総合防災の研究

Abstract

After enomous energy produced due to an extraordinary natural phenomenon propagates tothe domain of human living，various kinds of things on the earth and social systems are destroyedby such a destructive energy. Against such natural disasters，We have two kinds of measures:structural and non-structural measures. Analyzing these two measures by the method of fault-tree, the characteristics of prevention systems of measures are disclosed. Because the prevention system of structural measures is characterised by series formation andthe upper limits of natural destructive forces can not be defined，it is proposed that the structuralmeasures should be designed by the safe-fail priniciple. On the contrary，because the preventionsystem of non-structural measures is characterised by parallel fomation，it is also proposed that thenon-structural measures should be designed by the fail-safe principle. Finally，the several researches available for the design of such a system，for example，on thecomparison between magnitudes of design floods at upstream reach and downstream reach in ariver and on the use of runoff model in flood forecasting，are presented from viewpoint that theseare related to some elements of the prevention system.