Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet plateau: evidence from shear wave splitting of SKS, PKS and SKKS

doi:10.6038/cjg20130318

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 岩石圈演化国家重点实验室

	Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet plateau: evidence from shear wave splitting of SKS, PKS and SKKS
	Wang Qiong 1; Gao Yuan 1; Shi Yu-Tao 1; Wu Jing 2
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2013-03-01
卷号	56 期号:3 页码:892-905
关键词	Northeastern Margin Of Qinghai-tibet Plateau Upper Mantle Crust Anisotropy Shear-wave Splitting
ISSN号	0001-5733
DOI	10.6038/cjg20130318
文献子类	Article
英文摘要	Based on teleseismic PKS, SKS and SKKS phases (XKS) recorded by 41 permanent broadband stations in Gansu province in northeastern margin of Qinghai-Tibet plateau,this study obtains the splitting parameters of fast polarization direction and delay time between the fast and slow shear waves at each station using the minimum transverse energy method, and then,plots the distribution map of upper mantle anisotropy around this area. Furthermore, combined with GPS velocity field and crustal anisotropy from near-field shear-wave splitting using SAM method, we discuss the characteristics and formation mechanism of the crust-mantle anisotropy in the northeastern margin of Qinghai-Tibet plateau. The results can be summarized as follows. In the west part of Altun fault,the fast wave polarization trends NWW-SEE, siting at a certain degree angle to the strike of regional structures, while coinciding with the subduction direction from Tarim Basin to Qaidam Basin, which reveals that in this region, the upper mantle deformation is mainly affected by ancient tectonic movement so that it belongs to "fossil" anisotropy. In Qilian-Hexi Corridor tectonic region, the XKS fast direction is NW-SE, consistent with strike direction of the main fault in this area, while the fast direction obtained from near-field shear-wave splitting is NE-SW, consistent with GPS velocity relative to stable Eurasian Continent. The different direction between crust and mantle suggests that the deformation mechanism of them may be different in this area. Crust anisotropy represents the direction of regional principal compressive stress, and XKS anisotropy may reflect the direction where materials flow. In Longzhong Basin and adjacent regions, which located in the transition zone between the active Qinghai-Tibet block and comparatively stable Ordos block, with more complex tectonic background,the fast directions in the crust and in the upper mantle are consistent by and large, which means that the crust and the upper mantle possibly have the same deformation, but owing to local feature's influence, the results vary obviously with these stations.
WOS关键词	VELOCITY STRUCTURE ; ADJACENT REGIONS ; CENTRAL-ASIA ; ORDOS BLOCK ; CRUST ; CHINA ; DEFORMATION ; LITHOSPHERE ; MAINLAND ; AREA
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000317169200018
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/62612]
专题	地质与地球物理研究所_岩石圈演化国家重点实验室
通讯作者	Wang Qiong
作者单位	1.China Earthquake Adm, Inst Earthquake Sci, Beijing 100036, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Wang Qiong,Gao Yuan,Shi Yu-Tao,et al. Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet plateau: evidence from shear wave splitting of SKS, PKS and SKKS[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2013,56(3):892-905.
APA	Wang Qiong,Gao Yuan,Shi Yu-Tao,&Wu Jing.(2013).Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet plateau: evidence from shear wave splitting of SKS, PKS and SKKS.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,56(3),892-905.
MLA	Wang Qiong,et al."Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet plateau: evidence from shear wave splitting of SKS, PKS and SKKS".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 56.3(2013):892-905.