Simulation of the effects of faults movement on stress and deformation fields of Tibetan Plateau by discontinuous movement models
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摘要: 在青藏高原的运动变形过程中，断层活动起着至关重要的作用.本文利用有限元数值模拟的方法，分别计算了在GPS做边界约束下青藏高原及周边区域的连续体模型和含断层的不连续体模型的运动状态和应力场分布.从连续性模型和非连续体模型的差异发现，断层存在与否很大程度上影响了青藏高原现代运动场的分布.主要体现在，断层的滑移运动（1）增加了青藏高原东西两侧的拉张趋势；（2）加大了青藏高原物质东移的速度；（3）改变了塔里木和柴达木盆地的运动状态.模拟结果显示，非连续模型的运动场分布与GPS观测结果吻合程度大大高于连续体模型结果，表明断层活动在青藏高原的运动学和动力学过程中起着重要的作用，在研究青藏高原的动力学机制中，必须考虑断层作用的影响.Abstract: The activities of faults play key roles in the movement and deformation of Tibetan Plateau. In this article, with the continuous model of Tibetan Plateau and its adjacent areas as well as the discontinuous model with faults, both motion state and stress field distributions are calculated by finite element method under the constraints of GPS velocity field. Based on the difference between the simulations of the two models, it is found that the existence of faults influenced the modern movement field of Tibetan Plateau greatly. The effects mainly concentrate in the following aspects: 1. Increasing the extending trend of the east and west side of Tibetan Plateau; 2. Augmenting the velocity of eastward mass flow of Tibetan Plateau due to the strike-slip of faults; 3.Changing the motion state of Tarim Basin and Qaidam Basin. The simulation results indicate that the fitness between the motion field in discontinuous model and the GPS observations is much better than that of continuous model, which makes clear that faults' activity plays an important role in the kinematics and dynamics of Tibetan Plateau, and the influence of faults must be considered in further researches on the dynamics mechanism of Tibetan Plateau.
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Key words:
- Faults /
- GPS /
- Movement field /
- Discontinuous motion
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