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

摘要： 根据地壳厚度、重磁场特征、晚第四纪活动断裂、地貌差异、断陷盆地、地震活动差异等,将研究区作了一、二级块体的划分,其中一级块体7个,二级块体33个。一级块体平面上多数呈长条形,剖面上呈梯形、倒梯形,少数为多边形、三角形。二级块体平面上多数呈菱形,剖面上呈叠瓦状上冲形,少数呈条形或三角形。块体的主要运动形式有:水平挤压、垂直升降、流展和旋转。块体运动受地壳"压缩-挤出-旋转"机制控制,即地壳块体受到挤压后产生强烈收缩,随后产生地壳块体隆起并产生向东的侧向挤出,并在挤出过程中产生块体反时针方向旋转。这一结果对"高分辨率地形变的观测研究和地震预报"有重要的科学意义。

关键词: 青藏高原东北缘, 块体划分, 运动态势, 形成机制