Vesuvius Could Blow Again, Pompeii-Style

Sept. 10, 2008 -- French and Italian scientists said on Wednesday they could not rule out another cataclysmic explosion by Vesuvius, the volcano that destroyed Pompeii in A.D. 79.

Vesuvius has been capricious throughout history, blowing up in explosive clouds of dust and poisonous, superheated gas but at other times erupting more safely, rolling lava slowly down its conical flanks.

It has been dormant since 1944.

But in a paper published by the London science journal Nature, the Franco-Italian trio warn that this sleep will not be eternal.

They report that the volcano's magma chamber, deep beneath the surface, has been steadily rising over the past 20,000 years.

The shallowest reservoir now lies at a depth of five to 5.5 miles.

The chamber's depth determines the chemical composition of the magma and also the way in which its energy will be released, they explain.

Lead researcher Bruno Scaillet of the Institute of Earth Sciences in Orleans, France, said it was crucial to identify the composition of the magma lurking at the top of the chamber.

"If this magma is of a more acid composition, a type similar to the one which caused the Pompei eruption, you can can expect an extremely explosive, dangerous eruption," he said.