THE TECTONIC SETTING OF MOUNT VESUVIUS AND THE CORRELATION BETWEEN ITS ERUPTIONS AND THE EARTHQUAKES OF THE SOUTHERN APENNINES

Mount Vesuvius is emplaced on a regional NE-SW-trending fault that accommodates the stretching of the lithosphere caused by a backward retreat of the Calabrian are. The dynamics of the Calabrian are controls the temporal occurrence of earthquakes in the Southern Apennines and in Sicily. By means of a detailed statistical approach, we identified a significant correlation between seismic events occurring in different subsets of this geodynamic domain: seismicity changes in the Southern Apennines follow those in the Calabrian are after 18-21 years, while seismicity changes in Sicily follow those in the Calabrian are after 8-10 years. The seismicity changes in these three areas appear also to have affected the eruptive activity of Vesuvius in the period 1631-1944. The major effusive-explosive eruptions of this period followed the seismicity changes in the Southern Apennines after 6-13 years and those in the Calabrian are after 36-39 years. From a tectonic point of view, this indicates a direct link between the eruptive activity of Vesuvius and the dynamics of the Calabrian are. The backward retreat of the are produces strain pulses propagating to adjacent areas. From a volcanological point of view, we speculate that the arrival of an extension strain pulse in the area of Vesuvius may trigger the fast movement of magma-filled cracks that stay in unstable equilibrium in the roots of the volcano.