3-DIMENSIONAL P-WAVE VELOCITY STRUCTURE OF MT-ETNA, ITALY

The three-dimensional P-wave velocity structure of Mt. Etna is determi ned to depths of 15 km by tomographic inversion of first arrival times from local earthquakes recorded by a network of 29 permanent and temp orary seismographs. Results show a near-vertical low-velocity zone tha t extends from beneath the central craters to a depth of 10 km. This l ow-velocity region is coincident with a band of steeply-dipping seismi city, suggesting a magmatic conduit that feeds the summit eruptions. T he most prominent structure is an approximately 8-km-diameter high-vel ocity body located between 2 and 12 km depth below the southeast flank of the volcano. This high-velocity body is interpreted as a remnant m afic intrusion that is an important structural feature influencing bot h volcanism and east flank slope stability and faulting.