scholarly journals Application of Ground Magnetic Geophysical Method in the Delineation of Subsurface Structures of Dala Hill in Kano Ancient City, Northwest Nigeria

2020 ◽  
Vol 7 (4) ◽  
pp. 147-152
Author(s):  
Abdulazeez Shehu ◽  
Mohammed Saleh ◽  
Abubakar M. Hotoro ◽  
Abdulrahim A. Bunawa
Keyword(s):  
Magnetic Measurement ◽  
Intensity Data ◽  
Magnetic Intensity ◽  
Depth Of Penetration ◽  
Subsurface Structures ◽  
Ancient City ◽  
Ground Magnetic ◽  
The Hill ◽  
2D And 3D ◽  
Body Parameters

Ground Magnetic measurement was carried out with the aim of delineating the subsurface structures on Dala hill, Kano State. Total magnetic intensity data were acquired using the SCINTREX proton precession magnetometer along closely spaced traverses. The acquired total magnetic intensity data were reduced and plotted using Golden Surfer software to produce the 2D and 3D surface maps for visual inspection. Five profiles AB, CD, EF, GH and IJ were selected for forward modelling using Mag2dc software to give detail information about the causative body parameters. The depths of these bodies from the surface fall in the interval 0.0 m to 8.5 m. The high magnetic anomaly field ranges from -21,752 to 47,205 nT which suggested area of iron occurrences. The study categorized the identified major anomalous features into two: the shallower bodies which penetrated down to a maximum depth of 67.3 m were inferred to be disturbed sediments, fire pits and kilns; whereas the rest, the deep-rooted features with greater depth of penetration reaching up to 193.2m, have high susceptibility range of up to 7.3 SI units, were interpreted to be intrusive ferromagnetic bodies. The findings of the study were in close agreement with recent archaeological findings about the hill.

scholarly journals On the Tumulus of Choban Tepeh in the Troad

1897 ◽  
Vol 17 ◽  
pp. 319-320 ◽  
Author(s):  
Frank Calvert
Keyword(s):  
The Other ◽  
The Road ◽  
Ancient City ◽  
History Of ◽  
The Subject ◽  
On The Road ◽  
The Hill

I derive the materials of the present paper from some memoranda which I find amongst my archaeological notes and which relate to certain explorations to which I was not a party, made so long ago as 1887. I have thought that the particulars then obtained may be deemed sufficiently interesting to deserve a record in the history of Trojan archaeological discovery.The subject is one of the four small tumuli dotted about and near the hill of Balli-Dagh, the crest of which according to the now exploded theory of Le Chevalier (1785) was supposed to represent the Pergamos of Troy. In a memoir contributed to the Journal of the Archaeological Institute of 1864, I proved that the site in question was no other than that of the ancient city of Gergis. In the same paper I gave an account of the results of the excavation of one of the group of three tumuli on Balli-Dagh, the so-named Tomb of Priam. The other two, namely Le Chevalier's Tomb of Hector, and an unnamed hillock, were excavated respectively by Sir John Lubbock (about 1878) and Dr. Schliemann (1882) without result. The present relates to the fourth mound on the road between the villages of Bournarbashi and Arablar (as shown in the published maps), which goes by the name of Choban Tepeh (Shepherd's hillock) and the Tomb of Paris, according to Rancklin (1799).

AEROMAGNETIC FIELD TEST OF TOTAL INTENSITY UPWARD CONTINUATION

Geophysics ◽  
1971 ◽  
Vol 36 (2) ◽  
pp. 418-425 ◽  
Author(s):  
Angelo L. Kontis
Keyword(s):  
Dirichlet Problem ◽  
Field Test ◽  
Theoretical Basis ◽  
Numerical Evaluation ◽  
Integral Formula ◽  
Intensity Data ◽  
Magnetic Intensity ◽  
Normal Field ◽  
Area Of Interest ◽  
Upward Continuation

The theoretical basis for applying the upward‐continuation integral, [Formula: see text]z⩽0, (1) to total magnetic intensity data T(α, β) measured on the plane z=0 has been recently reviewed by Henderson (1970). To perform upward continuation in the spatial domain, weights or coefficients obtained by numerical evaluation of equation (1) (Peters, 1949; Henderson, 1960; Fuller, 1967) may be convolved with the total intensity anomaly T(α, β) to produce T(x, y, z) at heights z<0 (for z positive downward). The accuracy of upward continuation is, therefore, dependent on the validity of the numerical coefficients and of the assumptions required to show that T(α, β) satisfies the conditions of the Dirichlet problem for a plane. These assumptions are that the quantity sensed by a total‐intensity magnetometer is in the direction of the earth’s normal field and that this direction is invariant over the area of interest.

