【摘要】 本文采用朱介寿等(1984)提供的非均匀速度模型,使用Hypo2000地震定位方法,筛选出汶川MS8.0级地震前8年的2723条地震记录进行精定位;震源深度的优势分布介于5-20km之间,平均震源深度是12 km。结合地震震中分布图、震源深度剖面图、M-T图等结果,得出汶川MS8.0级地震前龙门山断裂带北段地震活动性比中段和南段的活动性弱;时间越临近2008年5月12日汶川8.0级地震发生前,周边的应力场逐步增强,靠近汶川主震区域的震群活动有增加的迹象。更多还原

【Abstract】 Based on inhomogeneous velocity model by Zhu et al., we deployed the Hypo2000 method to accurately locate 2723 selected events before the Wenchuan MS8.0 Earthquake, the dominant distribution of focal depth ranged between 5 and 20 km, the average focal depth is 12 km. A synthetic analysis of epicenter distribution, profile of focal depth and M-T diagram show that before the Wenchuan MS8.0 Earthquake, seismicity of the northern section of Longmenshan fault zone is weaker than that of middle and southern sections, stress field increased gradually when it is approaching May 12 th, 2008, earthquake swarm activity in vicinity of main shock area of Wenchuan earthquake show signs of increasing.更多还原