SEISMIC RISK ANALYSIS FOR CITY GAS NETWORK

This study develops a new procedure for quantitative seismic risk evaluation for a large-scale city gas system. To maximize the cost effectiveness of investments for earthquake disaster prevention, it is necessary to perform a quantitative and rational earthquake risk analysis. When there are several kinds of measures to reinforce or to replace city gas facilities, quantitative seismic risk analysis makes it possible to prioritize these measures. A new detailed “seismic hazard ” (PE: “probability of exceedance”) model for SI [spectrum intensity] value at every 50m mesh square is constructed on GIS, which contains SI value amplification factors, pipeline network data, and a damage assessment system. This model quantifies the possibility of direct damage to gas supply network. Finally, a calculation is made of the seismic risk for the network and this provides footing for estimation and comparison of the cost effectiveness of measures to prevent secondary disaster