## 3 Results
To proceed with the comparison between the strength values measured using traditional direct techniques (Schmidt hammer) and those obtainable from the laser scanner survey, a section of the wall was selected. This section contains discontinuities with different types and degrees of alteration. On the 3D model, for each of the sevendiscontinuities where rebound values (\(r\)) were measured, reflectivity values (\(I\)) were extracted from the point cloud returned by the laser scanner (Figure 4). Reflectivity values (\(I\)) ranging between 30% and 56% were measured. The lower values (30 \(\div\) 45), with an average value \(\mathrm{I_{m}}=39\%\) and generally more scattered, were associated with areas where the incident beam partially penetrates and scatters within micro-cavities, as in the case of corroded and vacuolar surfaces, or in the presence of very irregular surfaces due to flake detachment, or even at open discontinuities. On portions of discontinuities with altered but smooth surfaces, reflectance values (\(I\)) ranging between 53% and 56% were recorded, with generally less dispersion (Figure 5). For the Monte Catalan fionthotype as well, there is an observed increase in the average rebound value (\(r\)) with the growth of \(I\), and the data appear to be correlated. The lowest values of \(r\) and \(I\) are associated with the discontinuities (2) in Figure 5 characterized by significantly altered and highly fractured surfaces. Figure 4: Monte Catalanfano: Discontinuity 1–7 on the mesh in layer format reflectivity. Figure 3: Monte Catalanfano: points cloud of rock mass collected using a laser scanner. Highlighting the seventy discontinuities from which the sections have been extracted. Survey 3. At the site of Castronovo di Sicilia, a rock mass exhibiting an overall west-dipping monocline, interrupted by two main fault systems--one oriented NW-SE and the other NE-SW--was investigated. These faults tend to intersect, leading to varying degrees of fragmentation of the structure, particularly in the southwestern sector where the quarry in question is located. For this site, the FARO FOCUS 3D laser scanner was used. For the scanning investigation describing the morphology of the subject and ensuring the necessary overlap, two station points were established within an area adjacent to the surveyed zone, avoiding shadow zones and areas of unclear identification. This approach allowed for scanning at a density of 1 point every 4 mm, resulting in an overall collection of approximately 30 million points. This study was conducted by comparing the strength values measured using traditional direct techniques (Schmidt hammer) with those obtained from the survey through laser scanning in two specifically chosen zones (Zone 1 and Zone 2) within the quarry area (Figure 6). In Zone 1, near the alteration, an average reflectivity value (\(I_{m}\)) of 54.63% was measured, while in the area less affected by rock alteration, a mean reflectivity value (\(I_{m}\)) of 69.64% was observed. This analysis indicates that the zone characterized by alteration (Zone 1) exhibits lower average reflectivity values compared to those found in Zone 2. The average rebound value obtained on the wall identified in the first zone (Zone 1) is approximately (\(r_{m}\)) 19.75; in the area located a few meters away from the altered zone (Zone 2), we observed an average rebound value (\(r_{m}\)) of 41.1. Survey 4. The ancient quarries of the Latomine del Paradiso [54,55] are partially open-pit and partially underground. Reflectivity (\(I\)) measurements were conducted using the Leica Scan Station laser scanner, which has a scanning field of 360\({}^{\circ}\)\(\times\) 270\({}^{\circ}\). The acquisition speed can reach up to 4000 points/s, and the wavelength of the emitted ray (\(\lambda\)) is between 510 nm and 540 nm. The scan was performed with a density of 2 cm.