二维波动方程约束反演的大范围收敛广义脉冲谱方法   总被引：5，自引：3，他引：5       下载免费PDF全文

冯国峰  韩波  刘家琦 《地球物理学报》2003,46(2):265-270

针对二维波动方程，将大范围收敛的同伦 方法引入算子参数识别反演的过程，并结合求解不适定问题的Tikhonov正则化方法，设计了二维波动方程反演的大范围收敛广义脉冲谱方法，并利用测井资料进行了约束反演. 大量 的数值模拟结果以及抗噪实验均表明了方法的有效性.  相似文献   

地球物理联合反演研究综述   总被引：12，自引：7，他引：12  

敬荣中  鲍光淑  陈绍裘 《地球物理学进展》2003,18(3):535-540

地球物理联合反演由于使反演问题的非唯一性得到有效限制而越来越受到人们的重视。本文概述了联合反演的发展现状及实现的方法，并讨论了其发展趋势及其局限性，指出地球物理联合反演是地球物理数据分析的理想工具，而非线性联合反演方法则是地球物理联合反演发展的方向。  相似文献   

井间电阻率层析成象的某些进展   总被引：7，自引：2，他引：7  

董清华 《地球物理学进展》1997,12(3):77-89

用有限元法作电阻率层析成象的核心问题是Ｊａｃｏｂｉ矩阵的求取和反演成象算法的研究。本文主要论述了这两方面的最新进展，即求取Ｊａｃｏｂｉ矩阵的格林函数法，用于反演成象计算的平滑度约束反演。文中通过理论模型的成象计算，比较了两种反演算法的成象效果。  相似文献   

翁牛特东部地区基底折射资料的二维反演     

李平 《东北地震研究》1997,13(1):1-8

本文介绍了采用相遇观测系统中全部走时分支曲线双向同时二维反演拟合法。对翁牛特东部地区的三条剖面基底折射资料二维反演，文中展示了各条剖面的理论走时对比图，射线追踪图，二维速度结构分布图，一维速度柱状图以及理论地震图。  相似文献   

一类测井方程的解析反演     

阮晓青  赵冰 《地球物理学进展》1997,12(2):97-104

本文采用解析方法，给出了感应测井中当介质可表示成ｖ（ｘ，ｙ，ｚ）＝Σ↓ｋ，ｆｖｋ，ｊ＾ｘ＾ｋｙ＾ｊ时的反演公式，并讨论了径向浸入深度γ０的反演。  相似文献   

遗传算法在上地幔速度结构研究中的应用   总被引：1，自引：0，他引：1  

吴建平  明跃红 《地震地磁观测与研究》1997,18(2):11-25

遗传算法是近年来发展较快的一种求解非线性优化问题的有效方法。本文通过对遗传算法基本原理的介绍，对该方法的特点进行了分析。我们采用ＷＫＢＪ理论地震图作正演，遗传算法作反演，对用体波波形反演上地幔速度结构的方法进行了研究。在ＷＫＢＪ理论地震图的计算中，通过计算主要射线的平均吸收特征时间，考虑了衰减随距离的变化，通过对不同震源引入不同的虚拟界面，同时对多个地震的波形记录进行反演。探讨了观测误差对反演结果的影响。对理论记录的反演表明，用遗传算法研究上地幔速度结构具有较好的效果。  相似文献   

岩矿石电磁频散规律及其在电磁波法勘探中的影响和校正     

康国军  佟文琪 《物探与化探》1997,21(1):62-66

本文以大量的实测资料为依据,总结了岩矿石电磁频散的规律性。结合电磁波勘探方法中的实际问题,讨论了频散对相位常数α和吸收系数β所产生的影响及误差。提出了在实际工作中对频散进行校正的必要性,并且给出了校正公式。  相似文献   

Centroid moment tensor inversion of low-frequency seismic spectra using Green's functions for aspherical earth models     

Tatsuhiko Hara 《Geophysical Journal International》1997,130(1):251-256

We present a new method for centroid moment tensor (CMT) inversion, in which we employ the Green's function computed for aspherical earth models using the Direct Solution Method. We apply this method to CMT inversion of low-frequency seismic spectra for the 1994 Bolivia and 1996 Flores Sea deep earthquakes. The estimated centroid locations agree well with those obtained by multiple-shock analyses using body-wave data. This shows that it is possible to obtain reliable CMT solutions by analyses of low-frequency seismic spectra using accurate Green's functions computed for present 3-D earth models.  相似文献   

Recovering magnetic susceptibility from electromagnetic data over a one-dimensional earth   总被引：1，自引：0，他引：1  

Zhiyi Zhang  Douglas W. Oldenburg 《Geophysical Journal International》1997,130(2):422-434

While the inversion of electromagnetic data to recover electrical conductivity has received much attention, the inversion of those data to recover magnetic susceptibility has not been fully studied. In this paper we invert frequency-domain electromagnetic (EM) data from a horizontal coplanar system to recover a 1-D distribution of magnetic susceptibility under the assumption that the electrical conductivity is known. The inversion is carried out by dividing the earth into layers of constant susceptibility and minimizing an objective function of the susceptibility subject to fitting the data. An adjoint Green's function solution is used in the calculation of sensitivities, and it is apparent that the sensitivity problem is driven by three sources. One of the sources is the scaled electric field in the layer of interest, and the other two, related to effective magnetic charges, are located at the upper and lower boundaries of the layer. These charges give rise to a frequency-independent term in the sensitivities. Because different frequencies penetrate to different depths in the earth, the EM data contain inherent information about the depth distribution of susceptibility. This contrasts with static field measurements, which can be reproduced by a surface layer of magnetization. We illustrate the effectiveness of the inversion algorithm on synthetic and field data and show also the importance of knowing the background conductivity. In practical circumstances, where there is no a priori information about conductivity distribution, a simultaneous inversion of EM data to recover both electrical conductivity and susceptibility will be required.  相似文献   

Time-domain electromagnetic migration in the solution of inverse problems   总被引：5，自引：0，他引：5  

Michael S. Zhdanov  Oleg Portniaguine 《Geophysical Journal International》1997,131(2):293-309

Time-domain electromagnetic (TDEM) migration is based on downward extrapolation of the observed field in reverse time. In fact, the migrated EM field is the solution of the boundary-value problem for the adjoint Maxwell's equations. The important question is how this imaging technique can be related to the solution of the geoelectrical inverse problem. In this paper we introduce a new formulation of the inverse problem, based on the minimization of the residual-field energy flow through the surface or profile of observations. We demonstrate that TDEM migration can be interpreted as the first step in the solution of this specially formulated TDEM inverse problem. However, in many practical situations this first step produces a very efficient approximation to the geoelectrical model, which makes electromagnetic migration so attractive for practical applications. We demonstrate the effectiveness of this approach in inverting synthetic and practical TDEM data.  相似文献