考虑地震构造背景的地震活动性参数光滑方法在地震危险性概率评价中的应用

The Method of Spatially Smoothed Seismicity Parameter with Consideration of Seismotectonic Background and Its Application in Seismic Hazard Estimation

本文选取华北地震区作为研究区域,尝试利用空间光滑活动模型进行地震危险性评估。首先对研究区域进行划分网格,依据地震构造和地震空间分布特征建立地震构造模型,确定构造区特征参数(b值、M0、Mu、断层方位角及M—L关系等)。采用考虑了地震构造背景的椭圆光滑过程的地震活动参数模型,计算各网格点的地震发生率。并利用网格源的地震危险性概率评价方法,由不同输入地震目录通过综合加权得到该区域50年超越概率10%的加速度峰值区划结果。该方法充分体现了地震活动的空间非均一性,尤其适用于发震构造不甚清晰的中强地震可能造成的地震危险性,避免了常规潜在震源区的划分。且评价方法简单快捷,为地震区划以及重大工程地震安全性评价工作提供了新的技术方法。

In this study, we take the North China seismic region as study area, and try to assess seismic hazard by spatially smoothing seismic activity model. Firstly, we classify the study area into grids, and some parameter （like b-value, M0, Mu, azimuth and M-L relationship） about each seismo-tectonic model are assigned. Secondly, we take elliptical smoothing based on a seismo-tectonic background model to process the statistically earthquake incidence rate in each grid successively. Lastly, we choose relevant ground motion attenuation relation to assess of seismic hazard of general sites. The maps for the distribution of horizontal peak ground acceleration with 10% probability of exceedance in 50 years were obtained by using seismic hazard analysis method based on grid source. This seismicity model simplifies the methodology of probabilistic seismic hazard analysis, especially is appropriate for those place where not yet clearly master the seismic tectonic information. The method can provide valuable references for seismic safety assessment work for some significant engineering and the seismic zonation.