Assessment of slope processes in a deep-seated rockslide-earthslide by integrated investigation and monitoring: Brugneto case study (Northern Apennines, Italy)

Abstract

This study defines the reference geological model of the Brugneto deep-seated landslide (Northern Apennines, Piacenza province, Italy). An integrated mapping and monitoring approach reconstructs its internal structure and kinematics and defines its controlling factors for hazard assessment purposes. The landslide affects an area of approximately 1.18 km2 and develops mainly within the Monte Caio Flysch, in a structurally complex dip- slope setting. Specifically, the study integrates UAV-LiDAR derived DTM analysis, electrical resistivity tomography, boreholes logging, inclinometers, continuous GNSS monitoring, and multi-temporal InSAR analyses (RAINS and MT-SBAS) based on Sentinel-1 data. This multi-source approach allowed the identification of three main landslide sub-units, characterized by different materials, movement mechanisms, and displacement rates. Results show a kinematic transition from rotational rock sliding in the upper sector to translational earth sliding in the lower sector. Sliding surfaces reach depths of 70 m. GNSS data reveal increasing displacement rates toward the lower landslide sector and a clear relationship between acceleration phases and prolonged rainfall periods. InSAR data are consistent with ground-based measurements but tend to underestimate velocities in the most active areas. The resulting landslide map and cross sections represent the reference geological model for this complex landslide while the adopted study approach can be replicated in similar geological settings.