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Triggering and propagation of the 10 February 2022 pyroclastic avalanches at Mt. Etna (Italy): a multidisciplinary perspective

Francesco Zuccarello1, Daniele Andronico1, Boris Behncke1, Annalisa Cappello1, Francesco Ciancitto1, Paola Del Carlo2, Mattia de' Michieli Vitturi2, Alessio Di Roberto2, Tomaso Esposti Ongaro2, Ganci Gaetana1

  • Affiliations:  1Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Sezione di Catania, Italy  2Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Italy

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 182

  • Programme No: 3.9.16

  • Theme 3 > Session 9

Abstract

Pyroclastic avalanches generated at basaltic volcanoes have drawn increasing attention in recent years due to their potential high mobility and associated hazards. These dense granular flows are mainly triggered by the collapse of pyroclastic fall deposits on steep slopes and can exhibit unexpected runout distances, even in low-slope terrains. In the period 2020--2022, volcanic activity at Mt. Etna (Italy) was characterized by intense paroxysmal eruptions at the Southeast Crater (SEC). In particular, on the evening of 10 February 2022, some pyroclastic avalanches were emplaced during an energetic lava fountaining episode. The largest one occurred at 21:26 UTC, following the gravitational collapse of a portion of the SEC's south flank. The resulting reddish-brown deposits extended up to ~1.4 km southward, partially covering the upper scoria cone of the 2002--2003 eruption, and have been stratigraphically subdivided into four units, ranging from fine ash to blocks. Here we present a multidisciplinary study combining field surveys, textural and granulometric analyses of selected samples, and remote sensing data to unravel the triggering mechanisms and flow dynamics of this event. Numerical modeling of the avalanche propagation further supports our findings, highlighting the influence of the morpho-structural and thermal conditions of the ultra-proximal deposits in the generation of the flow and its behavior. Our approach provides new insights into the dynamics of pyroclastic avalanches in basaltic volcanic settings, contributing to a better understanding of their hazards and risk assessment strategies at volcanoes like Etna, highly frequented by both researchers and tourists.