DSGSDs as a source of multi-hazard for risk assessment: hints from the Stiffe-San Martino d'Ocre ridge (Central Apennines, Italy) case study

DSGSDs (Deep-Seated Gravitational Slope Deformations) manifest at the mountain relief scale through a wide variety of morphostructures, such as trenches, scarps, counter-scarps, double ridges, as well as evidence of bulging and landslides, distributed along the slope and mainly dependent on the local geological setting (Discenza & Esposito, 2021). A growing interest in the understanding of such processes has been recorded in the last few decades due to the related hazard and risk conditions. Indeed, as documented in the literature (e.g., Loew et al., 2024), the huge masses involved in an active DSGSDs even if with low rates of displacement can threat structures and infrastructures located on and in the deforming slopes (Frattini et al., 2013). Furthermore, the creep process usually featuring a DSGSD can reach the tertiary stage in a part or in the whole deforming slope and lead to generalized and/or localized massive slope collapses (Loew et al., 2024). Moreover, in tectonically active areas, DSGSD can amplify the ground motion, thereby increasing overall seismic hazard and related risk (Martino et al., 2020). In this frame, the hereby presented case study (Stiffe-San Martino d’Ocre mountain ridge, Abruzzi region, central Italy) is part of a wider project aimed at inventorying DSGSDs and has been selected as it highlights the relevant role played by karst processes that can activate and/or accelerate these deformations. This study also compares the geological model of the ridge, which highlights numerous signs of a DSGSD (Khalaf et al., 2024), with the existing, official geological hazard maps and landslide inventories (Figure 1).