Teleseismic tomography of the Campanian volcanic area and surrounding Apenninic belt

The three-dimensional P-velocity structure of the crust and upper mantle beneath the Vesuvius volcano and the surrounding Apenninic belt is derived by teleseismic tomography to describe the deep volcanic structure and its relationship with the Adriatic lithosphere subducting beneath the belt. ta consist of 1615 P and PKP travel times derived from 135 teleseismic events. We merged the data recorded by the stations of the Italian Seismic Network located on the southern Apennines with stations deployed in a temporary broad-band experiment around Vesuvius volcano (BROADVES). The traveltime residuals, computed with respect to the IASP91 1D reference model, are inverted using the ACH code. The 3D velocity structure shows a lower crust characterised by strong lateral heterogeneities with velocity perturbations ranging from −5 to +5%. In the lower crust along the Tyrrhenian margin, low-velocity anomalies are found beneath the volcanic complexes, suggesting the presence of deep crustal magmatic reservoirs. An almost continuous high-velocity body is reconstructed in the upper mantle beneath the Apenninic belt from 65 down to 285 km depth. This high-velocity anomaly is interpreted as the signature of the Adriatic lithosphere subducting westward toward the back-arc Tyrrhenian basin. The low-velocity anomaly in the crust beneath Vesuvius, located above the high-velocity zone dipping in the mantle, may indicate that magma is generated by the subducting slab and rises to lower crustal depths where it is stored.