Reduction‐to‐the‐pole of low latitude magnetic anomalies

Pearson, William C.; Skinner, Christopher

doi:10.1190/1.1826974

Cited by 16 publications

(6 citation statements)

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“…The total magnetic data were reduced to equator to reduce the magnetic anomalies to the magnetic equator with 0° inclination; as such, re-computes the TMI anomalies as if the causative bodies were magnetized in a horizontal direction. For the convenience of interpretation, a 180° phase reversal was introduced so that troughs become peaks, still positioned over the centers of the bodies (Leu 1981;Pearson and Skinner 1982), hence, the need for reduced to equator inverse (RTE_INV). Not only that RTE-inverse corrects the effects of low latitude on the magnetic anomaly (Kinnaird et al 1981;Ngama and Akanbi 2017), but eliminates distortions that would have been introduced in high amplitude anomaly correction if a reduction to pole (RTP) were to be applied.…”

Section: Theory and Methodologymentioning

confidence: 99%

Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Oguama

Okeke

Obiora

2020

Model. Earth Syst. Environ.

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Aeromagnetic data of some parts of Anambra Basin, Nigeria, covering Illushi, Nsukka, Igumale, Onitsha, Udi and Nkalagu areas were digitally processed, analyzed and interpreted qualitatively and quantitatively. The study was carried out to delineate the subsurface structural lineaments/trends that provide the locales for mineral deposit and hydrocarbon resources and to estimate the depth to magnetic sources/sedimentary thickness of the area. The data were qualitatively interpreted using reduction to equator-inverted (RTE_INV), vertical derivatives (VD), tilt derivative (TDR) filter, lineament density filter and Rose plot. Quantitative interpretation was done using source parameter imaging and Euler deconvolution methods. The results depicted that the study area has enormous structural lineaments especially in the northeast and northwest that showed a high cluster of these lineaments. The results showed that the trends of the structural lineaments have a dominance of NE-SW direction, with ancillary trends in E-W, NW-SE, N-S, NNE-SSW and ENE-WSW directions. The SPI depth result ranges from 318.45 m for shallow magnetic sources to − 11,253 m for sedimentary thickness. The 3D Euler deconvolution depth estimate revealed depths to magnetic sources ranging from − 400 to − 4300 m. The results show good evidence of the presence of the essential factors for the exploration of both mineral deposits and hydrocarbon resources in the study area.

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Section: Theory and Methodologymentioning

confidence: 99%

Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Oguama

Okeke

Obiora

2020

Model. Earth Syst. Environ.

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“…These include Wiener filtering (Hansen and Pawlowski, 1989;Pearson and Skinner, 1982;and Keating and Zerbo, 1996); modification of the RTP FFT algorithm (Grant and Dodds (1972);and MacLeod et al, 1993); and the Equivalent Source method (Roy, 1962;Silva, 1986;Xia et al, 1993). The modified RTP FFT algorithm (Grant and …”

Section: Computationmentioning

confidence: 99%

Analytic Signal vs. Reduction to Pole: Solutions for Low Magnetic Latitudes

Rajagopalan¹

2003

ASEG Extended Abstracts

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“…It can relocate the anomaly maximum directly over the subsurface source to yield an intuitive view of the data. The RTP method has also been applied in numerous large-scale magnetic data-interpretation applications (Pearson & Skinner 1982;Nabighian et al 2005;Fedi et al 2012;Foks & Li 2016;Li & Pilkington 2016). Moreover, it can be utilized as an efficient tool to identify the direction of total magnetization in rocks (Phillips 2005;Dannemiller & Li 2006;Reis et al 2016;Liu et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Low-latitude reduction-to-the-pole and upward continuation between arbitrary surfaces based on the partial differential equation framework

Zuo

Leão‐Santos

Cai

et al. 2021

Geophysical Journal International

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Summary Magnetic surveys conducted in complex conditions, such as low magnetic latitudes, uneven observation surfaces, or above high-susceptibility sources, pose significant challenges for obtaining stable solutions for reduction-to-the-pole (RTP) and upward-continuation processing on arbitrary surfaces. To tackle these challenges, in this study, we propose constructing an equivalent-susceptibility model based on the partial differential equation (PDE) framework in the space domain. A multilayer equivalent-susceptibility method was employed for RTP and upward-continuation operations, thus allowing for application on undulating observation surfaces and strong self-demagnetisation effect in a non-uniform mesh. A novel positivity constraint is introduced to improve the accuracy and efficiency of the inversion. We analysed the effect of the depth-weighting function in the inversion of equivalent susceptibility for RTP and upward-continuation reproduction. Iterative and direct solvers were utilised and compared in solving the large, sparse, nonsymmetric, and ill-conditioned system of linear equations produced by PDE-based equivalent-source construction. Two synthetic models were used to illustrate the efficiency and accuracy of the proposed method in processing both ground and airborne magnetic data. Aeromagnetic, ground data, and prior magnetic orebody information collected in Brazil at a low magnetic latitude region were used to validate the proposed method for processing RTP and upward-continuation operations on magnetic data sets with strong self-demagnetisation.

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Reduction‐to‐the‐pole of low latitude magnetic anomalies

Cited by 16 publications

References 0 publications

Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Mapping of subsurface structural features in some parts of Anambra Basin, Nigeria, using aeromagnetic data

Analytic Signal vs. Reduction to Pole: Solutions for Low Magnetic Latitudes

Low-latitude reduction-to-the-pole and upward continuation between arbitrary surfaces based on the partial differential equation framework

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