Reconstruction of the slope instability conditions before the 2016 failure in an urbanized district of Florence (Italy), a UNESCO world heritage site

On May 25th, 2016, following a massive water leakage from the city water supply pipeline a portion of the urbanized riverbank collapsed along the Arno River in the city centre of Florence (Italy), UNESCO World Heritage site. Understand the dynamics driving the landscape evolution (from the slope up to the riverbank) is useful to know the historical growth of such a territory and to plan a farsighted and sustainable urban development. Therefore, a historical characterization of the area surrounding the Arno riverbank collapse was made considering the interaction between the anthropic pressure and the local geological hazards or those factors that activate them. Based on this reconstruction, some advanced technologies (like satellite imaging), integrated with more traditional techniques, have been employed (a) to analyse the landscape condition almost up to the trigger moment, (b) to study the dynamics of the event, (c) to monitor the possible spatial evolution of the 2016 landslide, and (d) to characterize the damage condition of the involved structures. The results show very low deformation rates, indicating relatively stable ground conditions before the event.