Interpretation of self-potential anomalies by Enhanced Local Wave number technique

Srivastava, Shalivahan; Agarwal, B. N. P.

doi:10.1016/j.jappgeo.2008.11.011

Cited by 42 publications

(34 citation statements)

References 37 publications

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“…These data sets do not require residual-regional separation as they are the residual anomalies. That is why they have been inverted and interpreted without a regional correction in numerous published papers (e.g., Bigalke et al 2004;Dmitriev 2012;Mehanee 2014a;Revil et al 2001;Srivastava and Agarwal 2009;Stoll et al 1995). Regional anomalies are due to what are generally called telluric currents, and these may amount to 100 mV per kilometer or more (Meiser 1962;Yüngül 1950).…”

Section: Field Data Inversionmentioning

confidence: 99%

“…Revil et al (2001) applied a 2D tomography technique to this profile and interpreted the aforementioned SP anomalies as dipolar sources extending from 100 to 200 m deep. Srivastava and Agarwal (2009) inverted each of these two anomalies using the ELW number technique and obtained a depth of 135.5 and 80 m for Anomaly I and Anomaly II, respectively. On the basis of the resulting inverse parameters, they interpreted these anomalies as quasi-horizontal cylinders or quasi-sheet-like structures, which suggests that the abovementioned depths are in fact measured to the center of the anomalous bodies (Abdelrahman et al 1998).…”

Section: Ktb-borehole Anomaly Germanymentioning

confidence: 99%

“…The measured SP signatures generated by these graphite sheets (Bigalke et al 2004;Lehmann et al 1998;Srivastava and Agarwal 2009;Stoll et al 1995) can be inverted to extract information of some geologic significance such as depths, extensions in depth, and inclinations of the sheets. Here, this paper is exclusively devoted to the purpose of interpreting the SP data measured (observed) over the shear zones whose fault planes are coated by graphite films.…”

Section: Introductionmentioning

confidence: 99%

“…Here, this paper is exclusively devoted to the purpose of interpreting the SP data measured (observed) over the shear zones whose fault planes are coated by graphite films. For the diverse applications of the SP methods, the reader is referred to, for example, Essa et al (2008), Srivastava andAgarwal (2009), Soueid Ahmeda et al (2013), and Mehanee (2014a) and the references therein.…”

Section: Introductionmentioning

confidence: 99%

“…Radhakrishna Murthy et al (2005) applied the developed method to sheet-like mineralization data from the Surda area of the Rakha mines in India and the results obtained were found to be in good agreement with those reported in the literature. Srivastava and Agarwal (2009) introduced a method based on the concept of enhanced local wave (ELW) number for the interpretation of SP anomalies over 2D and three-dimensional (3D) sources including sheet structures. It appears, however, that the method was applied to recover only one parameter (depth of the structure).…”

Section: Introductionmentioning

confidence: 99%

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Tracing of paleo-shear zones by self-potential data inversion: case studies from the KTB, Rittsteig, and Grossensees graphite-bearing fault planes

Mehanee

2015

Earth Planets Space

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This paper describes a new method for tracing paleo-shear zones of the continental crust by self-potential (SP) data inversion. The method falls within the deterministic inversion framework, and it is exclusively applicable for the interpretation of the SP anomalies measured along a profile over sheet-type structures such as conductive thin films of interconnected graphite precipitations formed on shear planes. The inverse method fits a residual SP anomaly by a single thin sheet and recovers the characteristic parameters (depth to the top h, extension in depth a, amplitude coefficient k, and amount and direction of dip θ) of the sheet. This method minimizes an objective functional in the space of the logarithmed and non-logarithmed model parameters (log(h), log(a), log(k), and θ) successively by the steepest descent (SD) and Gauss-Newton (GN) techniques in order to essentially maintain the stability and convergence of this inverse method. Prior to applying the method to real data, its accuracy, convergence, and stability are successfully verified on numerical examples with and without noise. The method is then applied to SP profiles from the German Continental Deep Drilling Program (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschla -KTB), Rittsteig, and Grossensees sites in Germany for tracing paleo-shear planes coated with graphitic deposits. The comparisons of geologic sections constructed in this paper (based on the proposed deterministic approach) against the existing published interpretations (obtained based on trial-and-error modeling) for the SP data of the KTB and Rittsteig sites have revealed that the deterministic approach suggests some new details that are of some geological significance. The findings of the proposed inverse scheme are supported by available drilling and other geophysical data. Furthermore, the real SP data of the Grossensees site have been interpreted (apparently for the first time ever) by the deterministic inverse scheme from which interpretive geologic cross sections are suggested. The computational efficiency, analysis of the numerical examples investigated, and comparisons of the real data inverted here have demonstrated that the developed deterministic approach is advantageous to the existing interpretation methods, and it is suitable for meaningful interpretation of SP data acquired elsewhere over graphitic occurrences on fault planes.

