Stromboli. The paroxysmal eruptions of 2019 and the identification of possible precursory signals

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Analyzing an extraordinary amount of multiparametric data, INGV’s researchers identified possible precursory signals of the explosive paroxysms of summer 2019 up to about a month before the event

Through an in-depth analysis of the data of the paroxysmal eruptions of 2019, the researchers have rooted the hypothesis that the paroxysms of the Stromboli volcano manifest a phase of ‘destabilization’ that can originate up to a few weeks before the event and that determines a perturbation of the magmatic system. These are the conclusions reached by the scientists of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in the study “Uncovering the eruptivepatterns of the 2019 double paroxysm eruption crisis of Stromboli volcano”, just published in the journal ‘Nature Communications’.

Starting from the fact that in 2019 the Stromboli volcano experienced one of the most violent eruptive crisis of the last hundred years, the research- resulting from the multidisciplinary collaboration of the INGV’s researchers from the Sections of Rome 1, Pisa and Catania’s Etna Observatory – studied the various aspects of the eruptive activity of Stromboli, with the aim of understanding the dynamics of paroxysms and identifying potential precursory signals.

“First of all, we analyzed the data of the tephra deposits generated by the two paroxysms of 2019 thanks to the surveys carried out in the field” comments Daniele Andronico, INGV’s volcanologist and first author of the research, who continues “The study focused on the dispersal of volcanic products and on their textural and chemical characteristics. Through numerical simulations, we modeled the dispersal of explosive products and estimated the time necessary for tephra deposition in some critical areas of the island, such as, for example, the ferry dock and the helicopter pad, since they were particularly visited during the summer”.

“The integrated analysis of the video surveillance data made it possible to obtain the physical parameters of the two paroxysms, such as the extension and speed of propagation of the volcanic plume, as well as to describe the eruptive dynamics in detail”, explains Elisabetta Del Bello, INGV’s volcanologist and author of the research. “Furthermore, through the images of the video surveillance cameras, the pre-eruptive conditions were parameterized, revealing that the intensity and frequency of the normal explosive activity in Stromboli underwent a sudden change about a month before the first paroxysm, coinciding with the variation of the geochemical and geophysical parameters recorded starting from the same period. This observation indicates that the ‘perturbation’ of the magmatic system, which culminated in the explosive events of July-August 2019, began weeks before the paroxysmal events”, Elisabetta Del Bello concludes.

“Even during the paroxysmal events of 2003 and 2007, before the occurrence of the explosive events themselves, similar periods of perturbation in the ordinary activity and anomalies of geochemical and geophysical signals were recorded, thus opening interesting scenarios for the identification of precursors common to all the Stromboli’s paroxysms”, says Daniele Andronico, who concludes “We believe that through the development of a new observation and monitoring systems for the eruptive activity of Stromboli, it is also possible to provide information necessary for territorial planning in the event of a crisis, particularly during the high tourist season”.

“The research”, reports Piergiorgio Scarlato, INGV volcanologist, “was funded by the MUR as part of the funding program for projects of significant national interest PRIN 2017, and within the INGV’s strategic departmental project ‘UNO’, concerning the eruptive activity of the Stromboli volcano”.

The research has an essentially scientific value and it is currently devoid of immediate implications regarding the aspects of civil protection.

 

(Fonte Ingv)