检索结果-南通市图书馆

检索条件"作者=haiqiang lan and Zhongjie Zhang State Key Laboratory of Lithosphere Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing,100029,PR China"

共 5 条记录，以下是1-10 订阅

全选清除本页清除全部题录导出标记到"检索档案"

详细简洁

排序：

Three-Dimensional Wave-Field Simulation in Heterogeneous Transversely Isotropic Medium with Irregular Free Surface

Three-Dimensional Wave-Field Simulation in Heterogeneous Tra...

引用

中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： haiqiang lan and zhongjie zhang state key laboratory of lithosphere evolution institute of geology and geophysics chinese academy of sciences beijing,100029,pr china

Modeling of seismic-wave propagation in anisotropic medium with irregular topography is beneficial to interpret seismic data acquired by active and passive source seismology conducted in areas of interest such as mountain ranges and *** major challenge in this context is the difficulty in tackling the irregular free-surface boundary condition in a Cartesian coordinate *** implement surface topography,we use the boundary-conforming grid and map a rectangular grid onto a curved *** use a stable and explicit second-order accurate finite-difference scheme to discretize the elastic wave equations(in a curvilinear coordinate system) in a 3D heterogeneous transversely isotropic *** free-surface boundary conditions are accurately applied by introducing a discretization that uses boundary-modified difference operators for the mixed derivatives in the governing equations. The accuracy of the proposed method is checked by comparing the numerical results obtained by the trial algorithm with the analytical solutions of the Lamb’s problem,for an isotropic medium and a transversely isotropic medium with a vertical symmetry axis, *** tests performed by different numerical experiments illustrate clearly the influence of an irregular(nonflat) free surface on seismic-wave propagation.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Comparative study of the free-surface boundary condition in two-dimensional finite-difference elastic wave field simulation

Comparative study of the free-surface boundary condition in ...

引用

中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： haiqiang lan and zhongjie zhang state key laboratory of Lithospheric evolution,institute of geology and geophysics,chinese academy of sciences,beijing 100029,People’s Republic of china

The finite-difference(FD) method is a powerful tool in seismic wave field modelling for understanding seismic wave propagation in the Earth’s interior and interpreting the real seismic *** accuracy of FD modelling partly depends on the implementation of the free-surface (***-free) *** the past 40 years,at least six kinds of free-surface boundary condition approximate schemes(such as one-sided,centred finite-difference,composed,new composed,implicit and boundary-modified approximations) have been developed in FD second-order elastodynamic *** we simulate seismic wave fields in homogeneous and lateral heterogeneous models using tliese free-surface boundary condition approximate schemes and evaluate their stability and applicability by comparing with corresponding analytical solutions,and then quantitatively evaluate the accuracies of different approximate schemes from the misfit of the amplitude and phase between the numerical and analytical *** results confirm that the composed scheme becomes unstable for the V/V ratio less than 0.57, and suggest that(1) the one-sided scheme is only accurate to first order and therefore introduces serious errors for the shorter wavelengths,other schemes are all of second-order precision;(2) the new composed,implicit and boundary-modified schemes are stable even when the V/V ratio is less than 0.2;(3) the implicit and boundary-modified schemes are able to deal with laterally varying(heterogeneous) free surface;(4) in the corresponding stability range,the one-sided scheme shows remarkable errors in both phase and amplitude compared to analytical solution(which means larger errors in travel-time and reflection strength),the other five approximate schemes show better performance in travel-time(phase) than strength(amplitude).

关键词： free-surface boundary condition finite-difference modelling stability accuracy

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Topography-dependent eikonal equation and its solver for calculating first-arrival traveltimes with an irregular surface

Topography-dependent eikonal equation and its solver for cal...

