气候变化领域集成服务门户(CCPortal): Anisotropic upper crust above the aftershock zone of the 2013 Ms 7.0 Lushan earthquake from the shear wave splitting analysis

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DOI	10.1002/2015GC005972
	Anisotropic upper crust above the aftershock zone of the 2013 Ms 7.0 Lushan earthquake from the shear wave splitting analysis
	Liu, Ying; Zhang, Haijiang; Zhang, Xin; Pei, Shunping; An, Meijian; Dong, Shuwen
通讯作者	Zhang, HJ (通讯作者)
发表日期	2015
EISSN	1525-2027
起始页码	3679
结束页码	3696
卷号	16 期号:10
英文摘要	We have conducted a systematic shear wave splitting analysis using 1000 selected aftershocks with M>2 from the 2013 Ms 7.0 Lushan earthquake along the Longmenshan fault system in southwest China. Polarization directions of fast shear waves show a bimodal distribution with one dominant direction approximately parallel to the fault strike and the other close to the regional maximum horizontal compressive stress direction. This indicates that in this area mechanisms causing crustal seismic anisotropy are both stress induced and fault zone structure controlled. Delay times between fast and slow shear waves do not show a clear trend of increase for deeper events, suggesting the anisotropic zone is mostly above the aftershocks, which are generally located below 8 km. We further applied a shear wave splitting tomography method to measured delay times to characterize the spatial distribution of seismic anisotropy. The three-dimensional anisotropic percentage model shows strong anisotropy above 8 km but low anisotropy below it. The mainshock slip zone and its aftershocks are associated with very low or negligible anisotropy and high velocity, indicating that the zones with high anisotropy and low velocity above 8 km are mechanically weak and it is difficult for stress to accumulate there. The main and back reverse fault zones are associated with high anisotropic anomalies above approximate to 8 km, likely caused by shear fabric or microfractures aligned parallel to the fault zone.
关键词	SAN-ANDREAS FAULT W 6.6 LUSHAN 2008 WENCHUAN EARTHQUAKE KARADERE-DUZCE BRANCH SEISMIC ANISOTROPY FOCAL MECHANISMS SICHUAN STRESS RELOCATION PARKFIELD
英文关键词	shear wave splitting; seismic anisotropy; Lushan earthquake; anisotropy tomography
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000366133800019
来源期刊	GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258492
推荐引用方式 GB/T 7714	Liu, Ying,Zhang, Haijiang,Zhang, Xin,et al. Anisotropic upper crust above the aftershock zone of the 2013 Ms 7.0 Lushan earthquake from the shear wave splitting analysis[J]. 中国科学院青藏高原研究所,2015,16(10).
APA	Liu, Ying,Zhang, Haijiang,Zhang, Xin,Pei, Shunping,An, Meijian,&Dong, Shuwen.(2015).Anisotropic upper crust above the aftershock zone of the 2013 Ms 7.0 Lushan earthquake from the shear wave splitting analysis.GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,16(10).
MLA	Liu, Ying,et al."Anisotropic upper crust above the aftershock zone of the 2013 Ms 7.0 Lushan earthquake from the shear wave splitting analysis".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 16.10(2015).