Assessment of eruption source parameters using infrasound: a case study from the 2021 eruption of Mt.Etna, Italy

Abstract

Abstract Atmospheric injection of volcanic ash during eruptions is a threat to aviation. Reliable forecast of airborne ash dispersal relies on empirical and numerical models. Key inputs into these models are so-called eruption source parameters such as the rate at which pyroclastic material is ejected from the vent and the height of eruptive columns. Here, we use infrasound data recorded during eruptive activity in June 2021 at Mt. Etna, Italy, to demonstrate its potential for assessment of eruption rates in near-real time. We calculate a time series of flow velocity at the vent using data corrected for topographic scattering, and effect of vent geometry on the acoustic source radiation. We obtain values of flow velocity of 50-125 m/s during a period of sustained, paroxysmal, activity. These values agree with independent estimates from other ground-based remote sensing data. We use infrasound-derived flow velocities as input into a 1D plume model to estimate the maximum height of the eruption column. Our results suggest that infrasound data hold promise to inform modelling of volcanic plumes. We anticipate that implementation of real-time operational workflows based on infrasound data analysis and plume modelling will impact decision-making and risk mitigation at active volcanoes.