鄂北、豫南现今构造应力场研究

THE STUDY ON THE CURRENT STRESS FIELD IN THE AREA BETWEEN HUBEI AND HENAN

在分析本区震源机制解的基础上 ,结合小震综合断层面解、地应力测量、地壳形变、活动断裂等方面资料 ,将研究区现今构造应力场划分为四个区 ,即 :江汉平原区 (A区 )、桐柏～大别区 (B区 )、鄂西区 (C区 )、鄂西北～豫西南区 (D区 ) ,每个区各具特色。A区主压应力P轴的优选方位为SE12 7° ;B区主压应力轴具两个优选方位 (NE33°、NW 335°) ,反映出与走滑断裂相关的应力分布形式 ;C区主压应力P轴具明显优势方位 :NE6 2° ;D区主压应力P轴和压应力作用区近东西向展布。数值模拟进一步分析表明 :A、B、C、D四区的应力作用机制通过F6、F10 、F11等走滑活动断层处进行分异和转换。

By analysis and study on the focal mechanism of earthquakes in the area between Hubei and Henan from 1972 to 2001, the authors consider that the current stress field in the area can be divided into four districts with their different characteristics, namely the Jianghan plain district; Dongbo-Dabie district , Western Hubei district and Northwestern Hubei - Sounthwestern Henan district. The Jianghan plain district as a whole is in a compressive condition, where compressive stress arises up earthquakes with small scales , with principal compressive axis P in a preponderant orientation SE 127, the earth stress data also indicate its displacement deviates from east to south. This district moves toward SE direction.The Tongbo-Dabie district is in a shear condition with two preponderant orientation: NE and NW, where shear is focused on its active faults which arise up faults movement and lead to earthquake.