地震学报2025，Vol.47Issue(2)：254-268,15.DOI:10.11939/jass.20230085
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
摘要
Abstract
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 seis-mic ground motion using the variance principal axis method.And then the correlation is ex-amined 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 vertic-al.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 engineer-ing 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 dis-tribution.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 observa-tion points exhibits approximately time-invariant characteristics for the variance principal axes,while many other stations show strong randomness in the direction of the variance principal axes.For the stations with nearly time-invariant principal axes,the orientation may be closely related to the source mechanism.In the vicinity of reverse faults,the major variance principal axis is oriented perpendicular to the fault strike,while in the vicinity of strike-slip faults,it is parallel to the fault strike.In near-fault regions with complex source mechanisms,there exist both components parallel and perpendicular to the fault strike.关键词
多维抗震设计/地震动相关性/地震动主轴/震源参数Key words
multi-dimensional seismic design/ground motion correlation/ground motion principal axes/source parameter分类
地球科学引用本文复制引用
王元杰,赵晓芬,王君杰,温增平..基于方差主轴方法的地震动三分量相关性研究[J].地震学报,2025,47(2):254-268,15.基金项目
国家自然科学基金面上项目(52078384)资助. （52078384）
