:00:15. > :00:19.25 years ago this is what the small Hawaiian community Kalapana looked
:00:19. > :00:23.like. Lush, green and vibrant it was home to 3,500 people. And this
:00:23. > :00:29.is what it looks like now. In tonight's show we're going to show
:00:29. > :00:39.you what happened here and explain why our planet is just so active.
:00:39. > :01:09.
:01:10. > :01:16.This is Volcano Live. Welcome to Hawaii. Welcome to Volcanoes Live.
:01:16. > :01:19.We are in Kalapana on the south- eastern flank of the Kilauea
:01:19. > :01:23.volcano, which has been our home for the last three nights. It is
:01:23. > :01:32.the most active volcano in the world, and here you can really see
:01:32. > :01:35.the devastation that it has wreaked in the last few years. In 1990, a
:01:35. > :01:38.lot of lava work from the east rift came down and took out a community
:01:38. > :01:42.here, but amazingly, people are coming back and building their
:01:42. > :01:46.houses. They, are and we're going to be meeting someone in just a bit
:01:46. > :01:50.who has made that choice, who is rebuilding their home in this
:01:50. > :01:51.desolate landscape, but first, let's see what else is coming up on
:01:51. > :02:01.today's programme. Tonight:
:02:01. > :02:02.
:02:02. > :02:08.I take a Jules Verne-style adventure into the centre of the
:02:08. > :02:14.earth. I explore eruptions and earthquakes. Team of
:02:14. > :02:20.volcanootionologists turn to violence, but all in the name of
:02:20. > :02:25.silence. And Ed Byrne finds out what turns an innocuous wave into a
:02:25. > :02:35.deadly tsunami. Lots to look forward to and you can
:02:35. > :02:39.
:02:39. > :02:44.Or you can Tweet us. Let's give you a little bit of a reminder where we
:02:44. > :02:48.are. We're right in the middle of the Pacific Ocean, the island chain
:02:48. > :02:55.the archipelago of Hawaii, and we're on that Big Island at the
:02:55. > :02:58.bottom. Now, yesterday, we were at the site of the 1969 eruption on
:02:58. > :03:03.Mauna Ulu, another part of the killer volcano. On the show, we
:03:03. > :03:07.packed up and moved down here to the coast. It's quite warm here. We
:03:07. > :03:10.got used to being in the cold in the mist, but now we're in the
:03:10. > :03:16.balmy coastline. We keep talking about Kilauea being the most active
:03:16. > :03:19.volcano in the world. The reason for that is in 1993 lava started
:03:20. > :03:24.pouring out from the east rift over there. You can see it - along the
:03:24. > :03:30.rift is a line of fissures and craters. That's where the lava came
:03:30. > :03:36.out of. Down here that lava is cold. We can walk on it fine, but if you
:03:36. > :03:41.across to the foot of that slope, there is a lot of red stuff coming
:03:41. > :03:46.out. You can see the scale of it. It almost looks like a kind of lava
:03:46. > :03:51.ocean, doesn't it? Ever so often you get what you call break-out,
:03:52. > :03:56.rivers coming down. In other parts you get a hint of magma flowing
:03:56. > :03:59.underneath. It is an extraordinary sight to think that what looks like
:04:00. > :04:04.a dead landscape, which has been active and is no longer active,
:04:04. > :04:10.suddenly there are points which reMind you just of the force of the
:04:10. > :04:15.volcano. Exactly. It's good to get an idea of how volcanoes move that
:04:15. > :04:20.slow creeping across the landscape. Our time-collapse cameras have been
:04:20. > :04:25.set up at the edge of the volcano. You can see how it does creep in
:04:25. > :04:30.this insidious way. It's addictive watching it. It's hypnotic. It is.
:04:30. > :04:33.It's a beautiful movement, but as you said yesterday not a killer
:04:33. > :04:39.because it's so slow. The thing is it's so hot, you can't get a feel
:04:39. > :04:43.of how hot it is unless you see it at night. You can see the creeping
:04:43. > :04:50.lava. It starts to fire off - little bits of vegetation starts to
:04:50. > :04:53.burn, so those temperatures are easily 500, maybe 700 degrees.
:04:53. > :04:59.is a spectacular sight, less spectacular probably if you were
:04:59. > :05:03.one of the people living here when the lava flows started heading this
:05:03. > :05:07.way. We have some extraordinary footage of the day the lava crept
:05:07. > :05:11.towards this community, and as you can see, it was a slow creep.
:05:11. > :05:14.People were able to rescue their possessions. They were able to move
:05:14. > :05:17.- even move buildings. That's the church. The church moving - it's
:05:17. > :05:22.extraordinary. That's now about five miles down the road, but what
:05:22. > :05:25.a lot of people weren't able to do was obviously to move their houses,
:05:25. > :05:31.and the inevitable happened. What we must emphasise - absolutely no-
:05:31. > :05:37.one was killed in that eruption, but it did leave something like 180
:05:37. > :05:42.houses destroyed - many of them, sadly, under this lava. It's
:05:42. > :05:45.slightly eerie walking here because underneath are people's homes. Many
:05:45. > :05:49.times you get the debris of people's homes. You do. If you walk
:05:49. > :05:55.around the lava here, you can see what looks like people have just
:05:55. > :06:00.dumped rubbish. They haven't at all. The furniture you can see, the
:06:00. > :06:04.bathtub - those are actually entombed in lava. The car is one of
:06:04. > :06:08.the iconic images. It's a real reminder that this was once a
:06:08. > :06:11.vibrant community, and you would think that now it would be
:06:11. > :06:17.completely deserted, but that's not the case because just over there
:06:17. > :06:20.you can see that there are houses back being built on the lava. Now,
:06:21. > :06:25.that does seem to be an extraordinary - well, a madness,
:06:25. > :06:28.really. Well, one of the people that has moved back to Kalapana is
:06:28. > :06:32.Robert McKnight. Good morning. morning. Lovely to see you. Thank
:06:32. > :06:37.you for joining us today. You're welcome. Can you tell me when you
:06:37. > :06:43.moved here for the first time? moved out here on the lava about
:06:43. > :06:48.2005 I think it was, yeah. So there had already been lava flows - the
:06:48. > :06:52.very destructive lava flows we saw in that earlier film - had already
:06:52. > :06:57.happened? Yes. So you made a conscious decision to move to a
:06:57. > :07:01.place that had already been wiped out by a volcanic eruption? Yes, I
:07:01. > :07:05.did! Now, you laugh about that, and actually, we have had questions
:07:05. > :07:11.about people like you - I mean, you're not unique. There are plenty
:07:11. > :07:15.of people the world over who live in the shadow of volcanoes. One of
:07:15. > :07:19.our viewers, John, from Staffordshire, said, "Why do people
:07:19. > :07:22.insist in living near volcanoes even though they know the dangers?"
