Forward simulation and sensitivity analysis of run out scenarios using MassMov2D at the Trafoi rockslide (South Tyrol, Italy)

This paper presents forward simulation with MassMov2D code and sensitivity analysis of run out resulting from different scenarios of potential failure of a 40 million m3 active rockslide hanging above the village of Trafoi, in South Tyrol (Italy). Five scenarios of potential failure zones were identified, with the larger one being the failure of the entire rock slide. Forward simulations showed that the consequences for the Trafoi village would be potentially destructive. A parametric sensitivity analysis was carried out in order to increase the significance of risk assessment. Results obtained by varying friction and turbulent coefficients showed quite unequivocally that although the variability of the run out might be quite large it does not change risk scenarios significantly except in the smaller case of failure. This confirms the usefulness of forward simulations even if they might be affected by uncertainties related to the impossibility to retrieve optimized parameters.