关键词: 青藏高原东北缘, 块体划分, 运动态势, 形成机制

Abstract: Based on the crustal depth, gravity-magnetic feature, active faults in late-Quaternary, geomorphic variance, fault-depression basins and the difference of seismicity, the studied region is divided into first and second grade blocks. There are 7 first grade blocks and 33 second grade blocks. The shapes of the first grade blocks are mostly elongate in plane and trapezoid or up-down trapezoid in the section, and some are polygon or triangle. The shapes of the second blocks are mostly rhombus, thrust-type in the section, and some are elongate or triangle. The main motion types include:horizontal thrusting, vertical lifting or depressing, and flow-extending and rotation. The block motion is controlled by the mechanism of crust "contract-escaping-rotation". That is, when the crust block is exerted by extruding stress, the intense contraction happens. Then the crustal block lifts and escapes towards the east. The block rotation appears in the process. The result is of great importance for "high resolution observation of geo-deformation and earthquake prediction".

Key words: Northeast margin of Tibetan Plateau, Division of blocks, Motion status and formation mechanism