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Continuing advances within unmanned aerial vehicles and scalar magnetic sensor technology are revolutionizing geophysical remote sensing. For perspective, examples of high resolution, low noise data presented in this study enabled detection and accurate positioning of human-made objects ferrous objects with a total mass of 0.5 kg, from altitudes around and above 2 m. However, with these new possibilities come a requirement of higher fidelity, where good sensor position estimates in particular are key to achieving a data quality sufficient for reliable data interpretation and geophysical inversion. Apart from inherent instrument properties, typical factors that hamper sensor position estimation are lag and parallax errors. Lag errors arise from time-stamping delays between the positioning system and sensor reading, while parallax errors stem from the imperfect recovery of sensor positions due to a decoupling and/or distancing of the positioning system and sensor head. The impact from each of these error sources is typically similar and partially or even completely inseparable. A number of correctional techniques exist, typically based on large-scale data correlations, or collection of specific additional data. We present a survey data adjustment method based on the simultaneous inversion of source parameters and a number of independent survey shifts or lags in pre-specified sections of a survey. The method is particularly suited for surveys where the sensor path through space can be assumed well known, but the sensor position itself may suffer lags or shifts relative to the position measurement. The approach is based on modelling an existing source signature within the data and requires no data transformations, such as continuation to a two-dimensional plane, or enforcing of smoothness. The approach is an amendment to independent source inversion and is ideal for scenarios where the source behaviour is thought to be well known, such as processing efforts in which the objective is source–parameter inversion. In this study, we validate the approach using a simple point-dipole model to adjust synthetic data and subsequently demonstrate it on an unmanned airborne scalar magnetic survey for small unexploded ordnance targets, where a hardware malfunction resulted in unknown time-shifts between magnetic sensor readings and positioning unit output. The adjustment procedure was carried out on line data, based on a single anomaly from a 155 mm shell, and enabled the recovery of signatures from several other ferrous unexploded ordnance targets as small as 0.5 kg. Subsequent inversion on the corrected signatures provided unexploded ordnance positions with an accuracy suitable for recovery purposes.

The geological map of the old western region of Nigeria indicates the presence of iron ore deposit at Iboro village Ogun state (7.9983o - 7.99933o N, 3.5790o - 3.5890o E). Hence a ground magnetic survey was carried out at a location at Iboro village so as to delineate the subsurface magnetic anomalies and to know whether the anomalies favour accumulation of magnetic minerals. The survey was carried out using high resolution proton precession magnetometer model G-856X. Eight traverses were run at 5m separations and earth magnetic intensity values were measured at 10m intervals along each traverse; the acquired data were corrected for drift. The residual anomalies obtained by removal of regional gradient from observed data using trend analysis were presented as profiles and maps. The treated data were qualitatively and quantitatively interpreted and the results gave values for the total ground magnetic anomalies that varied between a minimum and maximum peak values of about -33.0 and 30.6nT respectively. Depth to the basement rock was estimated using Peter’s half slope method which gave a maximum depth of about 13m. The contour maps and the total relative graphs present the subsurface picture of the geological structure that is assumed to harbour the metallic minerals through the action of the field towards the concentration of anomalies. It was suspected that the overburden was relatively thin in the study area and the minerals were at a shallow depth.

– Magnetic signatures of urban structures. – Understand water distribution in a megalopolis thanks to geophysics prospecting.

– First complete geophysical survey coverage of the Mount Pleasant mega-henge. – Evaluation of plough damage and erosion of the henge earthworks using GPR. – Reprocessing and comparison of Clark’s original magnetic survey from 50 years ago.

High-bandwidth magnetic data are normally distorted by ubiquitous 50- or 60-Hz noise from powerlines and similar sources. The powerline noise can be orders of magnitude larger than the magnetic signal from targets and must be culled from data sets prior to interpretation. Suppression of the powerline noise by simple filtering can result in artifacts and an unacceptable reduction in resolution of ground-based and unmanned aerial vehicle magnetic surveys. Removal approaches such as those based on Biot-Savart modeling are sensitive to the estimated position of the powerline systems, in addition to their limited applicability due to the requirement of a DC source. Moreover, the powerline noise in data acquired from a moving platform is inherently nonstationary and removal techniques must be specifically developed with this in mind. We propose a model-based method that does not rely on a priori knowledge of the powerline system by fitting and subtracting a set of sinusoids to the data. These sinusoids are computed on small windows of data, tied together with regularization terms within the fitting process to reduce discontinuities between segments. We further incorporate powerline frequency as a nonlinear parameter, allowing for fluctuations in the fundamental frequency as loads on the power grid change. Through synthetic and field examples, we show that periodic noise can be reliably removed automatically without the need for filtering or significant alterations of the frequency content. Powerline noise is reduced by over 98% in the field example.

In this study Aeromagnetic, ground-based magnetic and satellite imagery data have been processed and analyzed to delineate surface and subsurface structures to clarify its impacts on groundwater flow direction, and to detect the thickness of groundwater aquifer’s (accumulation) in the study area. To achieve this target, an interpretation of satellite digital elevation data is processed to generate the main drainage pattern in the area to delineate the Watersheds basins and where the surface water can be accumulated. Moreover, Aeromagnetic data have been used to detect the sedimentary cover in the area, and to assess the thickness distribution of the Nubian aquifer to detect the most eligible aquifer with the largest thickness, consequently the largest amount of groundwater reserve. Also, the ground magnetic survey was conducted in Wadi El Amal to reassure the results obtained from the airborne data. Two main approach techniques were applied to the data. Firstly, the trend analysis applied to the first vertical derivative map to detect main trend analysis and faults. The second approach is to calculate the depth to the basement, which represents the base of the Nubian aquifer in the area under consideration. The final results of the main trend found as follow, the ENE-WSW, NW-SE, and NE-SW trend which found to be is the main trend. The water table in this area is about 100 m, the calculated depth to the basement in the deepest parts study area is ranging between −300 and −700 below ground surface. The integration between satellite techniques and geophysical tools can give us the whole picture of groundwater distribution and its recharge sources.

