Abstract
This study, from the point of view of contributing to the early action against Nankai Trough Earthquake or the like is expected, based on the case with reduced damage behind village and fishing port by breakwater that did not collapse completely in the Great East Japan Earthquake to reduce the tsunami, in addition to elucidating the expression characteristics of the tsunami reduction effect by the breakwater, we have proposed a simple evaluation method. As for the multiple protection by seawall and breakwater, and to understand the tsunami reduction effect as the target distribution base typical fishing port along the Nankai Trough, and verified its effectiveness.