Horizon S37E04 · Supervolcanoes

Overview

Hidden deep beneath the Earth's surface lie one of the most destructive and yet least-understood natural phenomena in the world - supervolcanoes. Only a handful exist in the world but when one erupts it will be unlike any volcano we have ever witnessed. The explosion will be heard around the world. The sky will darken, black rain will fall, and the Earth will be plunged into the equivalent of a nuclear winter. Normal volcanoes are formed by a column of magma - molten rock - rising from deep within the Earth, erupting on the surface, and hardening in layers down the sides. This forms the familiar cone shaped mountain we associate with volcanoes. Supervolcanoes, however, begin life when magma rises from the mantle to create a boiling reservoir in the Earth's crust. This chamber increases to an enormous size, building up colossal pressure until it finally erupts. The last supervolcano to erupt was Toba 74,000 years ago in Sumatra. Ten thousand times bigger than Mt St Helens, it created a global catastrophe dramatically affecting life on Earth. Scientists know that another one is due - they just don't know when... or where. Yellowstone National Park: It is little known that lying underneath one of America's areas of outstanding natural beauty - Yellowstone Park - is one of the largest supervolcanoes in the world. Scientists have revealed that it has been on a regular eruption cycle of 600,000 years. The last eruption was 640,000 years ago... so the next is overdue. And the sleeping giant is breathing: volcanologists have been tracking the movement of magma under the park and have calculated that in parts of Yellowstone the ground has risen over seventy centimetres this century. Is this just the harmless movement of lava, flowing from one part of the reservoir to another? Or does it presage something much more sinister, a pressurised build-up of molten lava? Scientists have very few answers, but they do know that the impact of a Yellowstone eruption is terrifying to comprehend. Huge areas of the USA would be destroyed, the US economy would probably collapse, and thousands might die. And it would devastate the planet. Climatologists now know that Toba blasted so much ash and sulphur dioxide into the stratosphere that it blocked out the sun, causing the Earth's temperature to plummet. Some geneticists now believe that this had a catastrophic effect on human life, possibly reducing the population on Earth to just a few thousand people. Mankind was pushed to the edge of extinction... and it could happen again.

Torrents

Subtitles

Episodes

1. 1 1. Breath of Life2000-01-12 · 1h 0mIn this moving film Horizon follows the Loughran family in their fight to save the life of their daughter Sheila who suffers from cystic fibrosis. They lost their youngest daughter
2. 2 2. The Lost City of Nasca2000-01-20 · 1h 0mOn a barren desert in South America lies one of the greatest archaeological puzzles in the world. Etched in the surface of the desert pampa sand are hundreds of straight lines, geo
3. 3 3. The Diamond Makers2000-01-27 · 1h 0mThere is something so special about diamonds, and they are so valuable, that people have always been prepared to go to the most extraordinary lengths to find them. But how would we
4. 4 4. Supervolcanoes2000-02-03 · 1h 0mHidden deep beneath the Earth's surface lie one of the most destructive and yet least-understood natural phenomena in the world - supervolcanoes. Only a handful exist in the world
5. 5 5. Miracle In Orbit2000-02-03 · 1h 0mWhen and how did space and time begin? The birth of the Universe is one of the biggest mysteries in astronomy. It has perplexed the best scientific minds for centuries. Decades bef
6. 6 6. Complete Obsession - Body Dysmorphia2000-02-17 · 1h 0mWhat happens when a completely healthy person wants their leg amputated? Gregg is 55 and does not feel physically whole. This is despite the fact that he is physically healthy and
7. 7 7. Is GM Safe?2000-03-09 · 1h 0mSome people see GM food as a ground-breaking scientific idea that could help to end world hunger and reduce global pollution. Others see it purely as 'Frankenstein foods' on 21st c
8. 8 8. Planet Hunters2000-03-16 · 1h 0mIf extra-terrestrials do exist they must have a home. Horizon tells the story of the race to find out where in the Universe this might be. The answer, for scientists across the wor
9. 9 9. Moon Children2000-04-04 · 1h 0mA handful of children around the world cannot tolerate the sun. Any exposure leads rapidly to skin cancer. They must either play indoors during daylight or be protected from head t
10. 10 10. Mega-tsunami: Wave of Destruction2000-10-12 · 1h 0mScattered across the world’s oceans are a handful of rare geological time-bombs. Once unleashed they create an extraordinary phenomenon, a gigantic tidal wave, far bigger than any
11. 11 11. Conjoined Twins2000-10-19 · 1h 0mConjoined twins are among the rarest of human beings. There are probably fewer than a dozen adult pairs living in the world today. Only a few hundred pairs of conjoined twins are b
12. 12 12. The Lost World of Lake Vostok2000-10-26 · 1h 0mIt sometimes seems as if our planet has no secrets left - but deep beneath the great Antarctic ice sheet scientists have made an astonishing discovery. They’ve found one of the lar
13. 13 13. Vanished: The Plane that Disappeared2000-11-02 · 1h 0mOn August 2nd 1947, a British civilian version of the wartime Lancaster bomber took off from Buenos Aires airport on a scheduled flight to Santiago. There were 5 crew and 6 passeng
14. 14 14. The Secret Treasures of Zeugma2000-11-09 · 1h 0mIn the summer of 2000, one of the great frontier cities of the Roman Empire, the city of Zeugma, all but disappeared from the face of the Earth under the flood waters of a dam. In
15. 15 15. Valley of Life or Death2000-11-16 · 1h 0mAt the heart of the AIDS epidemic in Africa, there is a deadly mystery that has puzzled scientists for years. There are groups of people who are four times less likely to get HIV t
16. 16 16. Extreme Dinosaurs2000-11-23 · 1h 0mAmazing new discoveries in South America are revolutionising what we thought we knew about the dinosaur world. It now seems that South America was home to both the largest meat-eat
17. 17 17. Supermassive Black Holes2000-11-30 · 1h 0mIn June 2000, astronomers made an extraordinary discovery. One that promises to solve one of the biggest problems in cosmology - how and why galaxies are created. Incredibly, the a
18. 18 18. The Boy who was Turned into a Girl2000-12-07 · 1h 0mIn 1965 in the Canadian town of Winnipeg, Janet Reimer gave birth to twin boys - Bruce and Brian. Six months later a bungled circumcision left Bruce without a penis. Based on a rad
19. 19 19. Atlantis Reborn Again2000-12-14 · 1h 0mHorizon puts Graham Hancock's controversial theories about the past to the test, dissecting his evidence for a lost civilisation. Graham Hancock offers various pieces of evidence