Application of 2‐D hilbert transform in potential field data (gravity and magnetic)

1986 ◽  
Author(s):  
Abdurruzag M. Ali Ushah ◽  
Wooil Moon
Keyword(s):  
Hilbert Transform ◽  
Potential Field ◽  
Field Data ◽  
Potential Field Data ◽  
Gravity And Magnetic

Direct Analytic Signal Interpretation of Potential Field Data Using 2-D Hilbert Transform

2011 ◽  
Vol 54 (4) ◽  
pp. 551-559 ◽  
Author(s):  
Yao LUO ◽  
Ming WANG ◽  
Feng LUO ◽  
Song TIAN
Keyword(s):  
Hilbert Transform ◽  
Potential Field ◽  
Field Data ◽  
Analytic Signal ◽  
Potential Field Data

Toward a three‐dimensional automatic interpretation of potential field data via generalized Hilbert transforms: Fundamental relations

Geophysics ◽  
1984 ◽  
Vol 49 (6) ◽  
pp. 780-786 ◽  
Author(s):  
Misac N. Nabighian
Keyword(s):  
Hilbert Transform ◽  
Potential Field ◽  
Field Data ◽  
Three Dimensional ◽  
Analytic Signal ◽  
Three Dimensions ◽  
Hilbert Transforms ◽  
Potential Field Data ◽  
Automatic Interpretation ◽  
The Hilbert Transform

The paper extends to three dimensions (3-D) the two‐dimensional (2-D) Hilbert transform relations between potential field components. For the 3-D case, it is shown that the Hilbert transform is composed of two parts, with one part acting on the X component and one part on the Y component. As for the previously developed 2-D case, it is shown that in 3-D the vertical and horizontal derivatives are the Hilbert transforms of each other. The 2-D Cauchy‐Riemann relations between a potential function and its Hilbert transform are generalized for the 3-D case. Finally, the previously developed concept of analytic signal in 2-D can be extended to 3-D as a first step toward the development of an automatic interpretation technique for potential field data.

3-D inversion of gravity and magnetic data with depth resolution

Geophysics ◽  
1999 ◽  
Vol 64 (2) ◽  
pp. 452-460 ◽  
Author(s):  
Maurizio Fedi ◽  
Antonio Rapolla
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Vertical Direction ◽  
Depth Resolution ◽  
Magnetic Data ◽  
Data Set ◽  
Potential Field Data ◽  
Magnetic Methods ◽  
Level Data ◽  
Gravity And Magnetic

Magnetization and density models with depth resolution are obtained by solving an inverse problem based on a 3-D set of potential field data. Such a data set is built from information on vertical and horizontal variations of the magnetic or gravity field. The a priori information consists of delimiting a source region and subdividing it in a set of blocks. In this case, the information related to a set of field data along the vertical direction is not generally redundant and is decisive in giving a depth resolution to the gravity and magnetic methods. Because of this depth resolution, which derives solely from the potential field data, an unconstrained and joint inversion of a multiobservation‐level data set is shown to provide surprising results for error‐free synthetic data. On the contrary, a single‐observation level data inversion produces an incorrect and too shallow model. Hence, a good depth resolution is likely to occur for the gravity and magnetic methods when based on the information along the vertical direction. This is also evidenced by an analysis of the kernel function versus the field altitude level and by a singular value analysis of the inversion operators for both the single and multilevel cases. Errors connected to numerical upward continuation do not affect the quality of the solution, provided that the data set extent is larger than that of the anomaly field. Application of the method to a 3-D magnetic data set relative to Vesuvius indicates that the method may significantly improve interpretation of potential fields.

scholarly journals GRAVITY AND MAGNETIC SIGNATURE OF THE TRANSBRASILIANO LINEAMENT IN THE EAST-CENTRAL PORTION OF THE PARNAÍBA BASIN, NORTHEASTERN BRAZIL

2017 ◽  
Vol 35 (1) ◽  
Author(s):  
Thuany Patrícia Costa de Lima ◽  
Emanuel Ferraz Jardim de Sá ◽  
Fernando Antonio Pessoa Lira Lins ◽  
Alex Francisco Antunes ◽  
José Antônio De Morais Moreira
Keyword(s):  
Shear Zone ◽  
Potential Field ◽  
Field Data ◽  
Magnetic Anomalies ◽  
Northeastern Brazil ◽  
Central Portion ◽  
East Central ◽  
Potential Field Data ◽  
Gravity And Magnetic ◽  
Parnaíba Basin