Electrical resistivity tomography (ERT) and ground magnetic surveys were applied to characterize an old uncontrolled landfill in a former exploited sand and gravel quarry in an area to the north-west of the city of Cologne, Germany. The total magnetic field and its vertical gradient were recorded using a proton precession magnetometer to cover an area of about 43,250 m2. The magnetic data were transferred to the frequency domain and then reduced to the north magnetic pole. The amplitude of the analytical signal was calculated to define the magnetic materials within and outside the landfill. Eight ERT profiles were constructed based on the results of the magnetic survey using different electrode arrays (Wenner, dipole–dipole, and Schlumberger). In order to increase both data coverage and sensitivity and to decrease uncertainty, a non-conventional mixed array was used. The subsurface resistivity distributions were imaged using the robust (L1-norm) inversion method. The resultant inverted subsurface true resistivity data were presented in the form of 2D cross sections and 3D fence diagram. These non-invasive geophysical tools helped us to portray the covering soil, the spatial limits of the landfill, and the depth of the waste body. We also successfully detected low resistivity zones at deeper depths than expected, which probably be associated with migration pathways of the leachate plumes. The findings of the present study provide valuable information for decision makers with regards to environmental monitoring and assessment., Volkswagen Foundation http://dx.doi.org/10.13039/501100001663, Universität zu Köln (1017)

Magmatic processes occurred during the Miocene period caused the formation of epithermal gold deposits in Cibaliung area. The deposit has previously been investigated through geological surveys which basically only covers the surface aspect, so in this study a subsurface analysis was carried out through magnetic and IP surveys to determine the distribution and continuity of the gold deposits. The magnetic survey was conducted over an area of about 3 km2 with sampling interval 20 m east and 100 m north. The magnetic data were processed using Oasis Montaj with magnetic intensity map as an output, which was then interpreted to determine the presence of structures and magnetite destruction zones as mineralization clues. The IP survey was conducted on 20 east-west oriented lines with length of about 1.2 km. The electrode configuration used is Wenner with 25 m spacing. IP data were processed using RES2DINV software to eliminate bad datum points and invert the apparent chargeability values into the true ones. IP data are then interpreted to clearly determine the position, direction, and distribution of gold mineralization body by detecting the presence of sulfide minerals as ligands carrying gold. Magnetic data analysis shows that gold mineralization tends to occur at low magnetic anomaly, ranging from 37 nT to 240 nT and generally associated with northwest-oriented structures. The mineralization zone is found in four main vein zones with resistivity and chargeability values < 51 Ωm and > 50 ms.

The present work aims to detect the Phanerozoic sedimentary sub-basins and their hydrocarbon potentialities within the Qattara Ridge in the northern Western Desert, Egypt, through the interpretation of high-resolution land magnetic data. The in-depth relations between observed magnetic anomalies and the magnetic mineralogy of the underlying rocks and the associated chemical reactions are essential to understanding the hydrocarbon potentialities. A high-resolution land magnetic survey has been conducted covering an area of 3600 km2, and several filters have been applied to the measured total field including reduction to pole, normalized source strength, tilt-depth and 3D Euler deconvolution with un-prescribed structural index, to accomplish the goals. Regularized focused inversion was applied to six selected profiles on the total magnetic intensity field to model variations in subsurface magnetic susceptibilities and to study the relation with hydrocarbon reservoirs in the area. Results show perfect structurally controlled sub-basins, with variable thickness of the sedimentary cover ranges for the Paleozoic to Miocene units. The depth of the top basement rocks ranges from 1500 to 7000 m. The calculated depths to the edges from magnetic analysis ranges from 292 to 3322 m. Some faults can be detected at 3900 m, and five possible sedimentary basins (depocenters) can be detected within the Qattara Ridge, trending NW–SE and N–S. Magnetic results also show that the central part of Qattara Ridge is affected by low magnetic anomaly, and many magnetization sources can be detected in the northern directions. The common trend in these sources is NW–SE. Most shallow depth to magnetic sources is concentrated at the northern part of the area, while the deeper sources are distributed in the west and south of the study area. The maximum depth recorded is about 3988 m. Inversion shows remarkable relations between the inverted magnetic susceptibilities and the different hydrocarbon productive and sealing zones in and close to the study area. The localized variations in the inverted anomalous magnetic susceptibilities in the Qattara Ridge were possibly produced by different intrasedimentary mineral magnetic phases developed near the surface due to hydrocarbon occurrences. Reducing gases, coming from the possible underlying hydrocarbon reservoir, play a critical role in the formation of these secondary magnetic minerals. The reservoir in the Qattara Ridge, based on the present study, is characterized by low magnetic susceptibility and low surface magnetic anomaly in the studied locations of productive wells. The interpretations show matching between the sedimentary thickness and position of the faults deduced from both the available drilled wells and seismic data with our magnetic results.

Hundreds of oil wells were drilled along Oil Creek in Pennsylvania in the mid-1800s, birthing the modern oil industry. No longer in operation, many wells are now classified as abandoned, and, due to their age, their locations are either unknown or inaccurately recorded. These historic-well sites present environmental, safety, and economic concerns in the form of possible methane leaks and physical hazards. Airborne magnetic and LiDAR surveys were conducted in the Pioneer Run watershed in Oil Creek State Park to find abandoned wells in a historically significant but physically challenging location. Wells were drilled in this area prior to modern geolocation and legal documentation. Although a large number of old wells were abandoned summarily without remediation of the site, much of the land area within Oil Creek State Park is now covered in trees and dense underbrush, which can obscure wellheads. The thick vegetation and steep terrain limited the possibility of ground-based surveys to easily find well sites for methane emissions studies. The data from remote sensing surveys were used to corroborate potential well locations from historic maps and photographs. Potential well sites were verified in a ground-based field survey and monitored for methane emissions. Two historic photographs documenting oil activity in the late 1800s were georeferenced using a combination of magnetic and LiDAR data. LiDAR data, which were more useful in georeferencing and in field verification, identified 290 field locations in the Pioneer Run watershed, 86% of which were possible well sites. Sixty-two percent of the ground-verified wells remained unplugged and comprised the majority of leaking wells. The mean methane emissions factor for unplugged wells was 0.027 ± 0.099 kg/day, lower than other Appalachian Basin methane emissions estimates. LiDAR was used for the first time, in combination with an airborne magnetic survey, to reveal underground oil industry features and inform well identification and remediation efforts in difficult-to-navigate regions. In the oldest oil fields, where well casing has been removed or wood conductor casing was installed, historic photographs provide additional lines of evidence for oil wells where ground disturbances have concealed surface features. Identification of well sites is necessary for mitigation efforts, as unplugged wells emit methane, a potent greenhouse gas.

