Estimation of near-surface velocity and seismic tomographic static corrections

	Estimation of near-surface velocity and seismic tomographic static corrections
	Liu, YK ; Chang, X ; Wang, H ; Li, FZ
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2001-03-01
卷号	44 期号:2 页码:272-278
关键词	static correction tomography fractals first-break
ISSN号	0001-5733
文献子类	Article
英文摘要	A static correction approach of 3-D tomographic inversion is presented based on surface-consistent model. This method can be applied to wide-line profiles,crooked lines. as well as conventional 2-D and 3-D seismic survey geometries. The accurate estimation of the thickness and velocities in shallow low-velocity zones is vital to proper static correction in rough topography and complicated low-velocity geological structure zones. We use a least-squares approach in conjunction with QR decomposition to reconstruct 3-D velocity model from the actual first-break times obtained from 3-D data, and then calculat concurrently the long and short wavelength components of static correction based on the reconstructed velocity images. We analyze characteristics of the first-break traveltime in complicated low-velocity layers. To improve the inversion accuracy of velocity model, the various first-break times from direct,reflection and refraction waves are considered for determining the observed traveltimes and the theoretical model calculation. The fractal algorithm is applied to determining the first breaks, which overcomes the error caused by the differences of wavelet shapes and the leg-jump of refractions. The method is capable of selecting large volume of first breaks automatically. The ray paths and traveltimes are calculated with a 3-D ray tracer which does not require more CPUs for complicated geological models. This method can determine the ray paths associated with minimum traveltimes regardless of the wave modes. The results indicate that the 3-D tomographic static correction method is more effective for field data.
WOS关键词	ALGORITHM
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000167723000015
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/76905]
专题	中国科学院地质与地球物理研究所
通讯作者	Liu, YK
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100101, Peoples R China 2.Chinese Natl Petr Co, Forth Geol Survey Div, Bur Oil Geophys Prospecting, Bazhou 300100, Peoples R China
推荐引用方式 GB/T 7714	Liu, YK,Chang, X,Wang, H,et al. Estimation of near-surface velocity and seismic tomographic static corrections[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2001,44(2):272-278.
APA	Liu, YK,Chang, X,Wang, H,&Li, FZ.(2001).Estimation of near-surface velocity and seismic tomographic static corrections.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,44(2),272-278.
MLA	Liu, YK,et al."Estimation of near-surface velocity and seismic tomographic static corrections".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 44.2(2001):272-278.