A new study suggests Mount Etna formed through an unusual process involving ancient magma pockets driven upward by tectonic forces. Researchers from the University of Lausanne say this mechanism could place the Sicilian volcano in a rare fourth category. The findings challenge traditional models of how large volcanoes develop.
Mount Etna, Europe's most active volcano, rises more than 3,000 meters above sea level on the Italian island of Sicily. For decades its formation has puzzled geologists because its lava chemistry does not match any of the three standard categories.
Researchers at the University of Lausanne, working with Anna Rosa Corsaro of the Istituto Nazionale di Geofisica e Vulcanologia, analyzed rock samples spanning 500,000 years. They conclude that pockets of magma already present in the upper mantle about 80 kilometers below the surface are squeezed upward as the African and Eurasian plates collide.
Lead author Sébastien Pilet said the process resembles that of small submarine "petit-spot" volcanoes first identified in 2006. The study appears in the Journal of Geophysical Research: Solid Earth and may improve future hazard assessments.