:07:22. > :07:32.why did you decide to move here? think the biggest reason was the
:07:32. > :07:35.openness of the area. It lacked mosquitoes and frogs, so that was
:07:35. > :07:40.something - I was allergic to mosquitoes, and probably one of the
:07:40. > :07:44.most important factors for me was the opportunity to get ocean-front
:07:44. > :07:47.land that was very reasonable in price and still just beautifully
:07:47. > :07:53.expansive, and the weather is great out here. The small issue of lava
:07:53. > :07:56.covering me was put in the background, and - you know...
:07:56. > :08:01.you slightly think, it's happened already. It probably won't happen
:08:01. > :08:07.again? Was that sort of in the back of your mind? It did. It was
:08:07. > :08:11.actually pouring a few miles past my house into the ocean. I just
:08:11. > :08:19.felt that the width of the lava pouring down the mountainside would
:08:19. > :08:23.be a high chance of running me over again, but lo and behold, you know,
:08:23. > :08:27.the Pu-u O'O vents shut down from an earthquake and moved eastward a
:08:28. > :08:32.few miles, and sure enough, it came down the hillside and went right
:08:32. > :08:37.next to my house and eventually took the house. So at that point, I
:08:37. > :08:40.mean, how - can you describe how it feels? You know, for us, we live in
:08:40. > :08:45.a very benign country. In England, we don't have any volcanic
:08:45. > :08:49.eruptions. How does it feel to witness that very slow creep of
:08:49. > :08:54.lava towards the thing that you've built with your own hands? You must
:08:54. > :09:00.have felt very emotional at that moment? I was, and reflecting maybe
:09:00. > :09:04.on people that were here 15 or 20 years earlier that had a lot of
:09:04. > :09:09.green vegetation and homes - they watched the pulsing of the lava
:09:09. > :09:14.coming and stopping and coming. It's torturous because it may or
:09:14. > :09:19.may not take your place, so there is a lot of waiting. It certainly
:09:19. > :09:25.interrupts one's life completely, and it's painful no matter what to
:09:25. > :09:28.see one's own house go up in flames and get covered. I suppose that
:09:28. > :09:33.then makes your decision to come back even more extraordinary
:09:33. > :09:39.because you lost your home - all of those years of work building it.
:09:39. > :09:44.You'd come, as you say, to your bit of paradise, and yet if we look,
:09:44. > :09:49.we've got a camera I think just over there. You are rebuilding
:09:49. > :09:52.again. Rebuilding. You're just a glutton for punishment, Robert?
:09:52. > :09:59.hope not. There were financial choices, of course, too. I couldn't
:09:59. > :10:04.hop on a jet and go where I wanted to, so it left me, unfortunately,
:10:04. > :10:07.with - out the assets to do much, with and that property once again
:10:07. > :10:11.was inexpensive - less expensive than my ocean front. I am slightly
:10:11. > :10:15.surprised you have to pay for it at all. Aren't they just giving it
:10:15. > :10:19.away? Some people feel that way and don't want to live here, but those
:10:19. > :10:23.of us who do - it is just a wonderful atmosphere if you're not
:10:23. > :10:29.looking at lava coming at you. Unfortunately for my second place
:10:29. > :10:35.that I quickly got to have a place to live in, actually, after losing
:10:35. > :10:41.my actual house - the lava after two years' time wound up 300 feet
:10:41. > :10:46.off of my doorstep again, and I was looking out at a very real threat
:10:46. > :10:53.of the lava covering me. My house wasn't, again, finished at the time,
:10:53. > :10:57.but that was, you know, a very terrible feeling that I just can't
:10:57. > :11:02.have that happen to me twice. Twice! And it subsided, actually
:11:02. > :11:06.has moved back to where it had been years before, so I get a little
:11:06. > :11:12.reprieve - at least to get my house finished and insurance on it this
:11:12. > :11:17.time. I won't have the financial losses, you know, just kind of the
:11:17. > :11:21.emotional - but, you know, with this compensation. But how would
:11:21. > :11:27.you describe the community that do live here? Do you think - are you
:11:27. > :11:31.kind of pioneers? What - how do you describe yourselves? I don't know.
:11:31. > :11:38.Everyone out on the lava I think is looking for, you know, the nice
:11:38. > :11:43.weather, and it is the expense. Homes were getting very expensive a
:11:43. > :11:47.few years back, and for the average person, it's stressful to find
:11:47. > :11:55.their paradise in Hawaii, so people that are out here on the lava can
:11:55. > :11:59.enjoy all the amenities of living in Hawaii, but, you know, the real
:12:00. > :12:03.estate itself is affordable. kind of unique. And very unique
:12:03. > :12:07.also, so there are a lot of pluses here, and everyone that does live
:12:07. > :12:12.out here in these communities now really do appreciate being out here.
:12:12. > :12:17.They really like being out here. Well, Robert, it is a very special
:12:17. > :12:21.place. I wish you all the luck, and I hope the lava stays at a good,
:12:21. > :12:25.safe distance. Thank you very much. Thank you. You're welcome. So it is
:12:25. > :12:29.perhaps surprising that people like Robert choose to live in areas of
:12:29. > :12:33.the world that are geologically volatile, and it's particularly, as
:12:33. > :12:43.Ian explains now, because science absolutely knows where those areas
:12:43. > :12:46.
:12:46. > :12:50.are and what makes them so I've come to the Bay of Naples to
:12:50. > :12:55.see what is for me the most important Roman ruin in the whole
:12:55. > :12:58.of Italy. There she is I know it doesn't seem like much just
:12:58. > :13:03.sandwiched between all of these kind of modern apartments and
:13:03. > :13:13.restaurants and right beside this busy road, but this - this is a
:13:13. > :13:14.
:13:14. > :13:18.This is the Temple of Serepus. Just a stone's throw from the sea, it's
:13:18. > :13:23.not actually a temple at all. It was a Roman marketplace built
:13:23. > :13:29.around 2,000 years ago, but it's still kind of a demp for gee olss
:13:29. > :13:32.because of this book, Charles Lyle's Principles of Geology. This
:13:32. > :13:40.book is the cornerstone of modern geology.
:13:40. > :13:45.And right here, embossed in gold on the front, the Temple of Serepus.
