高原冰川消融——青藏高原周缘特大地震的诱发因素

The Glacial Ablation-One of Inducing Factors of the Great Earthquakes in the Margin of the Tibetan Plateau

近20年来,青藏高原周缘地区特大地震频发,印—亚碰撞产生的构造应力固然是引发地震的能量库,而高原冰川快速消融产生的垂向力可被看作是诱发地震的导火索.运用地壳均衡理论,分析了近年来青藏高原周缘地区特大地震的成因,即随着全球气候的变暖,青藏高原大陆冰川迅速消融,冰川的消融使青藏高原的荷载量突然减轻,触发了下地壳顶面的回弹,进而产生了向上的垂向力,打破了地壳的均衡和青藏高原地壳表层的负载平衡,诱发了青藏高原周缘地区频频发生特大地震.该地区强震的优势发震深度即为上地壳顶面处均衡被打破的深度,即20km左右.

Last twenty years,the great earthquakes often occur in the margin of the Tibetan Plateau. The tectonic stress is the energy reservoir of earthquake,the vertical force caused by glacial ablation is the fuse of earthquake. To use isostasy theory,this paper analyzes the causes of the great earthquakes. The loading amount of the Tibetan Plateau is reduced by glacial ablation,the springback of the top of the upper crust is caused. The isostasy is broken and the great earthquake is induced. The seismogenic depth is the depth in which the isostasy of the top of the upper crust is broken,namely the depth is about 20 km.