's team as they start work.
23:48First, a thermometer is dropped into one of the fumaroles.
23:52It's at 490 degrees Celsius.
23:55Yeah, yeah, it's just above 100.
23:57In an eruption, what would the temperature here start to get up to, though?
24:01Yeah, of course, it's increasing during the increased activity.
24:04The temperature increased until 600 degrees.
24:08And the other crater over there, it was 800 degrees.
24:13800 degrees centigrade?
24:15Yes, centigrade, yeah.
24:16Can we look at the gas?
24:17Yes, sure.
24:19We go on to measure the mixture of gases coming out of the volcano.
24:24Hey, very good!
24:27It's the ratio of these gases which is the key to predicting an eruption.
24:32Increased sulphur dioxide gives us information
24:35about the increasing magma from the magma chamber onto the surface.
24:41And that's all telling us about the magma getting closer and closer
24:44and closer to the surface, is that right?
24:46Yes, that's right.
24:48Today, the sulphur dioxide is at normal levels
24:51and temperatures are stable, which suggests the volcano is safe.
24:55For now, at least.
24:57Have you made any predictions of eruptions here that have saved lives?
25:01Yes, for example, during the increased activity of 2001,
25:06we asked the local government to ask the people to leave their villages.
25:11How much time for warning can you give people around Marapi of an eruption?
25:16At least two or three days before the eruption.
25:22The good news is that with modern science,
25:25us geologists can predict reasonably accurately when a volcano is about to blow.
25:30The bad news is that we can only give a day or so's notice.
25:35When it comes to evacuating thousands of people, that just may not be enough.
25:41Just a few weeks after my visit,
25:44Marapi began spewing out clouds of ash, gas and rock.
25:53Rudi feared she was about to fully erupt
25:56and more than 20,000 locals were evacuated.
26:00The eruption was so intense,
26:02it was almost as if a volcano was about to erupt.
26:06It was about to fully erupt
26:08and more than 20,000 locals were evacuated from the immediate area.
26:13Elderly women and children were taken to special shelters.
26:18Things looked perilous as lava poured from the summit.
26:22Molten boulders crashed down the sides.
26:27And once again, pyroclastic flows swept four kilometres through fields at the base.
26:33In the end, Marapi calmed down and the threat of a serious eruption passed.
26:39But just as locals were breathing a sigh of relief,
26:43the area was struck by another geological disaster, a huge earthquake.
26:50Nearly 6,000 people were killed and up to 200,000 left homeless.
26:58It was a terrible reminder of just how unstable the geology is in this region.
27:07Throughout 10,000 years,
27:10Marapi has been the epicentre of the world's largest earthquake.
27:16Throughout history, Indonesia's volcanoes have been responsible for some awful catastrophes.
27:22But the story of the volcanoes here isn't all about destruction.
27:27In the West, we've developed a use of volcanic rocks as ingredients
27:31in rather exotic products like toothpaste and cat litter.
27:36But in the East, they've been considerably more ambitious.
27:39This is Borobudur, one of the great wonders of the world.
27:44One of the great wonders of the ancient world.
27:50It's the biggest monument in the southern hemisphere.
27:54Built between the 8th and 9th centuries as a Buddhist holy place,
27:59Borobudur is made entirely of andesite, a volcanic rock.
28:06The stone from which this astonishing monument was built
28:10originally came from Marapi and surrounding volcanoes.
28:14Andesite is the result of lava cooling quickly in contact with air,
28:18trapping bubbles which fill with a glassy crystal.
28:22And it's that which gives this volcanic rock great advantages as a building stone.
28:29It must have been hard to haul the stone to the site,
28:32but once there, stonemasons found it had great advantages as a building material.
28:41Tony Tak is an art historian who has studied Borobudur for 30 years.
28:46So is this rock pretty easy to carve?
28:48Yes, it's quite easy. It's easier than granite.
28:52But it has this character about it that it has crystals inside
28:57that have a tendency to explode.
29:00Right. I can see that.
29:03Can I get a little go, you think?
29:11I won't break it. It's not going to snap in two.
29:14You need goggles on that.
29:16You should. My students, I always tell them to always have goggles.
29:19Do I? It's more like this, isn't it?
29:22Yeah, it's all soft and kind of sandy, isn't it?
