Fogo Island has been the scene of an intense volcanic activity since its discovery and settlement on the XV century. The reported volcanic manifestations refer to events of hawaiian/strombolian-type, marked by effusive and explosive phases of variable duration, generated in the central volcano caldera. The reconstruction of Fogo eruptive history clearly shows that lava flows represent one of the main factors of volcanic risk in the island. The recent 1951 and 1995 lava flows destroyed houses and covered several square kilometres of productive land emphasising the need to develop strategies guided towards the minimisation of its impact in future occurrences. In this work a lava flow simulation model implemented on a Geographic Information System (GIS) is presented using, as eruptive parameters, the data collected during the eruption of April 1995.
Using the principles of Cellular Automata, the lava flow is visualised as a dynamic system of cells that evolves in space and time, in accordance with determined internal parameters of the cell and its spatial relationship with the adjacent cells. On a Digital Terrain Model (DTM) of the eruptive zone, implanted in a GIS, the area is discretized in cells of 15x15 meters and the transition of lava between them are established by a stochastic process. The model contemplates the conditions imposed by topography, the location of eruptive(s) centre(s) and the physical properties of lavas. The resultant simulated images in some periods of time, allows the evaluation of the uncertainty of spatial dispersion of lava and the elaboration of hazard and risk maps.