Six volcanic structures discovered in the Gulf of Naples facing Vesuvius. This was revealed by the results of an oceanographic campaign conducted by a team involving Ingv, the University of Naples Federico II and the CNR. The study was published in Geophysical Research Letters
Six underwater volcanic structures were discovered in the sea sector in front of Vesuvius, located at a distance of less than 3 km from the coast in the stretch between Torre Annunziata and Herculaneum. This was established in a work published in Geophysical Research Letters (http://onlinelibrary.wiley.com/doi/10.1002/2016GL070271/full, Subcircular conduits and dikes offshore the Somma‐Vesuvius volcano revealed by magnetic and seismic data), a team of researchers from the National Institute of Geophysics and Volcanology (INGV-Roma1 section), from the Department of Earth, Environmental and Resources (DISTAR) of the University of Naples Federico II and of the Institute for the Coastal Marine Environment of the National Research Council (IAMC-CNR). “We have detected new points of carbon dioxide emissions in the Gulf of Naples”, says Guido Ventura, a researcher at INGV, “which is quite common in geothermal and volcanic areas such as the Neapolitan one. And here we discovered six hitherto unknown volcanic structures (cones and domes), with a diameter of about 800 m. Furthermore, the fronts of the Vesuvian lava flows that poured into the sea in the mainly medieval age have been identified”. The exploration activity was carried out as part of the SAFE2014 oceanographic campaign, aimed at studying submarine gaseous emissions in the Gulf of Naples. The research, conducted in 2014 on board the CNR research vessel 'Urania', made it possible to survey, in extreme detail, the stretch of coast in front of Vesuvius. “During the 'SAFE2014' campaign, also aimed at acquiring new data on Vesuvius' products and their age, we used a series of exploration techniques, including magnetometric, seismic and bathymetric ones. The results of these investigations allowed us to establish that at least three of the volcanic structures detected were formed before 19.000 years, while one of them erupted in historical times", explains Maurizio Fedi, professor of DISTAR, Federico II University. These researches form the basis for the implementation of a sea monitoring system aimed at studying any submarine volcanic phenomena that could affect the coast.
Extended
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. Three cones emplaced before the Last Glacial Maximum, whereas a fourth one emplaced after 19 ka suggesting a rejuvenation of the eruptive system offshore the volcano in historical times. We also identified a NE–SW elongated magnetic anomaly consisting of a dike-like body associated with 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 entered the sea mainly during the Middle Ages.
Images
Fig. 1 Data acquisition phase in the Gulf of Naples on board the CNR oceanographic vessel 'Urania'
Fig.2 Schematic map of gaseous emissions and eruptive centers discovered during the SAFE2014 oceanographic campaign.