Landslide monitoring by using GNSS and InSAR observations: the south-eastern Alps case study

Landslides represent a well-known and pervasive hazard in the Italian territory, representing a substantial risk to both human safety and critical infrastructure. The Alpine region is particularly susceptible to slope instability due to its complex geomorphology and the heterogeneous nature of glacial and post-glacial deposits that characterize its valleys. In this framework, systematic landslide monitoring and the development of reliable stability models are essential for acquiring accurate and up-to-date data, enabling the assessment of evolving instability conditions and supporting effective risk mitigation strategies.

This study presents the results of an integrated approach of geomorphological mapping, monitoring, and numerical modeling applied to a landslide located in the southeastern Alps, within an area characterized by moraine and colluvial slope deposits, including evidence of a paleo-landslide. The investigation includes a detailed geotechnical characterization of the slope stratigraphy based on borehole logs and inclinometer measurements, as well as a hydrogeological analysis derived from piezometric data collected within the boreholes. Ground deformation has been quantified through displacement measurements obtained using single-frequency GPS receivers, high-precision GNSS sensors, and remote sensing (InSAR) techniques. In addition, slope stability has been evaluated through both two-dimensional and three-dimensional numerical modeling.

The integrated use of multiple monitoring techniques and modeling approaches enables cross-validation of the results and supports a more robust interpretation of the observed displacement patterns. While the preliminary two-dimensional stability analyses are corroborated by three-dimensional modeling outcomes, the incorporation of displacement measurements significantly enhances the reliability of the analytical models, allowing for a detailed reconstruction of the slope deformation mechanisms and their temporal evolution.