PSI - Issue 84

Erica Cernuto et al. / Procedia Structural Integrity 84 (2026) 1167–1174

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Assuming negligible longitudinal displacement, the transverse and vertical components were reconstructed for the synthetic PS in the landslide area. The results show a progressive increase of the transverse component up to about 40 mm and a gradual lowering reaching roughly –20 mm over the monitoring period (Figs. 7a,b), confirming a dominant horizontal deformation accompanied by a smaller vertical component. To evaluate the reliability of the results, a comparison was conducted between the displacements estimated from InSAR data and those recorded by traditional monitoring methods. Although ground-based measurements cover a wider portion of the landslide, the comparison focused on targets located in the upper area, near the synthetic PS. These observations indicate a clear reduction in landslide activity, with displacement rates decreasing from about 4 cm/year (1975–1999) to roughly 2 cm/year (2004–2015). InSAR data for 2018–2022 confirm this trend, showing maximum displacements of around 40 mm (about 1 cm/year), consistent with the long-term behaviour of the slope. A qualitative comparison was also carried out between the spatial distribution of displacements derived from InSAR and those predicted by numerical modelling. The comparison revealed a good correspondence in the upper portion of the landslide, where InSAR data confirm the critical areas identified by the model. In the lower portion, the absence of satellite measurements prevents a direct comparison, although numerical simulations indicate larger displacements, suggesting more intense movement in that sector.

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Fig. 7. Time evolution of the two components of the actual displacement of the identified synthetic PS: (a) transverse (d T ) and (b) vertical (d V ) (adapted from Cernuto et al. 2025). 5. Conclusion The combined use of InSAR satellite interferometry and three-dimensional numerical modelling has shown strong potential for analysing landslide–infrastructure interaction. The findings confirm that merging satellite observations with numerical simulations yields a more comprehensive understanding of the phenomenon than relying on either method alone. InSAR provided an updated and spatially continuous representation of surface displacements, while numerical modelling provides estimates of the actual displacement components and identifying the predominant direction of movement. The satellite data also enriched the information obtained from traditional monitoring, supplying more recent displacement measurements and contributing to a broader and more detailed depiction of the landslide’s evolution. Overall, integrating the two techniques enhances the interpretation of ground deformation processes and supports a more reliable estimation of displacement components, offering valuable insights for slope stability evaluation and infrastructure risk management. Acknowledgements This study was supported by FABRE – “Research consortium for the evaluation and monitoring of bridges, viaducts and other structures” (www.consorziofabre.it/en) within the activities of the FABRE-ANAS and FABRE ASTM 2021-2026 research programs. Any opinion expressed in the paper does not necessarily reflect the view of the funder. Additionally, this research was supported by the project “Methodological Approaches for RIsk assessment in the framework of landslide bridge IntEraction (MARIE)”. The authors would also like to thank ASTM for sharing the data used in this study; the views expressed in the paper are those of the authors and do not necessarily represent those