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在青藏高原东南边缘有一广大区域的地震活动性和GPS数据显示出形变活跃。本文描述该地区的活动断层作用,及其与GPS观测的速度场是何种的关系。在有些地方,速度场由垂直轴的旋转所调节,该地区地表的大部或全部应变看来都由地震所释放。然后将GPS观测速度与用重力驱动的形变模型所计算的速度进行比较。使用由实验导出的矿物流动定律计算的流变学,模型提供了与GPS观测速度非常一致的速度。不可能唯一地确定出深部的流变学或流动速度,与观测水平地表速度匹配的有两种类型的模型解。其一是垂直平面通过纯剪切形变,其二是地壳内存在水平速度的垂直梯度。该地区存在正断层作用地震的两个截然不同地区,其机制最容易由重力驱动的形变来解释。
Seismicity and GPS data over a large area on the southeastern margin of the Tibetan Plateau show an active deformation. This article describes the active faults in the area and how they relate to the velocity field of GPS observations. In some places, the velocity field is adjusted by the rotation of the vertical axis, and most or all of the earth’s surface strain in the area appears to have been released by the earthquake. The GPS observed velocities are then compared to the velocities calculated using gravity-driven deformation models. Using the rheology calculated from experimentally derived mineral mobility laws, the model provides very consistent velocity with GPS observations. It is impossible to uniquely identify deep rheology or flow rates, and there are two types of model solutions that match the observed horizontal surface velocities. One is that the vertical plane is deformed by pure shear and the other is the vertical gradient of the horizontal velocity in the crust. There are two distinct areas of normal-fault earthquakes in the area where the mechanism is most easily explained by gravity-driven deformation.