南北地震带中段深部构造与地震

南北地震带中段位于中国大腹部，是青藏块体、华北块体和扬子块体的中间枢纽部位。根据该区布格重力异常图，采用Ｐａｒｋｅｒ’ｓ三维位场方法进行莫氏面反演并计算该区不同窗口的剩余场推断和解释了条岩石圈断裂，进而研究它们与地震的关系。

THE DEEP STRUCTURE AND EARTHQUAKE OF THE CENTRAL SEGMENT IN THE NORTH-SOUTH SEISMIC BELT

The region is located in the belly of Chinese mainland,which is a pivot zone of the Qinghai-Tibet block, the North China block ahd the Yangtze block. We inverses the crustal thickness of the central segment in the North-South belt by Bouguer gravity anomaly map,using the Parker's three demension potential field method. We calculated the residual gravity anomaly with different windows. The four lithospheric fractures in the research region were inferred and interpreted.The paper has studied the relationship between the deep structure and the earthquakes.The favourable conditions of the deep development of the earthquakes are:the gravity anomaly gradient belt;the crustal thick variable belt;the suddenly turning position and the elevated margin of the Mohe surface;the zero line vicinity of the residual anomaly and the deep and large activity fractures..