Upper- and mid-crustal radial anisotropy beneath the central Himalaya and southern Tibet from seismic ambient noise tomography
文献类型：SCI/SSCI论文
| 作者 | Wang W. |
| 发表日期 | 2012 |
| 关键词 | Interferometry Tomography Surface waves and free oscillations Seismic anisotropy Crustal structure Rheology: crust and lithosphere surface-wave tomography phase-velocity maps 2-station analysis crustal structure array tomography heat-flow se tibet evolution plateau zone |
| 英文摘要 | Through analysis of the Rayleigh wave and Love wave empirical Green's functions recovered from cross-correlation of seismic ambient noise, we image the radial anisotropy and shear wave velocity structure beneath southern Tibet and the central Himalaya. Dense ray path coverage from 22 broadband seismic stations deployed by the Himalayan Nepal Tibet Seismic Experiment project provides the unprecedented opportunity to resolve the spatial distribution of the radial anisotropy within the crust of the central Himalaya and southern Tibet. In the shallow subsurface, the obtained results indicate significant radial anisotropy with negative magnitude (VSV > VSH) mainly associated with the Indus Yarlung Suture and central Himalaya, possibly related to the fossil microcracks or metamorphic foliations formed during the uplifting of the Tibetan Plateau. With increasing depth, the magnitude of radial anisotropy varies from predominantly negative to predominantly positive, and a mid-crustal layer with prominent positive radial anisotropy (VSV < VSH) has been detected. The top of the mid-crustal anisotropic layer correlates nicely with the starting depth of the mid-crustal lower velocity layers detected in our previous study. The spatial correlation of the positive radial anisotropy layers and mid-crustal lower velocity layers might suggest lateral crustal channel flow induced alignment of mineral grains, most likely micas or amphiboles, within the mid-crust of the central Himalaya and southern Tibet. This observation provides independent seismic evidence to support the thermo-mechanical model, which involves the southward extrusion of a low viscosity mid-crustal channel driven by the denudation effect focused at the southern flank of the Tibetan Plateau to explain the tectonic evolution of the TibetanHimalayan orogen. |
| 出处 | Geophysical Journal International |
| 卷 | 189 |
| 期 | 2 |
| 页 | 1169-1182 |
| 收录类别 | SCI |
| 语种 | 英语 |
| ISSN号 | 0956-540X |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/26918]  |
| 专题 | 地理科学与资源研究所_历年回溯文献 |
| 推荐引用方式 GB/T 7714 | Wang W.. Upper- and mid-crustal radial anisotropy beneath the central Himalaya and southern Tibet from seismic ambient noise tomography. 2012. |
入库方式： OAI收割
来源：地理科学与资源研究所
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