The new summit hazard map from lava flow inundation at Mt Etna volcano

Mt. Etna is one of the most active basaltic volcanoes worldwide, characterized by both explosive and effusive eruptive activity. Lava flows represent the main hazard linked to the volcanic activity, which can be emplaced at high rates during paroxysmal eruptions from the main vents located at summit, or through vents located on the flank of the volcano. In the last decades, the eruptive activity interested mainly the summit area, particularly the South East Crater (SEC), with vigorous lava fountains, as during the 2011-2013 and 2020-2022 series, alternated by effusive activity through fissures opened at the base of the scoria cone, as during the July-August 2014, February-April 2017, May-July 2019 and May-June 2022 eruptions. This posed the need to quantify the hazard from lava flow inundation in the summit area, which is essential during volcanic emergencies and for mitigation actions.

In this study, we present the new lava flows hazard map of Etna’s summit, which has been developed through a probabilistic approach that combines the statistical analyses of the volcanological historical data with the numerical simulations of lava flows on a 2022 Digital Surface Model (DSM). The probabilistic approach includes: i) the estimation of the spatiotemporal probability of future vent opening; ii) the calculation of the occurrence probability of the eruptive classes, which are defined considering the distribution of the lava volume erupted and the durations of eruptions; iii) the simulation of the lava flow paths for all the defined eruptive classes from each potential vent using the GPUFLOW model; iv) the mapping of the probability of inundation by combining the numerical simulations with the probability of future vent opening and the occurrence probability.

A grid of potential vents have been defined over an area corresponding to the Ellittico caldera, while the eruptive classes have been derived by considering both the short- and long-lasting eruptions that occurred at Etna’s summit since 1998. The highest probabilities of inundation of lava flows provided by the obtained map are linked to the vents located in the SEC’s area, according to the observation of the eruptive dynamics in the last decades.