- Ground displacements evaluation of areas affected by slope deformations through sar interferometric inspection: evidence in central – southern Italy

The activities of the FRASI project (Integrated and multi-scale approach for the definition of seismic-induced landslide hazard in the Italian territory) are developed in three Lines of Activities carried out at national, regional and local scale. The main purpose of the project is to define a methodological procedure that addresses the problems related to the mapping of areas potentially susceptible to earthquake-induced landslides. Such procedure is applied to local-scale phenomena to be extended on regional to national scale. The test areas have been selected on the base of the landslide type, the lithology and the morphostructural context. Particular attention is devoted to the analysis of Deep-seated Gravitational Slope Deformations (DGSD), whose movement can significantly affect the stability of infrastructures and the safety of people. To this aim, Synthetic Aperture Radar Interferometry, combined with analytical and numerical modelling, proved to be an accurate support for the monitoring and modelling of different types of landslides (e.g. rotational/translational slides and rock avalanches) [Frattini et al., 2018]. Understanding the factors (e.g. seismicity, geomechanical properties, interaction with underground aquifers) [Moro et al., 2012] that regulate the triggering and the extent of landslide displacements could allow to define the complex dynamics of several types of landslides. In this project, we investigate three different slope movements located in the Italian territory characterized by moderate-to-high seismic hazard (Fig. 1), exploiting the integration of geological and geotechnical data with the satellite SAR data processing. Specifically, the preliminary outcomes resulting from interferometric processing of SAR data are presented in terms of ground displacements. The first case study is represented by a DGSD located approximately 5 km West of Paternò village (Sicilia Region, Southern Italy). Such unknown paleo-landslide was recognized during the studies accomplished on the Etna Volcano eruption in December 2018 [Bignami et al., 2019]. The investigated area is part of the Gela fold and represents the most external sector of the Apennines-Magrebides chain. The site is composed of proximal molassic deposits belonging to the Terravecchia Formation (upper Miocene) consisting of grey-blue and brown marly clays with brown brecciated clays on the top of the formation [Carbone et al., 2010]. The second DGSD is sited approximately 3 km North-West of Pescosolido municipality (Lazio Region, Central Italy), in the southern sector of the Roveto Valley. Structural analysis indicates that the study area experienced a multi-stage tectonic activity, which involved the Latium-Abruzzi carbonate platform sequence and Plio-Quaternary continental deposits [Saroli et al., 2003]. The last results presented are referred to the Pisciotta landslide (Campania Region, Southern Italy), a DGSD situated in the Rizzico locality. The landslide develops in an exceptionally deformed turbidite series composed of intercalated calcarenites, marls and mudrocks [De Vita et al., 2017]. It produced several damages to the surrounding provincial road in the last decades and currently poses an hazard to the national railway that intersects the toe of the landslide.