29:25Sort of like volcanic beach, beach sand.
29:29But what about when this was getting built,
29:31there wouldn't have just been three of these people?
29:33There must have been able to hear the noise for kilometres.
29:37Hundreds of people.
29:39Gosh, you're quite a hand at this.
29:41Yeah, I like rocks. I do like rocks.
29:43I should stop, though. Our man here is much better.
29:45Why don't you try?
29:47You do it.
29:53Would you like to walk around and have a look at the monument?
29:55Yes, please. Absolutely.
29:57See where those rocks go.
29:59This artificial mountain is 35 metres high
30:03and covered in three kilometres of pictures known as bas-reliefs.
30:08So what does this magnificent monument represent?
30:11Amazing, isn't it?
30:13It's, of course, a Buddhist monument
30:15and it represents, tells the life of Buddha in stone,
30:20the bas-reliefs on the lower levels.
30:23And the function was that the monks long ago
30:26would circumambulate the monument and read the bas-reliefs
30:29because they couldn't read and write at that time.
30:32It's really, you could say,
30:34like a great 9th century comic strip, actually.
30:36A giant comic strip.
30:38Yeah. That's one way of looking at it.
30:43The crystals in the andesite helped to form a stone
30:46which could be easily carved.
30:48This allowed the ancient Buddhist craftsmen
30:50to sculpt beautifully detailed pictures.
30:55So here we are. This is a story about Buddha,
30:57but before he was born as a human being,
31:00he had many different incarnations.
31:02And here he is as a turtle.
31:04You see him swimming through the sea.
31:06It's the first panel.
31:08The second panel, you see that he comes across a ship.
31:12See the ship here?
31:14And there are merchants on the ship.
31:16And the ship is sinking.
31:18There's a huge storm. See the waves?
31:20And there's a strange-looking shark there with his mouth open.
31:23Buddha Turtle comes along and says,
31:25Have no fear. I will help you.
31:27I'll take you to safety.
31:29Climb on my back.
31:31And here he is, taking them all to safety.
31:33They're all clinging on his back.
31:35And he takes them to land, the last panel.
31:38And here you see the merchants are saved,
31:40and they're listening to Buddha Turtle,
31:42who is preaching to them.
31:44And then because there's nothing to eat,
31:46he offers his body to them.
31:48He sacrifices himself to these people.
31:50He gains merit because of this,
31:52and in his next life he has a higher incarnation.
31:55Isn't that beautiful?
32:04It's believed to have taken over 100 years
32:07to carve all the 1,500 bas-reliefs which grace the monument.
32:16But this extraordinary cultural heritage is under threat.
32:22Yes, here I'd like to show you one of the sadder aspects of Borobudur.
32:27This is a bas-relief of a sick man,
32:30and if you look at this photograph from about 100 years ago,
32:33and you can see clearly his ribs are visible here.
32:36Yeah, but you can hardly see any ribs at all in this one.
32:39No, and this has happened in other places on the monument, yes.
32:46It's the volcanic nature of the stone which makes it so vulnerable.
32:50Those glassy crystals in the underside have just been loosened out,
32:54and they're just falling out, and they're leaving behind holes,
32:57and, of course, then weathering just gets right in there and opens it up.
33:01I think that's producing pitting all over the surface.
33:04It's a bit tragic, really.
33:09The geological make-up of the stone
33:11means that some carvings are under greater threat than others.
33:15The difference in rates of weathering is often apparent in adjacent panels.
33:21I think what we're seeing here is different weathering rates
33:24from different parts of the lava flow.
33:26At the edge of the lava flow, it cools very fast,
33:29and the crystals are very, very small.
33:31If you get very small crystals, it's much harder to weather them.
33:34But if it's from the centre of the lava flow, it cools slowly,
33:37and you get big crystals growing, and it kind of falls out.
33:40So where it is in the lava flow determines the way that it weathers.
33:43How interesting.
33:54Merapi was also at the centre of the decisive event in the monument's history.
34:00In a terrible twist of irony,
34:02the very volcano that had created the materials to build this magnificent monument
34:07also proved to be its undoing.
34:10A thousand years ago,
34:12an angry Merapi spewed out vast quantities of ash,
34:16which fell from the skies and partially covered sacred Borobudur.
