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Predicting tsunamis generated by pyroclastic flows near the source: Application to the 2019-2021 paroxysms at Stromboli, Italy

Alexis Bougouin1, Raphaël Paris2, Olivier Roche2

  • Affiliations: 1DIMES, Università della Calabria, Rende, Italy; 2Laboratoire Magmas et Volcans, Université Clermont Auvergne, CNRS, IRD, OPGC, 6 avenue Blaise Pascal, Clermont-Ferrand, France

  • Presentation type: Poster

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

  • Poster Board Number: 150

  • Programme No: 2.2.14

  • Theme 2 > Session 2

Abstract

When volcanic explosive eruptions occur near the coastline, pyroclastic density currents may reach the sea and generate tsunamis (e.g., 1883 Karakatau, 1997-2003 Montserrat, 1994 Rabaul), increasing areas vulnerable to volcanic hazards. One of the major challenges is to be able to predict the amplitude of tsunamis close to the source. Due to their hazardousness, intermittency, and complexity, a better understanding of tsunamis requires laboratory experiments, theoretical description and numerical modelling. To this end, we investigate experimentally the entrance of pyroclastic flows into the sea, and consequently generated tsunamis, by considering fluidized granular flows that propagate along an inclined plane, and then enter a pool of water. By quantifying the flow parameters and wave properties, we reveal that mass flow rate and volume are the main contributing parameters in the wave generation process. By combining all flow conditions in a single dimensionless parameter, we provide an empirical prediction of the amplitude of the leading and largest wave near the source, which matches experimental data. Finally, we compare our empirical prediction with recent and unique field data recorded during the 2019-2021 paroxysms, at Stromboli (Italy), which encourages us to extend this comparison to other field data in order to assess its reliability and limitations.