Debris and mud-flows runout assessment: a comparison among empirical geometric equations in the Giampilieri and Briga basins (east Sicily, Italy) affected by the event of 1st October 2009

Abstract Empirical/geometric methods rely on simple geometrical connections between some landslide parameters and the runout distance reached by the displaced material. Despite the extreme simplification of the dynamic of this landslide typology, those methods can provide useful information about the propagation of this shallow and fast landslide typology, joining reliability of the results with easiness of use. The objective of this work is to compare the efficacy of different geometric relationships for the identification of the runout distances in a debris and mud-flows prone test area located in Sicily, southern Italy, where several events were analysed, and a consistent set of data was collected and processed. Notwithstanding some uncertainties in the methodological approach and not negligible scattering between expected and observed runout distances, the use of such geometric approaches, together with the evaluation of kinematic parameters such as velocity and kinetic energy, can significantly boost the implementation of site-specific analyses for a more detailed definition of landslides susceptibility at local scale.