:13:45. > :13:50.This place changed the way Lyle looked at the world, not because of
:13:50. > :13:56.the ruins themselves but because of the tiny holes that pock mark the
:13:56. > :14:03.three marble pillars. Crucially, he wreck niessed this as something you
:14:03. > :14:09.commonly find on piers around here. It's formed by a kind of clam, a
:14:09. > :14:17.tiny sea creature that nibbles its way into stone. He knew that the
:14:17. > :14:21.Romans originally built a structure on dry land, but the holes in the
:14:21. > :14:28.pillars meant it somehow got emerged in the sea only to rise
:14:28. > :14:31.back up again. It convinced Lyle that the land was constantly moving,
:14:31. > :14:37.constantly changing, and what's more is those processes are still
:14:37. > :14:42.going on today. It can be observed all around us. That principle is
:14:42. > :14:51.the foundation upon which modern geology rests. Today geologists
:14:51. > :14:57.have a theory to explain Lyle's observations, the theory of plate
:14:57. > :15:01.tectonics. Its surface is broken into lots of different pieces, like
:15:01. > :15:04.a jigsaw, and those plates are constantly moving. The boundary
:15:04. > :15:13.between two of the plates runs right the way through Italy. Here
:15:13. > :15:17.in the Bay of Naples I am on the Eurasian plate which is more or
:15:17. > :15:24.less stationary compared to the African one, which is to the north,
:15:24. > :15:30.shunting into the Eurasian plate, so effect lively the two plates
:15:30. > :15:37.have collided. Because the African plate is denser, it slides beneath
:15:37. > :15:42.the Eurasian plate. This is known as subduction. This is the Eurasian
:15:42. > :15:46.plate here, for an E. This is African plate that comes down and
:15:46. > :15:52.subducts below it, so here's Africa. That's moving in that direction
:15:52. > :15:56.there. As that slab descends deeper into the mantle, the temperatures
:15:56. > :15:59.get hotter and the pressures get higher. Down there hundreds of
:15:59. > :16:04.kilometres below the surface inside the plate and locked away in
:16:04. > :16:07.minerals of the rock was water, water that under that hot, pressure
:16:07. > :16:13.cooker environment gets forced out. The reason that's important is that
:16:13. > :16:18.the water reduces the melting temperature of the mantle rocks
:16:18. > :16:28.turning solid rock into magma, magma that pools and rises up
:16:28. > :16:29.
:16:29. > :16:34.through cracks and fractures in the The Temple of Serepus and this area
:16:34. > :16:38.is above the subducting plate. Beneath the ground lies a huge pool
:16:38. > :16:44.of magma. You don't have to go far from the temple ruins to find
:16:44. > :16:51.evidence of it. Just a kilometre down the road, hot gases seeping up
:16:51. > :16:56.from below have created this alien landscape. The subduction of the
:16:56. > :17:01.African plate beneath the Eurasian plate allowed magma to rise up
:17:01. > :17:07.towards the surface. Now, huge quantity tease of magma have pulled
:17:07. > :17:14.in a vast chamber just 10 dill meters beneath my feet. Gases paint
:17:14. > :17:19.the rocks yellow. Water, that has been heated to boiling point under
:17:19. > :17:23.ground, comes out as steam as the temperatures rises and falls the
:17:23. > :17:27.land in this areas goes upwards and sinks back down. Over time the
:17:27. > :17:34.Temple of Serepus, which was originally built on the shoreline,
:17:34. > :17:39.has found itself submerged beneath the sea. The magma chamber beneath
:17:39. > :17:44.the ground here is one string along this plate boundary. The same
:17:44. > :17:51.subducting plate produces the magma that fuels all of Italy's famous
:17:51. > :17:56.volcanoes like Etna and the others. Subducting plate boundaries like
:17:56. > :18:01.this one are responsible for 80% of all the volcanoes on the planet.
:18:01. > :18:04.Volcanoes are like beacons, marking out the places where these shifting
:18:04. > :18:10.plates collide. They are not the only evidence that the surface of
:18:10. > :18:15.our plan set constantly on the move. Plates are the ridgied skin of the
:18:15. > :18:21.earth. The Terra firma on which we live. Because the plates are
:18:21. > :18:23.constantly moving, when one continent-size slab of rock grinds
:18:23. > :18:28.into another, tremendous pressure builds up. Enough pressure for that
:18:28. > :18:32.crust to snap and break. When that happens, you get earthquakes.
:18:32. > :18:36.Another earthquake has struck northern Italy killing at least 15
:18:36. > :18:42.people and burying several others... Eight weeks ago, the same
:18:42. > :18:47.subducting plate boundary, that produces Italy's volcanoes, caused
:18:47. > :18:53.a series of lethal earthquakes. Over a year ago, subducting plates
:18:53. > :18:58.beneath the Pacific Ocean caused the massive erk which in turn
:18:58. > :19:02.triggered the Soviet Union that devastated the coast of Japan. 5%
:19:02. > :19:12.of all the world's earthquakes are caused by subducting plate
:19:12. > :19:14.
:19:14. > :19:18.boundaries. -- tsunami. It's driven by internal heat escaping from the
:19:18. > :19:24.heat of the plan wet that comes earthquakes and volcanoes. There is
:19:24. > :19:28.no Bert evidence that earth is a dynamic place, changing all the
:19:28. > :19:32.time, sometimes violently. It may seem to us as humans the ground on
:19:32. > :19:42.which we stand is fixed, but it's constantly on the move, just as
:19:42. > :19:43.
:19:43. > :19:48.A point that comes out of that film, we have known for a couple of
:19:49. > :19:54.centuries now the land moves in earthquakes and volcanos. We know
:19:54. > :20:01.where the plates are. We have a map where the plates are. We have a map
:20:01. > :20:07.here. You can see them there. What we can do, we can put all of the
:20:07. > :20:14.known volcanoes, 1600 that erupted. It is obvious that the majority of
:20:14. > :20:20.them run along coastlines. Along the coast of North America, South
:20:20. > :20:24.America. Through the Med and the Ring of Fire. A lot of these
:20:24. > :20:28.volcanoes are caused at the junction between the coast and the
:20:28. > :20:33.oceans. That is where the ocean plates are sinking. Getting forced
:20:33. > :20:37.under the continental ones. They are disappearing down there and
:20:37. > :20:41.creating subduction own volcanoes. If we look at the maps. These
:20:41. > :20:45.volcanoes have been active in the last 24-hours. They map really the
:20:45. > :20:50.majority of them are in those subduction zones. These are the
:20:50. > :20:56.nasty volcanoes, aren't they? They are the dangerous ones? The reason
:20:56. > :21:01.for that is, the ocean plate, as it pushes down here, in the film I
:21:01. > :21:07.explained how the magma melts, rises up and punctures through. As
:21:07. > :21:11.it rises through the continent it picks up minerals that makes the
:21:11. > :21:14.magma sticky. It traps gases which gather pressure, when they get to
:21:14. > :21:18.the surface they explode out. Those are the real killers. The other
:21:18. > :21:23.thing that causes us human beings to notice that our planet is as
:21:24. > :21:28.dynamic as it is is earthquakes. Is there a correlation between
:21:29. > :21:33.earthquakes and volcanoic explosion? Let's look at where the
:21:33. > :21:41.latest earthquakes have been. These are all these green circles are all
:21:41. > :21:46.the earthquakes that have happened in the last 24-hours that over 0.2?
