Tuesday, November 27, 2007

Naples: It's Pompeii II (on Mega-Disasters)

In January 2004 the Discovery Channel showed the lumpy film "Pompeii", to reenact the 79 AD mega-disaster -- an event with widespread advertising, even in the Washington DC Metro. (The July 25 2006 entry on this blog discusses that film.) Tonight (Nov. 27) The History Channel mega-disasters series "The Next Pompeii" related the possibility that Naples, to the northwest of Mount Vesuvius (Pompeii and Herculaneum had been to the SE) could be a mark for a mega-eruption.

Vesuvius eruptions can be "Plenian" "sub-plenian" and "strombolian". The largest (plenian) can end in pyroclastic flows (like Mt. St. Helens or Pinatubo) where the ash mushroom cloud collapses under its own weight, leading to the "surge" at 200 mph that incinerates everything in its path. If an eruption of the "Bronze Age" eruption occurred with a SE wind, it could blow the cloud and potential cloud over Naples. Up to 3 million people could be at risk.

There was a sub-plenian eruption around 1664 and a smaller eruption in 1944, when the Allies rescued the residents of a town of San Sebastian.

In the 1990s, the government started paying residents to leave, in order to make a potential evacuation easier. The program was resumed in 2003. There is an observatory on Vesuvius that purports to be able to anticipate a major event with about a week's notice, but this might not prepare for the largest events. Significant eruptions from Vesuvius may occur on an average of every 64 years.

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