岳阳地区震源机制与构造应力场

THE FOCAL MECHANISM AND TECTONIC STRESS FIELD IN YUEYANG AREA

由震源机制反映本区地壳构造应力场具有很好的统一性。主压应力轴优势方向近东西,主张应力轴近南北。并大都以N轴直立,P、T轴水平为特征。容易发生错动的断层系统为NE和NW向,以平推运动为主,前者顺扭,后者反扭。局部地区震源应力场显示不同程度的差异性。

From the focal mechanism in Yueyang area, we get the knowledge that there is a good unity in crust tectonic stress field. And some following characters are got. First, the superiority direction, of main pressure axis is approximate to east west direction, and that of main expansion axis is in the direction of north south; the second, almost all of the N axes are in vertical direction and the p, T axes in horizontal direction. The faults which are easy to occur dislocations are in the direction of NE and NW. which are mainly in transaltional motion, the former is in positive twist and the latter in negative twist. The focal stress field also shows some differences in some areas.