An extended notion of Cellular Automata for surface flows modelling.

Cellular Automata (CA) represent an alternative approach to differential equations to model and simulate complex fluid dynamical systems, whose evolution depends on the local interactions of their constituent parts. A new notion of CA was developed by our research group Empedocles. It permitted to improve significantly an empirical method for modelling macroscopic phenomena, concerning surface flows. This approach was applied to lava flows, to debris flows and to pyroclastic flows. This paper presents the CA extended notion together with the improved empirical method. Examples of simulations are exhibited and compared with the real events in order to show the method efficiency.