长江带现代地震构造应力场分布特征

根据长江带76个地震震源机制解与17个小震综合断层面解的结果统计分析,得到该带地震应力场主应力方向的优势分布。表明该带处于北东东—南东东向挤压和北北西—近南北向引张的构造应力作用之中。在力的性质上,该带水平张应力高于水平压应力,斜向压应力又高于斜向张应力,与华北地区比较,主应力方向相对向东南方向偏转,该带水平力和斜力所占比例均高于华北地区,同时讨论了该带中三个分区的现代构造应力场分布及它们的力源关系。

THE FEATURES OF DISTRIBUTION OF MODERN SEISMOTECTONIC STRESS FIELD IN CHANGJIANG RIVER ZONE

Based on 76 solutions of earthquake focus mechanism and 17 comprehensive fault plane solutions of small earthquakes, the statistic analysis gives the dominant distribution of main stress direction of the seismic stress field in Changjiang River zone. It shows that the zone has been acted under the NEE-SEE direction of compressional and the NWW-nearing SN direction of tensional tectonic stresses. In dynamics, the horizontal tensional stress is higher than the horizontal compressional one, and the oblique compressional stress is higher than the oblique tensional stress. In comparison with the region of north China, the main stress direction deviates comparatively to the southeast and the proportions of the horizontal and oblique stresses in the zone are higher than that in the reqion of north china. And in the paper the distribution of modern tectonic stress field of the three districts of the zone and their relations of force source have been discussed.