High-resolution aeromagnetic investigation for volcanic and seismo-tectonic characterization of the upper Crust: Examples from Mt. Etna and Calabria (Italy)

Abstract

High-resolution aeromagnetic surveys of Mt. Etna Volcano and southern Calabria were carried out during the last three years by the Airborne Geophysics Science Team of Istituto Nazionale di Geofisica e Vulcanologia (INGV). Different datasets of the total intensity of the Earth’s Magnetic Field were collected at different altitudes aimed at taking into account the huge topographic variations. Flight line spacing was kept constant at 1 km, or less. In the Etna volcano area we interpreted the magnetic anomaly pattern as due to the effects of thickness variation of magnetized volcanic products due to the complex pre-volcanic basement morphology of Etna. The survey of southern Calabria and the Messina Straits was aimed at locating the strongly debated seismogenic sources of the 1908 and 1783 M~7 earthquakes, likely the most destructive events of Italy in the last centuries. Low-intensity magnetic anomalies of Calabria clearly show a set on en-echelon lineaments that correspond to some of the faults putative for the 1908 and 1783 earthquakes. Modeling shows that lineaments are likely due to NW-dipping normal faults disrupting an upper crustal crystalline layer with moderate magnetic susceptibility in the order of 1x10-3.