:21:46. > :21:50.The size of the circle relates to the side size. This is a 5.2 in
:21:50. > :21:56.Papua New Guinea. Not very much for Papua New Guinea. If it happened in
:21:56. > :22:01.Britain it would be one of our biggest one ever. Volumes come
:22:01. > :22:06.along the plate boundaries. They related. If you think about the
:22:06. > :22:10.population centres... Yes, scary. If you think about the number of
:22:10. > :22:14.people who live along that coast of America, Southeast Asia in
:22:14. > :22:18.particular. It's not just the people of Kalapana who insist on
:22:18. > :22:22.coming back to a volume cannically active area, it seems to be
:22:22. > :22:27.something that people the world over do. It was a couple of those
:22:27. > :22:37.particularly densely populated areas in Southeast Asia and Japan
:22:37. > :22:37.
:22:37. > :22:42.that were so devastatingly affected by the tsunamis in 2004 and 20111.
:22:42. > :22:45.Ed Byrne went to investigate how an earthquake can trigger one of these
:22:45. > :22:50.earthquake can trigger one of these deadly waves. Powerful earthquakes
:22:50. > :22:58.and the immense tsunamis caused by them have killed over 800,000
:22:58. > :23:02.people. An experiment has been set up to show how the build-up of
:23:02. > :23:06.pressure is the primary cause between all earthquakes. These are
:23:06. > :23:10.our tectonic plates then? plates are moving together against
:23:10. > :23:13.each other. There is friction at their interface which is locking
:23:13. > :23:18.them together. The stress builds over what can be decades or even
:23:18. > :23:23.hundreds of years. As the energy increases and increases, hopefully
:23:23. > :23:26.we will see the time of the earthquake. They just popped.
:23:26. > :23:31.is the earthquake that happened. The energy that built up over
:23:31. > :23:36.hundreds of years is released in seconds. That generates the seismic
:23:36. > :23:43.wave that is cause earthquakes. That earthquake we demonstrated
:23:43. > :23:47.there, what type would we call that? Subduction events. That
:23:47. > :23:51.triggered the Indian tsunami. One plate can go below the other. They
:23:51. > :23:54.enter lock. The top plate is being dragged down as well. When the
:23:54. > :24:01.earthquake happens you have a spring back of the top plate, which
:24:01. > :24:06.is causing the movement of water above that generates a tsunami.
:24:06. > :24:10.2004 Boxing Day tsunami was formed 100 miles off the Indonesian coast
:24:10. > :24:14.when a subduction earthquake triggered a massive displacement of
:24:14. > :24:20.water above. It the wave travelled at the speed of a jet plane, but it
:24:20. > :24:26.was a meter or so high. How did such a small wave turn into the
:24:26. > :24:29.immense wall of water that killed so many people? I'm meeting Dr Adam
:24:29. > :24:35.Crewe from Bristol University to find out. Tim will help us show
:24:35. > :24:40.what happens when the tsunami hits the shoreline. Hello, Tim. It is
:24:40. > :24:44.not that high. Come coming down. There it breaks. A massive amount
:24:44. > :24:48.of money travelling at speed, what cause it is to break there on the
:24:48. > :24:52.shore? We were moving so much water up there, very, very deep, deep
:24:52. > :24:57.wave. It was going quite fast. As the waves get closer to the
:24:57. > :25:01.shoreline, they start slowing down because the water gets shallower.
:25:01. > :25:06.The front of the wave was slowing down, the back kept going, the
:25:06. > :25:11.water builds up. The back of the wave catches up with the front of
:25:11. > :25:16.the wave. As it gets high enough it starts breaking. Tsunamis are long
:25:16. > :25:21.waves. Once you have them, the water hits the shoreline, it keeps
:25:21. > :25:26.going. It does not act like a normal wave on the beach, it keeps
:25:26. > :25:32.going and that is why they cause so much damage. I understand how a
:25:32. > :25:36.subduction earthquake at sea can displace water and cause a tsunami.
:25:36. > :25:41.What makes earthquakes so destructive on land? It is to do
:25:41. > :25:44.with seismic waves. There are two different types of seismic wave
:25:44. > :25:49.that are generated at the time of an earthquake. The first one, the
:25:50. > :25:54.primary waves, travel like pulses in the ground, through compression
:25:54. > :25:58.and they are very much like sound waves travel through the air. The
:25:59. > :26:03.second type of wave travels side ways. Side to side movement causes
:26:03. > :26:07.the way to go... Forward. Forward. That is right. Primary and
:26:07. > :26:11.secondary waves bounce off or interact with the surface. They set
:26:11. > :26:16.up new ways called surface waves, which are the one that is cause the
:26:16. > :26:21.destruction. If I wanted to see the primary and secondary waves, and
:26:21. > :26:24.the surface waves in action, where better than the country's biggest
:26:24. > :26:29.earthquake simulator. Adam explains that one of the weigh ways to
:26:29. > :26:34.measure the seismic wave is using magnitude scale like the Rickster
:26:34. > :26:42.scale. The Rickster scale is surprisingly complicated, isn't it?
:26:42. > :26:47.If you start at, for example, two then jump to three it's 30 times
:26:47. > :26:57.more energy. 0 times more powerful the earthquake. When we go to four,
:26:57. > :26:57.
:26:58. > :27:07.30 times more powerful. A magnitude four earthquake is 900 times
:27:08. > :27:08.
:27:08. > :27:13.stronger than a two. That is headed close towards the six. That is what
:27:13. > :27:18.they would get down in Greece, Portugal and Italy. They come
:27:18. > :27:28.together to form these seismic surface waves. I have been
:27:28. > :27:30.
:27:30. > :27:35.listening. On to the Japanese and How long would they normally last
:27:35. > :27:41.in real-life? How long does an earthquake of this magnitude last?
:27:41. > :27:45.Two or three minutes. Really? would keep seeing,away. That lasted
:27:45. > :27:50.a minute. You could get three or four minutes of that. Today, I have
:27:50. > :27:56.learnt earthquakes come in all shapes, sizes, colours and flavours.
:27:56. > :28:06.Subduction faults under the sea can cause destructive tsunamis on land
:28:06. > :28:08.