ABSTRACT. The Transbrasiliano Lineament (TBL) corresponds to a NE-trending mega shear zone of late Neoproterozoic age with an extensive segment underneath the Parnaíba Basin (northeastern Brazil); the Eopaleozoic to Mesozoic section of the basin evidence the lineament’s brittle reactivation events. This paper presents a case study of TBL in the east-central portion of Parnaíba Basin with a special concern to the characterization of pre-Silurian grabens in the basement. The approach involves the interpretation of potential field data and seismic reflection line based on a plastic dextral transcurrent mega shear zone model. The gravity anomaly belts display a curvilinear shape joining the NE trend of the TBL, in accordance to a dextral S-C pair. A retrogressive stage with narrower ductile-brittle dextral structures controlled the opening of pull-apart grabens. Magnetic anomalies seem to be related to these late structures. The integration of the map analyses, seismic interpretation and 2D gravity modeling led to the conclusion that the sources causing the gravity and magnetic anomalies in the basin result from mass variations related to anisotropies of the crystalline basement and crustal heterogeneities, such as granite plutons, metasedimentary belts, shear zones and pre-Silurian grabens. The delimitation of grabens underneath the Parnaíba Basin suffers severe restrictions when solely interpreted based on potential field data. Keywords: gravity forward modeling, Transbrasiliano Lineament, magnetic anomaly. RESUMO. O Lineamento Transbrasiliano (LTB) corresponde a uma megazona de cisalhamento com direção NE, de idade Neoproterozoica, com um extenso segmento subjacente à Bacia do Parnaíba; a seção Eopaleozoica a Mesozoica da bacia evidencia seus eventos de reativação. Este trabalho aborda o LTB na porção centro-leste da Bacia do Parnaíba, com especial atenção à caracterização de grabens pré-Silurianos do embasamento. A abordagem envolve interpretações de dados de métodos potenciais e de linha sísmica de reflexão baseadas em um modelo de megazona de cisalhamento plástica transcorrente dextral. As faixas de anomalias gravimétricas exibem uma geometria curvilínea, aproximando-se em direção ao trend NE do Lineamento Transbrasiliano, em consonância a um par S-C dextral. Um estágio retrogressivo com estruturas dúcteis-frágeis mais estreitas controlaram a abertura de grabens pull-apart. As anomalias magnéticas imageam essas estruturas tardias. A integração da análise de mapas de anomalia, interpretação sísmica e modelagem gravimétrica 2D permite concluir que as fontes causadoras das anomalias gravimétricas e magnéticas na bacia resultam de variações de massa relacionadas a heterogeneidades crustais e às anisotropias do embasamento cristalino, tais como plútons graníticos, faixas de metassedimentos e zonas de cisalhamento, com contribuição subordinada dos grabens pré-Silurianos. A delimitação desses grabens subjacentes à Bacia do Parnaíba sofre severas restrições quando interpretadas unicamente com base nos dados de métodos potenciais. Palavras-chave: modelagem gravimétrica direta, Lineamento Transbrasiliano, anomalia magnética.

Preliminary Study on Fusion Scheme of Multi-dimensional and Multi-scale Potential Field Data

2020 ◽  
Author(s):  
Xiaolin Ji ◽  
Wanyin Wang ◽  
Fuxiang Liu ◽  
Min Yang ◽  
Shengqing Xiong ◽  
...  
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Gravity Data ◽  
Magnetic Data ◽  
Potential Field Data ◽  
Multi Scale ◽  
Gravity And Magnetic ◽  
Different Dimensions ◽  
Fusion Scheme ◽  
Gravity And Magnetic Data

