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| Shear-wave splitting in the crust: Regional compressive stress from polarizations of fast shear-waves |
| Yuan Gao1, Yutao Shi1, Jing Wu2, Lingxue Tai1 |
1 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
2 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
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Abstract When propagating through anisotropic rocks in the crust, shear-waves split into faster and slower components with almost orthogonal polarizations. For nearly vertical propagation the polarization of fast shearwave (PFS) is parallel to both the strike of the cracks and the direction of maximum horizontal stress, therefore it is possible to use PFS to study stress in the crust. This study discusses several examples in which PFS is applied to deduce the compressive stress in North China, Longmenshan fault zone of east edge of Tibetan plateau and Yunnan zone of southeast edge of Tibetan plateau, also discusses temporal variations of PFS orientations of 1999 Xiuyan earthquake sequences of northeastern China. The results are consistent to those of other independent traditional stress measurements. There is a bridge between crustal PFS and the crustal principal compressive stress although there are many unclear disturbance sources. This study suggests the PFS results could be used to deduce regional and in situ principal compressive stress in the crust only if there are enough seismic stations and enough data. At least, PFS is a useful choice in the zone where there are a large number of dense seismic stations.
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Received: 07 October 2011
Published: 10 February 2012
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| Fund:International Science and Technology Cooperation Program of China (2010DFB20190) and National Natural Science Foundation of China (41040034 and 41174042) |
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Corresponding Authors:
Yuan Gao
E-mail: gaoyuan@seis.ac.cn
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