:28:08. > :28:15.it's seismic waves which do all the damage. Now, Hawaii sits slap bang
:28:15. > :28:24.in the middle of the Pacific plate. Right in the middle is this set of
:28:24. > :28:28.islands, in 1946, Halo suffered a tragic tsunami disaster. This is
:28:28. > :28:33.the 1946 tsunami. You see the surge of water coming into the harbour
:28:33. > :28:42.town. 96 people lost their lives. As often is the case, these
:28:42. > :28:49.tragedies are the impetuous for doing something about it. I have Dr
:28:49. > :28:55.Fryer from the Pacific tsunami warning system. What is the remit
:28:55. > :28:59.of the organisation? Basically, we provide warnings, tsunami warnings,
:28:59. > :29:06.to the entire Pacific and the Indian Ocean and the Caribbean. The
:29:06. > :29:10.way we operate is, basically, we are looking for earthquakes. And,
:29:10. > :29:16.the worldwide seismic graphic network we get all that data in
:29:16. > :29:21.real time. So, we can issue a warning, within about 10 or 11
:29:21. > :29:26.minutes of any earthquake anywhere in earth. The last big one was the
:29:26. > :29:36.Japan one in 2011. You worked closely on that, haven't you?
:29:36. > :29:39.
:29:39. > :29:44.That earthquake, we knew about it 40 seconds later, monitors in Japan
:29:44. > :29:49.transferred to us. They got a warning out in 2 minutes and 40
:29:49. > :29:52.seconds. The earthquake lasted three minutes. They under estimated
:29:52. > :29:59.the magnitude of the earthquake which was part of their tragedy. We
:29:59. > :30:03.took a little longer. We issued our warning at nine minutes. You have
:30:03. > :30:11.footage of what that tsunami did. This is extraordinary. This is a
:30:11. > :30:16.set of waves. The heights are here, a meter high. That was Japan. Here
:30:16. > :30:20.are the Hawaii islands. We are now about six hours into it, the
:30:20. > :30:24.tsunami hit the Hawaii islands at about seven hours. It went on. You
:30:24. > :30:30.will notice behind the leading waves there are waves reflected so
:30:30. > :30:36.the ocean is just Oz lating. It's a few tens of metres or a meter in
:30:36. > :30:40.the ocean it's when it gets to the coast... The waves slow down in
:30:40. > :30:44.shallow water, to carry the same amount of energy they have to grow
:30:44. > :30:52.in height they will grow by a factor of four or five. It took 22
:30:52. > :30:56.hours to get to South America. The waves are big. Southern Chile was
:30:56. > :31:02.hit by waves 2.5 metres high. Significant damage. Boats were
:31:02. > :31:08.carried into the town. Now, we see the tsunami getting through the
:31:08. > :31:13.Drake Passage and into the South Atlantic. The waves are small.
:31:13. > :31:17.Outside of Japan how many people were killed? The warning system
:31:17. > :31:23.worked. Two deaths. A photographer who wanted a good picture. One
:31:23. > :31:32.death the other side of the ocean in Papu in the Indonesian part of
:31:32. > :31:35.What about Hawaii? Can it generate its own tsunamis? Yes, we have big
:31:35. > :31:40.earthquakes in Hawaii because we have big volcanoes, and the
:31:40. > :31:44.volcanoes are very large, very heavy, but weak. And they're
:31:44. > :31:49.constantly collapsing and oozing out sideways, but they're also
:31:49. > :31:52.being pushed. They have rift zones that fill up with magma, then exert
:31:52. > :31:57.with outward pressure, so every once in awhile the whole of the
:31:57. > :32:00.volcano will slip outwards 30 feet. The ocean gets pushed out of the
:32:00. > :32:05.way. Presumably that doesn't give you a warning to issue. That's
:32:05. > :32:10.right. The word around the Hawaiian islands is deep, so that means the
:32:10. > :32:13.tsunami travels very fast. The last time something like this happened
:32:13. > :32:18.was 1975. The epicentre was actually right at this spot. At
:32:18. > :32:23.that time it took us an hour to get a warning out. Now we're down to 20
:32:23. > :32:27.minutes. How about those subduction zone ones? How much warning do you
:32:27. > :32:35.give for people to get off the beachs? For Hawaii, there are
:32:35. > :32:42.sirens, and if we decide an earthquake is - provides a tsunami
:32:42. > :32:46.hazard, then we just go off on the blower and say, "All counties sound
:32:46. > :32:49.your sirens" and without question, they push their buttons. People
:32:49. > :32:53.react accordingly, do they People on the big islands certainly will,
:32:53. > :32:57.because they'll have felt the shaking. On the other islands,
:32:57. > :33:00.they'll have probably felt shaking, but fortunately the sequence of
:33:00. > :33:04.events that's happened in the recent past, everyone is educated
:33:04. > :33:08.what to do. You know, Hawaii sits right in the middle of plate, but
:33:08. > :33:18.it's along the edges of the plates where most of the geological action
:33:18. > :33:22.
:33:23. > :33:27.occurs, so we went off to Iceland From above it's clear that
:33:27. > :33:32.Iceland's landscape is scarred with great cracks and fissures, as if it
:33:32. > :33:37.has been ripped apart like paper. Some cracks are several miles long
:33:37. > :33:43.and added together, they form a huge rift, which crosses the entire
:33:43. > :33:48.country. For millions of years, the North American plate has been
:33:48. > :33:55.drifting westwards, while the Eurasian plate has been creeping to
:33:55. > :33:59.the east, like two enormous conveyor belts moving in opposite
:33:59. > :34:04.directions. These tectonic forces are tearing Iceland apart, and the
:34:04. > :34:10.results of this monumental tug-of- war are clearly visible in the
:34:11. > :34:16.landscape. As the plates pull apart, magma rises from the earth's mantle
:34:16. > :34:26.to fill the gap, so wherever there are cracks in the crust, there are
:34:26. > :34:31.volcanoes too, great long lines of them running along the central rift.
:34:31. > :34:38.I've come to south-west Iceland to find out more about these great
:34:38. > :34:42.tectonic features. For scientists like Bjorn Otson, studying active
:34:42. > :34:46.volcanoes can be a dangerous job, but here, there's a unique
:34:46. > :34:56.opportunity not just to get close to a volcano, but to go right
:34:56. > :34:57.
:34:57. > :35:04.Mountaineers who are making final preparations for an extraordinary
:35:04. > :35:08.descent, a real-life journey to the centre of the earth. They've rigged
:35:08. > :35:18.up a mechanical lift, which will lower us directly into what was
:35:18. > :35:22.once the fiery mouth of this volcano. It's a first for both of
:35:22. > :35:27.us, and I, for one, am slightly apprehensive. Are you a little bit
:35:27. > :35:31.nervous about this slightly Heath Robinson piece of kit that we're
:35:31. > :35:39.descending into the bowels of the earth in? I think it will work.
