Magma chamber beneath Mount Vesuvius rises towards the surface

September 11th, 2008 - 4:20 pm ICT by ANI  

National Geographic

Washington, September 11 (ANI): A new study has indicated that the magma reservoir beneath Mount Vesuvius in Italy has been migrating toward the surface over the past 20,000 years, which might result in a mild eruption.

According to a report in National Geographic News, the finding may be good news for some three million people living under the active volcanos shadow in Italys Campania region, where Vesuviuss famous A.D. 79 cataclysm buried Pompeii and Herculaneum.

Magma pools at shallower depths are less volatile and less likely to produce violent eruptions, according to a research team led by Bruno Scaillet of the Universite dOrleans in France.

Magma reservoirs hold a replenishing supply of lava, which is unleashed during volcanic eruptions. A reservoirs location and characteristics offer clues to the severity of future eruptions.

The difference in pressure depth between Pompeii and more recent eruptions (documented by) our experiments stresses that the next coming eruption may have little in common with that one which destroyed Pompeii, Scaillet said.

Scaillet examined the lava rock produced by four major historical eruptions and reconstructed the temperature and pressure of the magma reservoir during those events.

The data indicate that, between A.D. 79 and a later eruption in A.D. 472, the magma reservoir climbed from between 4.4 and 5 miles (7 and 8 kilometers) below the surface to between 1.8 and 2.5 miles (3 and 4 kilometers).

According to Scaillet, it is unknown if the reservoir has moved since the time of the last eruption or how big it may be today, but magma closer to the surface is likely to produce less destructive eruptions.

The deeper the reservoir, the colder and the more viscous is the magma being stored, he said, explaining that such magmas are prone to much more explosive eruptions when they reach the surface.

Mount Vesuvius is believed to have produced major eruptions some 22,500 years ago; 17,000 years ago; 15,000 years ago; 11,400 years ago; 8,000 years ago; 3,780 years ago; and 2,000 years ago. (ANI)

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