气候变化领域集成服务门户(CCPortal): Study on Pn velocity and anisotropy in the uppermost mantle of the Eastern Himalayan Syntaxis and surrounding regions

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DOI	10.3969/j.issn.0001-5733.2009.09.008
	Study on Pn velocity and anisotropy in the uppermost mantle of the Eastern Himalayan Syntaxis and surrounding regions
	Cui Zhong-Xiong; Pei Shun-Ping
通讯作者	Cui, ZX (通讯作者)
发表日期	2009
ISSN	0001-5733
起始页码	2245
结束页码	2254
卷号	52 期号:9
英文摘要	The Eastern Himalayan Syntaxis (EHS) is a singular point of continental collision between the Indian and Eurasian plates, and has been focused by many geoscientists. We added the ISC data of 1964 similar to 2006 to previous data set, Chinese national and provincial events data used by Pei et al, and 349475 Pn arrivals were selected in all. We have obtained seismic velocities and anisotropy in the uppermost mantle around EHS and surrounding regions by performing tomographic inversion of Pn travel times. Comparing Pn velocity variation with geological results, we find they have distinct correlation: particularly high velocities always exist in old stable regions such as Sichuan Basin and Indian Plate. Low Pn velocities lie in active tectonic regions, volcanic areas and magmatic rock regions, for example, eastern Tibetan Plateau and North-South Seismic Zone, southern Yunnan province and northern Indochina. Pn anisotropy results show that the fast directions of Pn are clockwise around the EHS from NE in southeastern Tibetan Plateau, then SE to NS in North-South Seismic Zone. But the direction sharply changes to EW in the northern Indochina. The clockwise Pn fast direction maybe results from movement of mass extruded from Tibet under simple shear, which is caused by mass flow in southeastern Tibetan Plateau and North-South Seismic Zone relative to stable EHS and Sichuan Basin. The EW Pn direction probably results from pure shear, which is caused by compression in NS and extension in EW in Burma back-arc extensional area. The polarization directions of SKS have similar rotation to Pn, but in northern Indochina the oriented EW fast direction area of Pn has a southward offset of about 3 degrees than SKS, which maybe results from the faster movement of upper lithosphere in this area.
关键词	SEISMIC ANISOTROPY TIBETAN PLATEAU LITHOSPHERE BENEATH WESTERN YUNNAN TRAVEL-TIMES TOMOGRAPHY CRUSTAL SUBDUCTION DEFORMATION TECTONICS
英文关键词	Pn wave; Inhomogeneity; Anisotropy; Decouple; Eastern Himalayan Syntaxis
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000270377100008
来源期刊	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
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/257628
推荐引用方式 GB/T 7714	Cui Zhong-Xiong,Pei Shun-Ping. Study on Pn velocity and anisotropy in the uppermost mantle of the Eastern Himalayan Syntaxis and surrounding regions[J]. 中国科学院青藏高原研究所,2009,52(9).
APA	Cui Zhong-Xiong,&Pei Shun-Ping.(2009).Study on Pn velocity and anisotropy in the uppermost mantle of the Eastern Himalayan Syntaxis and surrounding regions.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,52(9).
MLA	Cui Zhong-Xiong,et al."Study on Pn velocity and anisotropy in the uppermost mantle of the Eastern Himalayan Syntaxis and surrounding regions".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 52.9(2009).