A multidisciplinary investigation of the 10 February 2022 pyroclastic avalanches at Mt. Etna

The 10 February 2022 pyroclastic avalanche at Mt. Etna represents a significant example of high-mobility granular flow occurring at basaltic volcanoes. While such phenomena are typically associated with more explosive volcanic systems, their occurrence at Etna underlines their relevance for hazard assessment in volcanic environments dominated by effusive and mildly explosive eruptions.

This study focuses on a pyroclastic avalanche triggered by the gravitational collapse of the Southeast Crater’s (SEC) during an intense lava fountaining episode. The event produced a reddish-brown deposit that extended up to 1.4 km southward, covering part of the 2002–2003 scoria cone. Stratigraphic analysis revealed four distinct units, ranging from fine ash to blocks, with variations in granulometry and thickness.

A multidisciplinary approach was applied to unravel the trigger of the avalanche, combining field surveys, granulometric and textural analyses on products collected from the deposit and remote sensing data, supported by the numerical modeling to better constrain the flow propagation dynamics. Our results highlight how these pre-collapse factors, including the elevated residual temperature and the fast accumulation of ultra-proximal pyroclastic fall deposit during the previous lava fountaining episodes, played a crucial role in enhancing the partial collapse.

The findings of this study contribute to a deeper understanding of pyroclastic avalanche behavior in basaltic volcanic systems, offering valuable insights into the mechanisms controlling these hazardous flows in volcanic regions like Mt. Etna, where eruptions frequently interact with human activity and infrastructure.