Early medieval strongholds are a significant phenomenon in the archaeology of East Central Europe, as they mirror the political and socio-economic changes occurring towards the end of the Early Middle Ages. This contribution is concerned with the site of Břeclav-Pohansko (Czech Republic), which graphically illustrates the rise and fall of the Moravian principality during its short existence from the second half of the 9th to the beginning of the 10th century. The site has been systematically excavated over more than 60 years. The excavation work has been accompanied by numerous geophysical surveys. Based on comparing previous knowledge of settlement on the site and the results of magnetic prospection, we evaluated similarities and differences in the central district of the stronghold using statistics and spatial analysis. Upon analysis of the success rate of the applied geophysical method, we present the resulting model of the settlement structure. The results confirm that the structure of the builtup area in the central district at Pohansko follows an original pattern which has no analogues in the Central Danubian region in the given period.

Most earthen burial mounds of eastern North America have been destroyed—or have they? We review geophysical methods for assessing whether leveled mounds retain intact deposits or features. Magnetic survey holds promise for locating and evaluating leveled mounds because it is rapid and sensitive to magnetic variations associated with anticipated features such as pits and deposits of mound fill. As a case study, we discuss our magnetic survey of the Gast Farm site (13LA12) in eastern Iowa. The survey covered 8.64 ha, encompassing loci of one previously reported mound and possible geometric earthworks as well as Middle and Late Woodland habitation areas. Interpretation of survey results incorporated quantitative differentiation of magnetic anomaly types using GIS techniques, along with standard visual inspection. We found no evidence of geometric earthworks but identified at least six leveled mounds. Displaced mound fill appears to account for the earthwork-like features. We conclude that leveled mounds are detectable and may retain subsurface integrity. Their associated features, including burials, may be identifiable even when above-ground evidence has disappeared.

The geological structure of the White Sea area and the surrounding land areas has been well studied in the framework of individual case studies. There are a number of local models of the deep structure of the Earth’s crust available. We propose a uniform assessment of deep crustal bodies responsible for long-period (regional) magnetic anomalies and consider their correlation with surface structures. The aim of the study is to build a three-dimensional magnetic model of the Earth’s crust in the White Sea region using aeromagnetic data and modeling technologies of the Integro software package. The model is formed on the basis of a digital map of the anomalous magnetic field reduced to the pole. The sources of magnetic anomalies are considered to be located in the Earth’s crust. The 3D distribution of the relative magnetic susceptibility of rocks was obtained by solving the inverse problem of the magnetic survey. To separate the magnetic sources by frequency and depth, it was necessary to continue the magnetic field of the model upward and to calculate the TDR derivatives, which determine the lateral boundaries of the sources of positive magnetic field anomalies. 2D distributions of magnetic sources of the model for vertical and horizontal sections with depths of 10, 15 and 20 km are analyzed. The correlation between the surface and deep structures of magnetic sources of the Earth’s crust in the region is shown.

The purpose of the article is to highlight the process of establishing of the laboratory of natural science methods at the Institute of archaeology AS of the UkrSSR in the 1960s basing on archival sources from the Scientific archive of the Institute of archaeology NAS of Ukraine. The Research Methodology. Both general research methods and special methods of humanitarian and historical researches as the historiographic analysis, source critique and problem chronological method were applied by the author. The scientific novelty of the article consists in the fact that there are no publications on this topic and an initial period of the laboratory activity of natural science methods of the IA AS of the UkrSSR is unexplored. The Conclusions. In contrast to central archaeological research establishments of the USSR where forming of research infrastructure for applying methods of natural science in archaeology started in the 1950s, in Kyiv at the IA AS of UkrSSR this process began only in the middle of the 1960s despite an announce of the plans in 1956. Although the administrations of AS of the UkrSSR and the Institute supported the work in this field, but the laboratory of spectral analysis could not get things going for more than five years. The main technical equipment was bought by the IA AS of the UkrSSR as far back as in 1964 but because of the lack of free rooms, the need for qualified staff and bureaucratic delays of that period, which did not make it possible to solve problems rapidly, which appeared during the installation of new devices, researches did not start until the end of the decade. This situation changed only in the middle of the 1970s when the Institute of archaeology AS of the UkrSSR moved to a new building. But it was much better with applying geophysical methods in the survey of archaeological sites. Owing to V. P. Dudkin’s activity, who tested new equipment in the second half of the 1960s, a magnetic survey of the Trypillian settlement Maidanetske was completed in the first half of the next decade. In some period of time, despite the initial delay, the IA AS of the UkrSSR made progress in the use of research methods of natural science in archaeology. Keywords: history of archaeology, the Soviet archaeology, methods of natural science in archaeology, laboratory of natural science methods, Institute of archaeology AS of the UkrSSR.

The ground magnetic survey was carried out using a Scintrex proton precession magnetometer to map out subsurface structures and mineralization potentials at the Alajawa area in Shanon, Kano State. 2D forward modeling was in the delineation of geological structures that are potential mineralization zones. Surfer 15 software was used to produce a residual contour map. A total of five (5) profiles of the magnetic residual anomalies were modeled using Mag2dc software. The mineral potential locations were identified. The major zones with the potential of mineral resources were located at the depth of 14.81m, 1.71m, 10.83m, 14.25m, and 15.38m along profile AA’; 3.42m, 10.01m, 15.95m, 7.41m, and 2.28m along with profile BB’; 20.51m, 11.97m, 2.28m, and 27.35m along with profile CC’; 3.99m, 2.85m, 5.13m, and 6.27m along with profile DD’; 34.76m, 25.64m, 7.98m, and 8.55m along profile EE’. The bodies display susceptibility as high as 5.3380 SI Units and as low as -06.745 SI Units. The results of the research analysis revealed that the subsurface is composed of limestone, sandstone, and shale, granite or rhyolite rocks, gneiss, schist, slate, and quartzite.

