On the use of ground-based SAR interferometry for slope failure early-warning: the Cortenova rock slide (Italy)

This contribution illustrates the capabilities of ground-based SAR interferometry (GBInSAR) to be used as an early warning for the detection of precursory ground displacements that can suggest the imminent occurrence of a slope failure. SAR data were acquired by a ground-based SAR system, belonging to the LISA interferometer series designed by the Joint Research Centre of the European Commission, over the Cortenova rock slide (Regione Lombardia, Italy) and interferometrically analyzed in near-real time. The system was used to provide, during the 2002-2003 emergency caused by the landslide reactivation, the civil protection authorities with an operational tool for the assessment of the mass movement temporal evolution. After the main rupture occurred at the beginning of December 2002, which caused severe damage to the Bindo Village, destroying several houses and factories, interrupting one key connection road and partially damming a river, concern over the occurrence of further collapses of the still unstable slope led to the evacuation of 900 people living close to the run-out area. Such a situation induced the civil protection authorities to arrange a real-time monitoring system. Measurements of ground displacements continuously collected by the radar system up to May 2003, besides detecting the portions of the slope affected by movement, revealed the gradual deceleration of the residual movements passing from 5 cm d(-1) to 0.3 cm d(-1).