Trouble in the Mountain.(Vesuvius)(Brief Article)

In the towns and villages that dot the side of Mount Vesuvius, the volcano that buried the ancient Roman cities of Pompeii and Herculaneum, life seems normal enough, except there's expectation in the air. Ugo Corati, who has lived and worked on the mountain all his life, was 12 years old when it erupted, in 1944. It was a bad time. A slow stream of lava destroyed 800 homes and the villages of San Sebastiano and Massa di Somma, and killed a few dozen people. Since then, scientists have installed all sorts of fancy equipment to monitor the mountain for signs of trouble, and local authorities regularly sound sirens and lead evacuation drills. Corati, sipping espresso in a local cafe, doesn't seem at all reassured by this activity, but neither is he particularly troubled by the danger. "What can you do about it?" he says with a shrug. "All these safety measures and all this monitoring equipment are in place, but if the mountain goes, we're all as good as dead."

A chilling assessment, and it gets chillier. Earlier this month volcanologists said the mountain was beginning a new cycle of volcanic activity that could trigger an eruption "at any time." And this one will be nothing like the slow dribble of lava in 1944, they predict; it will be the biggest explosion in 2,000 years. The news is not good for the 2 million people who live and work within sight of the crater. The area around Mount Vesuvius is the world's most densely populated volcanic region. A big eruption could kill a million people in minutes, says Edoardo Del Pezzo, research professor with the Vesuvius Observatory in Naples. "We expect that a wide area could be destroyed in a few minutes."

This scenario sounds frighteningly similar to A.D. 79. Twenty thousand residents of Pompeii and Herculaneum thrived on the mountain's unusually rich soil, which they probably attributed to the blessings of Fauna, the goddess of farming and fertility. In August of that year the gods got ugly. Wells dried up, mountain streams stood still, birds and dogs went silent, the ground rumbled. One day hot gases, ash and pumice shot 30 kilometers into the sky. Ash rained down on Pompeii at the rate of six inches per hour, and then came the lava. In 1961, archeologists unearthed impressions of ancient Romans buried alive while trying to flee the mountain, their mouths agape and arms extended in poses of desperation.

Mount Vesuvius continued to erupt every hundred years or so until 1037, when a 600-year lull ensued, followed by a sudden eruption in 1631 that killed 4,000 people. It also kicked off a new cycle of eruptions, 21 in all, that ended in 1944. Despite constant monitoring since then, scientists didn't detect trouble until Gabriele Paparo, a geologist with the National Research Council, finished a three-year study this summer. Vesuvius' last eruption was relatively gentle because it was driven mainly by hot molten rock, or magma, percolating up from beneath the ...