Magnetic and ground penetrating radar (GPR) techniques are perhaps the most convenient and popular geophysical survey techniques for detecting the buried archaeological targets, because of their high speed and quality of information. The results of the two used techniques have been integrated in Dawwar Jabal, Fayoum Governorate, Egypt to detect the buried archaeological remains and their depths. The magnetic survey shows various high positive magnetic anomalies, some of these anomalies are related to the possible archaeological targets and the others are due to the mudstones which may include iron minerals. The results of the GPR survey after processing shows scattering and strong reflection of the subsurface oscillations along some profiles, which may reflect the existence of the possible buried objects. Meanwhile, no evidence of scattering or clear reflection for the signals are recorded along the other profiles which suggest that there is not any possibility of archaeological targets. The integration of the obtained results from the two used techniques indicates that there is some agreement in mapping the locations of the possible buried archaeological targets and their depths (1–7.5 m) for most of the detected targets. However, few targets are observed only on the data of one of the used techniques and disappeared along the other. This is related to the limitation of each technique. Therefore, such combination of the two mentioned techniques to detect the archaeological targets yields more information about the locations and depths of the buried targets than is obtain if each technique is used individually.

Magnetic measurements with an unmanned aerial vehicle are ideal for filling the gap between ground and airborne magnetic surveying. However, to obtain accurate aeromagnetic data, the compensation of magnetic effects of the unmanned aerial vehicle is a challenge. Typically, scalar magnetometers are towed several metres under the unmanned aerial vehicle to minimize its magnetic field. In this study, a fluxgate three‐component magnetometer is attached 42 cm in front of the unmanned aerial vehicle at the tip of a composite pipe. Using a scalar calibration, the sensor can be calibrated, and the permanent and induced magnetic fields of the unmanned aerial vehicle can be compensated. The contributions of the magnetic measurements at different altitudes to the unmanned aerial vehicle results were tested over an area of 1 km² in the Northern Vosges Mountains. The area is located in a hamlet surrounded by a forest where few geological outcrops are observed. Three magnetic surveys of the same area are obtained at different altitudes: 100, 30 and 1 m above the ground. The unmanned aerial vehicle magnetic data are compared with a helicopter aeromagnetic survey at 300 m above the ground and a ground magnetic survey using upward continuations of the maps to compare the results. The magnetic maps (300, 100, 30 and 1 m above the ground) show very different magnetic anomaly patterns (e.g. amplitude, shape, wavelength and orientation). The magnetic data at different altitudes improve the understanding of the geology from the local to more general scales.

В статье приведено обоснование применения геофизических методов, в частности магнито-метрического метода, для обследования сложной ритуальной и погребальной архитектуры кургана Туннуг-1 и его периферии (Пий-Хемский кожуун Республики Тыва). Результаты исследований показали, что территория в непосредственной близости к кургану использовалась в качестве места культовых мероприятий и ритуальных захоронений как в раннескифский период, так и племенами, проживавшими в данной местности в более поздние времена. В результате исследований обнаружены подповерхностные локальные каменные структуры, относящиеся к объектам погребальной архитектуры, неравномерно распределенные по всей околокурганной территории. Строительный материал каменных структур обладает разной магнитной восприимчивостью, что не мешает надежно локализовать данные археологические объекты с помощью магнитометрии. Площадная геомагнитная съемка оказалась эффективным методом для детального обследования погребальной архитектуры, определения и оконтуривания мест религиозно-культовой практики погребально-поминального цикла древних кочевников., The article provides the feasibility for the using of geophysical methods, in particular, the magnetometric probing for examining the complex ritual and funeral architecture of the early Scythian kurgan Tunnug-1 and its periphery (Piy-Khemsky District of the Tuva Republic). The survey results showed that the area near close to the kurgan was used as a place of religious events and ritual burials both in the early Scythian period and by tribes living in the area in later times. As a result of the studies, subsurface local stone structures belonging to the objects of burial architecture, unevenly distributed around the near the mound territory, were discovered. The building material of stone structures has different magnetic susceptibilities, which does not prevent to reliable magnetometry localization of these archaeological objects. Areal geomagnetic surveying has proven to be an effective approach for a detailed examination of the funeral architecture, determination, and contouring of places of the religious and cult practice of the funeral memorial cycle of ancient nomads.

We have developed the high-performance software and algorithmic software for solving the direct and inverse problems of modeling and inversion of spatially distributed magnetic, taking into account the relief. We show the results of solving the inverse problem of magnetic survey taking into account the relief for synthetic noisy data.

An algorithm for solving the inverse problem for determining the parameters of a buried archaeological object in the form of an elliptical cylinder (as a model of a typical burial or pit) is proposed. The estimation of accuracy of determination of parameters of the buried archaeological objects on the basis of the numerical solution of the inverse problem of magnetic prospecting for synthetic model is carried out. Its implementation included, firstly, the stage of modeling the magnetic field from a synthetic model of the archaeological site at three different heights for different parameters of the grid density and the size of the magnetic survey site and, secondly, the stage of solving the inverse problem from synthetic data at different heights, for different parameters of the magnetic survey and assessing the accuracy of the solution of the inverse problem. It is found that the accuracy of determining the parameters of the anomalous body is more affected by the size of the survey area than the density of the measurement network. There is also a tendency to increase the accuracy of determining parameters when using data of different heights. Approbation of the algorithm for solving the inverse problem on real data of different-altitude magnetic survey over the burial at the archaeological site Tartas-1 showed quite good results. The average error in determining the geometric parameters of the body and its occurrence is ~ 15 %.

The use of unmanned aerial vehicles (UAVs) in geophysical work is becoming a very popular area in the field of modern geological exploration. The advantage of unmanned systems is the optimal ratio of the quality of research results with a significant increase in work productivity and a decrease in cost. In this regard, the improvement of field techniques and the processing of UAV materials is of particular interest for exploration. On the subject, there are a number of unresolved issues that have been revealed to some extent as a result of the author’s comparison of ground-based magnetic exploration and aeromagnetic survey data. The purpose of the study was to assess the possibility of a full-fledged replacement of ground magnetic exploration work for aeromagnetic survey using unmanned aerial vehicles. The comparison of different types of magnetic survey is relevant, since on the basis of the actual material, the possibility of using an alternative more productive method – aeromagnetic survey using modern UAVs – instead of traditional expensive ground-based magnetic exploration works is analyzed. To compare the results of the studies, actual material obtained from field work on an area of 13,4 km2 was used. Based on the databases, maps of anomalous magnetic field and graphs on several geophysical profiles are built. Results of magnetic survey in air and ground versions are analyzed; correlation relationships between data of ground pedestrian magnetic survey and aeromagnetic system on An-3 and UAV aircraft are established. Based on the results of the study, correlation and determination coefficients were obtained, which indicate that geophysical methods on UAVs adequately occupy their place between classical aerogeophysics and ground-based pedestrian survey. Moreover, aeromagnetic survey using UAVs is able to replace pedestrian magnetic exploration during work at the same heights. Based on the results of the study, methodological recommendations for the production of aeromagnetic survey on UAVs were compiled

