The research work on piroclastic flows which was launched in the framework of the Volcanic Simulation Group aims to promote the use of physico-mathematical models in the study of various processus. This research work is presently developed by the Istituto Nazionale di Geofisica e Vulcanologia (Italy) in the framework of the European project Exploris whose objective is mainly to describe the 4-D (3 spatial + time) dynamic of eruptions, focusing on the Vesuvius. The animation proposed in this DVD is the result of complex calcuations which serve to better understand risk. (UNESCO)