Deep-seated Gravitational Slope Deformations of the Friuli Venezia Giulia region (Southern Alps, Italy)

Deep-seated Gravitational Slope Deformations (DGSDs) are large-scale slowly progressing mass movements that can have a prominent influence on long-term landscape evolution and slope stability in mountainous regions. However, despite their geomorphological relevance, they have only been partially mapped in the Friuli Venezia Giulia (FVG) region of northeast Italy. In this study, we compiled the first comprehensive inventory of DGSDs in this region based on the integration of high-resolution LiDARderived products and orthophotos, remote sensing datasets, and existing landslide inventories. A total of 21 DGSDs, covering areas ranging from 0.63 to 6.48 km2, were identified, 14 of which were previously unreported. Their spatial distribution shows a clear clustering in the Western and Central Carnic Alps, and is controlled by lithological variability, tectonic inheritance, glacial debuttressing, and relief energy. We selected four representative DGSDs for detailed geomorphological analysis using field surveys supported by Uncrewed Aerial Vehicle Digital Photogrammetry (UAV-DP), thereby enabling their high-resolution mapping and characterisation of their internal kinematics. Overall, the inventory provides a robust geomorphological framework for understanding the distribution of DGSDs in the FVG Alps and will contribute to future hazard assessments and land-use planning. Moreover, our findings highlight the value of UAVDP for detailed landform detection.