In 2019, Polish archaeologists took part in an expedition of the Hermitage Museum, led by K.V. Chugunov, in Chinge-Tey cemetery, Tuva (Russian Federation). This paper presents the results of magnetic surveys carried out within the so-called western chain of barrows and around the princely barrow of Chinge-Tey I. This method of non-invasive research is very well suited to the landscape and has produced a significant body of information. Among others, the survey of the western chain identified a stone mantle in barrow 8, which makes it different from other barrows from this group, whose mounds were built of earth. Another important result is the identification of a stone circle surrounding a cult feature (certainly associated with eschatological rituals) known as the northern complex. The presence of the circle came as a surprise for the investigators of the site, as it does not manifest itself at all on the surface of the site. On the other hand, worth noting is one negative result, which nevertheless allows for some conclusions, namely the lack of detectable anomalies connected with one of the tombs in the vicinity of Chinge-Tey I (barrow 15). Despite being clearly discernible in the landscape, and even more evident in LIDAR images, the barrow is invisible on images produced with a magnetometer. This means that one cannot rule out a possibility that other structures undetectable by magnetic surveys may be present within the investigated part of the cemetery. Nevertheless, one cannot but arrive at the conclusion that the results generated by the magnetic research provide significant information concerning the spatial arrangement of the cemetery and are helpful in planning of archaeological excavation.

В данной статье представляется экономический сравнительный анализ комплекса геофизических методов, состоящий из гравиразведки, сейсморазведки, магниторазведки и магниторазведки, и поискового бурения на участке Центральный в Казахстане. Предложенный комплекс методов позволяет значительно сэкономить общую стоимость исследования за счет уменьшения объема поискового бурения, а также за счет применения геофизических методов значительно улучшить качество выходных данных., This article presents an economic comparative analysis of a complex of geophysical methods, consisting of gravity, seismic, magnetic and magnetic surveys, and exploratory drilling in the Central area in Kazakhstan. The proposed set of methods can significantly save the total cost of the study by reducing the volume of exploratory drilling, as well as significantly improve the quality of the output data through the use of geophysical methods.

The purpose of the work is development of a complex seismic-density-magnetic model of the geological cross-section for the geotraverse SG-1 (67) (Nadvirna―Otynia―Ivano-Frankivsk) and appreciation of oil and gas bearing perspectives in the Kolomyia Paleovalley. The research methodology is based on the analysis of anomalous gravity and magnetic fields and the creation of density and magnetic models of geological cross-section. Local anomalies are defined by methods of transformations. Modeling of the geological cross-section structure is performed by methods of solving direct and inverse problems of gravity and magnetic survey, which implemented the ideas of the criteria approach to creating optimal models of geological environments that are consistent with the observed geophysical fields and do not conflict with the data of drilling and seismic survey. The reliability of interpreting gravimagnetic data method is achieved by geological subordination: the condition of maximum application of seismic survey and geological and tectonic maps. The conceptual density model and magnetic model of the geological environment along the seism-geological profile of CG-I (67) was developed. The distribution of densities and magnetization of rocks in sedimentary cover and basement blocks to a depth of 20 km is detailed. As a result of modeling within certain stratigraphic complexes, zones with anomalous in density and magnetization of rocks were defined. The decompression zones, which are within positive structures, are identified as perspective ones. It is also confirmed that there is a high probability of deep intrusions that are predicted from materials of seismic survey within the limits of the hidden tectonic zone and reaching the bottom of sedimentary cover. The analysis of morphology of gravity and magnetic anomalies and gravimagnetic modeling allowed clarifying the geological structure of the Kolomyia Paleovalley cross-section and to appreciate oil and gas perspectives of its separate areas.

Integrating geophysical survey with the study of community settlement patterns can be challenging because of cultural and environmental factors including (1) site formation and house preservation, (2) the coordination of domestic tasks at extra-household scales, and (3) the survey environment of the study area. In this article, we present the results of a program of geophysical survey comprising magnetic susceptibility and magnetometry at Weeden Island (8Pi1)—a shell-bearing, wooded site with nearly pure sand soils on the Gulf Coast of Florida. Combining remote sensing techniques mitigated some of the challenges of surveying forested terrain while providing insight into community organization at a site with minimal preserved structural remains. Compared with previous traditional surveys of the area, the geophysical survey extended the recognized boundaries of occupational activity, provided additional definition to the spatial structure of deposits, and allowed us to identify specific domestic features. Excavations at each area of intensive occupation provided evidence about the organization of the domestic economy at the site and showed the potential of this approach to reveal significant patterns of community settlement.

This work aims to identify sedimentary and basal rocks structures in the Sepetiba Bay Basin (Rio de Janeiro State, SE Brazil) located in the western portion of Guanabara Graben formed during the course of Paleocene tectonic activity. Two distinct geophysical tools were used to investigate the geological records by the integration of geological survey and geophysical data: Ground-penetrating radar (GPR) and Ground Magnetic survey. GPR results allowed to interpret and delimit subsurface layers of the basin. It was observed in the analyzed all sections, that the most superficial layers of the radargrams (about 8 meters; with Radar 100 Mhz) the presence of clay and silty sediment layers, related to a calm depositional environment and below 8 m sandy layers related to more energetic depositional environment were found. These sedimentological changes should be influenced by sea level oscillations and marine transgressions in this area. Magnetic ground survey allowed to identify basement rocks of the Sepetiba Bay Basin and to confirm the event of sea level rise. REGISTROS DE TRANSGRESSÃO MARINHA NA REGIÃO DE SEPETIBA BAY (RJ-BRASIL). PESQUISA COM GPR E MAGNÉTICA EM TERRAResumoEste trabalho tem como objetivo identificar estruturas de rochas sedimentares e basais na Bacia da Baía de Sepetiba (Estado do Rio de Janeiro, SE Brasil), localizada na porção oeste da Guanabara Graben, formada durante o curso da atividade tectônica do Paleoceno. Duas ferramentas geofísicas distintas foram usadas para investigar os registros geológicos pela integração do levantamento geológico e dos dados geofísicos: GPR e levantamento magnético do solo. Os resultados do GPR permitiram interpretar e delimitar as camadas subterrâneas da bacia. Observou-se nas seções analisadas, que nas camadas mais superficiais dos radargramas (cerca de 8 metros; com Radar 100 Mhz) a presença de camadas de argila e sedimentos sedimentares, relacionadas a um ambiente deposicional calmo e abaixo de 8 m de camadas arenosas relacionadas a ambiente deposicional mais energético. Essas mudanças sedimentológicas devem ser influenciadas por oscilações do nível do mar e transgressões marinhas na área. O levantamento magnético do solo permitiu identificar rochas subterrâneas da Bacia da Baía de Sepetiba e confirmar o evento de elevação do nível do mar. Palavras-chave: Área costeira. Evolução da bacia sedimentar. Alterações passadas no nível do mar. Magnetometria. GPR.

