Quantitative interpretation of self‐potential anomalies due to two‐dimensional sheet‐like bodies

Geophysics ◽  
1983 ◽  
Vol 48 (12) ◽  
pp. 1659-1664 ◽  
Author(s):  
D. Atchuta Rao ◽  
H. V. Ram Babu
Keyword(s):  
Finite Depth ◽  
Horizontal Gradient ◽  
Quantitative Interpretation ◽  
Two Dimensional ◽  
Analytical Relations ◽  
Depth Extent ◽  
Self Potential ◽  
Maximum Minimum ◽  
Inclined Sheet

A method for quantitative interpretation of self‐potential anomalies due to a two‐dimensional sheet of finite depth extent is proposed. In the case of an inclined sheet, positions and amplitudes of the maximum, minimum, and zero‐anomaly points are picked and then the origin is located on the horizontal gradient curve using the template of Rao et al (1965). The parameters of the sheet may be evaluated either geometrically or by using some analytical relations among the characteristic distances. When the sheet is vertical, the parameters may be evaluated using the positions of half and three‐quarter peak amplitudes.

On: “A rapid graphical method for the interpretation of the self‐potential anomaly over a two‐dimensional inclined sheet of finite depth extent” by H. V. Ram Babu and D. Atchuta Rao (GEOPHYSICS, 53, 1126–1128, August 1988).

Geophysics ◽  
1989 ◽  
Vol 54 (9) ◽  
pp. 1215-1216 ◽  
Author(s):  
L. Eskola ◽  
H. Hongisto
Keyword(s):  
Graphical Method ◽  
Theoretical Models ◽  
Finite Depth ◽  
The Self ◽  
Inversion Method ◽  
Two Dimensional ◽  
Depth Extent ◽  
Self Potential ◽  
Graphical Algorithm ◽  
Inclined Sheet

Ram Babu and Atchuta Rao (1988a, b) presented a graphical algorithm for the interpretation of a self‐potential anomaly over a sheet. Ram Babu and Atchuta Rao (1988b) also presented an inversion method based on iterative optimization for the self‐potential anomalies caused by spherical, cylindrical, and sheetlike bodies. The theoretical models on which the algorithms are based are very simple: for the sphere, an electrostatic dipole; for the cylinder, a line dipole; and for the sheet two line poles, the negative one along the upper edge of the sheet and the positive one along its lower edge.

A rapid graphical method for the interpretation of the self‐potential anomaly over a two‐dimensional inclined sheet of finite depth extent

Geophysics ◽  
1988 ◽  
Vol 53 (8) ◽  
pp. 1126-1128 ◽  
Author(s):  
H. V. Ram Babu ◽  
D. Atchuta Rao
Keyword(s):  
Graphical Method ◽  
Amplitude Ratio ◽  
Finite Depth ◽  
Ore Deposits ◽  
Characteristic Features ◽  
Zero Potential ◽  
Depth Extent ◽  
Self Potential ◽  
Sp Anomaly ◽  
Inclined Sheet

The inclined sheet is an important model for interpreting self‐potential (SP) anomalies over elongated ore deposits. Many techniques (Roy and Chowdhurry, 1959; Meiser, 1962; Paul, 1965; Atchuta Rao et al., 1982; Atchuta Rao and Ram Babu, 1983; Murty and Haricharan, 1985) have been proposed for interpreting SP anomalies over this model. We propose a simple graphical procedure for locating the upper and lower edges of an inclined sheet of infinite strike extent from its SP anomaly V(x) using a few characteristics points including [Formula: see text] [Formula: see text], and [Formula: see text] The amplitude ratio [Formula: see text], is shown to vary with θ, the dip of the sheet, making it possible to estimate θ. The two edges of the sheet are equidistant from the abscissa of [Formula: see text] the zero potential point. The sheet, when extrapolated onto the line of observation, meets the x‐axis at a point where [Formula: see text] From these characteristic features of V(x), the sheet can be located easily using the simple geometrical construction presented below.

scholarly journals A study of the self-potential field produced by a polarised inclined sheet in an electrically homogeneous and transversely anisotropic ground

2001 ◽  
Vol 34 (4) ◽  
pp. 1343
Author(s):  
Γ. Α. ΣΚΙΑΝΗΣ ◽  
Τ. Δ. ΠΑΠΑΔΟΠΟΥΛΟΣ ◽  
Δ. Α. ΒΑΪΟΠΟΥΛΟΣ
Keyword(s):  
Potential Field ◽  
The Self ◽  
Quantitative Interpretation ◽  
Potential Field Data ◽  
Synthetic Model ◽  
Transversely Anisotropic ◽  
Self Potential ◽  
Sp Anomaly ◽  
Interpretation Method ◽  
Inclined Sheet

In the present paper, the self-potential (sp) field is studied, which is produced by an inclined sheet (thin dyke) in an electrically homogeneous and transversely anisotropic ground. At first, the mathematical expression for the sp anomaly is deduced, by integration of the formula for the self-potential field produced by a point pole in a transversely anisotropic medium (Skianis & Herntmdez 1999). Then, the behavior of the sp curve is studied, for various angles of schistosity. The whole anomaly may be displaced along the horizontal axis and deformed in terms of amplitude and shape. Particular emphasis is given on the enhancement and suppression of the positive center of the self-potential, which depends on the values and orientations of the schistosity angle of the ground and the dip angle of the inclined sheet. These deformations of the sp anomaly, may introduce significant errors in the calculation of the parameters of the polarized body, if ground anisotropy is not taken into account. Therefore, new methodologies have to be developed, for a reliable quantitative interpretation of self-potential field data. In this paper, a direct interpretation method is proposed, which consists of two steps: In step one, the parameters of the inclined sheet are determined, assuming a homogeneous and isotropic ground. In this stage, any quantitative interpretation method, referred in the international bibliography, may be used. Secondly, the true parameters of the dyke are estimated, by a set of transformations in which the anisotropy coefficient and the schistosity angle are introduced. In order to apply this method, a priori information about ground anisotropy should be available, by dc geoelectrical and geological investigations. The efficiency of the method was tested on a synthetic model. In the first stage, the quantitative interpretation method of Murty & Haricharan 1985 was employed. In the second stage, the calculated parameters of the first step, served as input values of the transformations, and the real parameters of the inclined sheet were estimated. There was a good agreement between the parameter values of the synthetic model and the ones found by the proposed method. The results and conclusions of this paper, may be useful in detecting sulfide mineralization deposits or graphite.

Comparison principles for free-surface flows with gravity

1991 ◽  
Vol 230 ◽  
pp. 231-243 ◽  
Author(s):  
Walter Craig ◽  
Peter Sternberg
Keyword(s):  
Solitary Waves ◽  
Finite Depth ◽  
Free Surface Flows ◽  
Immiscible Fluids ◽  
Steady Flows ◽  
Two Dimensional ◽  
Surface Flows ◽  
Ship Hulls ◽  
Geometrical Information ◽  
Supercritical Flows

This article considers certain two-dimensional, irrotational, steady flows in fluid regions of finite depth and infinite horizontal extent. Geometrical information about these flows and their singularities is obtained, using a variant of a classical comparison principle. The results are applied to three types of problems: (i) supercritical solitary waves carrying planing surfaces or surfboards, (ii) supercritical flows past ship hulls and (iii) supercritical interfacial solitary waves in systems consisting of two immiscible fluids.

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