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Abstract

Raising the alert level concerning Vulcano has led to increased monitoring activities concerning the island. One of the leading research topics to enhance the knowledge of this volcanic system is the characterization of the volcano-tectonic structures of the island and their relation with the geothermal system. We present a 3D resistivity imaging obtained by the Magnetotelluric (MT) method, highlighting the structures of the La Fossa crater down to 2 km depth b.s.l. The geometry of the resistivity anomalies elucidates the different volcano-tectonic lineaments that characterize the volcanological evolution of Vulcano island and provides valuable indications for understanding the interaction between lithostratigraphic setting, fluid circulation, and the current dynamics recorded on the island. The most significant structure identified by the MT survey is a resistive anomaly located at La Fossa crater, which continuously deepens to the maximum depths detected and represents a conduit-type structure along which there is a preferential ascent of magmatic fluids. Furthermore, the resistivity anomalies are mainly aligned in the N-S direction and contain the outgassing structures of the N-NE sector of the crater. They probably represent the island sector where, in addition to the ascent of magmas from recent activity, the most significant quantities of fluids from the deep accumulate/channeling. The model also shows that the higher resistivity bodies emerging at the surface mainly correspond to volcanic buildings, craters, conduits, and/or eruptive fissures. The deep structures imaged by the MT model become very significant in light of the interpretation of the possible unrest dynamics at Vulcano.