A comparative study of both model expansion and topography flatten in topography handling in seismic traveltime tomography

doi:10.6038/cjg2019M0102

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

	A comparative study of both model expansion and topography flatten in topography handling in seismic traveltime tomography
	Guo GaoShan 1,2; Lan HaiQiang 1,2; Chen Ling 1,2,3
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2019-05-01
卷号	62 期号:5 页码:1704-1715
关键词	Model expansion scheme Topography flatten scheme Irregular topography Seismic tomography
ISSN号	0001-5733
DOI	10.6038/cjg2019M0102
英文摘要	Irregular surfaces are common situations in seismic exploration, especially at regions of middle and western China, making seismic processing and interpretation rather difficult in both oil/gas reservoir surveys and deep seismic soundings. The fine treatment of irregular topography becomes an inevitable requirement in high-precision seismic imaging. Traditionally, the problem of irregular topography is usually settled by model expansion scheme, in which the topography is regarded as an inner discontinuity after adding a low-velocity layer above the surface to expand an irregular physical space to a regular computational space. In recent years, a new method called topography flatten scheme, which involves the transformation between Cartesian and curvilinear coordinate systems, has been proposed to provide an alternative way to deal with rugged surfaces. In this paper, the both treatment schemes for irregular surfaces are briefly summarized. Then, a series of comparative tests are performed to comprehensively evaluate the accuracy, effectiveness and applicability of both methods from the first-arrival traveltimes, raypaths and imaging results of different synthetic models. These experiments indicate that the transition from a free surface to an inner discontinuity and the use of low-velocity media in model expansion scheme will cause many undesirable problems, such as loss of accuracy in calculating traveltimes and physically unrealistic seismic rays or spurious take-off angles, which can reduce seismic resolution and distort or smear structural images. For topography flatten scheme, the body-conforming grid can completely describe rugged surfaces and the topography-dependent eikonal equation (TDEE) is capable of exactly charactering the travel-time fields under complex surfaces, which establish a firm foundation for seismic imaging free from the effect of irregular surfaces. Therefore, we believe that topography flatten scheme has an exciting potential application in reconstructing high-quality seismic structures under complex topographical conditions.
WOS关键词	FAST-SWEEPING SCHEME ; P-WAVE TOMOGRAPHY ; UPPER-MANTLE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000467308600011
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/91476]
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	Lan HaiQiang
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China
推荐引用方式 GB/T 7714	Guo GaoShan,Lan HaiQiang,Chen Ling. A comparative study of both model expansion and topography flatten in topography handling in seismic traveltime tomography[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2019,62(5):1704-1715.
APA	Guo GaoShan,Lan HaiQiang,&Chen Ling.(2019).A comparative study of both model expansion and topography flatten in topography handling in seismic traveltime tomography.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,62(5),1704-1715.
MLA	Guo GaoShan,et al."A comparative study of both model expansion and topography flatten in topography handling in seismic traveltime tomography".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 62.5(2019):1704-1715.