Three-dimensional magnetotelluric modeling of Vulcano Island (Eolie, Italy) and its implications for understanding recent volcanic unrest

This paper presents the results of an original short-period magnetotelluric survey performed on Vulcano Island (Italy). The obtained three-dimensional resistivity model details structures up to 2.5 km depth, hitherto unexplored. The La Fossa caldera area corresponds to a moderate resistive anomaly, which extends down to the resolved depth and likely represents a conduit-like structure along which magmatic fluids stall and ascend. Other resistive anomalies characterize volcanic edifices, craters, volcanic conduits, and/or eruptive fissures. In addition, the shallower hydrothermal system is detected as a conductive anomaly. Sharp resistivity contrasts generally characterize caldera faults. A main N-S alignment characterizes the island sector, where considerable amounts of deep subsurface fluids accumulate and mix with the ascending magmas related to the most recent volcanic dynamics. The volcanological interpretation of such findings significantly contributes to understanding the geophysical and geochemical anomalies detected in the last year, which involved the Vulcano shallow hydrothermal system, highlighting the potential for possible hydrothermal/phreatic eruptive events.

Automated summary

This paper presents the results of a new short-period magnetotelluric survey conducted on Vulcano Island (Italy), which provides detailed information on previously unexplored structures up to a depth of 2.5 km. The study identifies a moderate resistive anomaly in the La Fossa caldera area, which likely represents a conduit-like structure for the ascent of magmatic fluids. Various resistive anomalies are also detected in volcanic edifices, craters, volcanic conduits, and eruptive fissures. Additionally, a conductive anomaly is observed in the shallower hydrothermal system. Caldear faults are characterized by sharp resistivity contrasts. The findings contribute significantly to the understanding of geophysical and geochemical anomalies detected in the past year, particularly in relation to the Vulcano shallow hydrothermal system, and highlight the potential for hydrothermal/phreatic eruptive events.