Quelques réflexions sur les catastrophes naturelles en montagne

摘要

ABSTRACT. - A definition of natural castrophic phenomena is proposed, with a general review of their diversity and inter-relations (for exemple between earthquakes, rockslides...). A classification based on the genesis is suggested. First natural disasters from geological or/and geomorphological origin are described : tectonic movements and climatic changes which generate deseqilibriums in the landscapes (for example glaciations and déglaciations) have a fundamental importance. A classification of mountains according to the degree of risk is proposed. Climatic disasters, theirs characteristics and consequences, are numerous. Factors such as interfaces land/air, landforms, altitude, man impact environments... must not be under-estimated. From these observations, a geographical classification of natural disasters, on the basis of the magnitude and the surface concerned, is suggested in table 2 : ponctuai phenomena, «normal» catastrophe, meso, mega and giga catastrophes.