地震危险性分析中潜在震源区范围与震级上限的不确定性分析

目前进行的地震危险性分析计算中, 潜在震源区范围和震级上限的确定过程中存在很大的不确定性。 采用二级划分和三级划分潜在震源区的方法, 对潜在震源区范围不确定性进行了研究; 用震级上限的单边正态分布模型代替固定的震级上限模型, 分析了这种改进对地震危险性分析结果的影响及其工程意义。 结果表明, 用三级划分潜源的方法代替二级划分潜在震源方法可降低局部地区的地震危险性, 对于在潜在震源区附近选址和降低工程成本有重要意义。 震级上限的改进, 使得地震危险性降低, 这对百年使用年限的工程更具有实用性。

Uncertainty analysis of latent focal region and upper magnitude limit in seismic hazard analysis

In seismic hazard analysis computation, there is much uncertainty in the process of defining latent focal region and upper magnitude limit. This thesis adopted two-level partition and three-level partition of latent focal region to study uncertainty of latent focal region. We use unilateral normal distribution of upper magnitude limit instead of fixed one and analyze the results of seismic hazard analysis of this change and engineer meaning of it. The results show that replacing the two-level partition of latent focal region by three-level one can decrease seismic hazard in some areas. It is of important significance in choosing site near latent focal region and meanwhile, the project cost can be reduced. This change of upper magnitude limit makes seismic hazard reduced, which is useful for project with one hundred years utilization limit.