| 青藏高原震源分布与板块运动 |
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| 引用本文： | 环文林,汪素云,时振梁,鄢家全.青藏高原震源分布与板块运动[J].地球物理学报,1980,23(3):269-280. |
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| 作者姓名： | 环文林 汪素云 时振梁 鄢家全 |
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| 作者单位： | 国家地震局地球物理研究所 |
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| 摘 要： | 本文分析了青藏高原及其邻区大量近期地震的震源深度分布资料,发现中源地震不仅分布在众所周知的兴都库什和印缅山弧一带,而且在印度洋板块与欧亚板块汇聚带印度河-雅鲁藏布江以南,以及欧亚板块内部的帕米尔、西昆仑、柴达木和天山南缘一带也有中源地震分布,它们构成了这一地区三条向南倾斜的震源带。 这些中源地震震源带的存在表明,向北运动的印度次大陆与亚洲大陆碰撞以后,印度次大陆北缘本身并没有消减,而是迫使亚洲大陆通过三条向南倾斜的岩石层消减带产生了大规模的消减作用。 中源地震在平面上分布的不连续性,揭示了这一地区的许多条走滑断层的现代活动。这些走滑断层的巨大位移显示了青藏高原内部各块体之间的横向运动也是很可观的。 最后,提出了亚洲大陆多条南倾消减带的形成和发展模式。
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| 关 键 词： | 消减带 中源地震 震源深度 震源分布 青藏高原 帕米尔 岩石层 向南倾斜 印度次大陆 板块汇聚 |
| 收稿时间： | 1980-02-01 |
THE DISTRIBUTION OF EARTHQUAKES FOCI AND PLATE MOTION IN THE QINGHAI-XIZANG PLATEAU |
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| Huan Wen-lin,Wang Su-yun,Shi Zhen-liang,Yan Jia-quan.THE DISTRIBUTION OF EARTHQUAKES FOCI AND PLATE MOTION IN THE QINGHAI-XIZANG PLATEAU[J].Chinese Journal of Geophysics,1980,23(3):269-280. |
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| Authors: | Huan Wen-lin Wang Su-yun Shi Zhen-liang Yan Jia-quan |
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| Institution: | Institute of Geophysics, State Seismological Bureau |
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| Abstract: | In this paper, the data of focal depths of a alrge number of earthquakes which occurred recently in the Qinghai-Xizang plateau and its vicinity are analysed. We find that not only there are widely distributed shallow earthquakes in this region, but also there are regularly distributed intermediate shocks. These intermediate earth-quakes form three seismic zones in this region.The first zone stretches along the plate convergence zone. The planes of foci in the Hindukush and in the India-Burma mountain arc which are located in the two flanks of Indian subcontinent are north-dipping and east-dipping respectively toward Asian continent. But the planes of foci of intermediate earthquakes in the Indus and Yarlung Zangbo River convergence zone are all southward dipping. The second zone is located in the areas of the Pamir, the West Kunlun mountain and the northern margin of the Qaidam Basin. The planes of foci here are all south-dipping. The third zone is located in the southern margin of the Tianshan. The plane of foci is south-dipping too.If the above-mentioned inclined focal planes along which many intermediate earthquakes occurred, is taken as the subduction zone, then there are three south-dipping lithospheric subduction zones from the Himalayas to Tianshan. The existence of the three southward inclined lithospheric subduction zones implies that it was the Asian plate rather than the Indian plate which has been subducted.If we regard the depth of the subduction zone as the part disappeared in the mantle, then the Asian continental crust along the above three subduction zones has shortened at feast 300-700 kms since the India-Eurasia collision.The discontinuous distribution of the intermediate earthquake zones indicates recent activity of some strike slip faults. The large displacements of some strike slip faults show that the lateral movement between the blocks is closely related to the northward movement of the Indian plate.In the last part of this paper, we proposed a model on the origin of three south-dipping subduction zones in the Asian continent. |
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