渤海地震构造区空间分布函数的确定

Determination the spatial distribution function in Bohai seismic tectonic area

空间分布函数将地震区、带的地震活动性参数按震级档分配到带内各潜在震源区,它的确定是综合概率地震危险性分析方法的关键性技术之一,其结果将直接影响所计算场点的地震危险性分析结果.然而,空间分布函数的确定由于地震样本的严重缺失难以统计得到,而实际工作中采用的评判因子太复杂、不独立等,使得到的空间分布函数缺乏可靠性.本文以渤海地震构造区为例,充分利用了该区近几十年来新建海洋石油平台工程获得的地质资料和历史疑难地震参数校核获得的地震活动资料,采用该区各潜在震源区面积、地震构造、地震活动度、中长期预报和强震复发间隔与构造空段五个因子,加权综合得到渤海地震构造区的空间分布函数,反映了该区地震活动的时空不均匀性,为概率危险性分析提供了计算参数.同时,本文运用综合概率地震危险性分析方法,由新的空间分布函数计算得到渤海地震构造区50年超越概率10%的海底泥面峰值加速度区划图,反映出研究区从〈0.05-0.20 g跨越五区,呈现西高东低的趋势,区域东部位于0.20 g（Ⅷ度区）,西部位于〈0.05 g（〈Ⅵ度区）范围内,该区划结果可供该地区海洋石油平台等工程地震危险性分析研究时参考,对地震区划和工程地震安全性评价均有意义。

Space distribution function allocated the seismicity parameters of the Seismic zone and belt to potential seismic source areas according to the magnitude interval,it influences not only is one of the key technology of comprehensive probabilistic seismic hazard analysis method,but also the result will directly affect the calculation sites result by seismic hazard analysis. It is difficult to determine the spatial distribution function or make the space distribution function to be trusted,because of the serious lack of earthquake sample statistics,and practice using the judgment factor is too complex,independence,etc. In this paper,taking the Bohai seismic tectonic area as an example,made full use of the geological data from the new offshore oil platform project in recent decades and seismic activity data obtained from the check of historical earthquake parameters,based on the area、seismic tectonic、seismicity、medium and long-term earthquake prediction and strong earthquake recurrence interval and construct the empty section factor of potential seismic source areas,weighted comprehensive spatial distribution function in Bohai seismic tectonic area. Reflects the space-time inhomogeneity of seismic activity and provides the calculation parameters for probability risk analysis. At the same time, based on the comprehensive probabilistic seismic hazard analysis method,using the new spatial distribution function by this article to calculate the peak acceleration zoning map of mud on the seabed surface in Boihai seismic tectonic area（ 50 a 10%）,and reflects the trend ＂high in the west and low in the east ＂ of the research area across the five area（ from 〈0.05 g to 0. 05 g）,the eastern region is located in the 0. 20 g（ Ⅷ degree area）,the west is located in the 〈0. 05 g（ 〈Ⅵ degree area）. The result is available for offshore oil platform and other projects in this region as a reference for seismic risk analysis,it is important value for seismic zone and seismic safety assessment.