Eruptive transition and vent activity during lava fountains at Etna volcano revealed by integrated remote sensing

Paroxysmal mafic activity is a relevant source of hazard at many active volcanoes. At volcanoes like Etna (Italy), paroxysmal eruptions have highly variable transient dynamics, thus monitoring activities are crucial for the understanding and quantification of the onset of climactic phases. We examined thermal videos from the INGV-OE (Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo) monitoring network of seven lava fountains that occurred at the South-East Crater in 2021. We identified the processes that precede and lead to the onset of the fountaining phase to implement a thermal analysis tool that can be used, in conjunction with radar data, to fully characterize the dynamics and duration of paroxysmal events. Based on the signal derived by our parameter, we recognized different phases (strombolian; waxing; waning) preceding and following the climax of the paroxysms. Our method, if linked with other monitoring data, could also be easily implemented in early warning systems.