34:25It was quickly abandoned and, in time, forgotten.
34:30But it was not forgotten.
34:33It was quickly abandoned and, in time, forgotten.
34:41The monument disappeared along with its Buddhist culture.
34:52Borobudur was not rediscovered until the beginning of the 19th century.
35:03The Volcanoes of Indonesia
35:11It's been a fascinating geological journey for me so far.
35:15The volcanoes of Indonesia seem to impact on everything.
35:19Religion, culture, art, literature.
35:22But this lush landscape of Java is a clue to an even grander claim
35:26made on behalf of the country's volcanoes.
35:29They were the key to the discovery of new worlds.
35:39This place is known as the Garden of Java because of its fertility.
35:45And for such productive land, we have the volcanoes to thank.
35:53This red-brown earth was once ash that fell from the sky during a volcanic eruption.
35:58As well as iron, which gives it the red colour,
36:00it contains a strong natural fertiliser, phosphorus,
36:03which, when combined with plant matter, makes for a uniquely rich soil.
36:07Perfect for growing cloves and nutmeg.
36:12Nutmeg is pretty fussy about where it grows, but it does love soil like this.
36:20500 years ago, when the spice first became popular in Europe,
36:24it could only be found in Indonesia on a small archipelago called the Spice Islands.
36:32Nowadays, nutmeg trees are much more widespread.
36:36The Ngobo plantation, on the slopes of the Ungaran volcano,
36:40is one of the largest in the country.
36:46It takes a certain skill to harvest the mature trees.
36:54Even though often precariously perched up to 15 metres above the ground,
36:59an experienced worker can pick the crop on one tree in just under an hour.
37:07And this is what she's harvesting.
37:12On the outside, it's a white pulp.
37:16And in the middle is the nutmeg itself.
37:19This humble nut changed the world in the most profound way.
37:25Between the 16th and 19th centuries, it was the must-have spice of Europe.
37:31Highly valued as a food preservative and for medicinal purposes.
37:41But there were curious applications as well.
37:44Popping a nutmeg under your left armpit prior to social events was believed to attract admirers.
37:51A 16th-century monk even advised young men to carry a vial of nutmeg oil with them
37:56to anoint their genitals for virility.
37:59Let me hang on to this one.
38:05Nutmeg became worth its weight in gold.
38:11Arab traders held a monopoly on its import to Europe
38:15and could charge a fine of up to £1,000.
38:18Not surprisingly, European buyers decided to take control of this lucrative trade for themselves.
38:24So they launched expeditions to find a route to the spice and bring it back directly.
38:35Christopher Columbus was searching for the fabled route to the Spice Islands
38:39when he stumbled upon the New World in 1492.
38:42So the idea was to find a route to the Spice Islands
38:45and the New World in 1492.
38:48So these nutmeg-friendly volcanic soils played a key role in the discovery of America, no less.
38:55A few years later, Ferdinand Magellan also set off to find a westward route to the Spice Islands.
39:01He died on the way, but his surviving crew continued west and made it back to Spain.
39:08They became the first men to circumnavigate the globe.
39:16Indonesia's volcanoes have been instrumental in shaping the history of the world.
39:21But so far, I've only looked at human history.
39:27Volcanoes provide the answer to one of the greatest and most intriguing mysteries of the plant and animal kingdoms.
39:36It's a story centred on these exotic islands.
39:40The principal character is a brilliant but forgotten hero of history.
39:44He should be a household name, as well known as Charles Darwin.
39:48But Alfred Russell Wallace somehow got lost in the mist of time.
39:53In the 19th century, he made a discovery which was hugely significant
39:57for our understanding of the world around us.
40:02To show you what I mean, I'm in one of the leading centres for bird conservation in the world.
40:07This is one of the leading centres for bird conservation.
40:10Here, Ria Sarianthi from BirdLife Indonesia will take me on the trail of Wallace's discovery.
40:16At first, he observed the many birds of Bali, such as the magpie robin.
40:21It's one of the popular songbirds for men.
40:25They have a house, they have a car, wife, and also that bird, the magpie robin.
40:31So it's a status symbol?
40:33Yes.
40:34Wallace catalogued these and thousands of other species.
40:37When it came to mapping out where they lived, he came across something that puzzled him.
40:41Generally, Asian birds like these are only found on Bali or to its west.