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Section: Field Data Inversionmentioning

confidence: 99%

Section: Ktb-borehole Anomaly Germanymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tracing of paleo-shear zones by self-potential data inversion: case studies from the KTB, Rittsteig, and Grossensees graphite-bearing fault planes

Mehanee

2015

Earth Planets Space

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Applications of Ant Colony Optimization in determination of source parameters from total gradient of potential fields

Srivastava

Datta²,

Agarwal³

et al. 2013

Near Surface Geophysics

Self Cite

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A unified interpretation technique, based on the computation of total gradient from first order horizontal and vertical derivatives of a measured anomaly, namely, magnetic, gravity or self-potential, can be used to determine horizontal location, depth, and the nature of the causative source geometry. The total gradient, in general, may exhibit several symmetrical bell-shaped functions of different magnitudes and with different decay rates β-termed as 'source geometry factor' to describe the nature of the causative sources. β-values have been presented for idealized source geometries producing three different types of measurements (anomalies). The non-linear inversion of the total gradient with multiple sources of different geometries is accomplished through Ant Colony Optimization (ACO) -a technique with only a few demonstrated applications in geophysical problems. We have also implemented the ACO which, in its original form, is suitable for discrete space or combinatorial optimization in a continuous model space using decimal coding. Moreover, unlike conventional techniques based on pre-specified moving/ fixed data length windows, the proposed technique uses much of the total gradient data points except at the ends of the profile (where error in the total gradient can be large). The presence of singularity in the Euler technique in the analysis of a gravity anomaly over a thick faulted slab has been overcome by the total gradient ACO method. A procedure has also been formulated for analysing gravity and reduced to pole (RTP) total field magnetic anomalies over spherical and vertical cylindrical source geometries. To evaluate the efficacy of the proposed technique, ACO results are compared with other modern techniques, namely, Particle Swarm Optimization (PSO), Enhanced Local Wavenumber (ELW) and the Euler method through simulated data contaminated with random noise and three field examples. This study has revealed that the total gradient ACO technique leads to better convergence towards the global minimum and also better inversion results than those obtained by the PSO and other techniques mentioned above. Unlike the ELW and Euler techniques, the total gradient analysis provides enhanced resolution for interfering sources.ity equation based on a moving window of a pre-specified length (ii) Enhanced local wavenumber (fixed window length around the center of the peak)/ tilt angle (Salem et al. , 2008 using a 2D moving window of a pre-specified length; and (iii) amplitude of the analytic signal analysed with a few selected points (Agarwal 1984;Roest et al. 1992;Shaw and Agarwal 1997;Keating and Sailhac 2004;Salem 2005; Srivastava and Agarwal 2010 and others). With these techniques, the interpreter first pre-selects a window length in one or two dimension(s) and then, depending upon the technique, situates the window over the centre of the peak position or moves it over the entire Geophysical Equipment Source FOR MARINE SALES AND RENTALS www.geomatrix.co.uk Our expertise covers all aspects of marine geophysical surv...

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Metaheuristics Inversion of Self-Potential Anomalies

Gobashy

Abdelazeem

2021

Self-Potential Method: Theoretical Modeling and Applications in Geosciences

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Interpretation of self-potential anomalies by Enhanced Local Wave number technique

Cited by 42 publications

References 37 publications

Tracing of paleo-shear zones by self-potential data inversion: case studies from the KTB, Rittsteig, and Grossensees graphite-bearing fault planes

Tracing of paleo-shear zones by self-potential data inversion: case studies from the KTB, Rittsteig, and Grossensees graphite-bearing fault planes

Applications of Ant Colony Optimization in determination of source parameters from total gradient of potential fields

Metaheuristics Inversion of Self-Potential Anomalies

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