Tomography research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan province

	Tomography research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan province
	Bai, ZM ; Wang, CY
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2004-03-01
卷号	47 期号:2 页码:257-267
关键词	finite difference inversion ray inversion Zhefang-Binchuan and Menglian-Malong wide-angle seismic profile crust and upper m antle structure tomography
ISSN号	0001-5733
文献子类	Article
英文摘要	Based on the finite difference inversion and ray inversion method, the crust and upper mantle's structure on the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles, both of which are located in Yunnan province, are tomographyed using the geophysical data of travel-time, amplitude ratio and Bouger anomaly. Thus some new recognitions about the geodynamics and the seismotectonic environment are derived. The crustal thickness of the Zhefang-Binchuan profile is 35 similar to 46km, and that of the Menglian-Malong profile is 33 similar to 44.5km. The geometry of the Moho interface is like that given by Hu Hongxiang. The P wave velocity on the top of the mantle of some places is relatively low and the fluctuating range of the velocity is very large, which may indicates that the Yunnan region is a typical tectonic active area. Moreover, there exits a prominent consistency between the shallow and deep structures, which implys that the activity of shallow material always has a deep background. The velocity structure of the Zhefang-Binchuan profile indicates that there exists a large low velocity anomaly across the crust to the east of the Nujiang fault exposed on the ground, and this maybe related with the deep material upwelling. The characteristic of the large faults which are the borders between some first order tectonic units can also be derived by both of the velocity structure profiles: the Honghe fault is a super-fault that cut the lithosphere, the Nujiang fault cuts deeply in the crust and even stretches downward into the top of the upper mantle, yet the Changning-Shuangjiang fault has a listric shape with a small dip angle, which may suggest that its incision depth is not very deep. The large earthquakes in Yunnan province always have a relationship with the large and deep faults, that stretch into the upper mantle. Some earthquakes with shallow focal depths are generally located at converge positions of faults within the upper and middle crust or the positions where the velocity contours on the belt between the high and low velocity anomaly blocks are crooked. It is inferred estimated that these locations are prone to the accumulation of the energy and the regional stress.
WOS关键词	FINITE-DIFFERENCE CALCULATION ; CRUSTAL STRUCTURE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000220590000012
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/79493]
专题	中国科学院地质与地球物理研究所
通讯作者	Bai, ZM
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.China Seismol Bur, Inst Geophys, Beijing 100081, Peoples R China
推荐引用方式 GB/T 7714	Bai, ZM,Wang, CY. Tomography research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan province[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2004,47(2):257-267.
APA	Bai, ZM,&Wang, CY.(2004).Tomography research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan province.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,47(2),257-267.
MLA	Bai, ZM,et al."Tomography research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan province".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 47.2(2004):257-267.