:35:39. > :35:43.hope so. I hope so too. Crossing over to the lift feels a bit like
:35:43. > :35:53.walking plank, and the gaping hole beneath is impossible to ignore,
:35:53. > :36:01.
:36:01. > :36:09.narrow bit here. It's a strange feeling, being
:36:09. > :36:14.slowly swallowed up by the mouth of a volcano. It's a very kind of
:36:14. > :36:20.organic feeling - space, this, isn't it? Yes. It feels almost
:36:20. > :36:24.alive, the kind of shapes of the rock. It's just like it happened
:36:24. > :36:30.yesterday. Yeah! You can see the bits of magma kind of left on the
:36:30. > :36:34.side of the chamber. When it was plastered on the wall, it was not
:36:34. > :36:40.fully solidified. So these sort of chocolate-like drips stuck to the
:36:40. > :36:50.walls, that's the remnants of magma? Yes, the remnants. Gravity
:36:50. > :36:53.
:36:53. > :36:58.pulls it down and it freezes. That's incredible. As we descend
:36:58. > :37:08.further, the tube widens out, and we lose sight of the walls. We're
:37:08. > :37:31.
:37:31. > :37:41.taller than St Paul's Cathedral. Powerful lights help to reveal the
:37:41. > :37:47.
:37:47. > :37:53.huge space which is truly an extraordinary that I really wasn't
:37:53. > :37:57.expecting - was the colour. It's just a riot of every colour you can
:37:57. > :38:02.think of. That's true to the Icelandic mountains. They're built
:38:02. > :38:07.up with many layers and many events of volcanic eruption, and we see
:38:07. > :38:14.both ash and lava from different types of volcanic eruptions, so
:38:14. > :38:19.this is like an open book. You can read the story of this mountain.
:38:19. > :38:23.The red and orange rocks down here are all old lava flows from
:38:23. > :38:28.different periods in the history of this fissure. As lava flowed to the
:38:28. > :38:33.surface, layer after layer built up to create the mass of the volcano
:38:33. > :38:38.above our heads. In the damp air of the cave, chemical reactions have
:38:38. > :38:48.changed the colour of the rocks in those old lava flows, like the rust
:38:48. > :38:50.
:38:50. > :39:00.it's important to remember the significance of this huge crack in
:39:00. > :39:09.the earth. We're not only exploring the bowels of a volcano - this
:39:09. > :39:15.place is part of a much bigger system. Most volcanic eruptions in
:39:15. > :39:18.Iceland are on fissures, so Iceland is pulled apart, so this is the
:39:18. > :39:24.centre, and on your one side, we see the North American plate. On
:39:24. > :39:28.the other side, we see the Eurasian plate. So we're sort of standing in
:39:28. > :39:32.the middle of those two tectonic plates? Yes, the two continents.
:39:32. > :39:41.Does that mean effectively what we're doing is standing in a kind
:39:41. > :39:46.of no-man's-land between the two? We're in Iceland! Good answer. It's
:39:46. > :39:51.hard to predict which part of Iceland's rift will open up next.
:39:51. > :39:56.But by studying these active zones, not only on the surface, but now
:39:56. > :40:02.also within the fissure itself, Bjorn and his team stand to learn
:40:02. > :40:12.much more about how Iceland's tectonic forces give birth to
:40:12. > :40:14.
:40:14. > :40:18.do that, I thought she's just going to get into a big, black hole where
:40:18. > :40:24.you can't see, but just looking at that film... You have gone slightly
:40:24. > :40:27.green. I didn't think it was going to be - like you said... It was an
:40:27. > :40:30.incredible experience. And it was just a really great way to
:40:30. > :40:34.understand that formation of Iceland, so, you know, if we just
:40:34. > :40:38.run through it again - you've got your North American plate and your
:40:38. > :40:44.Eurasian plate. Will you be my plume for me? Yes. So you've got
:40:44. > :40:47.the plume coming up, and that plume is basically creating Iceland.
:40:47. > :40:51.there. But what's really interesting is, it was the exact
:40:51. > :40:56.same process that also helped create some of the features that we
:40:56. > :41:00.love in Britain because if we do it again - our North American - and -
:41:00. > :41:05.this is the UK. Exactly. This is North America. That's the UK. If we
:41:05. > :41:10.go back 55 million years ago, you don't have an Iceland. You don't
:41:10. > :41:14.even have a North Atlantic ocean. The plume comes up - it breaks the
:41:14. > :41:21.continent apart. You get a chain of volcanic centres, so you have
:41:21. > :41:24.volcanic centres that are in Aaron, in Mull, in Sky. It's spewing out
:41:24. > :41:29.the lava. The Giant's Causeway is one. Then what happens is that
:41:29. > :41:32.plume kind of breaks it up... Pushes it apart. The ocean just
:41:32. > :41:36.drifts apart, so that today North America is here. Britain is here.
:41:36. > :41:40.So the plume is coming up here - that's where Iceland is. Could you
:41:40. > :41:45.get to a point where Iceland stops effectively being the grout between
:41:45. > :41:49.the two plates, and that then gets forced apart, and you get sort of
:41:49. > :41:53.ice and land? Yeah, I guess. I think what'll happen is if the
:41:53. > :41:58.plume starts to be less dynamic, then what'll happen is there will
:41:58. > :42:02.be less material coming out, and you'll get a west and east
:42:02. > :42:07.Iceland... That drifts apart. Hawaii is a bit of an anomaly then
:42:07. > :42:11.- I said it! I can never say that word. It's not on plate boundary,
:42:11. > :42:15.is it? No, but it's on a moving plate. One of the issues is you
:42:15. > :42:20.have one plate and then one moving up. We have a Graf graphic that's
:42:20. > :42:25.going to explain it. We have the plume coming up. It punches its way
:42:25. > :42:28.through and creates this volcanic island. Because it's on the moving
:42:28. > :42:33.plate it carries itself north- westwards on almost a conveyor belt,
:42:33. > :42:39.and the magma is still coming up. So another new island pops up.
:42:39. > :42:44.Create another new island. There we go. That's why when you look at the
:42:44. > :42:49.Hawaiian archipelago it is a new line of islands. Exactly. It looks
:42:49. > :42:53.like the checkout in the supermarket - the whole set of
:42:53. > :42:57.things become a volcanic island. Eventually, we'll get a new island.
:42:57. > :43:01.Hawaii will become inactive. So the one we're standing on will drift
:43:01. > :43:05.north. We'll actually get a new island. The new Hawaii is over
:43:05. > :43:11.there, so about 22 miles offshore, there is an island, which is only a
:43:11. > :43:15.thousand metres - 3,000 feet below sea level. It's rising up. So if
:43:15. > :43:20.anyone on Kalapana really want new land, hang around for tens of
:43:20. > :43:24.thousands of years and occupy that one that pops up. Fascinating stuff.
