In this study, Synthetic Aperture Radar (SAR) methods that exploit both co- and cross-polarized channels are used to detect volcanic deposits caused by the eruption occurred the Sangay Volcano, Ecuador, at the end of November and the beginning of December 2021. First, a change detection scheme, based on the ratio of a pair of images collected before and after the event, is separately applied to the co- and cross-polarized channels. Then, the outputs are analyzed to detect the different phenomena (i.e., lava flow, pyroclastic currents, landslides), that occurred over the scene. Results, undertaken over a pair of images collected before and after the event with the C-band Sentinel-1 Dual Polarimetric (DP) SAR sensor, show that the proposed approach allows for detecting the different phenomena that occurred on the volcanic area. In addition, the co- and cross-polarized channels carried out different information which suggests the combination of them to obtain additional information.

Deep-Seated Gravitational Slope Deformations (DSGSD) comprise a collection of slow and complex deformational processes driven by gravity, which involve entire slopes over long time intervals [1] . These phenomena occur in various morpho-structural conditions and are characterized by typical morphological features. Even though DSGSD rarely claim lives, they can cause significant damage to infrastructures and sometimes fail catastrophically [2] .

On 24 December 2018 a new lateral eruption of Mt. Etna volcano began. The phenomenon produced an intense seismic swarm, strong gaseous emissions from the summit craters and a well-defined lava flow, emplaced on the southwestern portion of the Valle del Bove depression. During the following paroxysm occurred on 29 May 2019, a new lava flow partially covered the previous ones. Aiming to evaluate the effects over time that the emplacement of lava flows produces over the volcanic structure, here we exploited a multidisciplinary approach, comprising both optical (Sentinel-2) and radar (Sentinel-1 and Cosmo-SkyMed) satellite data, processed through different remote sensing techniques. In detail, Sentinel-2 data allowed to retrieve the lava flows boundaries, Sentinel-1 data permitted to reconstruct ground displacement maps and related time series during the January 2016 – July 2021 time span whilst Cosmo-SkyMed ones were used to estimate the topographic changes caused by the lava emplacement.

Mt. Etna is one of the world's most active volcanoes and its activity is characterized both by explosive eruptive episodes and by effusive activity. On 24 December 2018 a new lateral eruption of Etna began. The phenomenon was caused by the intrusion of a magmatic dike in the upper eastern flank of the volcano which produced an intense seismic swarm and strong gaseous emissions from the summit craters. In this work Synthetic Aperture Radar (SAR) data acquired from the Sentinel-1 satellite mission were elaborated adopting the Small Baseline Subset technique (SBAS). This multi-temporal method of SAR Interferometry (InSAR) allowed us to obtain the ground displacement map of the area and the deformation evolution of some eruption-induced phenomena, i.e., we tracked the lava flows originated from the opening of eruptive fissures in the western flank of the Valle del Bove depression, and we monitored a paleo-landslide located about 5 kilometers West from the Paternò village, which reactivated during the volcanic unrest.

Synthetic Aperture RADAR data acquired during several space missions (Envisat, COSMO-SkyMed and Sentinel-1) were treated in order to obtain the ground displacement of the Ischia island (Naples, Italy) and to retrieve the deformation evolution during the investigated time period. The results, validated with available GPS measurements, were found by applying the Small Baseline Subset (SBAS) technique [1], one of the main algorithms proposed in the context of multitemporal methods of Differential SAR Interferometry. This technique permitted to identify and monitor areas affected by slope instability phenomena in a quite continuous time period, from 2002 to the end of 2019. The presented results constitute the basic information for the future application of a GIS-based interdisciplinary approach aimed at the prevention of natural disasters in correspondence with the Ischia island.

The activity of Aso and Sakurajima volcanoes is monitored through interferometric analysis of SAR data, ALOS Palsar-2 and Sentinel-1, to obtain caldera displacements over the observed period, from 2014 to 2018 and to investigate deformations correlation with inflation and deflation cycles of magma plumbing system, eruptions and diking. The time series, calibrated through global navigation satellite System (GNSS) measurements, are used to identify the pre and post seismic effects of the Mw 7.0 Kumamoto earthquake, occurred in April 2016, to identify the effects on Aso volcano and the most dramatic events affecting the active Sakurajima area since 2015.

The intense activity of Sakurajima volcano is defined through interferometric analysis of SAR data, ALOS Palsar-2 and Sentinel-1, to obtain the caldera displacement over the observed period, between October 2014 and March 2018. Displacement evolution is derived to investigate its correlation with eruptions and diking. The time series, calibrated through global navigation satellite System (GNSS) measurements, are used to identify the most dramatic events affecting Sakurajima area since 2015. Moreover, modeling of a rapid intrusion occurred in August 2015 is presented.