## 5 Numerical Modeling
### Slope Characterization  
The rock mass was zoned considering the jointing conditions, the properties of intact rock, the geological setting, the weathering, and the confinement conditions. In particular, 102 regions were identified within the geological cross-section A-A' (Figure 7, see trace in Figure 2), also considering the portions related to the different unloading phases (Figure 4). For each region, the mass was characterized through the available laboratory and geomechanical properties and by applying the previously exposed relationship. The unit weight of each single region was estimated according to [PERSON] et al. [48], by considering different mass structures. For the intact rock constituting the jointed mass, the unit weight derived from the laboratory test was utilized. The jointed mass involved in DSGSD was characterized by measuring the discontinuities sets' attitude and a unit weight of 20.0 kN/m\({}^{3}\) for joint infilling material and 0.0 kN/m\({}^{3}\) for an empty joint. Discontinuities were considered to be progressively more closed towards the bottom in relation to the lithostatic stress. For the cataclastic zones, astride to the faults, a unit weight of 20.0 kN/m\({}^{3}\) was considered for the fine matrix present inside the rock blocks. The matrix was estimated to be 10% in the most superficial horizons and progressively less at depth. For the recent soil covers on the slope and the lacustrine sequence in the central portion of the Fucino plain, a unit weight of 20.0 kN/m\({}^{3}\) was considered. The rock mass strength was computed through the upgraded Hoek-Brown failure criterion [45], considering the results of the laboratory test and the _GSI_ values derived from geomechanical surveys. The \(m_{i}\) parameter was considered equal to 12 for all the calcareous lithotypes. Starting from the value measured at the surface, the _GSI_ was increased by 5 every 100 m of depth, in order to simulate the improvement of characteristics due to the confining stress. In the jointed mass, the _GSI_ was increased up to the maximum value of 80,  
Figure 7: Engineering-geological model used in the numerical analyses, showing the 102 regions identified, the different types of materials, and the boundary conditions considered. The model indicates the different unloading stages and the numbers of the regions for which the geomechanical characteristics are described in Tables 3–5. \(x\)-axis is in meters, while \(y\)-axis is in meters a.s.l. while in the cataclastic zones the _GSI_ was increased up to 50. In the calculation of tensile strength, the approach of Hoek-Martin [50] was used always, considering a \(m_{i}\) parameter of 12. Recent covers, lacustrine deposits, marginal regions, and a very deep portion of rock mass were considered as perfectly elastic, in order to not have localized ruptures which have little influence on the analysis of the slope process. Regarding the elastic parameters, in this case, the rock mass was also characterized by using the laboratory data and considering the jointing conditions observed on site. The Poisson ratio was adopted equal to those measured in UCS tests, while the Young modulus was calculated according to [PERSON] et al. [43]. For each region in the model, the vertical load was determined at the central point, while the horizontal pressure was estimated by using the considered \(K_{0}\). The rock mass strength \(r\) was computed assuming filled joints at the surface and joints without infilling below 200 m of depth. To assign the joint dip \(n\), the presence of bedding planes was considered in rock mass, while high angle discontinuities were considered for a cataclastic zone. The \(J_{v}\) parameter was determined through the spacing of joint sets, making it slightly decrease with depth to account for the increase in thickness of bedding planes and the decrease in jointing conditions. Both the Bulk and shear moduli were computed by using the previously described equation [9; 10] through the Young modulus derived from the Sitharam approach.