This study analyses aIl the parameters necessary to understand the formation of the cirques and the present days slope movements in which it results, this in order to define the geoteohnioal conditions necessary for natural hazards mapping and planning. * First section presents general features of the island, the land-use in the cirques, and underlines hydro-meteorological characteristics. * Second section deal with aIl the geological events which took plaoe before the end of the active period of the Piton des Neiges volcano, round about 25,000 years ago. The geotectonical , lithostratigraphical and structural context, as weIl as the hydrothermal alteration that the original materials underwent, are presented in this section, emphasizing the geological facts which are relevant from a geotechnical stand point. * Third section analyses the action of the main morphogenetic agents controlling the slope evolution during the dormant periods and ends with an interpretation of the creation and developpement mechanisms of the cirques. * The last section uses, for an analysis of the erosion and the dynamics of slopes, geotechnical classification of grounds and methodical natural hazards mapping, the spatial and temporal distribution scheme which result from the previous calculations .
