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.
Volcanic eruptions fascinate and frighten at the same time. If an unexpected large deadly eruption occurs at a perceived "trustworthy" volcano, which also happens to be a renowned touristic place, such as Stromboli, the impact is even higher. During a large-scale eruptive event such as the one that occurred on 3 July 2019 at Stromboli, there are many stories to be told: personal (i.e., people living on Stromboli and the tourists visiting the island), official (i.e., local authorities), scientific (i.e., scientists monitoring the volcano) and hidden (i.e., what actually happens inside the volcano's underlying magmatic system). Working with local authorities, local communities and the many scientists monitoring the volcano, we will capitalize on our expertise to convey the findings from this study telling the hidden story, i.e., the magmatic perspective, of the 3 July 2019 paroxysm of the volcano. Overall, the proposed project falls within the remit of hazard mitigation addressing two societal challenges: 1) managing environmental change and 2) resilience to environmental hazard strands. We will combine the results from this research proposal with coeval timescales from multiproxy monitoring signals of the day of the event and afterwards available from INGV. This will enable us to investigate the decoupling between the occurrence of the paroxysm and the monitoring data clarifying how and why there is a disconnection between magma dynamics during paroxysms and the detected surficial signals. Crucial time-integrated magmatic parameters such as timescales of gas transfer, magma injection and mush remobilisation; rate of magma ascent and crystal growth alongside pre-eruptive P-T-H2O will be determined for the erupted products of the 3 July 2019 paroxysm. This will improve our understanding of magma dynamics during a paroxysm and will help to explain why the 3 July paroxysm behaved differently from the current hypothesis of a direct causal link between the cumulative volume of erupted lava and the triggering mechanism of the paroxysm and if there is an actual change on the eruption behavior. Inspection of coeval monitoring signals will also identify those magmatic parameters which can be used to interpret the decoupling of monitoring signals with magma dynamics, providing some useful precursory data.