起始破裂点位置对1932年昌马地震动的影响分析  

Analysis of the impact of initial rupture point location on the 1932 Changma earthquake ground motion

作　　者：夏晨 张雨青 任乐馨 李宗超[3] XIA Chen;ZHANG Yuqing;REN Lexin;LI Zongchao(School of Civil and Transportation Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;Beijing Advanced Innovation Center for Future Urban Design,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]北京建筑大学土木与交通工程学院,北京100044 [2]北京建筑大学城市交通基础设施建设北京国际科技合作基地,北京100044 [3]中国地震局地球物理研究所,北京100081

出　　处：《世界地震工程》2024年第2期156-165,共10页World Earthquake Engineering

基　　金：国家自然科学基金项目(51708018,51774018);北京市教委科研项目-科技计划一般项目(KM202010016016);北京建筑大学“建大英才计划”项目(JDYC20200308)。

摘　　要：起始破裂点位置是强地面运动模拟和预测的关键输入参数。为了进一步探究起始破裂点位置对强震模拟结果的影响,本文将非均匀凹凸体模型引入随机有限断层法,模拟了1932年昌马地震的强地面运动。结果显示:震中PGA随着起始破裂点位置的变化呈现明显的差异,产生高PGA值的起始破裂点大部分分布在断层左侧。起始破裂点对区域内PGA≥800 cm/s^(2)的空间分布影响有限,并且震中区PGA是整个区域内的最大值;对100~200 cm/s^(2)的PGA空间分布有较大影响;对其余范围PGA的空间分布影响较小。PGA衰减关系受起始破裂点位置的影响较大,起始破裂点位于断层中部和中下部偏右时,计算结果与第五代中国地震动参数区划图中的预测衰减关系较为符合。起始破裂点位置对反应谱影响的结果表明:震中的反应谱受到的影响有限。对不同周期反应谱空间分布的研究发现:反应谱值分布均呈现随周期增大而衰减的趋势。相较于其他部位的起始破裂点,起始破裂点位于断层底部时的反应谱值分布随周期的变化规律有明显不同。本文讨论了起始破裂点位置对昌马地震研究区域内PGA和反应谱的影响,研究结果可为地震动模拟时起始破裂点位置在断层上的选择提供参考。The initial rupture point location is a crucial input parameter for the simulation and prediction of strong ground motions.To further delve into the impact of the initial rupture point on the results of strong earthquake simulations,this study integrates the non-uniform asperity model into the random finite fault method to simulate the strong ground motion of the 1932 Changma earthquake.The results demonstrate that the Peak Ground Acceleration(PGA)at the epicenter exhibits significant variations with the change in the location of the initial rupture point,with most of the initial rupture points generating high PGA values distributed on the left side of the fault.The influence of the initial rupture point on the spatial distribution of PGA≥800 cm/s^(2)within the region is limited,while it significantly impacts the spatial distribution of PGA values ranging from 100 cm/s^(2)to 200 cm/s^(2).The effect on the attenuation relationship between PGA and source distance is substantial,with the results from the initial rupture points located towards the right of the middle and lower parts of the fault aligning well with the predictive model of the seismic ground motion parameters zonation map of China.The findings regarding the impact of the initial rupture point on the response spectrum reveal that the impact on the response spectrum at the epicenter is slight.The study on the spatial distribution of the response spectrum for different periods reveals that the distribution of response spectrum values shows a decaying trend as the period increases.The variation in response spectrum value distribution with the period is significantly different for the initial rupture points located at the bottom of the fault compared to other locations.The findings elucidate the impact of the initial rupture point location on PGA and the response spectrum within the research area of the Changma Earthquake,offering a reference for the selection of the initial rupture point on the fault.

关 键 词：强震动模拟 昌马M s 7.6地震 随机有限断层法 起始破裂点位置 凹凸体 

分 类 号：P315[天文地球—地震学]