40:48But to the east of Bali, there were completely different birds.
40:52Instead, they were all Australian species, such as a cockatoo.
40:57This is Anne Marie.
40:59This is one of the Australian species.
41:01The name is a palm cockatoo.
41:03It came from the eastern part of Indonesia.
41:06Magnificent.
41:07It's well known as a mimic bird.
41:10Do you think it will understand Scottish?
41:12Hello.
41:17But if it's Australian, I'd have to say g'day or something to it.
41:22Anne Marie, hello.
41:25I keep feeling it's going to bite my nose off.
41:27Oh, look at that. Hello.
41:30It was a mystery.
41:32Why should there be Asian birds on one side and Australian on the other?
41:38Wallace realised there was some kind of line dividing bird species.
41:41And it didn't just stop at birds.
41:43It affected other animals too.
41:46Hold on.
41:48Look what I've got. I've got some eggs.
41:53Greedy.
41:54They're so cheeky.
41:55Hiya.
41:56He's got two.
41:59Cheeky one.
42:00From Bali and to the west,
42:02Wallace found mammals that were more typical of Asia,
42:05species like monkeys,
42:07which carried their unborn offspring in their wombs.
42:10To the east, there were marsupials,
42:12who carried their young in pouches.
42:14They are more associated with Australia.
42:19Wallace carefully mapped out this division,
42:22which became known as the Wallace Line.
42:25It extended northwards right through Indonesia.
42:28To the west, Asian species dominated.
42:31To the east of Bali,
42:33there were completely different Australian species.
42:40For all his genius,
42:41Wallace never completely understood the mechanisms
42:44that made the species on either side so different.
42:47Today, partly thanks to volcanoes,
42:50we have the means to find an answer.
42:55This rock, called a lodestone,
42:57is like a miniature version of the earth
42:59because, just like the earth, it's magnetic.
43:02If I put these iron filings on top of it,
43:05they line up with the magnetic field of the rock.
43:12Over millions of years,
43:14as the surface of the earth was being formed,
43:17volcanoes spewed out red-hot molten lava.
43:20That liquid rock contained particles like the iron filings,
43:24which aligned themselves with the earth's magnetic field.
43:28As a molten volcanic rock cooled and hardened,
43:31their alignment became fixed.
43:33They were like tiny compass needles stuck in time.
43:36And these were the key to solving the mystery of the Wallace Line.
43:44The earth's surface consists of giant plates,
43:47which float on a viscous interior.
43:49The original north-south alignment of the stuck compass needles
43:53reveals how these plates have moved through time.
43:58Today, that alignment is out of sync with the earth's magnetic field.
44:03Let me show you with these rocks.
44:05This is Asia, with Indonesia, and this is Australia.
44:09And today they meet across the Wallace Line.
44:12But if we spool back in time 150 million years,
44:15this is what happens.
44:17Australia breaks from Asia and heads south.
44:22But Asia drifts a little bit northwards.
44:25So these were two completely separate landmasses,
44:28and the fauna and flora evolved entirely independently of each other.
44:34We discover that Asia and Australia
44:36have come together from opposite ends of the world.
44:39And that explains why animals on either side of the Wallace Line
44:43have evolved to be so profoundly different.
44:46And it's volcanoes that have helped solve the mystery.
44:51Volcanoes have a much more obvious role to play in evolution.
44:56Every so often, eruptions suddenly obliterate
45:00every animal and plant for miles around.
45:04Quite simply, life has to begin all over again.
45:11For flora and fauna to recolonize an island laid bare by volcanoes
45:15and surrounded by miles of water is an extraordinary feat.
45:21I want to know how they do this.
45:23I'm off to look for clues
45:25on one of the most famous volcanoes in the world, Krakatoa.
45:29Krakatoa sits ominously between Java and Sumatra.
45:33Its most notorious eruption was in 1883
45:36when nearly 40,000 people died.
45:43There was a subsequent eruption of Krakatoa in 1930,
45:47which is not so well-known.
45:53But it happened to be one of the largest eruptions in history.
45:58But it has allowed scientists to discover how plants and animals
46:02re-established themselves following volcanic annihilation.
46:14I'm meeting up with Dr Tukorin Partumihardjo,
46:17a biologist who has spent years studying Krakatoa.
