基于方差主轴方法的地震动三分量相关性研究  

The correlation between three components of ground motion at the same point based on the variance principal axis method

作　　者：王元杰 赵晓芬 王君杰[1] 温增平[2] Wang Yuanjie;Zhao Xiaofen;Wang Junjie;Wen Zengping(College of Civil Engineering,Tongji University,Shanghai 200092,China;Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]中国地震局地球物理研究所,北京100081

出　　处：《地震学报》2025年第2期254-268,共15页Acta Seismologica Sinica

基　　金：国家自然科学基金面上项目(52078384)资助。

摘　　要：基于国内外11次中、强地震的近场和远场强震动记录,采用方差主轴方法对地震动三个平动分量的相关性进行了研究。将地震动划分为上升段、强震段和下降段,进行最小主轴的时变特性分析,结果显示,强震段和下降段的最小方差主轴几乎沿竖向,而上升段的主轴变化规律比较复杂,不能简单认为该时段的主轴同样也位于竖向。按照断层距和场地条件进行参数统计分析,结果表明:最大方差主轴在水平面上近似服从均匀分布。对汶川M_(W)7.9、集集M_(W)7.6和花莲M_(W)6.4三次典型地震事件的方差主轴进行了精细化分析,结果显示:在近断层区域,一小部分观测位置的方差主轴存在近似时不变特性,最大方差主轴指向可能与震源机制密切相关。Based on near-field and far-field strong motion records from 11 moderate-to-large earthquakes,the study investigates the correlation of the three translational components of seismic ground motion using the variance principal axis method.And then the correlation is examined at different scales,with the characteristics of the correlation described at both the sample level and the statistical level.By considering the time-varying characteristics of the principal axes,the ground motion records are divided into three segments:the ascending phase,the strong ground motion phase,and the descending phase.The study investigates the direction of the minor variance principal axis in these three phases.Both at the sample level and statistical level,it is found that the minor variance principal axis during the strong ground motion and descending phases is nearly vertical.However,the principal axis in the ascending phase exhibits a more complex variation and cannot simply be assumed to be vertical.Since the earthquake intensity during the ascending phase is typically lower or the duration is shorter,it can be approximated as vertical in engineering practice by ignoring the ascending phase.Statistical analysis of parameters based on fault distance and site conditions indicates that the major variance principal axis in the horizontal plane follows an approximately uniform distribution.The direction of the major variance principal axis exhibits significant time-dependent variability and strong randomness in the horizontal plane,far exceeding its variability in the vertical direction.Statistically,the occurrence probability of the major variance principal axis in any direction is approximately equal,following a uniform distribution.Detailed analysis of the 1999 Chi-Chi earthquake,the 2008 Wenchuan earthquake,and the 2018 Hualien earthquake indicates that in the near-fault region,a small subset of observation points exhibits approximately time-invariant characteristics for the variance principal axes,while many other stations show s

关 键 词：多维抗震设计 地震动相关性 地震动主轴 震源参数 

分 类 号：P315.9[天文地球—地震学]