:43:24. > :43:30.The lava plume below Hawaii doesn't just create new islands. It moves
:43:30. > :43:35.the earth in a way that scientists at the Volcano Observatory have to
:43:35. > :43:40.be very busy indeed. My name is Weston, and I am the seismic
:43:40. > :43:47.network manager here at the Hawaiian Volcano Observatory. I
:43:47. > :43:51.study specifically earthquakes that Obviously, we've got a very active
:43:51. > :43:57.volcano setting here. We have Kilauea that's active and has been
:43:57. > :44:02.active for several decades. We've got Mauna Loa that isn't currently
:44:03. > :44:10.erupting but has a long history of very frequent eruptions, so by
:44:10. > :44:15.recording earthquakes, we can start to understand some of the process's
:44:15. > :44:17.that are going on under the volcanoes. We start to forecast
:44:18. > :44:21.volcanoes and when they might happen. What's really, really fun
:44:21. > :44:25.is when you find something out about the volcano you didn't know
:44:25. > :44:31.before. That's what I think I live for, and I think what a lot of the
:44:31. > :44:35.scientists around here live for. Earthquakes that occur under
:44:35. > :44:40.volcanoes occur from many different sources. You have magma moving from
:44:40. > :44:43.shallow deep to the short part of the crust. As it moves up, it uses
:44:43. > :44:48.fractures already existing in the crust, and those cracks or
:44:48. > :44:52.fractures have walls on them that vibrate, and those vibrate much
:44:52. > :44:58.like a piano string does, and that creates low-frequency earthquakes
:44:58. > :45:03.that we see and typically look for before a volcanic eruption. So here
:45:03. > :45:09.we have a seismometer. Essentially all it is made out of is a magnet,
:45:09. > :45:15.and that magnet lies within a coil. When an earthquake passes by the
:45:15. > :45:18.station, the seismometer here records that ground motion as a
:45:18. > :45:23.voltage that is then being sent back to the digitiser and the
:45:23. > :45:26.electronics box behind us. Around the island of Hawaii, we have
:45:26. > :45:30.somewhere on the order of 70 stations, and we need a network in
:45:30. > :45:36.order to record those so that we can surround the earthquake, and we
:45:36. > :45:45.can triangulate and locate the earthquake and find out how big it
:45:45. > :45:49.is. In 2011, the Samoamoa earthquake we saw an increase in
:45:49. > :45:52.earthquakes and tremour, which you can see at the beginning where we
:45:52. > :45:57.didn't have the eruption, there are no traces no, earthquakes. As we
:45:57. > :46:01.move into the eruption, you can see the earthquakes - the vertical
:46:01. > :46:04.lines here - are increasing quite dramatically. As they do, that is
:46:04. > :46:07.an indication magma is on the move up to the shallow part of the crust,
:46:07. > :46:11.and the location of these earthquakes tells us essentially
:46:11. > :46:17.where that magma is moving from and to. That's kind of one of the
:46:17. > :46:27.reasons why we all got into this field was to look for eruptions,
:46:27. > :46:27.
:46:27. > :46:32.study eruptions, forecast eruptions Well, it's that connection between
:46:32. > :46:38.earthquakes and volcanoes that actually leads us to our very first
:46:38. > :46:43.viewer's question. You got in touch with us. I know some of you will be
:46:43. > :46:48.shouting at the telly saying "it's not working". At the moment our
:46:48. > :46:53.website is down. We are doing everything we can to get it back up
:46:53. > :46:59.and running. Here we are. Our first question from Paul Metcalfe. A lot
:46:59. > :47:05.of other people worried about their summer holidays. The Canary Islands.
:47:05. > :47:10.There have been numerous quakes the island has apparently risen by nine
:47:10. > :47:14.centimetres. Does that mean it will erupt? It has been going on since
:47:14. > :47:19.late last year when it was predicted there will be renewed
:47:19. > :47:24.activity. It has had quite a lot of activity. In the last few weeks it
:47:24. > :47:30.has calmed down. That is why it's not on our map. It hasn't been
:47:30. > :47:35.doing much. It's our closest active volcano. A lot of people go there
:47:35. > :47:39.on holiday. We will be watching it. Is it a common occurance that it
:47:39. > :47:43.looks like volcanoes will build up to an erruption and it fades away?
:47:43. > :47:48.Yes. We can tell when the magma is coming up. What it will do when it
:47:48. > :47:51.gets really close, will it burst out or sink back down? That is a
:47:51. > :47:56.tricky one. There is another question, slightly connected to all
:47:56. > :47:59.the things we have been talking about. We know why we don't have
:47:59. > :48:04.volcano erruptions in Britain, but we do have earthquakes, why is
:48:04. > :48:09.that? We do. We are sitting in the middle of a plate between Iceland
:48:09. > :48:15.and Italy. The two places we have been doing our film. We have
:48:15. > :48:21.passive. We have lots of faultlines, lines ever weakness. We used to be
:48:21. > :48:29.right at plate boundaries. Those faultlines are places where stress
:48:29. > :48:36.builds up and it gets released in earthquakes. The 5.2 one today will
:48:37. > :48:42.be our biggest. We have a lovely question from Katri, who is six.
:48:42. > :48:47.She wants to know why lav have is red? That is a good question. As
:48:47. > :48:54.you heat something up it gives out light energy. If you want to see it.
:48:54. > :48:59.Go to your oven, with your mum, she turns on the hob and it will go red.
:48:59. > :49:06.When we have cool lava it's black. When you see it at night you
:49:06. > :49:11.tkpwhaet wonderful red glow. I hope that answers your question. Owen
:49:11. > :49:18.has another one. Owen will be here in two weeks. You can visit the
:49:18. > :49:25.places we have been do. Why are crators almost always round? They
:49:25. > :49:30.are explosive in one or two ways. From magma coming out, or because
:49:30. > :49:36.the magma comes up, explodes out and collapses in. The same thing,
:49:36. > :49:44.collapses in on itself. Broadly round. We have time for one more.
:49:44. > :49:51.This has come in from Mrs Bell's Year 10 geography students. She
:49:51. > :49:56.teaches in Norfolk. They all say - where are volcanoes called
:49:56. > :50:02."volcanoes"? It goes back to the Roman times actually. There is a
:50:02. > :50:11.lovely volcano in Italy and it's perfect cone shape called volcan.
:50:11. > :50:18.That is where they thought the God Volcan was. We stole it from Italy.