引用

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： haiqiang lan zhongjie zhang state key laboratory of Lithospheric evolution Institute of Geology and GeophysicsChinese Academy of Sciences

First-arrival traveltime is commonly used in problems that involve static correction,prestack migration,earthquake location,seismic tomography,*** classical eikonal equation discretized with regular rectilinear grids is effective for calculating the first-arrival traveltimes in a rectangular domain,but is less efficient for an Earth model that has an irregular surface. Here,we present a topography-dependent eikonal equation in 2-D that makes use of the wave equation in a curvilinear coordinate system,and is equivalent to a direct derivation of the classical eikonal equation together with a transformation from Cartesian to curvilinear *** topography-dependent eikonal equation is reduced to the classical version when the surface is *** topography-dependent equation(in the curvilinear coordinate system)displays the mathematical form of an anisotropic eikonal equation(even though the medium is isotropic in the Cartesian coordinate system).Then,we use a Lax-Friedrichs sweeping scheme,which has been developed as an iterative method for Hamilton-Jacobi equations,to approximate the viscosity solutions(first-arrival traveltimes)of the topographydependent eikonal equation formulated in the curvilinear coordinate *** numerical experiments performed with different models illustrate that the method is stable and accurate in calculating seismic traveltimes with an irregular(non-flat)surface.

关键词： Numerical solutions Computational seismology Theoretical seismology

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A High-Order Fast-Sweeping Scheme for Calculating First-Arrival Travel Times with an Irregular Surface

A High-Order Fast-Sweeping Scheme for Calculating First-Arri...

引用

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： haiqiang lan zhongjie zhang state key laboratory of Lithosphefic evolution institute of geology and geophysics chinese academy of sciences

Topography-dependent eikonal equation(TDEE)formulated in a curvilinear coordinate system has been recently established and is effective for calculating first-arrival travel times in an Earth model with an irregular *** previous work, the Lax-Friedrichs sweeping scheme used to approximate the TDEE viscosity solutions was only first-order *** present a high-order fast-sweeping scheme to solve the TDEE with the aim of achieving high-order accuracy in the travel-time calculation. The scheme takes advantage of high-order weighted essentially nonoscillatory (WENO)derivative approximations,monotone numerical Hamiltonians,and Gauss Seidel iterations with alternating-direction *** incorporates high-order approximations of the derivatives into the numerical representation of the Hamiltonian such that the resulting numerical scheme is formally high-order accurate and inherits fast convergence from the alternating sweeping *** numerical examples are presented to verify its efficiency,convergence,and high-order accuracy.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Reverse time migration from irregular surface by flattening surface topography

Reverse time migration from irregular surface by flattening ...

引用

中国科学院地质与地球物理研究所2014年度（第14届）学术年会

作者： haiqiang lan zhongjie zhang Jingyi Chen Youshan Liu state key laboratory of Lithospheric evolution Institute of Geology and GeophysicsChinese Academy of Sciences Department of Geosciences The University of Tulsa

prestack reverse time migration(RTM)is a powerful tool to provide high resolution structure images of crust and upper mantle in wide-angle seismic *** a standard migration algorithm assumes that data are recorded on a flat surface,RTM meets severe challenge on the issue of complicated topography where many seismic surveys are carried *** till now,there are two popular techniques for handling elevation changes,i.e.,elevation-static correction(or time shift)and wave equation *** studies demonstrate that the elevation-static correction is inaccurate for non-vertically traveling energy and subsequently may migrate reflectors to incorrect *** equation datuming is more accurate but more sophisticated and too computationally demanding for routine ***,we present an alternative scheme to deal with topography in prestack RTM that can migrate seismic data acquired in areas with irregular topography to the reflector positions directly without datuming or elevation static *** this scheme,surface topography is flattened by a transformation of coordinates from Cartesian to *** a transformation is equivalent to map a rectangular grid onto a curved one,and is implemented by the introduction of boundary conforming *** we use an explicit finite-difference scheme with second-order accuracy to discretize the elastic wave equations and perform the RTM in the curvilinear coordinate ***,a flux-corrected transport(FCT)algorithm,adapted from hydrodynamics,is incorporated in the RTM implementation,which can not only overcome problems of numerical dispersion that arise in finite difference algorithms,but also offer the opportunity to use a coarse grid to obtain the same accuracy as conventional finite difference methods on a dense *** FCTRTM method presented here has no limitations on surface irregularity,complexity of the subsurface structure,or velocity *** numerical examples demonstrate

关键词： Reverse time migration Irregular surface Boundary conforming grid Finite difference Flux corrected transport

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

全选清除本页清除全部题录导出标记到“检索档案”

共1页 << < 1 > >>

回到顶部

执行限定条件

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：