Washington: A new study has provided a deeper insight into the extent of Moon's most unusual and giant volcanic eruption's debris. Scientists have produced a new map of the Moon's most unusual volcano showing that its explosive eruption spread debris over an area much greater than previously thought.

A team of astronomers and geologists, led by experts in the Institute for Computational Cosmology and Department of Earth Sciences at Durham University, UK, studied an area of the lunar surface in the Compton-Belkovich Volcanic Complex.

By mapping the radioactive element thorium which spewed out during the eruption they discovered that, with the help of the Moon's low gravity, debris from the unnamed volcano was able to cover an area the size of Scotland, or around 70,000km2. The eruption, which happened 3.5 billion years ago, threw rock five times further than the pyroclastic flow of molten rock and hot gases that buried the Roman city of Pompeii, the researchers added.

The research used data from NASA's Lunar Prospector spacecraft which first spotted the volcanic site in 1999 when it detected an isolated deposit of thorium on the Moon's far-side between the Compton and Belkovich impact craters. Since its discovery, the deposit had been hard to study because it is hidden beneath debris from meteorite impacts, but Lunar Prospector did detect gamma rays emitted by the thorium that can pass through up to a metre of rock.

Based on this information, the Durham-led team used a "pixon" image enhancement technique, originally designed to peer into the distant Universe, to sharpen the map and reveal the enormous size of the thorium deposit from the volcanic eruption.

The research team was now planning to apply its mapping technique to the largest known volcano in the Solar system, Olympus Mons on Mars.