GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.2 GNGTS 2024 Figure 1 – The lef panel shows the Etna volcano study area overview (from Beccaro et al., 2023). Black segments indicate the main tectonic structures, while the red triangles indicate the locaton of the selected GNSS statons used for InSAR results validaton purposes. The dashed red rectangle delineates the study area zoomed in the inset panel where past (2011-2017) and recent (2018-2021) lava fow footprints are shown (data for the pre-2015 period are available from the Etna Observatory geoportal at htp://geodb.ct.ingv.it/geoportale/; data for the 2017 and 2020-2021 period are available from Ganci et al. (2023) and De Beni et al. (2021)). The upper right panel shows the Sangay volcano study area locaton inside Ecuador country (from Google Maps), instead the lower right panel shows a Sentnel-1 amplitude image of the Sangay volcano with the area afected by the pyroclastc current and the lava fow emplaced at the end of 2021 (Hidalgo et al., 2022) and investgated in this work. The applicability of the approach used for studying the dynamics of Etna lava fows was tested on an additonal actve andesitc stratovolcano, namely Sangay, located in Ecuador (Figure 1 – right panel). We applied the SBAS InSAR method to retrieve the ground displacements on the Sangay volcano from June 2021 to August 2023. Unfortunately, in this case, the lack of adequate (i.e., with low cloud cover) Sentnel-2 optcal data and suitable (i.e., with sufciently diferent angles of incidence) Cosmo-SkyMed data did not allow for delineatng the boundaries of emplaced lava fow and generatng DEMs to evaluate the lava body height. Therefore, aiming to correlate peculiar behaviors evidenced by the InSAR DTS with volcanic phenomena emited during the investgated tme period, i.e., lava fows and pyroclastc currents, we used a polarimetric change detecton technique that exploits SAR data set collected before and afer the event. Preliminary results made it possible to correlate the peculiar subsidence trend visible on the northern fank of the volcano with the pyroclastc current emited on November 28, 2021.