## 5 Discussion  
This paper has described features of and variations in the fracture network at the outcrop scale in correspondence to major faults zone. Fracture networks were sampled at sites that were considered representative of the general fracture conditions of the rock masses. Fracture collection was performed via traditional geomechanical survey combined with topological analysis to estimate the abundance and degree of fracturing in terms of the fracture intensity and connectivity. The resulting values of fracture intensity (P\({}_{21}\) values) revealed an increase in the \"highly fractured zones\" (HFZs) around the fault traces, starting from background values of adjacent rock masses that were defined as the frequent P\({}_{21}\) values observed in outcrops at a distance from the fault trace. However, the estimated background and peak of P\({}_{21}\) values and the widths of their correlated HFZ vary significantly in the different analysed sectors. Considering the NE-SW-trending fault zone in Claviere-Cesana Torinese area, calc-schist record maximum P\({}_{21}\) values of about 10 m/m\({}^{2}\), while the adjacent dolomitic rocks reach up to 80 m/m\({}^{2}\), with average background values of 20-25 m/m\({}^{2}\). The distribution of P\({}_{21}\) values indicates an amplitude of HFZs between 400 m and 200 m along the northern fault trace, while P\({}_{21}\) is significantly higher within a 150 m wide zone along the eastern termination of the southern fault. In the Salbertrand area, NE-SW-trending faults cross micaschist and show P\({}_{21}\) background values in the order of 8-10 m/m\({}^{2}\) and increasing up to 15 m/m\({}^{2}\) within a 150 m wide zone around the fault trace. For the N-S fault located in the Seguret river sector, quarzitic rocks record an increase in fracture intensity approaching the creek, going from P\({}_{21}\) values around 5 m/m\({}^{2}\) to maximum values of 20 m/m\({}^{2}\) in less than one hundred meters. Considering the variation in the fracture intensity affecting quarzitic rocks, it is possible to determine a fracture zone that is characterized by a width of almost 150 m, in which the intensity trend shows higher values than those found in adjacent outcrops. Taken together, these results suggest that the increase in P\({}_{21}\) observed in the HFZ is approximately centred around the fault traces and is clearly related to the geometric fracture superposition of the fault-localized damage zones over the extended junction (which somehow defines the background values of fracturing). Therefore, in the first analysis, the estimated HFZ in correspondence to the fault can represent the fault damage zone. However, the term \"damage zone\" (e.g., [21] and references therein) was avoided in this study when describing the highly fractured zone around the fault, because a detailed study of the kinematics and genetic relationships of the fractures with respect to the fault was not carried out, and only geometry and relations of discontinuities were considered. Then, the P\({}_{21}\) values estimated in the rock masses result from the superimposition of several factors: (i) the strength and rheology of the rocks (i.e., mechanical stratigraphy and fabrics), largely controlling the formation of brittle structures (e.g., [46; 47; 48; 49; 50; 51]), (ii) the complexity of the damage zones, with an evolution through space and time of different types  
Figure 8: Topological data corresponding to the sites in section A–A’ (**A–C**) in Figure 7: **(A)** Triangular plot showing nodal topology in terms of relative percentage of I, X, and Y nodes; **(B)** triangular plot showing relative percentage of II, IC, and CC branches; **(C)** variation in fracture intensity P\({}_{21}\) with relative digitized fracture network, estimation of highly fractured zone (HFZ). The position of mapped faults in the transect are reported with blue dotted lines.