An integrated geophysical survey was carried out in Igbo Oritaa, a suburb of Iwo town (southwest Nigeria). The study was part of an archaeological investigation initiated by the Iwo community to identify and preserve the town’s ancient sites. The geophysical investigations involved ground magnetic profiling, 1D vertical electrical sounding (VES), and 2D electrical resistivity imaging. The magnetic survey revealed anomalies of dyke-like features (central magnetic low [negative] flanked by low amplitude positive shoulders), linear depressions with prominent negative amplitude magnetic lows, and a moderately high amplitude magnetic anomaly coinciding with an old trench and several anthropogenic mounds. The resistivity survey also indicates the presence of subsurface archaeological features, including ditches and walls. Excavation units were selected based on these geophysical attributes. The excavations uncovered dense deposits of potsherds, animal bones, shells, beads, iron slag fragments, a human premolar, metallic objects, a flute, and an architectural feature, possibly the foundation of a house. The geophysical survey and the test excavations confirm that Igbo Oritaa was an ancient settlement, consistent with the oral traditions. This paper presents the geophysical methods and results, the relationships between geophysical prospecting and test excavations, as well as the implications for community-focused archaeological research design, and site interpretation and preservation.

Using remote sensing technology, GIS technology and virtual reality technology, the remote sensing image and DEM data are superimposed to establish a three-dimensional remote sensing image model of the low-altitude magnetic survey flight work area. The three-dimensional model can clearly reflect the distribution of surface vegetation, rivers, wetlands and other ground features with topographical features, and can design flight routes based on survey lines to achieve simulated flight and generate three-dimensional animations. In the preparatory stage of flight work, simulated flight animation can visually display terrain undulations and surface coverage to technical personnel, guide the deployment of flight work, and provide decision support for large-scale low-altitude aeromagnetic surveys.

Summary The use of advanced solid-state gyroscopic sensors has become both a viable and practical option for high-accuracy wellbore placement, with the potential to outperform traditional mechanical gyroscopic systems. In this paper, we describe how the contributions of the new gyroscope technology are causing service providers to reconsider current survey practices, and to examine how the new gyroscopic-survey tools can best be used for wellbore surveying and real-time wellbore placement. The simultaneous application of multiple survey tools, largely made possible as a result of the unique attributes of solid-state gyroscopic sensors (including small size and significant power reduction), has clear benefits in terms of enhanced well placement, reliability, and the detection of gross errors in the survey process. Further advantages accrue through the combination of different but complementary survey methods. In this paper, we focus mainly on the benefits of combining gyroscopic and magnetic measurements to reduce or remove the known errors related to the Earth's magnetic field to which magnetic-survey systems are susceptible: errors in total magnetic field, declination, and dip angle. In this context, the use of statistical estimation techniques depending on the performance models of the survey systems used is described. For post-drilling surveys (using drop-survey tools or wireline-conveyed tools, for example), post-run analysis of the data using least-squares estimation techniques is appropriate. Alternative methods capable of achieving real-time data correction during drilling are also described, and results are presented to demonstrate the potential for enhanced magnetic-survey performance. The principles described can be used when running basic magnetic measurement-while-drilling (MWD) systems and for systems that use field correction methods, such as the various in-field referencing (IFR) techniques, that are frequently used. The proposed methodology is of particular benefit in the former case, allowing enhanced magnetic surveying to be achieved without the need for expensive and complex magnetic-field correction procedures. The potential also exists either to identify or to correct possible errors in the IFR data when such methods are used. The particular strength of the methods described in this paper is in the estimation and correction of errors in the Earth's magnetic-field parameters while drilling, or after a section of the well has been drilled. Currently, all the magnetic models are dependent on magnetic measurements alone and at the surface or in space. Although there are techniques to estimate the downhole values, such techniques are difficult to quality control (QC) or validate. These updated magnetic-field data allow further sections of the same well, or additional wells in the same region, to be drilled using MWD alone, without the need to use field referencing techniques to achieve accurate well placement. The consequent rig-time and cost savings are expected to be significant.

Parallel pipeline detection is a difficult problem in underground pipeline detection. Gravity and magnetic surveys have the advantages of convenient monitoring, high sensitivity, and high accuracy. Therefore, we used gravity and magnetic surveys to detect parallel pipelines. In this paper, the effect of parallel pipeline parameters on the characteristics of gravity and magnetic surveys is studied in order to find out the quantitative relationships between them and to provide the theoretical basis for inversion interpretation. When calculating the magnetic anomaly of a pipeline, we considered the demagnetization effect of the pipeline and determined its demagnetization coefficient to be 0.12 by numerical calculation. Parallel pipeline parameters include geometric parameters (such as outer diameter ratio, pipe axis spacing, buried depth, and azimuth, etc.) and physical parameters (density and magnetic susceptibility). The characteristics of gravity and magnetic surveys include not only the amplitude of abnormal peaks, the number of abnormal peaks, and abnormal peak spacing of gravity and magnetic anomaly curves, but also the detection error of gravity and magnetic surveys in parallel pipelines. We defined the relative error of the pipe axis spacing of parallel pipelines as the detection error. We established a forward model for parallel pipeline detection and analyzed the effect of model parameters on the characteristics of gravity and magnetic surveys. Results show that gravity and magnetic surveys cannot detect pipelines parallel to the measurement line and the magnetic survey can only detect pipelines with ferromagnetism . The amplitude of abnormal peaks is affected by all parallel pipeline parameters, while the number of abnormal peaks, abnormal peak spacing, and detection error are only affected by the outer diameter ratio, pipe axis spacing and buried depth. If the upper limit of the detection error is determined to be 10%, gravity and magnetic surveys of parallel pipelines have minimum discernible pipe axis spacing. Through further research, it is found that when the outer diameter ratio is 1, the minimum discernible pipe axis spacing is minimal. The minimum discernible pipe axis spacing increases linearly with the increase of buried depth. When all parallel pipeline parameters are identical, the minimum discernible pipe axis spacing of the gravity survey is greater than that of the magnetic survey. The research results show that the magnetic survey is more suitable for detecting parallel underground pipelines than the gravity survey, and the experiment of magnetic anomaly measurement of parallel pipelines also shows that it is feasible to detect parallel underground pipelines by the magnetic survey.