:50:18. > :50:22.Someone saying we have one of those volcan's, you don't need to go to
:50:22. > :50:26.Italy. Thank you for your questions. Tomorrow is our last show. Once the
:50:26. > :50:32.website is up and running you can keep them coming in and you can
:50:32. > :50:35.also tweet them. It is a constant frustration for volcanologist that
:50:35. > :50:39.they can't go deep inside the volcano to collect the material
:50:39. > :50:45.that would tell them all the answers to their questions about
:50:45. > :50:47.their mist tierious inner workings. John Blundy who works at the
:50:47. > :50:51.University of Bristol has discovered there is a particular
:50:51. > :51:01.sort of rock that could answer the questions that keep him awake at
:51:01. > :51:17.
:51:17. > :51:22.night. He went to the Caribbean to As a igneous petrologist, someone
:51:22. > :51:25.who looks at molten rocks I work on the projects of volcanoic
:51:25. > :51:30.erruptions I interrogate them to find out what happens before they
:51:30. > :51:33.came out of the ground. A bit like a pathologist. I find rocks
:51:33. > :51:38.fascinating. There is something about them that is really
:51:38. > :51:48.tantalising. It's like a little puzzle that Mother Nature has
:51:48. > :51:52.throne up -- thrown up. The challenge is to analyse the rocks.
:51:52. > :51:59.I go with colleagues from Bristol University to do field work in the
:51:59. > :52:09.Caribbean. In spring this year we went to Dominica, which is a lush
:52:09. > :52:14.tropical rainforest. There are nine active volcanoes on Dominica, none
:52:14. > :52:18.of them terribly well studied. There hasn't been a really big
:52:18. > :52:22.erruption for about 1500 years. In the last year or so, there have
:52:22. > :52:26.been a number of shallow earthquakes under the north of the
:52:26. > :52:34.island, beneath the volcanic centre. The real objective was to
:52:34. > :52:43.understand a little bit more about what goes on so we can understand
:52:43. > :52:48.these earthquakes. We are here at the northern end of the island of
:52:48. > :52:52.Domonica. I'm looking over the volcanic peak. If I was living in
:52:52. > :53:02.these coastal villages here, or even in Portsmouth, beautiful
:53:02. > :53:04.
:53:04. > :53:09.harbour to our left, I would want to know a bit more about the
:53:09. > :53:16.volcano. The rocks we sample are like the witnesses to an event, in
:53:16. > :53:19.this case the event is a volcanic erruption. As detectives want it
:53:19. > :53:26.find the best possible witnesses, we want it find the best possible
:53:26. > :53:34.rocks. This is really clear. A great sample. Sometimes if you are
:53:34. > :53:43.really lucky, the volcano throws up bits of its guts. This is a cum lit.
:53:43. > :53:47.It's a culmination of crystals deposited from magmas under the
:53:47. > :53:54.ground. Each one represents a dissecret moment in the evolution
:53:54. > :54:00.of the volcano. Within them there are clues there are -- to the past
:54:00. > :54:04.history of the volcano. They're not very common. In some ways, it's a
:54:04. > :54:14.bit like searching for gold or looking for diamonds. It's reward
:54:14. > :54:14.
:54:14. > :54:18.if anything you find some, frustrating if you don't! -- you
:54:18. > :54:26.find some, frustrating if you don't! The first couple of days we
:54:26. > :54:36.didn't find any at all. We were also looking for volcanic rocks
:54:36. > :54:37.
:54:37. > :54:44.themselves. Here is a bit of pumis. It's an air-filled rock. The
:54:44. > :54:53.bubbles is where there was once volcanic gas. That expands and
:54:53. > :54:57.pushes the magma out of the volcano. They contain crystals. I'm hoping
:54:57. > :55:03.these are fresh. The compositions of the crystals can give us clues
:55:03. > :55:10.as to where the magma was stored before the erruption. Which, in
:55:10. > :55:20.turn, tells us where we ought to be looking for signs of unrest before
:55:20. > :55:22.
:55:22. > :55:31.future volcanic erruptions. Day Three, we were now starting to feel
:55:31. > :55:36.a little bit despondent about our failure to find any cumulates. We
:55:37. > :55:42.got intelligence there had been a dam break a few years ago. A
:55:42. > :55:45.natural dam had broken through and dumped an enormous volume of
:55:45. > :55:55.material from the volcanic centres into the river. We set out to see
:55:55. > :55:58.
:55:58. > :56:06.what we might find. Have I got a goodie for you? What have you got?
:56:06. > :56:16.Yes! The river was flanked on either side by huge banks of gravel.
:56:16. > :56:19.
:56:19. > :56:26.Because of the action of water, the gravel deposits were unusual rich,
:56:26. > :56:30.it was a bonanza. This volcano really did spew its guts up. It's
:56:30. > :56:35.exciting. It comes at the end of a couple of days of frustration. A
:56:35. > :56:45.couple of days of thinking that, perhaps, it will not work out here
:56:45. > :56:50.as it has on other islands. Dominica is the place to be. It's a
:56:50. > :56:56.perfect spot for collecting these things. The work we do will
:56:56. > :57:00.ultimately contribute to a better understanding of these volcanoes. I
:57:00. > :57:03.think, volcanologists have a responsibility to do the best they
:57:03. > :57:10.can to understand restless volcanoes because only through that
:57:10. > :57:20.understanding can we be in a better position to anticipating and
:57:20. > :57:21.
:57:21. > :57:29.mitigate volcano incidents and help people living in volcanoic areas.
:57:29. > :57:37.They are really nice looking rocks as well! I have one of the rocks
:57:37. > :57:46.here. It is lovely. This is like a forensic time capsule that allows
:57:46. > :57:53.us to go into the depths and back in time. Jon Blundy will man our
:57:53. > :58:00.web blog tomorrow night. Save up your difficult questions for him.
:58:00. > :58:06.You can get us on at: It will get there. It is extraordinary really
:58:06. > :58:10.that what we uncovered in the last hour is the fact that science has -
:58:10. > :58:14.knows the planet quite well. We know where the at the time tonic
:58:14. > :58:18.place are, the volcanoes and where we will get earthquakes. You look
:58:18. > :58:21.at communities like this and you look at Kalapana, you can't help
:58:21. > :58:25.celebrating the human spirit. Human beings do want to live in places
:58:25. > :58:31.like this. The first thing is, this stuff is the way the planet works.
:58:31. > :58:37.We have to get used to it. People do it for all sorts of reasons. For
:58:37. > :58:44.the frontier spirit. For the human nature by now being cowed by the
:58:44. > :58:52.volcano. It's our last programme tomorrow. We have lots of treats in
:58:52. > :58:58.store. I go to Italy. Ed Byrne creates a super volcano with
:58:58. > :59:03.plastic balls and a rubbish bin. go to the ends of the earth to