); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (G.P. );  
[EMAIL_ADDRESS] (G.S.) [PERSON]  
1 National Research Council of Italy, CNR-IREA, Via Amendola 122, 70126 Bari, Italy;  
[EMAIL_ADDRESS] (I.A. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (G.P. );  
[EMAIL_ADDRESS] (G.S.) [PERSON]  
1 National Research Council of Italy, CNR-IREA, Via Amendola 122, 70126 Bari, Italy;  
[EMAIL_ADDRESS] (I.A. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.G.P. );  
[EMAIL_ADDRESS] (G.S.) [PERSON]  
1 National Research Council of Italy, CNR-IREA, Via Amendola 122, 70126 Bari, Italy;  
[EMAIL_ADDRESS] (I.A. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (G.P. );  
[EMAIL_ADDRESS] (G.S.) [PERSON]  
1 National Research Council of Italy, CNR-IREA, Via Amendola 122, 70126 Bari, Italy;  
[EMAIL_ADDRESS] (I.A. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (I.A.R. ); [EMAIL_ADDRESS] (G.P. );  
[EMAIL_ADDRESS] (G.S.) [PERSON]  
1 National Research Council of Italy, CNR-IREA, Via Amendolavegetation or variable land cover; and (ii) the advanced time series analysis required for identifying complex kinematics (related, for instance, to early warning signals) [7]. Currently, several satellite data are available, from both past and current missions, providing stacks of interferometric SAR images at different wavelengths, spatial resolutions, and revisit times [8]. Recent satellite missions have improved the monitoring of unstable slopes. L-band missions such as ALOS-2/PALSAR-2 [9] and SAOCOM [10] provide interesting monitoring capabilities over vegetated areas, despite the low sensitivity to small displacements and the limited revisit time. The high-resolution X-Band COSMO-SkyMed (CSK) constellation [11], and the upcoming COSMO-SkyMed second generation [12], acquire data with a spatial resolution reaching metric values, and provide revisit times of up to a few days, leading to an increase in the density of the measurable targets, thus improving the monitoring of local scale events and the detection of non-linear displacement trends. The Sentinel-1 (S1) C-band mission from the European Space Agency (ESA) [13] provides a spatial resolution comparable to that of previous ESA missions, but a nominal revisit time reduced to 6 days. On December 2021, a failure on Sentinel-1B occurred, leading to a doubling in the revisit time. Nonetheless, by offering regular global-scale coverage, better temporal resolution, and freely available imagery, S1 improves the performance of MTInSAR for ground displacement investigations. In particular, the short revisit time allows a better time series analysis by improving the temporal sampling and the chances to identify pre-failure signals characterized by a high-rate and non-linear behavior. Moreover, it allows collecting large data stacks in a short time, thus improving the MTInSAR performance in emergency (post-event) scenarios. These characteristics are very promising for early warning of slope failure events and monitoring subsequent displacement trends, in the larger framework of Disaster Risk Reduction (DRR). However, when dealing with large data stacks, the distinction between the sensitivity and significance of the measurements is essential. Indeed, detection of velocity changes can be related to changes in the equilibrium of forces affecting terrain stability, provided that all variations due to other natural phenomena (e.g., thermal expansion and differences in soil moisture) have been excluded. Consequently, reliable monitoring and early warning require a detailed analysis of the displacement time series looking for signals actually related to ground instabilities.