Simulations of flow-like landslides invading urban areas: a cellular automata approach with SCIDDICA

Different methodologies are used for modelling flow-like landslides. A common critical point concerns the flooding into town areas, which cannot be assimilated straight to a morphology, especially, when the urban tissue is very irregular with narrow streets and odd setting of buildings, so that discretization processes of approximating numerical methods have to be carefully examined in their limits. A semi-empirical approach by the computational paradigm of cellular automata is here considered with SCIDDICA, a competitive (related to PDE approach) cellular automata model for 3-dimensions simulation of flow-like landslides. This paper presents innovations to the transition function of SCIDDICA-SS2, which manage opportunely building data in the cells corresponding to the urban tissue. The novelties of the transition function need a theorem, here demonstrated which regards the Algorithm of Minimization of Differences in the new context of inhomogeneous cells. This progress permits to simulate the complete evolution of landslides, from the detachment area to its exhaustion almost on the same precision level. This is an advantage for hazard and risk analyses in threatened zones. Improved SCIDDICA-SS2 was applied successfully to all the well-known 2009 debris flows of Giampilieri Superiore (Sicily) also in comparison with simulation results of the previous versions.