西藏中部的发震构造

Seismogenic Tectonics in the Central Tibet

西藏中部的发震构造是晚第四纪以来强烈活动的北东、北西和近南北向的活动断层及受其控制的地堑半地堑型盆地和拉分盆地，东西向缝合线和断层晚第四纪以来的运动性不明显，对地震活动没有明显的控制作用，活动断层的规模和晚第四纪以来的运动性质对地震的震级和数量有明显的控制作用。８级地震的发生与拉分盆地内部张剪切断层与盆地一侧新活动幅度大的次级走滑断层的相互作用密切相关。

The seismogenic tectonics on central Tibet can be identified as the active with NE, NW and SNtrending and the structral basins which is mainly pull-apart basians, grabens and half-grabens. The sutures with EW-trending are not obviousely active in the late Quaternary(Holocene), they are not the set sismogenic tectonics. The size and sense of motion of the active faults play an important part in controlling the size and numbers of earthquake occurred. The two great earthquakes of magnutide 8 occurred as an result of intreaction of the interior extentional shear fault in the interior of pull-apart basin and one of the secondary strike-slip faults which consist of the boundary of a pull-apaft basin, and shows strong movement in the late Quaternary.