Reduction to the Pole at the Geomagnetic Equator

Luo, Yao; Xue, Dian-Jun; Wang, Ming

doi:10.1002/cjg2.1578

Cited by 31 publications

(19 citation statements)

References 14 publications

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“…Reduction to equator (RTE) is a useful and effective operation designed to transform a total magnetic intensity (TMI) anomaly caused by an arbitrary source into the anomaly that this same source would produce if it were located at the pole and magnetised by induction only [21]. Reduction to pole (RTP) converts the mag-netic field from the magnetic latitude where the Earth's field is inclined to that field at a magnetic equator where the inducing field is vertical [22]. When the field of the Earth is inclined, magnetic anomalies caused by induction are related to their sources asymmetrically, but when the Earth`s inducing field is vertical, the associated anomalies would be directly over their sources [20].…”

Section: Reduction To Equatormentioning

confidence: 99%

“…where A p (u, v) is the Fourier transform of these observed magnetic data; A c (u, v) is the Fourier transform of the vertical magnetic field; I and D are the inclination and declination of core field, respectively; (u, v) is the wavenumber corresponding to the (x, y) directions, respectively; and Ω = arctan(u/v) [22]. The RTE for low geomagnetic latitudes was applied to the magnetic anomaly data.…”

Section: Reduction To Equatormentioning

confidence: 99%

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Estimation of Magnetic Contact Location and Depth of Magnetic Sources in a Sedimentary Formation

Alabi

Makinde

Adewale³

et al. 2019

Materials and Geoenvironment

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The aeromagnetic data of Idogo, Southwestern Nigeria, have been used to study the lithology and to determine the magnetic source parameters within Idogo and its environs. Idogo lies between latitudes 6°30′N and 7°00′N and between longitudes 2°30′E and 3°00′E. The magnetic anomaly map, the regional geology, the analytic signal and the local wavenumber were used to identify the nature and depth of the magnetic sources in the region. Data enhancement was carried out to delineate the residual features relative to the strong regional gradients and intense anomalies due to the basin features. The estimated basement depth using the horizontal gradient method revealed depths ranging between 0.55 km and 2.49 km, while the analytic signal amplitude and local wavenumber methods estimated depth to the magnetic sources to range from 0.57 km to 4.22 km and 0.96 km to 2.43 km, respectively. Depth computations suggested the presence of both shallow and deep sources. The total magnetic intensity values ranged from 3.1 nT to 108.3 nT. The area shows magnetic closures of various sizes in different parts of the area trending West, with prominence at the centre and distributed East–West.

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Section: Reduction To Equatormentioning

confidence: 99%

Section: Reduction To Equatormentioning

confidence: 99%

Estimation of Magnetic Contact Location and Depth of Magnetic Sources in a Sedimentary Formation

Alabi

Makinde

Adewale³

et al. 2019

Materials and Geoenvironment

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“…This makes interpretation of magnetic anomalies complex. However, at low magnetic latitude, Luo et al [13] proposed special reduction to equator, which transforms the observed magnetic anomaly at the equator into an anomaly that would have been measured if the magne-tisation and ambient field were both vertical. This operation transforms theoretical magnetic anomalies located at the pole and magnetised by induction only into the observed magnetic anomalies.…”

Section: Reduced-to-equator (Rte) Mapmentioning

confidence: 99%

“…The desired improvements in the quality of the aeromagnetic data were achieved by the application of two-dimensional fast Fourier transform technique. In 2010, Luo et al [13] assumed the set of observed magnetic data acquired on planar observation surface. Earlier work done by Gun [14] was adopted, where reduction-to-pole operation in wave number domain was performed, given as Equation 1: D -Ɵ is close to ±90, which makes the imaginary part close to zero; thus, reduction-to-pole processing will be unstable at low latitudes and singular at the equator.…”

Section: Reduced-to-equator (Rte) Mapmentioning

confidence: 99%

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Interpretation of high resolution airborne magnetic data (HRAMD) of Ilesha and its environs, Southwest Nigeria, using Euler deconvolution method

Olurin

2017

Materials and Geoenvironment

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Interpretation of high resolution aeromagnetic data of Ilesha and its environs within the basement complex of the geological setting of Southwestern Nigeria was carried out in the study. The study area is delimited by geographic latitudes 7°30′–8°00′N and longitudes 4°30′–5°00′E. This investigation was carried out using Euler deconvolution on filtered digitised total magnetic data (Sheet Number 243) to delineate geological structures within the area under consideration. The digitised airborne magnetic data acquired in 2009 were obtained from the archives of the Nigeria Geological Survey Agency (NGSA). The airborne magnetic data were filtered, processed and enhanced; the resultant data were subjected to qualitative and quantitative magnetic interpretation, geometry and depth weighting analyses across the study area using Euler deconvolution filter control file in Oasis Montag software. Total magnetic intensity distribution in the field ranged from –77.7 to 139.7 nT. Total magnetic field intensities reveal high-magnitude magnetic intensity values (high-amplitude anomaly) and magnetic low intensities (low-amplitude magnetic anomaly) in the area under consideration. The study area is characterised with high intensity correlated with lithological variation in the basement. The sharp contrast is enhanced due to the sharp contrast in magnetic intensity between the magnetic susceptibilities of the crystalline and sedimentary rocks. The reduced-to-equator (RTE) map is characterised by high frequencies, short wavelengths, small size, weak intensity, sharp low amplitude and nearly irregular shaped anomalies, which may due to near-surface sources, such as shallow geologic units and cultural features. Euler deconvolution solution indicates a generally undulating basement, with a depth ranging from −500 to 1000 m. The Euler deconvolution results show that the basement relief is generally gentle and flat, lying within the basement terrain.

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Quantitative analysis of total magnetic anomaly maps on archaeological sites—Part 1

Toktay

Aydoğan

Yüksel

2021

Math Methods in App Sciences

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In this study, which is the first part of quantitative analysis of total magnetic anomaly maps on archaeological sites, it is aimed to analyze the horizontal boundary values of potential buried structures that cause anomalies from the total magnetic anomaly maps of an archaeological excavation area. In the first step, the model was created in accordance with the archaeological structure.Noisy and noiseless anomaly maps of this model were calculated. These maps were enhanced using the reduction to pole and upward continuation methods. Tilt angle and automatic gain control methods were used. The responses of these methods on the total magnetic anomaly maps of the model were analyzed.In the second step, by applying the same procedures on the total magnetic anomaly map obtained from the magnetic measurements on the area that has not been excavated in the Amasya Oluz Mound archaeological excavation area, the horizontal boundaries of the potential structure elements of the region were analyzed.

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Reduction to the Pole at the Geomagnetic Equator

Cited by 31 publications

References 14 publications

Estimation of Magnetic Contact Location and Depth of Magnetic Sources in a Sedimentary Formation

Estimation of Magnetic Contact Location and Depth of Magnetic Sources in a Sedimentary Formation

Interpretation of high resolution airborne magnetic data (HRAMD) of Ilesha and its environs, Southwest Nigeria, using Euler deconvolution method

Quantitative analysis of total magnetic anomaly maps on archaeological sites—Part 1

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