46:20I'm hoping he'll be able to explain to me
46:23the process of natural colonization.
46:28How are you?
46:29Fine.
46:30Look at the weather. This is amazing.
46:32Krakatoa.
46:33Welcome to Krakatoa.
46:34Thank you very much.
46:35Fantastic.
46:36When the first scientists visited the island two months after the eruption,
46:40they could find no sign of life.
46:44The first organism arrived on Krakatoa is spider.
46:48Look at the size of that.
46:50They get here by floating,
46:52using their seal,
46:54and then landed on the island.
46:56They parachute in, do they?
46:58That's right.
46:59And so when they get here, there's absolutely nothing.
47:01Yes, there's no food, so they die.
47:05However, the pollen of simple plants,
47:07such as mosses, lichens and grasses,
47:10was carried out to the island by the wind.
47:13Here is the first plant established.
47:15So the first plant is moss,
47:17within three months after eruption,
47:20and then followed by fern,
47:22about a year later.
47:26The big breakthrough came with the arrival of larger plants.
47:30This is the pioneer grasses.
47:33Usually, within three years after eruption,
47:37it's established.
47:39And this is a very important plant,
47:41because after the grasses die,
47:43then it provides humus for the next plant.
47:48Right, so when this arrives,
47:49it provides the food, then,
47:50for the other plants and insects and everything else to come.
47:53Yes, that's right.
47:55We are to spend the night
47:57in a hut in the shadow of the volcano.
48:03As dinner is prepared,
48:04Dukrun tells me how seven years ago
48:07he experienced Krakatoa's terrifying power for himself.
48:11Inside the ramp, when we landed,
48:13within about ten minutes,
48:15it suddenly erupted.
48:17It was a very big bang,
48:19so everybody got scared.
48:21So what's it like being in the middle of an eruption?
48:23I felt like I was going to die.
48:27It was that strong?
48:29Yes, because there was no place for me to escape.
48:34And what was coming down on you?
48:36Was it just ash?
48:37No, not only ash, but also stone.
48:40So, fwoom, fwoom, fwoom, fwoom, coming down.
48:42And then, after us coming down,
48:45everybody in the booth said,
48:48wow, they were very surprised,
48:51because they assumed that we were already dead.
48:54Wow.
49:02After the 1930 eruption,
49:04animals and plants were carried great distances to the island,
49:08often transported on logs, branches,
49:11and other more surprising rafts.
49:16Pumice like this would have been hurled a great distance by the eruption.
49:20Air holes inside make it light and extremely buoyant.
49:25Large boulders of pumice often get tangled up with other debris
49:29to create a seaworthy platform.
49:32And it would have acted like a kind of Noah's Ark,
49:34carrying small insects, eggs and seeds thousands of miles.
49:38And when it got washed up onto the shore,
49:40this floating life raft would have introduced new and exotic species.
49:51From their studies, scientists found that within three years of an eruption,
49:56insects could survive on the island
49:58by eating the simple plants already growing there.
50:03But bigger creatures had a more difficult time.
50:06They needed to eat more nourishing food if they were to survive.
50:12One breakthrough plant allowed them to get established.
50:20What's this tree?
50:21Oh, this is a fig tree.
50:23It is a very important tree colonising this island.
50:26So what sort of animals eat the figs?
50:28The animal that eat figs is bat and bird.
50:32Right, so bigger, bigger animals now.
50:35Relatively bigger.
50:39The fig was quickly followed by other fruit trees.
50:42And not long afterwards, higher order land animals made the island their home.
50:48So what are the biggest animals on Krakatoa?
50:52The biggest animal at the moment on Krakatoa is a pig.
50:56Pig?
50:57Yes, a wild pig.
50:58Wow, how did that get here?
51:00They can swim.
51:01Can they? I didn't know that.
51:03And what about things that might bite you? Anything dangerous?
51:06Actually, it's not really dangerous.
51:08The animal that can bite you is a python.
51:11Oh right, that's quite dangerous. How did that get there?
51:14Also, similar to pigs, they can swim.
51:16Can they?
51:22However, there's not the same mix of species here as on the Indonesian mainland.
51:33As life returns to islands like Krakatoa, it seems that there is a natural filter.
51:38Only species with mechanisms to travel across the ocean can colonise them.
