Abstract:We analyze characteristics of present-day crustal 3D movement with GNSS data since 1999 and precise leveling data since the 1970s from Hainan island and the adjacent area. Combining these data with the horizontal movement field in the region of southeast Asia, we discuss how horizontal velocity in Hainan and the continental margin of the south China block(SCB) are influencedby surrounding tectonic plates. The results show that 3D movement of Hainan island is bounded with the Baisha fault, and the boundary of that in north island is Haikou-Tunchang line. The values of the east movement of SCB decrease from west to east, the rates of the epicontinental stations are smallest and their differences are smaller. The values of the south movement increase gradually from west to east. The velocities of stations at 23°~26° N(west of Taiwan island) are different from that of those stations on its north and south. The movement of SCB is affected by Indo-European collision and extrusion, the continental margin affected by movement of the Pacific Ocean and the Philippine sea plate, and the expansion of the south China sea(SCS). The Australia plate has less impact on the regional movement.
HU Yaxuan,HU Jiuchang,ZHAO Bin et al. Analysis of Present-Day Crustal 3D Movement and Geodynamic Environment in Hainan Island and the Adjacent Area[J]. jgg, 2020, 40(6): 559-564.