Lithospheric and upper mantle structure of southern Tibet from a seismological passive source experiment
Lithospheric and upper mantle structure of southern Tibet from a seismological passive source experiment
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DOI：
10.1029/97jb02379
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发表时间：
1997-12
影响因子：
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通讯作者：
X. Yuan;J. Ni;R. Kind;J. Mechie;E. Sandvol
中科院分区：
文献类型：
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作者：
X. Yuan;J. Ni;R. Kind;J. Mechie;E. Sandvol
1994年5月至10月，在西藏南部跨越藏布缝合线（印度和亚洲之间的碰撞区）的15个地震站以约20公里的间距进行了操作，这是西藏和喜马拉雅国际深度剖面测量项目（INDEPTH II）的一部分，用于受控源实验的广角记录和被动地震记录。此外，德国西藏和喜马拉雅山深度剖面（GEDEPTH）项目中密集部署的台站（间距为4公里）也记录了一些强震。第三个数据源是拉萨市永久宽带站点的记录。已经获得了足够数量和质量的Teleseeps记录，以从P-to-S转换相位导出岩石圈和上地幔结构的图像。重要结果如下。在藏博缝合带南北两侧的整个剖面上，均观测到莫霍面和第二个不连续面，莫霍面深度分别为70-80 km和50-60 km。来自GEDEPTH密集阵列的数据能够探测穿透藏布缝合线地壳的倾斜结构。藏布缝合带以北约10-20 km处存在明显的低速带。在喜马拉雅山和藏南的大部分地区，410和660 km深度的上地幔不连续面的位置与全球参考模式IASP 91 [肯内特，1991]一致。
Fifteen seismic stations were operated with about 20-km spacing in southern Tibet across the Zangbo suture (the collision zone between India and Asia) between May and October 1994 as part of the International Deep Profiling of Tibet and the Himalaya project (INDEPTH II) for wide-angle recording of the controlled source experiment and for passive earthquake recording. In addition, a dense deployment (4-km spacing) of stations within the German Depth Profiling of Tibet and the Himalayas (GEDEPTH) project also recorded a number of teleseismic earthquakes. The third data source used in this study is the records of the permanent broadband station at Lhasa. Teleseismic records have been obtained in sufficient quantity and quality to derive an image of the structure of the lithosphere and upper mantle from P-to-S converted phases. Important results are as follows. The Moho at 70–80 km and a second discontinuity at 50–60 km depth are observed over the entire profile south and north of the Zangbo suture. The data from the GEDEPTH dense array enable the detection of inclined structures penetrating the crust at the Zangbo suture. A pronounced low-velocity zone exists north of the Zangbo suture at about 10–20 km depth. The locations of the upper mantle discontinuities at 410 and 660 km depth are in agreement with the global reference model IASP91 [Kennett, 1991] over a large region of the Himalaya and southern Tibet.