Integration of advanced monitoring and numerical modeling techniques for the complete risk scenario analysis of rockslides: the case of Mt. Beni (Florence, Italy)

On December 28, 2002 a landslide occurred on the eastern flank of Mt. Beni (Florence, Italy), on a slope where jointed basalts and ophiolitic breccias overlie Mesozoic limestones (Calcari a Calpionelle Formation). The collapse was preceded by several forewarning signals: the evolution of the slope deformation was the most important of them, and its analysis was the starting point for a risk scenario assessment. In fact, during the management of the emergency period, which began on April 13, 2002, in effort to evaluate the actual extension of the landslide, the distribution of the displacements within the mass, its kinematical characteristics and its spatial and temporal evolution, data obtained by means of geomechanical surveys, laboratory analyses, geotechnical investigations, geophysical surveys (seismic and GBInSAR), monitoring systems (distometric and automatic) and distinct element numerical modeling were integrated. Thus, it has been possible to provide public authorities with all necessary information to plan suitable measures for risk management and reduction. After the event, the study was completed with a runout back-analysis that highlighted successes and failures of the predictive investigations.