Ricerc@Sapienza

On the afternoon of 3 July 2019, a violent explosive event (called paroxysm) affected the entire crater terrace of Stromboli volcano in Southern Italy. The eruptive column rose for about 4 km above the summit and was accompanied by intense fall of scoriae and pumice, setting the vegetation on fire and causing one fatality and one injured person. The death toll could have been much higher, considering that during the summer months there are hundreds of tourists climbing the volcano every evening. On the afternoon of 3 July 2019 there were 230 people waiting to start their climb. Stromboli is well-known for low-energy explosions occurring every 10-20 minutes from multiple vents located in the crater area. This persistent activity is interrupted by discrete violent explosive events, such as the one that occurred on 3 July that, however, was preceded by very limited effusive activity only two minutes before the explosive event. At the same time, and rather untypical for the most recent activity of Stromboli, effusive activity started immediately after the explosive event. We propose to exploit this unique opportunity to capitalise on this unexpected event on 3 July 2019 through a detailed petrological and geochemical investigation of the eruptive products to unravel pre- and syn-eruptive magma ascent and degassing processes and their timescales, magma storage and crystallisation conditions as well as magma mixing processes and their timescales prior to eruption. This is a unique opportunity to obtain, for the first time, crucial and novel information on the processes and timescales of magma ascent and degassing of such a disruptive event using the solid eruptive products that directly probe the underlying magma plumbing system.