Abstract
It is important to clarify the role and the limitation of a facility against tsunami to sustain constructing required facilities and motivating hazard reduction activities. Considering generation frequency of earthquake, several tsunami-damage estimations are conducted for several earthquakes and several scales, H, of facility. These analyses evaluate an expected value of account of damage reduction, B(H), by construction of facility of scale H and an expected value of account of damage, D(H), under existence of facility of scale H. This method is available in a scheme to obtaine a rapid agreement with local government on scale of facility. Considering cost, C(H), in addition to B(H) and D(H), a scheme is proposed to minimize the total social burden against tsunami. This method specifies the residual risk, and indicatees an adequate target for damage reduction.
