THE DEEP STRUCTURE CHARACTERISTICS OF THE TAN-LU FAULT ZONE,BOHAI SEGMENT--A CASE STUDY ON THE CRUSTAL THICKNESS AND THE CURIE DEPTH
Liu Guangxia (Research Center of Exploration Geophysics, SSB, Zhengzhou, 450003) Zhao WenjunZhang Xian (Seismological Bureau of Hainan Province)(Research Cevter of Exploration Geophysics, SSB )
The authors of this paper discuss the deep structure characteristics of the Bohai Segruent of the TanLu fault in two aspects, e.g. the burried depth of the Curie isothermal surface and the crustal thickness. With the help of the aeromagmetis data, the authors calculated the depth of Curie in the studied marine area using the method of 3D magnetic stratum inversion, with the help of the Bouguer anomaly data, we calculated the crustal thickness in the studied marine area using the method of 3D gravity forward inversion calculation. Based on the data about we proposed the geothermal and the electrical structure of the crust/mantle as followings:①dipping toward east steeply,②clearly segmented showing the difference on the crustal geodynamics since Cenozoic Era.The TanLu Fault can be divided into three segments in Bohai Sea,e.g.,①Bozhaing segment which Curie surface are crustal thickness are the thinnest 13 km,and 25 km respectively,its crustal movement is extension in brief.②Liaodong Bay segment,the depth of Curie surface is 16-17 km crustal thickness is 28-30 km.③Laizhou Bay segment,the depth of Curie surface is 20 km,its crustal thickness is 30-32 km.