Tectonically active landscapes are dynamic systems which record the effects of geological processes acting on Earth interior and Earth surface processes. In such environments, threshold conditions on hillslopes are often reached, with considerable implications for natural hazards. Although there is a wide literature on landslide erosion in tectonically active regions, especially for what concerns earthquake-induced impulsive landslides, only few works focused on time-dependent rock mass deformations (Mass Rock Creep, MRC) which can evolve into massive rock slope failures (i.e. rock avalanches). The temporal evolution of such progressive deformation into failure may be accelerated by external forcing, such as earthquakes, so that the risk associated to this kind of phenomena should be better referred to as a "dynamic risk", which is variable in space and time. Multi-scale landscape evolution modelling represents a useful tool for constraining the rates of erosion/deposition dynamics in tectonically active regions. Aim of this project is to define the role of landscape evolution rates in the development of MRC deformations and their evolution into massive rock slope failures. An already tested multi-modelling approach, which includes morpho-evolutionary tasks, will be implemented in selected case studies and improved with numerical Landscape Evolution Models (LEMs), as better inputs for numerical, time-dependent stress-strain numerical modelling of slope stability. Such an objective will be achieved with the contribution and expertise by a geomorphological team from Sapienza and with the international collaborations with the University of Sevilla and Potsdam, respectively for what concerns: i) the structural analysis and the definition of the tectonic evolution of selected morpho-structures; ii) the implementation of multi-scale LEMs.
Innovation of the proposed research is manifold:
1) Despite a wide literature on earthquake-induced impulsive landslides, few studies have been focused on massive rock slope failures associated to MRC in tectonically active regions, which represent impacting hazardous processes to be considered when attempting to mitigate the geological risks.
2) The study of time-dependent rock mass deformation and the associated massive rock slope failures in tectonically active regions lead to the introduction of a modern concept of geological risk, the ¿dynamic risk¿, which is variable in space and time. This new concept overcomes the need of defining absolute thresholds for external forcing to the trigger of such catastrophic events, since the same external input can trigger or not a massive rock slope failures depending on the ¿aging¿ (i.e. stage of MRC) of the involved rock mass.
3) Recent works demonstrated the suitability of a multi-modelling approach to the study of massive rock slope failures associated to MRC (Martino et al., 2017), which encompasses multi-scale morpho-evolutionary modelling, detailed engineering-geology modeling and time-dependent stress-strain numerical modeling of slope stability. With respect to discretized morpho-evolutionary models of valley slopes based on geomorphic markers and geo-morphometric data used so far (i.e. Bozzano et al., 2016; Della Seta et al., 2017), the introduction of multi-scale LEMs as input for the stress-strain numerical modelling of slope stability, both in back and forward analysis, will considerably improve the multi-modelling approach to the study of massive rock slope failures in tectonically active regions.
4) Several reasons motivate the choice of the study sites, which can be summarized as follows:
i) a robust geological (in its broadest meaning) database available from both the literature and published/unpublished data collected by the proposing research group; ii). the presence of geomorphic signatures of both DSGSD and massive rock slope failures, associated to different structural geological settings; iii) the potential risk conditions due to the presence of important urban settlements, industrial plants and road infrastructures.