Long-term versus short-term deformation processes at Mt. Etna volcano

Volcanoes may deform as a consequence of several geophysical processes that evolve at different spatial and temporal scales. In this work, we focus on Mt. Etna stratovolcano and we investigate the relationship between the deformation behaviours related to long- and short-term volcanic processes and the ascent of magma. Generally, at the long-term scale, the main processes are those responsible of the volcano deformation style (e.g., volcano spreading, sagging or basement extrusion) that can promote the evolution of deep dikes or pressurized reservoirs; on the other hand, the short-term mechanisms lead to unrest phenomena that may cause eruptions due to the shallow emplacement of magma batches. To discriminate between long- and short-term effects, we analyse a large Synthetic Aperture Radar (SAR) data archive acquired on Mt. Etna by several satellites during the past 20 years. In particular, SAR data collected by ERS-1/2, ENVISAT, ALOS, and COSMO-SkyMed platforms were independently processed through the SBAS-DInSAR approach to capture the long-term behaviour. Moreover, the short-term behaviour has been analysed by using TerraSAR-X and Sentinel-1A DInSAR data pairs, collected across the last paroxysm occurred on 28 December 2014. The preliminary analysis reveals a firm interaction between the structural surface deformation phenomena and the eruptive style of the entire volcanic edifice. This finding represents the base for future and extensive studies aimed at understanding the status of Mt. Etna and its evolution, particularly considering the forthcoming availability of SAR data continuously collected by the European Sentinel-1 satellite constellation.