利用断层围陷波资料研究汶川M_S8.0地震构造特征

Study on Seismic Structure of Wenchuan M_S8.0 Earthquake Using Fault Zone Trapped Waves

利用汶川地震区不同地段的断层围陷波记录,分析了该地震断层的分段性特征。对断层北东段的关庄测线分析研究结果表明：地壳内破碎带的宽度大约160~180m,地下破碎带的中间与地表破裂的位置对应,并且地下破碎带在断层的两盘边缘较均匀地分布,反映了北东段的断层倾角较陡,近似直立断层。对断层南西段的虹口测线研究结果表明：地壳内破碎带的宽度大约180~200m,地下破碎带主要分布在地表断层陡坎上盘所对应的地壳内,反映了南西段断层倾角比北东段断层倾角小。本文的研究结果可以为汶川8.0级地震的构造背景研究提供依据。

Using the trapped waves data on different sections of Wenchuan earthquake region, the segmen- tation characteristic of the fault is obtained. Guanzhuang observation line is located at the northeastern portion of the fault, and the result indicates that the width of the rupture zone underground is about 160-180 m. The center position of rupture zone underground corresponds to the surface breaking trace, and is equally distributed at the edges of the two fault walls. It reveals that, for the northeastern portion, the dip angle of the fault is greater and the fault is near vertical. However, Hongkou observation line is located at the southwestern portion of the fault, and the result indicates that the width of the rupture zone under- ground is about 180~200 m. The rupture zone underground is mainly distributed below fault scarp. It re- veals that, for the southwestern portion, the dip angle of the fault is smaller. The results will provide evi- dence for the research on the structure background of Wenchuan Ms8.0 earthquakes.