Sunday, August 20, 2006
Mount Etna scan's results reveal that it is preparing a volcano eruption
The Sicilian volcano is almost always bubbling with activity, but despite this thousands of people live safely on its slopes. In 2002, however, there was an unusually violent eruption that geophysicists believe was caused by gas-rich magma rising within the volcano.
Now a team led by Domenico Patanè at Italy's National Institute of Geophysics and Volcanology in Catania, Sicily, has used seismic data to peek inside the volcano. From variations in the seismic waves from local earthquakes that passed through Mount Etna before and after the 2002 outburst they were able to build up a 3D picture showing magma rising within the volcano a few months before the eruption (Science, vol 313, p 821). "We used a technique similar to a medical CAT scan," Patanè says.
The monitoring exercise was helped by the existence of a dense grid of seismic stations around the volcano. Patanè hopes that such networks will be placed around other volcanoes too. "This could be a powerful tool for forecasting highly explosive eruptions," he says.