基于概率情景的多场点系统地震风险分析方法

该文针对传统地震危险性分析方法面向多场点系统(诸如某一区域内多个建筑、某个基础设施网络)整体地震风险计算时的局限性,提出了基于概率场景的多场点地震风险分析方法。该方法首先结合地震潜在震源的震级概率分布函数以及地震动预测公式,并考虑地震动空间相关性模型,通过随机模拟生成大量的概率地震情景(地震动分布图),在地震情景集及相应概率信息的基础上对一些典型的多场点系统,例如独立多场点系统、串联多场点系统、并联多场点系统等进行了系统风险分析。并通过对比分析单场点与多场点系统的地震风险,对比分析考虑和不考虑地震动估计误差空间相关性两种情况下的多场点系统地震风险,最终得出了三种类型多场点系统地震风险表现的不同特征。结果表明:不考虑空间相关性会导致独立多场点系统高估低水平损失的概率、低估高水平损失的概率;会导致串联系统风险估计整体偏高;会导致并联系统风险估计整体偏低。

Multi-site seismic risk analysis based on probabilistic scenarios

Traditional seismic hazard analyses are less accurate when applied to integrated risk analyses of multi-site systems(such as multiple buildings in a specific region or a specific infrastructure network).This paper presents a multi-site seismic risk analysis based on probabilistic scenarios.This method applies a magnitude probability density function to potential earthquake sources and ground motion intensity prediction formulas with spatial correlation of the ground motion intensities at different sites to generate various probabilistic earthquake scenarios(ground motion maps) through stochastic simulations.These earthquake scenarios and the probability information are then used to analyze the systematic risks of typical multi-site systems such as multiple isolated sites and series and parallel systems.Finally,the characteristics of the earthquake risks of three multi-site systems are identified by comparison of single site and multiple site earthquake risks and spatial correlations of multi-site earthquake risks.The results show that without consideration of the spatial correlation,for a multiple isolated sites system,the probability of lower loss will be overestimated with the probability of higher loss being underestimated,and that for a series system,the risk will be thoroughly overestimated while for a parallel system,the risk will be underestimated.