Underwater craters in the Gulf of Naples
Discovered by a research team involving the University's Department of Earth Sciences
A cluster of craters forming an underwater "dome", i.e. a gas-emitting swelling of the seafloor in the Gulf of Naples was discovered during an oceanographic campaign coordinated by the Institute of Coastal Marine Environment of the National Research Council (CNR) in Naples in collaboration with the research team of the Department of Earth Sciences led by Franco Tassi and Orlando Vasselli, the National Institute of Geophysics and Volcanology and the Institute of Geosciences and Georesources of CNR. The Study has been published in Scientific Reports (“Seafloor doming driven by degassing processes unveils sprouting volcanism in coastal areas”).
In the surveys carried out during the SAFE_2014 campaign on board the R/V Urania ship, researchers have located a raise of the seafloor - technically called "dome" - associated to gas emissions just 5 km off Naples harbour and 2.5 km from Posillipo Cape, exactly mid-way from two active volcanoes: Campi Flegrei and Somma-Vesuvius, at depths between 100 and 170 metres.
"The seabed has swollen by 15 m - reports Orlando Vasselli, professor of Geochemistry and Volcanology - and it covers an area of 25 sq km. During the survey we have recorded 35 active emissions of CO2 and over 650 small craters linked to a recent activity of degassing."
Researchers attribute the formation of this structure to an upraising of magmatic gas coming from variable depths situated both in the Earth's crust and mantle. Gases have resurfaced via ducts that have a diameter at their outlet between 50 and 200 metres, penetrating, fracturing and deforming current marine sediments.
Based on the data acquired, researchers have established that the phenomenon has initiated no more than 12,000 years ago and in spite of its magmatic nature, the gas emissions are not, at the moment, associated with magma upraising.
15 March 2016