Analysis on Bouguer Gravity Anomaly Characteristics and Boundary Identification in China and Surrounding Regions

China is located in the southeast of the Eurasian Plate and is subject to the effects of subducting, squeezing and collision by the Pacific Plate to the east, Philippine Plate to the southeast and Indian Ocean Plate to the southwest. It has exceptional geotectonic structure. Based on the satellite gravity data with high precision, high resolution and ample geophysical information, combined with geological data, by using satellite gravity potential field and its full tensor gradient, this paper studies the distribution characteristics of gravity anomalies and the identification of tectonic boundaries in China and surrounding regions. Results suggest that the Bouguer gravity anomaly in eastern China reduces gradually from east to west, mostly in the direction of NNE; in the western, it reduces gradually in a wave mode from north to south, mainly in the directions of NW and NWW. In general, the stress field reduces gradually from west to east, and the tectonic of stress field in western China is complex. The maximum principal compressive stress in Xinjiang exists in SN direction and that in Qinghai-Tibet Plateau mostly changes gradually from NNE to SSE; the change in eastern China is relatively simple, and the maximum principal compressive stress direction gradually changes from NE to WE and then to SE. In addition to the above study results, by comprehensively referencing the previous studies by other people and by using the boundary identification methods based on the satellite gravity full-tensor gradient data and its combinations, we update the extension route of Red River fault zone and deduce the tectonic unit boundary between the North China and South China active tectonic block regions. This paper identifies in China and surrounding regions 6 primary active tectonic blocks, 22 secondary active tectonic blocks, 3 tertiary active tectonic blocks and the 20 active tectonic block boundary zones constituted of deformation belts and active tectonic belts with various geometric structures and width variations. The results of this study can improve the understanding of gravity anomalies and boundary structures in China and surrounding regions, and provide certain geophysical supports for geological structure analysis and crustal dynamic process.