Vesuvius: Europe’s ticking time bomb

Nature : Vesuvius has been dormant since a small eruption in 1944, writes Katherine Barnes for Nature, but it could be more dangerous than previously assumed. Seismic imaging studies have detected an unusual layer 810 kilometers deep under the mountain’s surface. Giuseppe Mastrolorenzo and Lucia Pappalardo, of the Vesuvius Volcano Observatory in Naples, Italy, think this is an active magma reservoir, which could produce large-scale explosions even larger than the one that destroyed Pompeii, with pyroclastic flows traveling up to 20 kilometers. Geological evidence shows that such a blast occurred about 3800 years ago and covered the whole of present-day Naples. The Vesuvius observatory team has therefore urged Neapolitan authorities to base their emergency plan on a worst-case eruption. However, Bruno Scaillet, of the University of Orléans in France, and colleagues believe that Vesuvius has become less explosive over time, with magma chambers migrating upward. The 1944 eruption came from a relatively shallow level 3 kilometers below the surface; magma stored there is probably less viscous and therefore less prone to causing large explosions.