Magnetic surveys are conventionally performed by scanning a domain with a portable scalar magnetic sensor. Unfortunately, scalar magnetometers are expensive, power consuming and bulky. In many applications, calibrated vector magnetometers can be used to perform magnetic surveys. In recent years algorithms based on artificial intelligence (AI) achieve state-of-the-art results in many modern applications. In this work we investigate an AI algorithm for the classical scalar calibration of magnetometers. A simple, low cost method for performing a magnetic survey is presented. The method utilizes a low power consumption sensor with an AI calibration procedure that improves the common calibration methods and suggests an alternative to the conventional technology and algorithms. The setup of the survey system is optimized for quick deployment in-situ right before performing the magnetic survey. We present a calibration method based on a procedure of rotating the sensor in the natural earth magnetic field for an optimal time period. This technique can deal with a constant field offset and non-orthogonality issues and does not require any external reference. The calibration is done by finding an estimator that yields the calibration parameters and produces the best geometric fit to the sensor readings. A comprehensive model considering the physical, algorithmic and hardware properties of the magnetometer of the survey system is presented. The geometric ellipsoid fitting approach is parametrically tested. The calibration procedure reduced the root-mean-squared noise from the order of 104 nT to less than 10 nT with variance lower than 1 nT in a complete 360 degrees rotation in the natural earth magnetic field.

Recent advances in autonomous unmanned aerial vehicle (UAV) technology, along with successful efforts to miniaturize total field magnetometers, offer a unique opportunity to test low-cost UAV-mounted systems for wide-area high-resolution magnetic surveys. Modern UAV platforms capable of flying at low altitudes and collecting dense aerial surveys, coupled with sensitive and compact instruments, allow identification of anthropogenic targets previously identifiable only in ground magnetometer surveys. We present results of a proof-of-concept study focused on developing and field testing a UAV-based magnetometer system to detect and identify abandoned and unmarked oil and gas wells in an area of historical hydrocarbon exploration and development in New York state. Our results indicate that magnetic anomalies associated with metal casing of vertical wells are pronounced considerably above background levels both at the surface and up to 50 m above-ground elevation. We determine that a detection altitude of 40 m is optimal to avoid any canopy interference while recording magnetic data at the highest signal-to-noise ratio. This methodology makes rapid detection and identification of unmarked wells possible and, in turn, allows for future sustainable development of these areas.

A geophysical survey was carried out at Tattapani thermal spring Azad Kashmir to delineate structure,thickness, depth, lithology and migration of hot plumes contaminating fresh water. The study area was investigated byVertical Electrical Sounding (VES) using schlumberger array at 21 locations arranged in ten profiles to a maximumdepth of 500 m and 200 magnetic observations. The extension and tectonic setup of thermal spring was mapped bygeoelectrical litho sections, subsurface geological sections (20m, 20-100m and 100-500m) pseudo section, apparentresistivity map, geoelectrical parameters, statistical distribution of apparent resistivity, total magnetic intensity andanomaly map. The data show that Tattapani hot spring is concentrated along the fault line delineated by geoelectricallitho sections and magnetic section with value of -120 nT to -300 nT, total field intensity of 50000-50450 nT andconfirm by macro anisotropy (1.0 to 2.7). The geoelectrical lithological section portrays that study area compriseslithological fabric of dolomite (≥400 ohm.m), sandstone (150-200 ohm.m), clay (80-150 ohm.m), Shaley clay (50-80)and shale (≤ 50). The Thermal Plumes (10-70 ohm.m) were pictured by resistivity section and pseudo section ataverage depth of 30-60 m and showing migration of hot plumes in the North-Eastern direction contaminating freshwater (100-200 ohm.m). The longitudinal conductance (0.95-15 mhos), transverse resistance (20-300 ohm.m2) are seenhaving maximum value in the North-Eastern and North-Western side of the study area. The study also shows that freshground water is mostly concentrated in sandstone (150-200 ohm.m), dolomite (≥400 ohm.m) and lies above the thermalplumes and thus highly prone to contamination due to upwelling of thermal water.

A newly developed quantitative method, Data-Coordinate Interpolation Technique (DCIT) was used by matching the secondary and primary data to correct the variation that exists between airborne and g...

Magnetic survey methods have recently shown tremendous potential for the detection of archaeological hearths in Eastern Beringia, ranging from intermittent open-air camp fires to larger heat intensive activity areas. Here we present an overview of the method along with eight supporting case studies from seven U.S. National Park Service units in the U.S. state of Alaska, covering diverse geographic settings and time-periods. Together, these case studies demonstrate the capabilities of magnetic detection instruments in various modes of operation for finding datable archaeological deposits that span the breadth of known human occupation of this region. The examples range from the simplest use of the magnetometer as a single sensor reconnaissance instrument in a “search mode”, to use as a gradiometer in conjunction with other geophysical methods such as ground-penetrating radar, to record precise measurements and inform nuanced interpretations. Examples presented here range from the terminal Pleistocene to historic periods, spanning 12,000 years of human activity in Eastern Beringia, and encompassing the arrival, emergence, and expansion of multiple human groups or cultural traditions in the New World.