51:43As a result, there's a real uniqueness to their habitats.
51:50And even when the ecosystem is fully fledged,
51:53fresh eruptions can render barren swathes of the island all over again.
52:02There have been dozens on Krakatoa since 1930,
52:06and each one has left its own trail of destruction.
52:13Just like Tambora, which I visited at the beginning of my journey,
52:17Krakatoa erupted so violently in 1883 that it affected world climate.
52:23But Krakatoa and Tambora are small fry compared with what may lie ahead.
52:36There could be an unfathomably huge eruption on the horizon,
52:40one which would eclipse anything I've talked about so far.
52:43And there's evidence that it all happened right here in Indonesia.
52:47One ancient eruption of this monster volcano came close to wiping out the entire human race.
52:54KRAKATOA
53:08I'm now travelling to Sumatra in the far west of Indonesia,
53:12on the trail of the world's most ominous volcano.
53:16Toba
53:20Toba is the biggest lake in Southeast Asia.
53:26It's a lovely place, a real tourist attraction with its cool, refreshing waters.
53:32But don't be fooled by its serenity.
53:3574,000 years ago, this place couldn't have been more different.
53:41The proof that something happened here is written into these rocks.
53:45They're called ignimbrites, and they can only be formed by those hot pyroclastic flows.
53:51The lake itself, well, that's a pretty big clue too.
53:54It's a volcanic crater filled with water, the biggest in the world.
53:58You can see the edge of it over there.
54:03As for the other end, that's 100 kilometres away.
54:08When the Toba volcano blew, it must have been ferocious.
54:13Geologists have found ash from here as far away as India.
54:18The eruption was probably the biggest in the history of mankind.
54:38Mount St Helens
54:48Toba is estimated to have ejected some 7,000 cubic kilometres of magma.
54:58It was over 3,000 times more powerful than the 1980 Mount St Helens eruption.
55:08Volcanologists have adopted the term humongous to describe Toba's eruption.
55:14I can't argue with that one.
55:25The ash and sulphur thrown up by Toba into the atmosphere
55:29caused six to seven years of global volcanic winter
55:33and may even have kick-started a new ice age.
55:37There is evidence that this dealt a devastating blow to early man
55:41and even affects the way we are today.
55:46There are significantly fewer genetic variations in the human race
55:50than would be expected for a species that has been around for as long as we have.
55:55One explanation is that the food shortages caused by Toba
55:59wiped out 75% of the human population,
56:02meaning that we are all related to a surprisingly small genetic pool of distant ancestors.
56:20These are the ancient Karobatak people
56:23who have lived with this sleeping giant for millennia.
56:27They are bringing me to their sacred ceremonial pools.
56:41The Batak are worried.
56:43Recently the area has been shaken by big earthquakes.
56:46So today the villagers pray to the gods and make offerings
56:50before submerging in the steamy water and anointing their heads.
56:56This is their prayer.
57:01This boiling pool is a sign that the area is geologically unstable.
57:06These bubbles are coming up from a series of fault lines
57:10or cracks in the earth's surface caused by earthquakes.
57:1615 kilometres below Toba is a massive reservoir of molten rock
57:21known as a magma lake.
57:26It's the only one in this part of the world
57:29and it's meshed into this network of unstable fault lines.
57:41The fear is that the earthquakes could open up the faults
57:44which would act as pathways to allow the magma to burst through
57:47and create a super volcano.
57:49It could be as bad as the one that shook the world 74,000 years ago.
57:57The big question is, how would the human race survive?
58:01Should Lake Toba erupt once again and become a cataclysmic super volcano?
58:12Some scientists predict that if one of these eruptions happens again
58:16we'll have to escape the effects by colonising space.
58:19For my money, I think we'd be better off trying to figure out
58:24how to cope with such a colossal event back here on Earth.
58:27The people of Indonesia have been living with their fiery peaks
58:30for thousands of years.
58:32I just hope that we can do as good a job.
58:38More Journeys Into The Ring Of Fire with Ian Stewart
58:41here next Wednesday at 9 o'clock
58:44and have your say about tonight's programme at...
58:48Elemental forces are at play tonight.
58:52Thea Musgrave's turbulent landscapes
58:55and Rachmaninoff's passionate first piano concerto at the Proms next.