地震断层破裂的方向性会造成在地震动记录和地震动分布场中出现一些典型的特征,分析方向性效应的特点以及方向性效应产生的原因对于揭示近场地震动的特征有重要的意义。文中以诸多研究文献为基础,从方向性效应的研究回顾开始,分析了方向性效应的概念,并重点论述了方向性效应对地震动影响的特点、方向性效应的产生原因及其影响因素。为了阐明与方向性相关的几个概念,文中还分析了破裂传播效应,有限移动源效应和多普勒效应等概念,以及方向性对震源时间函数的影响。通过这些概念的探讨和分析,使得这些相关概念的意义更加清晰,最后给出了地震动方向性效应研究中存在的问题和建议。
The single ground motion and distribution of ground motion on the ground surface are affected by the rupture directivity effect.Based on a large amount of studies,we discuss the concepts of directivity effect,the reason to cause it and the characteristics and factors which affect the directivity effect.We also discuss some related concepts,such as the finite moving source effect,rupture propagation effect and Doppler effect.Through the comparison and discussion of these concepts,results indicate that the directivity effect can be simply explained by the finite moving source effect,or rupture propagation effect,or Doppler effect,but it is different in nature.Finally,some suggestions are given to further study the directivity effect in earthquake engineering.