<p>Gravity and magnetic surveys are widely used in geology exploration because of its advantages, such as efficient and economy, green and environment-friendly, widely coverage and strong horizontal resolution. In order to well study in the geology exploration, it is required to comprehensively combine the different scales (different scales data) and different dimensions (satellite data, aeronautical data, ground data, ocean data, well data, etc.) of gravity and magnetic data that were observed in different periods, however, the comprehensive application of the multi-dimensional and multi-scale gravity and magnetic data still stays in the initial stage. In this paper, we do research on the key point of the fusion of potential field data (gravity and magnetic data): the way to fuse the different scales and different dimensions of potential field data into a benchmark and the same surface. Based on this research, we propose a scheme to fuse the multi-dimensional and multi-scale gravity and magnetic data. The synthetic models show that this fusion scheme is able to fuse the multi-dimensional and multi-scale gravity and magnetic data with great fusion results and small errors, in addition, the most important is that the fusion data conform to the characteristics of the potential field data and can meet the needs of data processing in the following steps. One of case studies in China has been accomplished to fuse aeronautical and ground gravity data that are different scales by using this fusion scheme. The fusion scheme we proposed in this study can be used in the fusion of the multi-dimensional (aeronautical, ground and ocean) and multi-scale gravity and magnetic data, which is good for interpretation and popularization.</p>

An improved terracing algorithm for potential-field data

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. G109-G113
Author(s):  
G. R. J. Cooper
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Shape Index ◽  
Magnetic Data ◽  
Threshold Parameter ◽  
Potential Field Data ◽  
Gravity And Magnetic ◽  
Realistic Result ◽  
Geologic Map ◽  
Gravity And Magnetic Data

Although the boundaries between geologic units with different physical properties are usually quite distinct, the potential-field anomalies associated with them are relatively smooth, particularly for deeper bodies. The terracing filter has been introduced to sharpen anomaly edges and to produce regions of constant amplitude between them, mimicking geologic units on a geologic map. The boundaries between the pseudogeologic units are defined by the zero contour of the Laplacian function. Unfortunately, this can result in the domains of terraced anomalies extending far from the original location of the causative body, producing an image that poorly represents the geology. I have determined that the use of the mathematical shape index of the anomalies, rather than their Laplacian, produces a much more geologically realistic result. The effect can be controlled as desired using a threshold parameter. I evaluate the benefits of the method on gravity and magnetic data from southern Africa.

Homomorphic deconvolution of potential field data in one and two dimensions

1983 ◽  
Vol 20 (8) ◽  
pp. 1260-1281 ◽  
Author(s):  
Oliver G. Jensen ◽  
Pandelis P. Papazis
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Seismic Analysis ◽  
Geological Structure ◽  
Two Dimensions ◽  
Magnetic Data ◽  
Wave Form ◽  
Potential Field Data ◽  
Gravity And Magnetic ◽  
Geophysical Measurement

A signal in a non-dispersive reverberent environment can generally be represented as the sum of overlapping delayed replicas of a basic wave form. This convolutional data model has long been employed in seismic analysis and can be usefully extended for the analysis of gravity and magnetic potential field data along with a host of other geophysical measurements. The deconvolution of gravity or magnetic data requires the separation of two basic components of the potential fields: one component represents a basic irreducible wave form or signature of the potential field, and the other represents the position and scale or distribution of this wave form throughout the area of measurement. The basic wave form often derives from the process of geophysical measurement (e.g., the upward-continuation operator) but may also be due to an inherent, common character of the geological structure of an area.Oppenheim obtained the formalism for a generalized theory of superposition that allows for a description of the deconvolution process in terms of non-linear homomorphic transformations. These methods have already found application in the geophysical analysis of seismic data; it now provides a useful tool for the deconvolution of geophysical potential field data.

Algorithm for error adjustment of potential field data along a survey network

Geophysics ◽  
1984 ◽  
Vol 49 (4) ◽  
pp. 467-469 ◽  
Author(s):  
P. K. Mittal
Keyword(s):  
Potential Field ◽  
Statistical Estimation ◽  
Field Data ◽  
Aeromagnetic Data ◽  
Rectangular Grid ◽  
Contour Map ◽  
Potential Field Data ◽  
Error Adjustment ◽  
Gravity And Magnetic ◽  
Instrumental Drift

Gravity and magnetic surveys on sea, land, or air invariably exhibit discrepancies at intersections of survey lines. These “misties” have to be removed before any meaningful contour map can be prepared. The misties are caused by many errors. Errors in location fixing, instrumental drift, diurnal magnetic variations, inaccuracies in Eötvös corrections because of errors in heading, and speed of ship or aircraft play a major role. Foster (1970) proposed a method for statistical estimation of the misties at line intersections with special reference to aeromagnetic data. The method can be extended to all gravity and magnetic surveys on land, sea, or air. However, it requires an approximately rectangular grid of survey lines. In case the network is irregular and there are lines in various directions crossing each other, Foster’s method would not be applicable.

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