Potential‐field continuation between irregular surfaces—Remarks on the method by Xia et al.

Geophysics ◽  
1998 ◽  
Vol 63 (1) ◽  
pp. 104-108 ◽  
Author(s):  
Bruno Meurers ◽  
Roland Pail
Keyword(s):  
Magnetic Fields ◽  
Potential Field ◽  
Field Data ◽  
Potential Field Data ◽  
Irregular Surfaces ◽  
Equivalent Source ◽  
Wavenumber Domain ◽  
Excellent Method ◽  
Reducing Potential ◽  
Field Continuation

Xia et al. (1993) offer an excellent method for potential‐field continuation between irregular surfaces by applying the equivalent source technique. This method has proven to be the fastest and most stable procedure for solving the problem of reducing potential‐field data to a constant datum (e.g., Pail, 1995) as long as no sources exist between observation surface and the equivalent stratum. The authors suggest using special equations for the continuation of magnetic fields. Theoretically this is correct, but neither necessary nor well suited, because of the characteristics of the operator for magnetic fields applied in the wavenumber domain.

scholarly journals Potential field continuation: a comparative analysis of three different types of software

1998 ◽  
Vol 41 (3) ◽  
Author(s):  
M. Ciminale ◽  
M. Loddo
Keyword(s):  
Comparative Analysis ◽  
Potential Field ◽  
Field Data ◽  
Sparse Matrix ◽  
Linear Equations ◽  
System Of Linear Equations ◽  
Potential Field Data ◽  
Equivalent Source ◽  
Different Types ◽  
Field Continuation

DARING.F is a new Fortran77 computer program which has been developed to perform the continuation of potential field data between arbitrary surfaces. The implemented equivalent source algorithm inverts a system of linear equations by using sparse matrix. A comparative analysis between the performance of this software and that of two computer programs (named UPWARD.F and UPNEW.F) previously written by the same authors is carried out. As a result of this analysis, some useful and important suggestions on how to obtain the highest level of accuracy of transformed data in various situations (i.e. large matrices of data, close surfaces) are given.

An adaptive iterative method for downward continuation of potential-field data from a horizontal plane

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. J43-J52 ◽  
Author(s):  
Xiaoniu Zeng ◽  
Xihai Li ◽  
Juan Su ◽  
Daizhi Liu ◽  
Hongxing Zou
Keyword(s):  
Iterative Method ◽  
Tikhonov Regularization ◽  
Potential Field ◽  
Horizontal Plane ◽  
Field Data ◽  
Regularization Parameter ◽  
Downward Continuation ◽  
Tikhonov Regularization Method ◽  
Potential Field Data ◽  
Wavenumber Domain

We have developed an improved adaptive iterative method based on the nonstationary iterative Tikhonov regularization method for performing a downward continuation of the potential-field data from a horizontal plane. Our method uses the Tikhonov regularization result as initial value and has an incremental geometric choice of the regularization parameter. We compared our method with previous methods (Tikhonov regularization, Landweber iteration, and integral-iteration method). The downward-continuation performance of these methods in spatial and wavenumber domains were compared with the aspects of their iterative schemes, filter functions, and downward-continuation operators. Applications to synthetic gravity and real aeromagnetic data showed that our iterative method yields a better downward continuation of the data than other methods. Our method shows fast computation times and a stable convergence. In addition, the [Formula: see text]-curve criterion for choosing the regularization parameter is expressed here in the wavenumber domain and used to speed up computations and to adapt the wavenumber-domain iterative method.

Correction of topographic distortions in potential‐field data: A fast and accurate approach

Geophysics ◽  
1993 ◽  
Vol 58 (4) ◽  
pp. 515-523 ◽  
Author(s):  
Jianghai Xia ◽  
Donald R. Sprowl ◽  
Dana Adkins‐Heljeson
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Gravity Data ◽  
Source Distribution ◽  
Potential Field Data ◽  
Equivalent Source ◽  
Horizontal Shift ◽  
Maximum Elevation ◽  
Rms Error ◽  
Forward Calculation

The equivalent source concept is used in the wavenumber domain to correct distortions in potential‐field data caused by topographic relief. The equivalent source distribution on a horizontal surface is determined iteratively through forward calculation of the anomaly on the topographic surface. Convergence of the solution is stable and rapid. The accuracy of the Fourier‐based approach is demonstrated by two synthetic examples. For the gravity example, the rms error between the corrected anomaly and the desired anomaly is 0.01 mGal, which is less than 0.5 percent of the maximum synthetic anomaly. For the magnetic example, the rms error is 0.7 nT, which is less than 1 percent of the maximum synthetic anomaly. The efficiency of the approach is shown by application to the gravity and aeromagnetic grids for Kansas. For gravity data, with a maximum elevation change of 500 m reducing to a horizontal datum results in a maximum correction in gravity anomaly amplitude of up to 2.6 mGal. For aeromagnetic data, the method results in a maximum horizontal shift of anomalies of 470 m with a maximum correction in aeromagnetic anomaly amplitudes up to 270 nT.

Werner deconvolution of profile potential field data

Geophysics ◽  
1983 ◽  
Vol 48 (2) ◽  
pp. 234-237 ◽  
Author(s):  
Kevin T. Kilty
Keyword(s):  
Magnetic Fields ◽  
Convenient Method ◽  
Potential Field ◽  
Digital Computer ◽  
Field Data ◽  
Potential Field Data ◽  
Automatic Interpretation

Werner (1953), in analyzing the magnetic fields of dipping, magnetized dikes, proposed a method of separating the field contributed by a particular dike under study from the interference of neighboring dikes. In addition to being a means of effecting a regional‐residual separation, Werner’s method of analysis also had the advantage of being easily programmed on a digital computer. This made it a convenient method for analyzing the large amounts of data from reconnaissance aeromagnetic surveys, and it became the basis of the automatic interpretation schemes of Hartmann et al (1971) and Jain (1976). The purpose of this note is to discuss some limitations of the Werner method of deconvolution and also to point out some possible extensions of the method to the general interpretation of potential field data.

Inversion of potential‐field data by iterative forward modeling in the wavenumber domain

Geophysics ◽  
1992 ◽  
Vol 57 (1) ◽  
pp. 126-130 ◽  
Author(s):  
Jianghai Xia ◽  
Donald R. Sprowl
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Single Layer ◽  
Large Data ◽  
Uniform Density ◽  
Data Sets ◽  
Potential Field Data ◽  
Wavenumber Domain ◽  
Solution Convergence ◽  
Forward Calculation

Direct inversion of potential‐field data is hindered by the nonuniqueness of the general solution. Convergence to a single solution can only be obtained when external constraints are placed on the subsurface geometry. Two such constrained geometries are dealt with here: a single, nonplanar interface between two layers, each of uniform density or magnetization, and the distribution of the density or magnetization contrast within a single layer. Both of these simple geometries have geologic application. Inversion is accomplished by iterative improvement in an initial subsurface model in the wavenumber domain. The inversion process is stable and is efficient for usage on large data sets. Forward calculation of anomalies is by Parker’s (1973) algorithm (Blakely, 1981).

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