A super-eruption and its catastrophic effects on the world are the subject of fact-based drama released on DVD by the BBC.
Supervolcano charts the possible consequences of a nearfuture eruption in Yellowstone National Park in Wyoming, USA.
The Yellowstone supervolcano has a mouth 85km long and 45km wide. Its magma chamber, 8km below ground, holds more than 25,000km 3 of molten rock. A super-eruption is predicted to eject more than 2,000Mt of sulphuric acid into the stratosphere, triggering a volcanic winter and causing an estimated 1bn deaths.
Yellowstone has erupted three times in the past, on a 600-700,000 year cycle. The last happened 640,000 years ago, so it would appear an eruption is due.
Supervolcano is based on evidence from the previous eruptions and new research from bodies including the US Geological Survey and Yellowstone Volcano Observatory.
Supervolcano is available on DVD from BBC Video, £15.99.
It includes a 50-minute documentary on supervolcanoes.