## 4 Results
### InSAR Site-Specific Analysis  
A site-specific analysis was carried out to obtain more detailed information about the kinematics of the three landslides detected by the areal analysis. Besides using different reference areas, we performed an independent interferogram selection for each case study. The results described below consist of deformation maps obtained by stacking the selected interferograms of the whole analysis period (2016-2019). Figure 6 shows the total stacks obtained for the ascending and descending orbits for the three case studies. The deformation fields show similar shapes in both orbits, while the direction of the displacement is inverted for the different orbits. This difference is common in landslides and should be interpreted as a displacement along the downslope direction. As expected, in the case of Braina and Carbona, the analysis reveals positive displacement rates (movement away from the satellite) for the ascending orbit and negative displacement rates for the descending orbit along the east-facing slopes. In the case of Spareda, the displacement signals are reverted in relation to the orbit and compatible with the south-west facing slope. The total stacks indicate that the three landslide bodies have been subject to some degree of deformation in the four years preceding the catastrophic failure. The Braina earthflow (Figure 6a,b) has been subject to pre-failure deformations mostly affecting the upper part, between approximately 440 m and 550 m a.s.l. This area shows average values of LOS(Line Of Sight)-displacements ranging from 40 mm/year to 120 mm/year. Figure 5: Results of areal radar interferometry (InSAR) analysis (descending orbit #95), 2018–2019 interferometric stack. Similarly, the Carbona earth ow underwent continuous deformations during the study period. Figure 6c,d shows that the upper portion of the main landslide body was affected by large displacements with maximum LOS-displacement values of 100-110 mm/year. The total stack in descending geometry (Figure 6d) gives values of the displacement rate along the LOS of 30 mm/year in the upper part (about 530 m a.s.l. ); it also reveals that in the period of analysis, the whole upper portion of the main landslide body moved remarkably. The last pair of images (Figure 6e,f illustrate the Spareda landslide, showing the area affected by deformations during the four years preceding the landslide reactivation. In this case, the landslide is smaller, and the displacement signal entirely covers the mapped landslide. The movements extend from the toe of the landslide, locally incised by the Reno River at an altitude of 220 m a.s.l., up to 580 m a.s.l. The maximum displacement along the LOS exceeds 120 mm/year. The movements also affect the Municipal Road running along the slope, which was damaged by the landslide reactivation of November 2019. The descending orbit is almost parallel to the direction of movement of the Spareda landslide, while the ascending orbit forms an azimuth angle of 25-30. Therefore, the descending dataset solely detects the vertical component of movement, while the ascending record a combination between vertical and horizontal. The  
Figure 6: Results of site-speci c analysis; stacks from January 2016 to December 2019 in both acquisition geometries for Braina (a,b), Carbona (c,d), Spareda (e,f). observed LOS-deformation signals are compatible with a downslope movement whose vertical lowering component can only be seen from the descending orbit. The ascending orbit, instead, records the vertical (range increase) and the horizontal components (range decrease) with opposite signs indicating that the latter is larger, as demonstrated by the negative LOS-displacement sign. In order to investigate the dynamics of deformation through time, short timescale stacks can be used. We analyzed monthly stacks during the four year investigation period and discuss some of them below.