On the 2021 Volcanic Paroxysmal Activity of Mount Etna: a Ground Deformation Analysis Using InSAR

Measuring how the surface deforms in time and space plays a crucial role, not only for understanding volcanic mechanisms, but also for hazard assessment, risk mitigation and supporting crisis management. Mount Etna, one of the most active volcanoes in the world, with a growing population in its vicinity, has experienced an intense period of activity in recent years, mainly characterized by continuous degassing and recurring lava fountains. Due to this activity, continuous deformation can be observed at Mount Etna.

The summit craters showed brisk activity in the last months of 2020, accompanied by increasing seismicity. A period of paroxysms started in December 2020 and intensified in February 2021, with brief but violent eruptive lava-fountaining episodes, that continued throughout all the year. The focus of this study is to understand the dynamics of the near-surface feeding system by constraining the sources responsible for the observed paroxysms. To localize and describe the time-dependent ground deformation, we examine surface deformation at Mount Etna by means of an Interferometric Synthetic Aperture Radar time series analysis utilizing Sentinel-1 data between the second half of 2020 and the end of 2021. The onset of the paroxysms was preceded by an inflation period and deflation episodes were observed during the paroxysms period, which suggests a link between the volcano activity and the observed deformation. The findings may contribute to the discussion on the distribution and dynamics of magma reservoirs that form Mount Etna's conduit system and its interaction with the local tectonic regime.