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Shear-wave splitting beneath Yunnan area of Southwest China |
Yutao Shi1, 2, Yuan Gao1, 2, Youjin Su3, Qiong Wang2 |
1 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
3 Earthquake Administration of Yunnan Province, Kunming 650041, China |
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Abstract Systematic analyses of seismic data recorded by the Yunnan regional seismograph network reveal significant crustal and upper mantle anisotropy. Splitting of the S phase of local earthquakes and teleseismic SKS, PKS, and SKKS phases indicates time-delays from 1.60 ms/km to 2.30 ms/km in the crust, and from 0.55 s to 1.65 s in the upper mantle which corresponds to an anisotropic layer with a thickness about between 55–165 km. The polarization orientations of fast shear waves in the crust are complicated with a predominantly north-south direction, and the mantle anisotropy has a nearly west-east direction. Our results show different deformation styles and mechanisms exist between the crust and upper mantle.
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Received: 30 September 2011
Published: 10 February 2012
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Fund:National Natural Science Foundation of China Project (No. 41174042), China National Special Fund for Earthquake Scientific Research in Public Interest (No. 201008001) and Basic Research Project of Institute of Earthquake Science, CEA (No. 2009-21) |
Corresponding Authors:
Yutao Shi
E-mail: shiyt@seis.ac.cn
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