ON THE VALIDITY OF THE USE OF THE UPWARD CONTINUATION INTEGRAL FOR TOTAL MAGNETIC INTENSITY DATA

Geophysics ◽  
1970 ◽  
Vol 35 (5) ◽  
pp. 916-919 ◽  
Author(s):  
Roland G. Henderson
Keyword(s):  
Dirichlet Problem ◽  
Coordinate System ◽  
Intensity Data ◽  
Magnetic Intensity ◽  
Rectangular Coordinate System ◽  
Normal Field ◽  
Upward Continuation ◽  
Gravity Fields

The integral solving the Dirichlet problem for a plane, known as the “upward continuation integral” to exploration geophysicists working with magnetic and gravity fields, is sometimes misunderstood. Recently, some geophysicists have commented that its use in continuing ΔT, the component of the total intensity anomaly in the direction of the earth’s normal field, is suspect, the thought being that only components normal to the surface can be so continued. The integral in question is [Formula: see text]where ΔT(α, β) represents measured total intensity values on the plane of observations z=0, in a right handed rectangular coordinate system in which the z axis is positive vertically downward.

A new regional/residual separation for magnetic data sets using susceptibility from frequency-domain electromagnetic data

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. B351-B359 ◽  
Author(s):  
Peter Tschirhart ◽  
Bill Morris ◽  
Greg Hodges
Keyword(s):  
Magnetic Field ◽  
Frequency Domain ◽  
Forward Modeling ◽  
Anthropogenic Sources ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Depth Of Penetration ◽  
Near Surface ◽  
Long Wavelength ◽  
Magnetic Remanence

Regional-residual separation is a fundamental processing step required before interpreting any magnetic anomaly data. Numerous methods have been devised to separate deep-seated long-wavelength (regional) anomalies from the near-surface high-frequency (residual) content. Such methods range in complexity from simple wavelength filtering to full 3D inversions, but most procedures rely on the assumption that all long-wavelength anomalies are associated with deep source bodies: an incorrect assumption in some geologic environments. We evaluated a new method for determining the contributions of near-surface magnetic sources using frequency-domain helicopter-borne electromagnetic (HFEM) data. We inverted the in-phase and quadrature components of the HFEM data to produce an estimate of the spatial variation of magnetic susceptibility. Using this susceptibility information along with known topography and original survey flight path data, we calculated a magnetic intensity grid by forward modeling. There are two immediate benefits to this approach. First, HFEM systems have a limited effective depth of penetration, within the first hundred meters from the surface, so any magnetic sources detected by this method must be located in the near surface. Second, the HFEM-derived susceptibility is completely independent of magnetic remanence. In contrast, apparent susceptibility computed from the original magnetic intensity data incorporates all magnetic signal sources in its derivation. Crossplotting of [Formula: see text] versus [Formula: see text] served to reveal areas where the observed magnetic field was dominated by magnetic remanence and provided an estimate of the polarity of the remanence contribution. We evaluated an example, and discussed the limitations of this method using data from an area in the Bathurst Mining Camp, New Brunswick. Though it is broadly successful, caution is needed when using this method because near-surface conductive bodies and anthropogenic sources can cause erroneous HFEM susceptibility values, which in turn produce invalid magnetic field estimates in the forward modeling exercise.

scholarly journals Shear joints and its relations with subsurface structures in Batu Melintang, Jeli, Kelantan, Malaysia

