Gravity And Magnetic Field Characteristic And Distribution Of Fault In The Southern South China Sea

The region of southern South China Sea has the most complex geological structure in South China Sea, where the three blocks of the Indian-Australian Plate, the Eurasian Plate and the Pacific plate have the strong interaction. The most developed fracture system dominates the type of oil and gas basins, structural style and basin tectonic units within the second level after a number of tectonic movement and multi-stage tectonic evolution. The accuracy of satellite altimetry gravity anomaly has gradually reached the demand of 1:100 million with the developing of the science and technology in recent years. So it is very important for structural studies of the southern South China Sea to determine the fracture and the relationship of spatial distribution using the data of new gravity and magnetic anomalies in the southern South China Sea.In this paper, the fracture of southern South China Sea is divided into three to discuss after processing and transforming the gravitational and magnetic data, and combine with the abnormity of gravity and magnetic and the inversion of fracture parameters to explain the fracture classification, which is based on previous research. There obtains some new understanding of the fracture classification comparing with the previous studies. Firstly, the fracture of western edge in South China Sea is not direct southward extension. It is cut by the northeast fracture and has a greater change in its position. Secondly, the scope of the southwest basin and the location of the expansive ridge are more clearly. The expansive ridge is cut by a number of fractures and the extended length is shorter. Thirdly, the northern scope of the Ting Jia fracture is only division in the southwest of the Nansha trough. But the south of it extends to the south side of the island of Kalimantan.Finally, the force direction is studied with the characteristics of the regional stress field in the region of southern South China Sea. The fracture of southern South China Sea is mainly formed in northeast through tectonic forces of these areas. There is the tectonic pattern. It is the northwest fracture cut the northeast fracture, while the north-south fracture is located in the two sides of east and west.