考虑场地放大效应的全国地震危险分析  

Seismic hazard analysis for China considering site amplification effect

作　　者：陈兰生 冀昆[1] 温瑞智[1] 周宝峰[1] CHEN Lansheng;JI Kun;WEN Ruizhi;ZHOU Baofeng(Institute of Engineering Mechanics,China Earthquake Administration,Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration,Harbin 150080,China)

机构地区：[1]中国地震局工程力学研究所,中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨150080

出　　处：《地震工程与工程振动》2021年第6期177-185,共9页Earthquake Engineering and Engineering Dynamics

基　　金：中国地震局工程力学研究所所长基金项目(2019B09);黑龙江省自然科学基金联合引导项目(LH2020E022);国家自然科学基金项目(51908518);国家自然科学基金项目地区合作基金项目(U1901602)。

摘　　要：目前我国第五代地震动参数区划图是以Ⅰ_(1)类基岩场地的计算结果为基准,通过统一场地放大系数调整得到Ⅱ类场地的地震危险分布图,没有直接给出实际场地的地震危险分布图。因此,文中以地形坡度法插值得到的全国30 m剪切波速(V_(S30))分布结果为基础,并在CPSHA计算过程中引入NGA-West 2地震动衰减关系,进行考虑场地放大效应的全国地震危险性分析。首先,基于全球地震模型(GEM)提供的开源OpenQuake平台,将中国CPSHA计算过程中的三级潜源划分,地震活动性空间分布不均匀,长短轴衰减关系等特色技术环节实现了融入。为验证计算流程的可靠性,对比了某工程基岩场地安评资料的PGA的危险性曲线,得到的概率地震危险性分析结果与其基本一致;基于全国基岩场地的CPSHA计算结果进行Ⅱ类场地调整系数放大后,全国34个城市的PGA值基本均位于第五代区划图给出的PGA区间内。进而结合每一个计算栅格点的V_(S30)值,通过应用NGA衰减关系计算得到考虑场地效应的全国地震危险分布结果。对比发现,局部地区较软场地的场地放大系数已超出了目前区划图的场地调整系数范围。基于文中计算结果分别统计了我国四类工程场地的放大系数,除Ⅰ类场地外,Ⅱ、Ⅲ、Ⅳ类场地的放大系数分布要整体略大于区划图的场地调整系数范围。文中研究成果可为我国第五代地震动参数区划图进一步考虑场地放大效应提供依据,并为下一代区划图的编制提供参考思路。The fifth generation of China ground motion parameter zonation map refers to the class II site anddeveloped by rock site results multiplying the corresponding site amplification factors.But the seismic hazard distribution of actual site is not given directly in zonation map.Therefore,in this paper,the 30 m shear wave velocity(V_(S30))distribution map of China wasderived by its relationship with topographic slope,then the national seismic hazard considering the site amplification effect were developed using the NGA-west 2 ground motion attenuation relationships.Firstly,three-level potential source area type,uniform distribution of seismicity and long/short axis attenuation relationship were implemented in the OpenQuake platform developed by global seismic model(GEM).To validate theapplicability of the CPSHA computation procedure,we compared the hazard curve of the PGA with the results provided in the safety evaluation projects.It indicates that the results were basically consistent regarding different return periods.The PGA values of 34 provincial capital cities in our hazard map are basically within the PGArange given in the fifth generation zonation map.Then,the national seismic hazard map with site effect is obtained by using NGA attenuation relationship and the V_(S30)value of each computation grid.In some areas with soft site condition,the computed site amplification factors are beyond the current scope of the site amplification coefficient.The amplification factors of four site classes in China were calculated.It can be seen that the site amplification factors of class Ⅱ, Ⅲ and Ⅳ sites are distributed larger than the range of site adjustment factors in the zonation map.The research results of this paper can provide tips for scientifically using the fifth generation seismic zoning map when site amplification effect need to be further considered,It is also meaningful for development of the next generation of China seismic parameter zonationmap.

关 键 词：地震危险分布图 中国概率地震分析方法 地震动衰减关系 场地放大 危险性曲线 

分 类 号：TU4[建筑科学—土工工程]