抄録
Fire outbreaks in 1948 Fukui, 1964 Niigata, 1968 Tokachi-oki and 1978 Miyagiken-oki earthquakes have been analysed to obtain date for the estimation of fires in future earthquakes in urban regions Japan. The change of fuel from solid to liquid and gas has caused the change of fire apparatus for cooking and heating used in houes, which has decreased the fires in recent earthquakes occureed in restaurants, food shops and dwellings that were the dominant fire origins in Kanto and Fukui earthquakes. Instead, though the number is very small, fires of oil or gas tanks have begun to occur since 1964 Niigata earthquake. Analysing the five major earthquakes, it is estimated that fire outbreak rate (number of fires per household) of all fires in a city in future earthquakes of intensity 5 to 6 (JMA) does not exceed 2.0×10^<-4> and that of general fires does not exceed 1.5×10^<-4> and that of chemical fires does not exceed 0.5×10^<-4>. And self-extinguishment of general fires is expected to be about 60% at intensity 5, 30% at intensity 6 and 0% at intensity 7 and that of chemical fires is expected to be about 60% at intensity 5 to 6. Following these data, the number of fires in future earthquakes is estimated to be less than those calculated by former methods. But in the earthquakes of intensity 7, quite different from intensity 5 to 6, there is no denying the occurence of much higher fire outbreak ration.