2021 ◽  
Vol 8 (2) ◽  
pp. 86-93
Author(s):  
Mohd Syakir Sulaiman ◽  
Wani Sofia Udin ◽  
Aweng Eh Rak
Keyword(s):  
Structural Analysis ◽  
Research Area ◽  
Geological Mapping ◽  
Electrode Spacing ◽  
Depth Of Penetration ◽  
Surface Shear ◽  
Subsurface Structures ◽  
Resistivity Method ◽  
Shear Joint ◽  
Minimum Stress

Shear joint is the common rock deformation structures formed in Batu Melintang, Jeli due to its location within Bentong-Raub Suture zone. The structural analysis of shear joint can give information about the direction of maximum and minimum stress exerted on a rock while undergoing deformation as the effect of stress fields in the study area. The subsurface structural analysis is done by using the geophysical resistivity method. It displays the subsurface structure in the area for confirmation of the structure found on the surface whether it is highly fractured, moderately fractured or low fractured. The research area was divided into six grids for systematic field measurement. The shear joints orientation were taken while conducting geological mapping and recorded using rose diagram analysis; while the geophysical resistivity method was carried out with a varied length of survey lines set at 200/100m and 1.25/2.5/5m electrode spacing. The subsurface depth of penetration for each survey line is varied, ranging from 0m to 50m. The data is processed in RES2DINV software to obtain the pseudosection profile of the subsurface. The study area principal stress was identified; the maximum stress force ?1 was directed in NW-SE in direction of S107°E and N287°W, while minimum stress ?3 was directed in NE-SW in direction of N17°E and S197°W. The pseudosection subsurface image also displayed a correlation between surface shear joint structures and subsurface structures. The subsurface investigation; according to the pseudosection found that the study area consists of highly fractured structure displayed as several weak zones and fractures of bedrock.

scholarly journals CONSERVING BUILT HERITAGE FOR POSTERITY: A CONSERVATION APPROACH IN BAGAN

2019 ◽  
Vol XLII-2/W15 ◽  
pp. 1179-1185
Author(s):  
D. Tse ◽  
A. Paladini ◽  
A. Dhanda ◽  
A. Weigert ◽  
M. Reina Ortiz ◽  
...  
Keyword(s):  
Case Studies ◽  
New Technologies ◽  
Local Staff ◽  
Built Heritage ◽  
Passive Sensing ◽  
Ancient City ◽  
Technological University ◽  
2D And 3D ◽  
The City ◽  
Recording Techniques

<p><strong>Abstract.</strong> The new age of digital technologies has led to a shift in conservation approaches when documenting historic places for posterity. The availability of these new technologies has provided tools for better decision-making with respect to the conservation of fragile built heritage. For sites vulnerable to seismic activity, such as Bagan, frequent catastrophic events have strengthened the need for proper documentation.</p> <p>A multidisciplinary team, comprised of students from Carleton University, students from Mandalay Technological University, and staff from the Department of Archaeology and Library of Bagan, conducted a documentation workshop using digital recording techniques. The team selected four Buddhist temples in the city of Bagan, Myanmar, as case studies for the documentation expedition. The strategy included using active and passive sensing techniques (Figure 1), which were used to assess the character-defining elements associated to the built heritage of the case studies. Furthermore, the strategy involved examining the state of conservation of the built heritage. Following the on-site documentation, the data collected was processed to give 2D and 3D representations of the documented sites. These representations serve as a record for future use in conservation. Additional objectives related to the documentation of the four sites were to understand the obstacles in conserving built heritage with respect to the ancient city of Bagan, to expand the technical knowledge of the local staff and the future professionals, and to examine the values and limitations of the recording techniques employed.</p>

scholarly journals Multi-Dimensional Inversion of Airborne Total Magnetic Intensity Data at the West-of-Edfu Region, Upper Egypt

2017 ◽  
Vol 05 (01) ◽  
pp. 01-13
Author(s):  
Karam. S. I. Farag ◽  
Ahmad H. M. Habeeb ◽  
Ali M. S. Abdelaziz ◽  
Sami H. Abd El Nabi
Keyword(s):  
Intensity Data ◽  
Magnetic Intensity ◽  
The West ◽  
Upper Egypt
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