The project is aimed at tuning a multi-step, multi-scale and multi-disciplinary comprehensive analysis of Deep-seated gravitational slope deformation (DSGSD) processes, to better address their peculiarities in terms of both spatial and temporal scale in a hazard-oriented perspective. After a first phase of inventorying over large areas representative of the Apennine chain, especially where DSGSDs have been poorly studied, the application of techniques for landslides susceptibility assessment, properly adapted to the specificity of slope-scale processes, will allow for a better understanding of the physical process in relation to the conditioning factors, such as geological-structural and geomorphological properties. Satellite-based InSAR analyses will be applied for supporting the detection and assessing the state of activity, while catchment-scale geomorphometric analyses will be performed to assess the potential of geomorphic markers as proxies for DSGSD detection. Moving to the evaluation of risk associated to DSGSDs, especially in terms of potential to evolve as catastrophic failures, the project will focus on the detailed study of selected case histories to tune and refine a multi-modeling approach aimed at: i) framing the present stress-strain conditions in the long-term morpho-evolution that influences the process and ii) providing hints on the rock mass damage in terms of visco-plasticity properties of deforming slopes. Landscape evolution modeling will provide constraints to back-analyze in space and time the processes; multi-physics monitoring and modeling of an already equipped "site lab" will provide criteria for the visco-plastic parametrization of the slopes. The results will be integrated in a calibrated numerical model aimed at properly understanding the deformation rates inferred by satellite InSAR data in light of the creep behavior governing the process, thus providing useful hints for an efficient failure forecasting.
The proposed research presents some innovative features that can be related to the different study scales characterizing the methodological approach. In general terms, the first strength point of this project is the general aim of providing a comprehensive approach to DSGSDs strongly focused on a hazard/risk perspective, which is then conceived to couple different modeling methodologies and analyses at different scales.
From the large-scale perspective the main innovations include an upgrade of the knowledge about the investigated processes. In a first instance a preliminary goal of the research, which is preparatory to other specific objectives but is still a self-standing objective, is a first attempt to provide a systematic mapping of DSGSDs and analysis of predisposing factors in wide sectors of the central Apennines. Beyond a more detailed knowledge on the location of the DSGSDs and, thus, of the related hazards (also based on the inferred level of maturity), the analysis of relations with both "static" (i.e., geological-structural and morpho-structural features) and "dynamic" (i.e., morpho-evolutionary contexts) factors can provide hints for a susceptibility criterion to be applied in other mountain ranges with similar features. Still in the frame of large-scale analyses, we think that the research will provide a scientific advancement in the upgrade and adaptation of landscape numerical modeling to match the requisites needed to frame MRC processes in the wider context of morpho-evolutionary stages of connected channel-hillslope systems.
This latter aspect requires a shifting in the scale of analysis as a coupling of large-scale boundary spatial and temporal conditions (i.e. present morphology and ongoing morpho-evolutionary stage) and detailed knowledge about rock-mass rheological properties is needed. Significant scientific advancements are then expected from the results of studies on the pilot site selected to test methods and tools for the definition of visco-plastic properties of rock masses. In particular, with respect to previous studies and experiences addressed to calibrate viscosity parameters via back analyses and validated by comparing simulated and surveyed geomorphic features, this research aims at providing innovative methods, such as the multi-physics approach, to properly characterize damaged rock masses. With these premises, the numerical (multi)modeling (i.e., the application of numerical simulations accounting for the results of landscape and morpho-evolutionary models) should become an integrated tool for forecasting the mid/long-term evolution of deforming slopes and to assess the sensitivity to external triggers for possible short / mid-term paroxysmal evolution. At this aim, the susceptibility index derived from both geomorphometric and rheological background could be applied for thematic mapping useful for the environmental management at a regional-scale.
Finally, it is worth mentioning what has been recalled in the first introductory paragraph: the knowledge of DSGSDs location and of the related mechanical properties of damaged rock mass has relevant implications also for seismic zonation purposes, as slopes involved in deformational processes - even if with low or no potential of catastrophic evolution - can be regarded as zones susceptible to amplification of the seismic signal.