Subcircular conduits and dikes offshore the Somma‐Vesuvius volcano revealed by magnetic and seismic data

We analyzed new magnetic, bathymetric, and seismic data acquired in the offshore sector of Somma‐Vesuvius volcano (Italy). We detected a group of high‐intensity, short wavelength magnetic anomalies corresponding to partly buried volcanic dome‐like structures located by seismic data. The magnetic anomalies are aligned along a NW‐SE strike that is the preferential orientation of an eruptive fracture of the pre‐19 ka activity of Vesuvius. Four cones emplaced after the Last Glacial Maximum (19 ka), whereas a fifth one emplaced more recently suggesting a rejuvenation of the eruptive system offshore the volcano in historical times. We also identified a NE‐SW elongated magnetic anomaly consistent with a dike‐like body associated to an on‐land tectonic structure that was active in recent times at Vesuvius. A delta‐like area with diffuse low‐intensity magnetic anomalies reflects the seaward fronts of lava flows that entered the sea mainly during the Middle Ages.