Geomorphological mapping of the Becca d'Aver deep-seated gravitational slope deformation (Aosta Valley, Italy) based on multi-scale and multi-sensor analysis

The aim of this work is a multi-scale, multi-sensor geomorphological characterization of the Becca d'Aver deep-seated gravitational slope deformation (DsGSD). Particular attention was given to the pseudo-badlands morphologies that crop out in the area, which are producing sediments that are subsequently reactivated by debris flows. A geomorphological map at a scale of 1:10000 was generated in the Cretaz–Comba Basset basin area, left side of the Aosta Valley in northern Italy, ending at the Champagne fan. The study area is characterized by gravitational and runoff associated processes that interact with anthropic structures. However, pseudo-badlands landforms represent the main source of sediments providing loose materials highly connected with the main drainage system. The landforms in the area were characterized and mapped using Google Earth and remote sensing interpretation as well as with field campaigns. Especially radar (Interferometric Synthetic Aperture Radar, InSAR) and optical (multispectral) data were employed to map active deformation areas and detect bare soil using the Bare Soil Index (BSI). Furthermore, we conducted a detailed terrain analysis (TA) and derived the Geological Strength Index (GSI). Moreover, we applied the connectivity index (IC) model and used remotely sensed data to assess the contribution of pseudo-badlands to the general sediment transport. The results highlight how altered bedrock materials and anthropic deposits of mined serpentinite (waste deposits) contribute to the provision of sediments that are related to hydrogeological hazard in the area.