## 3 GHM Characterization of the Landslide Classes: A Preliminary Attempt

\begin{tabular}{c c} \hline \hline
**Property** & **Flowslide** & **Lateral Spread** & **Landslide Factors** & **Saint-Jude** \\  & & & [74; 101] \\ \hline PI & 1–47\% & 3–46\% & Formation & CSC \\ \hline LI & 1.5–16.5 & 1.3–5.1 & \multirow{2}{*}{Geological} & \multirow{2}{*}{Tectonic structures} \\ \cline{1-1} \cline{5-5} S\({}_{\text{u}}\) & 0.08–0.8 kPa & 0.08–1.3 kPa & First-time failure & Current \\ \hline S\({}_{\text{t}}\) & 10–1890 & 12–1500 & \multirow{2}{*}{ClassificationClass 4 landslides are represented by the earthflows [42] and mudslides [15]; see Figure 2 (box 4) and Figure 11. Several earthflow case studies are reported in the literature for Italian sites [12; 107; 108; 109; 110; 111; 112; 113; 114; 115; 116] and provide the values of the landslide factors, as well as the features of the earthflow kinematics. In particular, Figure 16 shows a morphological map of some of the Italian earthflows reviewed using the present GHM characterization: Vadoncello (Senerchia, AV; [117]), Serrone (Motta Montecorvino, FG; [118]), Costa della Gaveta (PZ; [119; 120; 114; 121; 122]), Montaguto (BN; [122; 123]), Brindisi di Montagna (PZ; [124; 125; 126; 127]), Masseria Marino (AV; [126; 127; 108; 113; 128]). The corresponding landslide factor values are reported in Table 6.  
Figure 14: Saint-Jude landslide: (**a**) map and section ([PERSON] et al., 2017); (**b**) Equivalent shear strain field after 87 s (PFEM code; [PERSON] et al., 2019). Figure 15: Timpone landslide: finite element numerical modelling performed by means of Tochnog code—2D ((a); [72]) and 3D analyses ((b); [73]). \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{2}{c}{**Landslide Factors**} & \multicolumn{2}{c}{**Timpone**} \\ \hline \multirow{3}{*}{Geological} & Formation & Aliano Sands \\ \cline{2-3}  & \multicolumn{2}{c}{Tectonic structures} \\ \cline{2-3}  & First-time failure & Current \\ \hline \multirow{3}{*}{Geotechnical} & Classification & (a) & Silty sands \\  & & (b) & Silty clays \\ \cline{2-3}  & Grain-size data & (a) & CF = 3\%, MF = 23\%, SF = 80\% \\  & Grain-size data & (b) & CF = 50\%, MF = 43\%, SF = 11\% \\ \cline{2-3}  & Index properties & (b) & PI = 26\%, A = 0.54 \\ \cline{2-3}  & Shear strength & (a) & c\({}^{\prime}\)p = 50–120 kPa \(\Phi^{\prime}\)p = 42\({}^{\circ}\); \(\Phi^{\prime}\)r = 34\({}^{\circ}\) \\  & parameters & (b) & c\({}^{\prime}\)p = 70 kPa \(\Phi^{\prime}\)p = 24\({}^{\circ}\); \(\Phi^{\prime}\)r = 13\({}^{\circ}\) \\ \hline \multirow{3}{*}{Piezometric} & \multirow{3}{*}{Water table} & Slope involved in landsl: no groundwater immediately downstream the landslide: water table at 23 m below g.l. As shown in Figure 16, the detachment area of the landslide mass, where failure is triggered, may extend through one or more source areas, from which the mass propagates through a channel experiencing major straining, reaching a distant accumulation area downslope. The morphological features of these landslides are largely controlled by the soil hydro-mechanical properties and the slope orography. Based upon the data in Table 6, earthquakes often appear to involve slopes where structurally complex [130], clayey formations outcrop. These are sedimentary successions of fine soils, sedimented in pre-orogenic marine basins and subsequently involved in orogenic processes. At the locations of the case studies in Table 6, these successions are chaotic and jointed as a consequence of an intense tectonic history, so that fractured rock blocks float in an intensely disturbed and highly fissured plastic clay matrix which controls the overall slope behavior. In addition, faults and overthrusts may affect the slopes, determining the presence of localized weaker portions across the slope [131; 132; 133; 134; 135]. Irrespective of the geological and geo-structural history, the clays in these slopes exhibit the behavior of overconsolidated clays, with yield stress ratios in compression, i.e., YSR \(\geq\) 3 [134].