Introduction

Supervolcano, a factual drama which transmits in March on BBC ONE, charts the possible consequences of one of nature's most cataclysmic events - a supervolcanic eruption.

The film uses specially commissioned research, studies of previous supervolcanic eruptions and predictions drawn from a range of scientific disciplines to tell the story of how such an eruption would affect the United States and the world.

Set in the near future, Supervolcano draws on scientific evidence available from a number of previous eruptions at Yellowstone as well as research, much of it specially commissioned for this production, from major scientific bodies, including the United States Geological Survey, Yellowstone Volcano Observatory, the Federal Emergency Management Agency, the UK Met Office and NOAA (The National Oceanic and Atmospheric Administration).

The characters in Supervolcano are based on the people who work for these organisations.

Supervolcanoes are on a totally different scale to ordinary volcanoes: Mount St Helens released enough magma to bury London beneath an ash layer a metre thick. A supervolcano would release enough to cover the entire UK under four metres of ash.

When Vesuvius erupted, Pompeii and at least 5,000 of its citizens were killed by a wave of red hot ash and gas called a pyroclastic flow.

Flows from a supervolcano would scorch and destroy all life around the volcano in an area the size of an English county or small American state.

There are several supervolcano sites around the world but the one with the most lethal potential lies beneath Yellowstone.

Satellites have photographed the mouth of the volcano and, at 85 kilometres long and 45 kilometress wide, it would easily swallow Tokyo, the largest city in the world.

The chamber itself, five miles underground, is big enough to hold over 25,000 cubic kilometres of molten rock.

The land around Yellowstone regularly swells and subsides in response to the shifting levels of magma and volcanologists believe that one day the molten magma contained within the chamber will burst out - as it has done many times before. They just don't know when.

Accompanying the drama will be two half-hour documentaries, The Truth About Yellowstone, which will be shown on BBC TWO immediately afterwards (Sunday 13 March and Monday 14 March, 10.00pm).

The documentaries examine recent volcanic activity at Yellowstone and give a range of views from scientists on whether Yellowstone is likely to erupt again in our lifetime.

Supervolcano is a BBC/Discovery/Pro-Sieben/Mediaset/NHK production for BBC ONE.