## 2 The Stage-Wise Methodology for the GHM Characterization of the Landslide Mechanisms
\begin{table}
\begin{tabular}{l} \hline (1). Historical data and indications of displacements and instability of the slope in the past, damage, etc. (*) \\ (2). Topographic data \\ (3). Vegetation cover and land use data \\ (4). Data from geomorphological surveys: changes of local sloping angle due to excavation, erosion, (*) \\ morphologies caused by instability related to the current landslide process or past processes (e.g., main and internal scarps, accumulation areas, channel areas, detachment niches, etc.). \\ (5). Data from geo-structural survey of discontinuities \\ (6). Surficial lithost stratigraphic, geological and geo-structural data (map of outcrops and covers, \\ map of tectonic features) \\ (7). Deep lithost stratigraphic and geo-structural data, description of the geotechnical corings \\ (8). Index properties and hydro-mechanical parameters of the lithotypes, from geotechnical testing, either in situ, or in the laboratory \\ (9). Hydro-geological boundary conditions of the slope: feeding and drainage areas \\ (10). Piezometric data \\ (11). Superficial and deep displacements (e.g., incinometric data), with the possible identification of \\ pre-existing shear bands linked with the morphology of active landslide bodies (*) \\ \hline \end{tabular}
\end{table} 
Table 2: Macrocategories of data to be acquired in the context of analyses and surveys. For the Pisciolo slope, based upon the Stage I analyses, the low values of the strength parameters characterizing the clays at any depth in the slope, together with the high piezometric levels (in the range of 2 m-5 m below the ground level in most part of the hillslope, even at large depth) were recognized as predisposing factors for a landslide. In particular, the high piezometric levels were shown to be connected to the slope-scale permeability, which was higher than typical values for clay slopes, since the Pisciolo slope clays are highly fissured and include coarser soil strata and fractured rock blocks (Figure 6), which, on the whole, increase rainfall infiltration rates. Accordingly, the piezometric monitoring data show that the slope hydraulic features, combined with the climatic regime of the area, bring about a transient seepage in the slope that, down to large depths, determines seasonal variations of the piezometric heads, which influence slope stability. In particular, monitoring displacements at depths from a few meters to 40-50 m and the use of piezometric heads gives evidence of the occurrence of both a mild rate of increase of the piezometric heads and a mild acceleration of the landslide bodies from late autumn to late winter/early spring, with both the maximum piezometric heads and maximum the displacement peak rates occurring in early spring ([10; 40; 41]; Figure 8). It follows that the stage  
Figure 6: Geological map (**a**) and section (**b**) of the Pisciolo slope (modified from [40]). Key: (1) debris and alluvial deposits; (2) Numidian Flysch; (3) Paola Doce clays, and fractured rock inclusions (a); (4) Red Plysch; (5) stratigraphic contact (a), fault (b) and anticline axis (c); (6) landslide crown (a) and body (b); (7) borehole with piezometers (P), borehole with inclinometer (I), GPS sensor (S); (8) line of section; (9) inclinometer shear bending (a), disturbed soil (b) and piezometer cell with corresponding hydraulic heads (c); (10) labelled landslide: crown (a), slip surface (b). I data suggest that the landslide activity at Pisciolo is climate-induced and, hence, is connected to slope-vegetation-atmosphere interactions. [PERSON] et al. [20] reviewed the mathematical laws which are useful to represent the hydraulic, mechanical and thermodynamic processes which evolve in slopes as an effect of both the climate and vegetation, and which, on the whole, are able to describe slope-vegetation-atmosphere interactions. The authors reported the various modeling strategies of such interactions, which account for different coupling degrees.