【摘要】 通过对武汉—信阳地区1972～2001年50个MS≥2.8地震震源机制解的分析研究,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—淮北区(B区)、鄂西区(C区)、鄂北区(D区)。A区主压应力P轴的优选方位为SE127°,低倾角,地震规模小,震源深度浅;B区的主压应力轴以NE33°为主,NW333°为辅,反映出与该区走滑断裂相关的应力分布形式。数值模拟分析表明,最大主应力和最大剪应力沿该区活动断层集中,地震主要由剪应力引起断层走滑错动而产生;A、B、C、D四区的应力作用机制是通过F6、F10、F11、F12等走滑活动断层进行分异和转换的。更多还原

【Abstract】 Based on analysis and study on the focal mechanism solutions of 50 M_S≥2.8 earthquakes in Wuhan-Xinyang area from 1972 to 2001, the current stress field in the area is divided into four districts with their own characteristics, namely Jianghan plain district,Tongbo-Dabie-Huaibei district,West Hubei district and North hubei district.Combining the result of numerical modeling,we find out that:in Jianghan plain district,the principal compressive stress P axes are in a preponderant direction of SE127°,with shallow earthquakes in small magintudes;in Tongbo-Dabie-Huaibei district,the P axes are mainly NE33° and some NW333°,which indicates that the field stress is in a shear condition and most of earthquakes distribute along the strike-slip active faults.The functional mechanism of current stress field to seismicity is seperated and transformed through the main strike-slip active faults in the area.更多还原