## 3 GHM Characterization of the Landslide Classes: A Preliminary Attempt
However, the locations of slopes of this landslide class, despite being formed of materials similar to those involved in the earthflows discussed above (Figure 16), are characterized by an orography and geo-structural settings which are less chaotic than those involved in earthflows. In addition, the presence of clays of low strength parameters down to great depths makes these landslide mechanisms deeper, involving the whole slope down to the bottom of the valley. FEM modelling has also shown the extent to which valley excavation determined by river erosion over geological time periods can give rise to the onset of failure progression in these slopes, from the toe upwards. At present, the current activity of these landslides is often related to slope-vegetation-atmosphere interactions [11; 40; 64; 65; 66]; Figures 7, 9 and 10). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Landslide Factors**} & **Pisciolo** & **Pianello** \\  & & [40; 41] & [150] \\ \hline \multirow{4}{*}{Geological} & Formation & PD & FAEa \\ \cline{2-4}  & Tectonic structures & Fault and fold & Overthrust \\ \cline{2-4}  & First-time failure & Current & Before the ‘50 s \\  & & Current & Current \\ \hline \multirow{4}{*}{Geotechnical} & Classification & \(\mathrm{C_{imFoc}}\) & \(\mathrm{C_{Foc}}\) \\ \cline{2-4}  & Grain-size data & \(\mathrm{CF}=49\%\)\(\mathrm{MF}=45\%\) & \(\mathrm{CF}=45\%\)\(\mathrm{MF}=27\%\) \\  & & \(\mathrm{SF}=6\%\) & \(\mathrm{SF}=14\%\) \\ \cline{2-4}  & Index properties & \(\mathrm{PI}=40\%\)\(\mathrm{A}=0.85\) & \(\mathrm{PI}=44\%\)\(\mathrm{A}=0.9\) \\ \cline{2-4}  & Shear strength & \(\mathrm{c^{\prime}}_{\mathrm{P}}=20\)\(\mathrm{kPa}\) & \(\mathrm{c^{\prime}}_{\mathrm{P}}=0\)–\(25\)\(\mathrm{kPa}\) \\  & parameters & \(\mathrm{\phi^{\prime}}_{\mathrm{P}}=18^{\circ}\) & \(\mathrm{\phi^{\prime}}_{\mathrm{P}}=13^{\circ}\)–\(26^{\circ}\) \\  & & \(\mathrm{\phi^{\prime}}_{\mathrm{r}}=10^{\circ}\) & \(\mathrm{\phi^{\prime}}_{\mathrm{r}}=8.5^{\circ}\) \\ \cline{2-4}  & Permeability coefficient (m/s) & Lab: \(10^{-9}\)–\(10^{-10}\) & Lab: \(10^{-9}\)–\(10^{-10}\) \\ \hline \multirow{2}{*}{Piezometric} & Piezolectric levels from & \multirow{2}{*}{\(-2/-3\)} & \multirow{2}{*}{\(-2/-3\)} \\  & shallow to large depth (m g.l.) & & \\ \hline \hline \multicolumn{2}{c}{(PD) Paola DOC Clays; (FAE) [PERSON] (FAEc clayy member); (\(\mathrm{C_{imFoc}}\)) intensely to medium fissured, highly overconsolidated clays; (\(\mathrm{C_{Foc}}\)) fissured and highly overconsolidated clay.} \\ \end{tabular}
\end{table} 
Table 7: Landslide factors for deep rototranslational landslides (class 5; Figure 11; [40; 150]); for the geotechnical parameters referring to Tables 3 and 5. Debris-flow, debris-avalanche and debris/sand flowslides ([42]; box 6 in Figures 2 and 11) are part of the 6 th landslide class examined in this paper. They are generally triggered by more or less critical rainfall events, which mobilize coarse to loamy soil covers, propagating downslope as rapid flows. In the following paragraphs, we will refer to this class with the term \"flow\". These flows occur in different geological contexts, where pyroclastic soils (Central America: [151]; New Zealand: [152; 153; 154; 155; 156; 157; 158; 159; 160; 161]), residual soils (Hong Kong: [162]; Japan: [163]) or colluvial soils (Brazil: [164]; Hong Kong: [165]) overlay rock bedrocks. In Campania, Italy, these landslides are very common, where pyroclastic deposits outcrop on the fractured limestones of the Apennine platform. The flows of reference in the analysis occur at Mt. Lattari (1997), Mt. Pizzo D'Alvano and San Felice a Cancello (1998), Cervinara (1999), Nocera Inferiore (2005) and Ischia (2006). In some cases, these flows involve pyroclastic soils lying on flysch outcroppings within the Apennines (event 2005 in the area of Mt. Le Croci-Monte Termito).