In August–September, 2018 in the Pechora Sea during the 38th flight of NIS “Academician Nikolay Strakhov” complex geologic-geophysical researches were conducted. Magnetic survey was carried out along with seismic profiling where as the radiator of elastic fluctuations the electrospark Sparker radiator was used. The group of a sea magnetometry was faced by a problem of mapping of the top layer of a sedimentary cover, including allocation of zones of development of thin deposits, buried paleochannels, zones of jointing and geological explosive violations. Hydromagnetic survey and interpretation of the received materials was as a result executed that allowed to estimate spectral structure of the abnormal magnetic field (AMF) and to allocate three frequency components to which there corresponds the deep range of sources of the field. Leaning on the received estimates of depths, and comparing them to the description of wells, also temporary bindings for the allocated deep ranges of sources of magnetic field were defined. High-frequency component, there corresponds the arrangement of sources of AMF in the topmost part of a section. The top edges of sources lie in the range of depths from 35 to 70 m that possibly correspond to deposits of pleystotsenovy age. It is possible that the thin deposits created during the last Valdai freezing can be sources of these high-frequency anomalies. The second deep range is created by sources of AMF the top edges of which are located in the range of depths of 260–510 m that possibly corresponds to stratigrafichesky range from top Yura to the lower chalk. The third, the deep range of bedding of the top edges of sources of AMF allocated by authors is determined by the most low-frequency part of a range and according to authors reflects the late Devonian stage of activization of magmatism.

Gravity and magnetic surveys were carried out in southwestern part of Cuddapah basin (CB) covering an area of ~3660 km2. Southwestern part of CB gained lot of attention after discovery of second most important uranium province in India. Some non-metallic industrial minerals and base metal occurrence are also reported in the study area. Present study with high spatial resolution gravity-magnetic survey aims to decipher detail basin geometry, nature of sediments, along with possible mineral deposits in SW part of CB. The gravity survey comprising short and long wavelength anomalies brought out sedimentary characteristics and basement architecture underneath the sediments. The long wavelength features of the gravity map shows gneissic basement, which is characterized by both basic and acid magmatic intrusive. Residual gravity anomaly map shows good correspondence with the exposed high density basaltic rock units and also brought out occurrence of concealed high density litho-units, which have significance for mineral prospecting. The magnetic map shows that both sediments and underneath basement are non-magnetic in nature except SW part of the study area, where study suggests occurrence of concealed mafic lensoid body. Euler solutions and combined gravity-magnetic modelling further facilitated for understanding of structural feature and basement geometry. Based on the integrated gravity and magnetic study mineral prospecting zones have been delineated for further detailed study.

An integrated magnetic survey was carried out on key places within the La Quemada archaeological complex, built over a hill on the northern frontier of Classic period Mesoamerica. Samples were collected from the Plaza of Sacrifices and Hall of Columns in an attempt to precisely determine the age intervals corresponding to the decline and abandonment of the site, apparently due to the intentional firing as a closure ritual. Well-defined characteristic remanent magnetizations were retrieved from 23 of 32 samples. Moreover, twelve samples belonging to two areas yielded reliable determinations under criteria curtailed in this study. In any case, a primary remanent magnetization is carried by pseudo-single-domain Ti-poor titanomagnetite, as evidenced by hysteresis and continuous thermomagnetic curves. The archaeomagnetic dating was performed using full geomagnetic vector (directions and absolute intensity) using the last SHADIF14k model. The Plaza of Sacrifices seems to been burned between a time interval from 854 to 968 CE, while a late interval from 1018 to 1163 CE is assigned to the samples collected in the Hall of Columns, which suggest the gradual abandonment of the site. The first abandonment stage is almost synchronous to the same phenomena observed for other sites at the Bajio area (central and western Mesoamerica) region. Under these circumstances, it cannot be discarded that La Quemada was burned in its entirety during the first stage of abandonment, but the Hall of Columns was again burned later.

The present study aimed to develop an integrated approach that utilized field geology, remote sensing and airborne magnetic data to identify the Quaternary aquifers impounded by dykes and explain the dykes/lineaments relationship and their effects on the storage and flow of the groundwater of Sadiyah sub-basin, lower part of Wadi Yalamlam basin, Western Arabian Shield, Saudi Arabia. Field visits supported by Landsat ETM + ratio images (5/7, 5/4 and 5/1) revealed the presence of three main dyke types that can be chronologically arranged from older to younger as: Sheared mafic and acidic dykes (D1); Damm dyke complex (D2); and Ghumayqah dykes (D3). Two dykes referred to the first type (D1) were traced with depth using airborne magnetic survey crosscutting the main course of Wadi Yalamlam around Sadiyah village at high angle. According to water table elevation measurements, the aquifer of lower Wadi Yalamlam area is divided into three parts namely I, II and III. The water table elevations decreased from 158 m in the first part (I) to reach 66 m in the third part (III) of the aquifer. This drop is attributed to the effect of dykes which act as natural barriers. The study area was affected by three major fault systems as confirmed by field study and total magnetic map. Two of these systems have NE–SW to ENE–WSW and N–S to NNW–SSE directions, whereas the third one represents the Najd fault system trends in NW–SE direction. The present study identifies two locations valid for agricultural expansion lie just to the north of Sheikh Said and Abu Helal Farms.

U radu se prikazuju rezultati arheoloških istraživanja na osam nalazišta sopotske kulture na području sjeverno od Đakovštine. Nalazišta su u raznim stupnjevima istraženosti – od zračne daljinske prospekcije i rekognosciranja, do arheološkoga iskopavanja te primjene magnetometrijske metode. Istraživanjima se ustanovilo kako su nalazišta sopotske kulture mnogo većega opsega i mnogo kompleksnije strukture nego što se to do sada smatralo te se predlaže reevaluacija dosadašnjih spoznaja. Sva su naselja omeđena s jednim ili više opkopa, osim naselja Đakovo – Grabrovac/Ciglana za kojega nije moguće utvrditi da li je imalo opkop, budući da je veći dio nalazišta uklonjen aktivnostima ciglane. Nalazi s osam naselja analizirani su tipološki i kronološki u kontekstu ostalih nalazišta sopotske kulture na području Slavonije., The paper presents the results of archaeological research at eight sites of Sopot culture in the area north of the town of Đakovo. The sites are in various stages of investigation – from aerial remote sensing and reconnaissance, to archaeological excavation and the application of the magnetic survey. It has been established through recent research that the sites of the Sopot culture are of a much larger scale and of a much more complex structure than previously thought, and it is proposed to re-evaluate the current interpretations. All settlements are enclosed by one or more ditches, except for the Đakovo – Grabrovac/Ciglana settlement for which it is not possible to determine whether it had a ditch, since most of the site was removed by the activities of the brickworks during the 20th century. The findings from eight settlements were analysed typologically and chronologically in the context of other sites of Sopot culture in Slavonia.