Seismic relocation, focal mechanism and crustal seismic anisotropy associated with the 2010 Yushu M S7.1 earthquake and its aftershocks

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• 作者：Bo Zhao (1) (2)
  Yutao Shi (2) (3)
  Yuan Gao (2)
  
• 关键词：Yushu earthquake ; double difference algorithm ; focal mechanism ; shear ; wave splitting ; stress ; P315.3+3
• 刊名：Earthquake Science
• 出版年：2012
• 出版时间：February 2012
• 年：2012
• 卷：25
• 期：1
• 页码：111-119
• 全文大小：841KB
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• 作者单位：Bo Zhao (1) (2)
  Yutao Shi (2) (3)
  Yuan Gao (2)
  
  1. China Earthquake Networks Center, Beijing, 100045, China
  2. Institute of Earthquake Science, China Earthquake Administration, Beijing, 100036, China
  3. Institute of Geophysics, China Earthquake Administration, Beijing, 100081, China
  
• ISSN：1867-8777

文摘

The 2010 Yushu M S7.1 earthquake occurred in Ganzi-Yushu fault, which is the south boundary of Bayan Har block. In this study, by using double difference algorithm, the locations of mainshock (33.13°N, 96.59°E, focal depth 10.22 km) and more than 600 aftershocks were obtained. The focal mechanisms of the mainshock and some aftershocks with M S>3.5 were estimated by jointly using broadband velocity waveforms from Global Seismic Network (GSN) and Qinghai Seismic Network as well. The focal mechanisms and relocation show that the strike of the fault plane is about 125° (WNW-ESE), and the mainshock is left-laterally strikeslip. The parameters of shear-wave splitting were obtained at seismic stations of YUS and L6304 by systematic analysis method of shear-wave splitting (SAM) method. Based on the parameters of shear-wave splitting and focal mechanism, the characteristics of stress field in seismic source zone were analyzed. The directions of polarization at stations YUS and L6304 are different. It is concluded that after the mainshock and the M S6.3 aftershock on April 14, the stress-field was changed.