Multiphase simulations of collapsing eruptive columns and propagation of pyroclastic density currents (pdc’s) at Sete Cidades Volcano (Azores) were performed at CINECA High Performance Computing facilities, under the HPC-EUROPA Project. Numerical simulations in 2D were carried out with the code PDAC (Pyroclastic Dispersal Analysis Code), based on multiphase transport laws. The eruptive scenarios were constrained to Subplinian scale events of the recent (<5.000 years) eruptive history of Sete Cidades Volcano. Preliminary studies revealed that the transition between convecting and collapsing eruptive columns is very sensitive to variations of the input conditions. The simulations showed that instabilities generated in the eruptive fountain lead to oscillations of the collapse height, producing pdc’s that are fed by pluses of collapsed eruptive mixture. As the pdc’s propagate along the topography, phoenix clouds form due to the deceleration of the flow or when it reaches an obstacle. The numerical simulations also revealed that, for the eruptive conditions and vent location investigated, the pdc’s were not capable of overcoming the topographic obstacles, demonstrating the strong effect of the topography on the propagation of the pdc’s.