Abstract
　A method for estimating the probable damage caused by heavy rainfall is proposed that considers the occurrence rate of disasters caused by natural phenomena and the distribution of things that must be protected. Flood and mountain slope failures are regarded as natural phenomena in our study, and the population density is seen as a thing to be protected. This method was applied to the base of the mountain area along the Sumiyoshi River in Kobe City which had experienced flooding and mountain slope failures in 1938 and 1967. The results obtained for the occurrence rates of natural phenomena reflect the effects of the counter-measures taken after 1938, as well as urban development that has spread along the base of the Rokko Mountains.

【キーワード】：被災危険度，自然災害，山くずれ，洪水，人口密度，豪雨，数値地形モデル
Key words: damage potential, natural disaster, mountain slope failure, flood, population density, heavy rainfall, digital elevation model

*神戸大学工学部土地造成工学研究施設
Faculty of Engineering, Kobe University
**東京電力（株）、元神戸大学院生
Tokyo Electric Power Co., Ltd. former graduate student, Kobe University