## 3 Methodology
### Third Phase  
#### 3.3.1 Detachment and Landslide Susceptibility  
The theoretical-practical evaluation procedure used in this phase was based on the criteria of several authors, such as [PERSON] [62], [PERSON] [57], [PERSON], [63], [PERSON] [61] and [PERSON] [33]. The geomechanical characteristics were defined (Tables 4 and 5) by assigning values attained following expert criteria. The selected parameters were lithology, geological structure, morphometry, discontinuity, water presence, vegetable cover, seismic activity and weathering rank, which were evaluated from 0 to 4 (Supplementary Table S1) based on the conditions observed in the field (see definitions of the parameters in Supplementary Table S2).  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Weight** \\ \hline Lithology (L) & 0.0 to 4.0 \\ Geological structure (Gs) & 0.0 to 4.0 \\ Morphometry (M) & 0.0 to 4.0 \\ Discontinuity (D) & 0.0 to 4.0 \\ Weathering rank (Wr) & 0.0 to 4.0 \\ Water presence (W) & 0.0 to 3.0 \\ Vegetable cover (Vc) & 0.0 to 3.0 \\ Seismic activity (S) & 0.0 to 4.0 \\ SC: (L + Gs + M + D + Wr + W + Vc + S) & 0.0 to 30.0 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Main parameters and weights assigned to rock mass in the susceptibility coefficient estimation, based on [21; 57; 61; 63; 64].  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Term** & **Description** & **Weathering Degree** \\ \hline Fresh & No visible sign of rock material weathering. Perhaps slight & I \\  & discolouration on major discontinuity surface. & \\  & Discolouration indicates weathering of rock material and & \\  & discontinuity surfaces. All rock material may be discoloured & II \\  & by weathering. & \\  & Less than half of the rock material is decomposed or disintegrated & \\  & into the soil. Fresh or discoloured rock is present either as a & III \\  & continuous framework or as a core stone. & \\  & More than half of the rock material is decomposed or & \\  & disintegrated into the soil. Fresh or discoloured rock is present & IV \\  & either as a continuous framework or as a core stone. & \\  & All rock material is decomposed or disintegrated into the soil. & V \\  & The original mass structure is still largely intact. & \\  & All rock material is converted to the soil. The mass structure and & \\  & soil & the material fabric is destroyed. There is a significant volume & VI \\ \hline \hline \end{tabular}
\end{table}
Table 3: Weathering degree based on ISMR [53].  
This method allows the susceptibility levels to detachment and landslide (Tables 6 and 7) to be defined. The susceptibility level is a qualitative value (I to V), and it is related to the susceptibility coefficient (SC) estimated [21, 64]. Thus, the grade and susceptibility levels for rocks are: I for SC \(\leq\) 5.0; II for 5.0 \(<\) SC \(\leq\) 10.0; III for 10.0 \(<\) SC \(\leq\) 15.0; IV for 15.0 \(<\) SC \(\leq\) 20.0; and V for SC \(>\) 20.0. The grade or susceptibility levels for soils are: I for SC \(\leq\) 5.0; II for 5.0 \(<\) SC \(\leq\) 8.0; III for 8.0 \(<\) SC \(\leq\) 12.0; IV for 12.0 \(<\) SC \(\leq\) 16.0; and V for SC \(>\) 16.0. As a result, the susceptibility map of instability (detachment and landslide) was prepared from the geomechanical evaluations obtained using the geostatistical kriging tool that allows the values to be interpolated.