兰德斯地震断层面及其附近余震产生的位移场研究  

STUDY ON DISPLACEMENT FIELD GENERATED BY AFTERSHOCKS IN LANDERS SEISMIC FAULT PLANE AND ITS ADJACENT AREAS

作　　者：万永革[1,2] 沈正康[1,3] 兰从欣[4] 

机构地区：[1]中国地震局地质研究所 [2]中国北京东燕郊101601中国地震局防灾技术高等专科学校 [3]DepartmentofEarthandSpaceSciences,UniversityofCalifornia,LosAngeles,CA900951567,USA [4]北京市地震局

出　　处：《地震学报》2005年第2期139-146,共8页Acta Seismologica Sinica

基　　金：国家自然科学基金项目(40374012);基础研究重大项目前期研究(2002CCA04500)共同资助

摘　　要：根据兰德斯(Landers)地震断层面及其附近余震目录计算这些余震产生的位移场, 并与根据兰德斯地震破裂面滑动分布计算的主震产生的位移场进行对比. 结果表明, 断层面及其附近余震产生位移场的方向与主震大体一致, 余震破裂总体来看是继承性的. 余震产生的位移场达厘米量级, 足可以被GPS观测所捕获. 在利用地震震后随时间变化位移场研究地球粘性结构、地震震后滑动分布等地球物理问题时, 扣除余震产生的位移场可以最大限度地减小反演结果的不确定性, 得到符合实际的结果.The displacement field generated by aftershocks in Landers seismic fault plane and its adjacent areas is calculated in this study. The result is compared with the displacement field of the main shock calculated by co seismic slip model of Wald and Heaton (1994). The result shows that the direction of displacement field generated by aftershocks in Landers seismic fault plane and its adjacent areas is consistent with that generated by main shock. The rupture of aftershock is generally inherited from main shock. The displacement field generated by aftershocks is up to an order of centimeter and can be measured by GPS sites nearby. So when we use geodetic data measured after earthquake to study the geophysical problem such as crustal viscosity structure, afterslip distribution, etc ., only the displacement field generated by aftershocks be considered that uncertainty would reduce to minimum and practical result could be obtained.

关 键 词：余震 位移场 震源机制 兰德斯地震 

分 类 号：P315.725[天文地球—地震学]