丸山 喜久

Lifelines such as drinking water and sewage systems provide the means and conveyance for daily critical services, and they are essential systems for recovery operations after a damaging earthquake. Therefore, earthquake damage to lifeline components needs to be reliably assessed for a possible future seismic scenario. This study presents an earthquake damage assessment of buried pipeline networks in the Lima Metropolitan Area (LMA). It includes seismic hazard analysis, a review of pipeline network datasets, and the selection of empirical fragility functions. Deterministic seismic hazard analysis was performed for an inter-plate earthquake scenario using ground motion prediction equations and site conditions to compute the distribution of the peak ground velocity (PGV). Recommenda-tions are offered for an adequate selection of fragility functions developed in other regions, and a logic tree of fragility functions is proposed to be used in pipelines of LMA according to the data of pipeline damage after the 2007 Pisco Earthquake. Finally, the pipeline repair ratios and the total number of repairs are estimated for the earthquake scenario, and the results are geographically presented for each pipeline network.

The restoration period of the water supply system in Lima, Peru, after a scenario earthquake was estimated in this study. To achieve the objective, the probabilistic assessment model for post-earthquake residual capacity of the utility lifeline system initially proposed by Nojima and Sugito (2005) and revised by following related studies was employed. The dataset of water distribution pipelines was provided by Potable Water and Sewer System Service in Lima, Peru (SEDAPAL), and the spatial distribution of ground motion with a moment magnitude of 8.6 was considered as a scenario earthquake in this study. The water disruption was anticipated to continue for approximately one month in certain districts of Lima, Peru. The estimated smallest water supplying ratio was 21.1% in Villa El Salvador after the scenario earthquake.