丁佳伟, 吕大刚, 曹正罡. 考虑地震事件内空间相关性的区域概率地震危险性分析[J]. 工程力学, 2024, 41(S): 117-128. DOI: 10.6052/j.issn.1000-4750.2023.05.S038
引用本文: 丁佳伟, 吕大刚, 曹正罡. 考虑地震事件内空间相关性的区域概率地震危险性分析[J]. 工程力学, 2024, 41(S): 117-128. DOI: 10.6052/j.issn.1000-4750.2023.05.S038
DING Jia-wei, LYU Da-gang, CAO Zheng-gang. PROBABILISTIC SEISMIC HAZARD ANALYSIS OF REGIONS CONSIDERING INTRA-EVENT SPATIAL CORRELATIONS[J]. Engineering Mechanics, 2024, 41(S): 117-128. DOI: 10.6052/j.issn.1000-4750.2023.05.S038
Citation: DING Jia-wei, LYU Da-gang, CAO Zheng-gang. PROBABILISTIC SEISMIC HAZARD ANALYSIS OF REGIONS CONSIDERING INTRA-EVENT SPATIAL CORRELATIONS[J]. Engineering Mechanics, 2024, 41(S): 117-128. DOI: 10.6052/j.issn.1000-4750.2023.05.S038

考虑地震事件内空间相关性的区域概率地震危险性分析

PROBABILISTIC SEISMIC HAZARD ANALYSIS OF REGIONS CONSIDERING INTRA-EVENT SPATIAL CORRELATIONS

  • 摘要: 一次地震事件不同地点的地震动强度参数与结构响应参数之间是空间相关的,相关的地震效应将导致地震损失急剧集中与积累,从而造成灾难性事件,但是现有的区域尺度地震风险评估并没有考虑地震动的空间相关性。该文采用地统计学方法表征地震事件内地震动强度参数的空间相关性,提出了理论半变异函数的几何稳健估计方法,并采用加权最小二乘法实现对短距离空间相关性的准确高效评估。以新潟越冲地震为例,基于指数半变异函数模型,采用加权最小二乘法对几何稳健估计半变异函数值进行拟合,得到了PGA、PGV和0 s~10 s谱加速度的空间相关性函数,提出了变程b值的预测模型,结果表明:相比于短周期谱加速度,长周期谱加速度的空间相关性衰减速率更小,且在T=0.45 s处存在拐点。将所开发的空间相关性模型应用于区域概率地震危险性分析,采用Monte Carlo方法实现了空间相关随机场的区域地震动强度参数的模拟,改进了传统区域地震危险性分析的方法,发现绝大多数情况下考虑空间相关性的年超越概率大于未考虑空间相关性的年超越概率,表明考虑空间相关性对于建筑群落及基础设施风险评估、韧性城市建设等具有重要的指导意义。

     

    Abstract: The ground motion intensity parameters and structural response parameters at different sites of an earthquake event are spatially correlated, and the related seismic effects will lead to the sharp concentration and accumulation of earthquake losses, resulting in catastrophic events. However, the traditional regional seismic risk assessment does not consider the spatial correlation of ground motion intensity measures. In this paper, geo-statistical methods are used to characterize the spatial correlation of ground motion intensity measures in earthquake events. A geometrically robust estimation method of theoretical semi-variogram is proposed, and the weighted least squares method is used to accurately and efficiently evaluate the short-distance spatial correlation. Taking the Chuetsu-Oki earthquake as an example, based on the exponential semi-variogram model, the weighted least squares method is used to fit the geometrically robust estimation of semi-variogram value, and the spatial correlation functions of PGA, PGV and 0-10 s spectral acceleration are obtained. A prediction model of the range b value is proposed. The results show that the spatial correlation decay rate of the long-period spectral acceleration is smaller than that of the short-period spectral acceleration, and there is an inflection point at T=0.45 s. The developed spatial correlation model is applied to regional probabilistic seismic hazard analysis. The Monte Carlo method is used to simulate the spatially correlated random field of ground motion intensity measures of a hypothetic region. The traditional regional seismic hazard analysis method is refined. It is found that the annual exceedance probability considering spatial correlation is greater than that without considering spatial correlation in most cases, and it further shows that the consideration of spatial correlation has important guiding significance on risk assessment of portfolio buildings and infrastructures as well as the construction of resilient cities.

     

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