With a pioneering investigation, a research team from INGV and CNR has revealed important details on the nature of the volcano's activity and opened new avenues in risk assessment. The study is published on Geophysical Research Letters
By analyzing advanced satellite data and seismic signals, a team of researchers from the National Institute of Geophysics and Volcanology (INGV) and the Institute for electromagnetic sensing of the environment of the National Research Council (Cnr-Irea) has traced the map of the source volcano of the island of Vulcano, and clearly outlined the implications of this discovery for the safety of the area. The study, published in the journal Geophysical Research Letters, provided results that represent a fundamental starting point for future assessments of the volcanic danger of the island.
"The Island of Vulcano, home of the imposing 'La Fossa', has attracted attention since September 2021, showing signs of volcanic reactivation. Our study, focused on InSAR (Satellite Radar Interferometry) and GNSS (Global Navigation Satellite System) data, explored this dynamic, localizing the source, evaluating its characteristics and impact on volcanic hazard” explains Federico Di Traglia, researcher at the INGV Vesuvian Observatory (INGV – OV) and first author of the article.
The main focus of the study was understanding volcanic reactivation and estimating the associated hazard.
“By analyzing InSAR satellite data and seismic signals, we identified the source, positioned 500 meters below the crater area of Vulcano, operating between July and December 2021”, adds Valentina Bruno, researcher at the INGV Etna Observatory (INGV – OE) and co-author of the article. “Using InSAR time series and GNSS data from Sentinel 1 and the INGV Etna Observatory, we localized and evaluated the evolution of the source. The VLP events (Very Long Period, seismic events linked to the pressurization of fluids in the hydrothermal system of Vulcano), found between July and December 2021, supported the increase in the dilation of the volcanic area and were associated with the hydrothermal system under the cone of La Fossa".
The analysis traced the 2021 activity to volcanic events linked to the internal pressure of the hydrothermal system, similar to those of 1970.
"The work outlines a peripheral hazard picture, focusing on phreatic explosions and limiting current assessments to these scenarios. The next steps will be aimed at studying the elastic properties of the rocks of the La Fossa cone to evaluate the pressure levels necessary for phreatic explosions, opening a new frontier in the understanding and prevention of potential volcanic risks”, concludes Francesco Casu, research director of the Cnr-Irea.
The published research has an essentially scientific value, currently devoid of immediate implications regarding the aspects of civil protection, representing a potentially useful contribution in the future to refine the forecasting and prevention tools of civil protection. At the moment the research results have no direct implication on measures affecting the safety of the population.
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National Institute of Geophysics and Volcanology (INGV)
picture 1: Study area between Vulcano and Lipari, which includes the area of the Tindari Letojanni aeolian fault.
picture 2: Variations in volume of the volcanic source, in relation to the variation in ground deformations and seismic events called VLP. Furthermore, in panel f the five phases of the activity are detailed: (i) initial expansion phase of the hydrothermal system due to thermal and volatile inputs coming from the deeper magmatic accumulation (August 2021); (ii) release of volatiles from the expanding hydrothermal system (onset of VLPs) and increased fumarolic activity (September 2021); (iii) culmination of this phase of activity (October 2021); (iv) calm phase observed in November 2021, characterized by the cessation of inflation and a temporary reduction in VLPs; (v) intense fluid release phase, accompanied by a significant number and amplitude of VLP signals, without concomitant expansion of the hydrothermal system (December 2021).