Local governments must prepare the regional mitigation plans on the basis of seismic hazard and risk estimation. The seismic risk estimation of 36 patterns of assumable scenario earthquakes with a variety of source parameters was done for Kitami City, Hokkaido Prefecture that is our research target. Taking account of each priority in the bureaus related to disaster prevention measures of the government, we proposed a new approach for choosing the more prior earthquakes among the assumable scenario earthquakes. By applying the Analytic Hierarchy Process (abbreviated to AHP) to the damage data, which we simulated under the 36 patterns of scenario earthquakes, multiplying by the weighted coefficients on the priority of each bureau; we selected the most important earthquakes of Kitami hazardous areas.

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This study is examined the probability of liquefaction occurrence in terms of seismic intensities for each geomorphologic classification unit in the Japan Engineering Geomorphologic Classification Map based on the dataset of strong ground motion maps of recent earthquakes interpolated by the observation records and the liquefied sites during the past earthquakes. The geomorphologic units of similar ground conditions and liquefaction susceptibilities are grouped and their liquefaction probability functions are proposed based on cumulative normal distribution. Finally, the model was applied to the hypothetical Tonankai-Nankai earthquake and estimated liquefaction potential map with 250 m grid-cells was performed.

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When an earthquake occurs and ground motion observed along railway line exceeds a criterion, the railway line operation is suspended to inspect railway facilities and structures. Furthermore if they are damaged due to the earthquake, the railway line operation is suspended until damaged structures finish repairing. In this study, the methods to estimate the suspension time which need to inspect and to repair railway facilities and structures are constructed. The validation of the methods is checked by comparing estimated and observed suspension times during the 1987 Chiba-ken Toho-oki earthquake. Applying the method in the Tokyo metropolitan area, suspension time of railway lines during scenario earthquakes are estimated. The estimation indicates the operation of major railway lines in the area may be suspended for two weeks or more when the anticipated Tokyo M_JMA7.3 earthquake occurs.

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