Shear-wave splitting beneath Yunnan area of Southwest China

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• 作者：Yutao Shi (1) (2)
  Yuan Gao (1) (2)
  Youjin Su (3)
  Qiong Wang (2)
  
• 关键词：seismic anisotropy ; polarization orientation ; principal compressive stress ; shear wave ; SKS ; PKS and SKKS ; P315.3 ; P315.63
• 刊名：Earthquake Science
• 出版年：2012
• 出版时间：February 2012
• 年：2012
• 卷：25
• 期：1
• 页码：25-34
• 全文大小：2305KB
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• 作者单位：Yutao Shi (1) (2)
  Yuan Gao (1) (2)
  Youjin Su (3)
  Qiong Wang (2)
  
  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
  
• ISSN：1867-8777

文摘

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 55-65 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.