青藏高原东部地壳物质流变模型及汶川地震机理探讨

Discussion of Crustal Flow Beneath the Eastern Tibetan Plateau and Mechanism of the Wenchuan Earthquake

  • 摘要: 利用GPS、大地电磁、P波层析成像等数据分析了青藏高原东部地壳运动情况和中下地壳物质流的分布及运动情况,提出了青藏高原东部地壳物质流变模型,认为在青藏高原东部存在两条巨大的、具有固定通道和边界的弱物质流,其他区域则有离散的、不均匀的弱物质流分布。巴颜喀拉块体内部的弱物质流在向东流至龙门山断裂带时,大部分弱物质沿断裂带向南北方向分流,小部分弱物质在断裂带附近沉积、上涌,造成通道堵塞,最终引发了汶川地震。

     

    Abstract: The crustal deformation of eastern Tibetan Plateau using GPS is analysed.Then,the distri-bution and movement of viscous flows in the mid-lower crust of eastern Tibetan is discussed in termsof MT data and seismic tomography.A new viscous flows model is put forward,showing that thereare two large-scale crustal flow channels and many unevenly distributed viscous flows in eastern Tibet-an Plateau.Most viscous flows in the Bayan Har block may turn to south or north along the Longmen Mountain fault when meeting the fault,while limited viscous flows are depositing and upwelling near-by the Longmen Mountain fault,which has caused channel blockage,eventually triggeing the Wen-chuan earthquake.

     

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