Three-dimensional P wave azimuthal anisotropy in the lithosphere beneath China

Zhouchuan Huang, Pan Wang, Dapeng Zhao, Liangshu Wang, Mingjie Xu

研究成果: Article査読

33 被引用数 (Scopus)

抄録

Seismic anisotropy in the upper mantle beneath East Asia has been studied extensively using shear wave (SKS) splitting measurements, which have provided important information on mantle dynamics in this region. However, SKS measurements have poor vertical resolution, and so their interpretations are usually not unique. In this work we use a large number of traveltime data from 34,036 local earthquakes recorded by 1563 seismic stations to determine the first model of 3-D P wave azimuthal anisotropy in the lithosphere beneath China. Our results show that the fast velocity directions (FVDs) are generally correlated with the surface geologic features, such as the strikes of the orogens, active faults, and tectonic boundaries. The FVDs in the upper crust are normal to the maximal horizontal stress (σH) in regions with extensive compression such as the Tibetan Plateau, whereas they are subparallel to σH in strike-slip shear zones such as the western and eastern Himalayan syntax. The comparison of the FVDs of P wave anisotropy with SKS splitting measurements indicates that beneath the Tibetan Plateau the seismic anisotropy in the lithosphere contributes significantly to the SKS splitting observations. In contrast, in east China the P wave FVDs in the lithosphere are different from the SKS splitting measurements, suggesting that the SKS splitting is mainly caused by the anisotropy in the deeper mantle such as the asthenosphere and the mantle transition zone under east China. These novel results provide important new information on the lithospheric deformation and mantle dynamics in East Asia. Key Points We determined the first 3-D P wave azimuthal anisotropy beneath China Anisotropy in the lithosphere is important in and around the Tibet Plateau Anisotropy in east China is mainly located in the asthenosphere

本文言語English
ページ(範囲)5686-5712
ページ数27
ジャーナルJournal of Geophysical Research: Solid Earth
119
7
DOI
出版ステータスPublished - 2014 7

ASJC Scopus subject areas

  • 地球物理学
  • 地球化学および岩石学
  • 地球惑星科学(その他)
  • 宇宙惑星科学

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