SEISMIC TOMOGRAPHY OF ETNA VOLCANO

A 3-D velocity model beneath Etna volcano has been obtained through inversion of P-wave arrivals of local earthquakes. About 300 seismic events distributed around this volcano from surface up to a depth of 20 km have been used to infer the P-wave velocity structure. High P-wave velocity bodies have been found in the upper portion of the volcanic edifice, in a region where positive values of Bouguer anomalies have previously been found. Low-velocity bodies are identified at depths lower than 10 km and may be related to magmatic reservoirs. The spatial pattern of these deeper velocity anomalies appears to be correlated at surface with the distribution of spatter cones. In the NW quadrant, a high-velocity anomaly is correlated to the presence of a deeper seismicity. The distribution of relocated hypocenters is not homogeneous but shows some features apparently related to the presence of magmatic bodies.