DEEP-SEATED GRAVITATIONAL SLOPE DEFORMATION: INSIGHTS INTO THE GEOMORPHOLOGICAL AND KINEMATIC EVOLUTION. (EASTERN CENTRAL SARDINIA - WESTERN MEDITERRANEAN SEA).

The PhD research project concerned to the study of Deep-Seated Gravitational Slope Deformations (DSGSDs) in Sardinia. The aim is to identify the areas affected by these processes and understand their geo-structural features and their evolution. These gravitational processes related to the geodynamic evolution of the western Mediterranean in the Pliocene and Quaternary, and in particular with the Uplift processes. A multiscale approach will be used based on the geo-structural and geomorphological analysis of the slopes affected by DSGSDs processes. On a local scale, the study was based on the geological, geomorphological, structural and geotechnical characterization of the slopes, using also innovative technologies such as drone photogrammetry for high resolution reconstruction of the ground surface. The objectives are to contribute to the knowledge on the DSGSDs obtaining three-dimensional interpretative models related to the geomorphological and geostructural structure on a local scale and to insert them in the complex geodynamic context of the Mediterranean and active tectonics in Sardinia. In conclusion multi-source and multi-scale monitoring system was build in Ogliastra (Sardinia). Space-borne Interferometric Synthetic Aperture Radar (InSAR) data using ERS and Sentinel-1 satellites identified downslope movement identified as DSGSDs active in the past decades. To better understand the kinematics and short-term deformation of the unstable slopes, a monitoring system, consisting of GNSS antenna, tiltmeter, and extensometer, have been installed along the DSGSDs near urban areas. A distribution of GNSS measurement points in the unstable area and adjacent stable areas have since 2020 provided periodic measurements of the deformation. With a temporal resolution of 30 seconds, extensometers and tiltmeters have been recording changes in large block inclinations and movements over prominent fractures. Historical InSAR displacement rate and monitoring data support the model of rock slope deformation indicating large scale-toppling and deep landslides. 24/7 monitoring system could become an essential component of a for early-warning system.