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Title:: Topographic Effect Related Seismic Simulation with the Stochastic Finite-fault Method

作者:: 贾晓辉¹; 曹秀玲¹; 王晓山²; (1.河北地质大学城市地质与工程学院,河北省地下人工环境智慧开发与管控技术创新中心,河北石家庄 050031; 2.河北红山巨厚沉积与地震灾害国家野外科学观测研究站,河北邢台 054000)

Author(s):: JIA Xiaohui¹; CAO Xiuling¹; WANG Xiaoshan²; (1.School of Urban Geology and Engineering,Hebei Technology Innovation Center for Intelligent Development and Control of Underground Built Environment,Hebei GEO University,Shijiazhuang 050031,Hebei,China)(2.Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards,Xingtai 054000,Hebei,China)

Keywords:: topographic effect; the Stochastic Finite-fault method; strong ground motion simulation; the Winter Olympic Games Site

摘要:: 为在强地震动模拟计算中实现地震动的地形效应,采用地震动随机模拟中的有限断层法,依据山地中的局部场地条件和地形特征,提出在随机模型中构建局部场地放大项和高频衰减联合的场地效应项表征地形效应的方法,并以位处于张家口典型山地地形的崇礼冬奥会场址区为研究区,结合近场地震构造背景,完成场址区可能面临的强地震动场计算分析。结果表明:①计算得到崇礼场址区潜在最大地震动强度可能会达到210 cm/s²; ②山地模型与平层模型的对比研究得到不考虑地形效应的平层模型会低估地震动特性在山地地形的真实性; ③在随机有限断层法中采用相应的局部场地放大系数和高频衰减因子组成的场地联合效应实现地形效应的表达途径是可行的,并且本方法在山体地形效应强度估计的准确性和地震动场计算效率方面具有一定优势。

Abstract:: Based on the local site condition and topographical features of the mountain land,and according to the Stochastic Finite-fault method,we propose a method of illustrating the topographical effect with the site response effect including local site amplification and high frequency attenuation to estimate the topographical effect by simulating the strong ground motion.Taking Chongli,the Winter Olympic Games site in the typical mountainous topography in Zhangjiakou region as a study case,we calculate and analyze the strong ground motion field.The results show that:① The maximum value of PGA at Chongli site may reach 210 Gal.② The comparison of the mountain model with the flat-layer model shows that the flat-layer model ignoring the topographical effect will underestimate the validity of the strong ground motion in the mountain land.③ When using the Stochastic Finite-fault method,it is feasible to take into account the site combined effect consisting of the local site amplification factor and the high frequency attenuation factor to express the topographical effect.This method is superior in estimating the topographical effect intensity and computing the ground motion field.