本文利用CAP波形反演方法,获取了汶川M_S8.0地震序列中312个具有较高信噪比波形资料的4级以上余震的震源机制解和震源深度. 基于震源深度空间分布与震源机制时空分布,分析了主震后余震区断层行为特征与应力场时空变化,并对龙门山断裂带中北段的发震断层面几何形态进行了初步探讨. 获得的主要认识如下:(1)余震震源深度分布存在显著的空间分段差异. 绵竹以西的余震区南段与平武以东的北段余震深度范围大于中段(绵竹—平武段),但深度小于5 km的5级以上超浅源地震主要分布在明显偏离龙门山断裂带走向的理县NW向分支与余震区北端NNE向分支,而中段余震主要分布在7~19 km深度...

Focal mechanism solutions and depths of 312 M≥4 aftershocks with relatively high signal-to-noise ratio waveforms of the 2008 Wenchuan M_S8.0 earthquake have been derived by CAP method. Following this, we analyzed the aftershock faulting behavior and spatial-temporal variation of stress field, and further discussed preliminarily the geometry of the central-northern segment of the Longmen Shan fault zone. The major results are as follows. (1) The range of focal depths is significantly different between various segments of aftershock area. The depth ranges of aftershocks on the southern segment west of Mianzhu and northern segment east of Pingwu are greater than that on the central segment from Mianzhu to Pingwu. Relatively shallow (<5 km) aftershocks mainly occurred along NW-striking Lixian branch on the southern segment and NNE-striking branch at the northern end of the aftershock area. On the central segment, aftershocks are concentrated at the depths of 7~19 km...