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Satellite observations of the Antarctic surface since the 1990s, coupled with geophysical surveys of the flow and form of its giant ice sheet, have revealed accelerating loss of ice to the oceans. This, coupled with a reduction in floating sea ice surrounding the continent and the occurrence of unprecedented heatwaves, point to a continent being changed irreversibly by fossil-fuel burning and the global heating that results. A changing Antarctic continent will have global consequences, including sea level rise of possibly more than 1 meter in this century (and much more afterward) and by a reduced ability to naturally reflect incoming solar energy—which would lead to further heating by absorption on land and at sea as the ice pack retreats. [ABSTRACT FROM AUTHOR]

Core drilling has been used successfully in archaeology for a variety of applications, including mapping stratigraphy across large areas, estimating feature depth and content, understanding site formation processes, as well as complementing information obtained through surface collection and geophysical survey. In this paper, we provide an overview of the first core drilling campaign carried out in 2021 on the outer settlement of the Bronze Age tell from Toboliu in western Romania. The overall aim of this coring program was to gather information regarding the nature of various features within the settlement, with a focus on the anomalies visible in the geomagnetic site plan. Based on 165 drilled cores, a reconstruction of the site's stratigraphy is presented in this paper. This reconstruction was controlled and confirmed by excavations in one of the coring transects where the stratigraphic interpretation of the cores could be linked with the excavated stratigraphy. Additionally, samples for radiocarbon dating were collected from several cores. Based on this data, we discuss preliminary insights into possible house locations and preservation issues, as well as the chronological development and occupation sequence of this complex site. [ABSTRACT FROM AUTHOR]

ABSTRACT The understanding of urban centres in the ancient Near East, one of the main regions for investigating the development of cities, has been transformed in recent years through investigations using archaeological geophysical prospection tools. This paper presents results of our recent magnetic gradiometry survey at the large urban site of Türkmen‐Karahöyük (Konya Plain, Turkey) conducted using a SENSYS Magneto MXPDA cart‐based system. Results of the survey have successfully identified and characterized numerous areas of ancient settlement, industrial activity and burials across the massive site, offering new insights into the history of occupation at Türkmen‐Karahöyük. Our findings are thereby helping to shape future investigations at the site and, more broadly, demonstrate the opportunities and challenges presented by cart‐based geophysical survey instruments for archaeological investigations of mounded urban sites with extensive lower towns. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms responsible for the origin, evolution, and failure of pingos with explosive gas emissions and the formation of craters in the Arctic permafrost requires comprehensive studies in the context of fluid dynamic processes. Properly choosing modeling methods for the joint interpretation of geophysical results and analytical data on core samples from suitable sites are prerequisites for predicting pending pingo failure hazards. We suggest an optimal theoretically grounded workflow for such studies, in a site where pingo collapse induced gas blowout and crater formation in the Yamal Peninsula. The site was chosen with reference to the classification of periglacial landforms and their relation to the local deformation pattern, according to deciphered satellite images and reconnaissance geophysical surveys. The deciphered satellite images and combined geophysical data from the site reveal a pattern of periglacial landforms matching the structural framework with uplifted stable permafrost blocks (polygons) bounded by eroded fractured zones (lineaments). Greater percentages of landforms associated with permafrost degradation fall within the lineaments. Resistivity anomalies beneath pingo-like mounds presumably trace deeply rooted fluid conduits. This distribution can be explained in terms of fluid dynamics. N–E and W–E faults, and especially their junctions with N–W structures, are potentially the most widely open conduits for gas and water which migrate into shallow sediments in the modern stress field of N–S (or rather NEN) extension and cause a warming effect on permafrost. The results obtained with a new workflow and joint interpretation of remote sensing, geophysical, and analytical data from the site of explosive gas emission in the Yamal Peninsula confirm the advantages of the suggested approach and its applicability for future integrated fluid dynamics research. [ABSTRACT FROM AUTHOR]

This study introduces a novel multi-channel predictive deconvolution method enhanced by Shearlet-based sparse regularization, aimed at improving the accuracy and stability of subsurface seismic imaging, particularly in offshore wind farm site assessments. Traditional multi-channel predictive deconvolution techniques often struggle with noise interference, limiting their effectiveness. By integrating Shearlet transform into the multi-channel predictive framework, our approach leverages its directional and multiscale properties to enhance sparsity and directionality in seismic data representation. Tests on both synthetic and field data demonstrate that our method not only provides more accurate seismic images but also shows significant resilience to noise, compared to conventional methods. These findings suggest that the proposed technique can substantially improve geological feature identification and has great potential for enhancing the efficiency of seabed surveys in marine renewable energy development. [ABSTRACT FROM AUTHOR]

The growing expansion of the economy and population has resulted in an increased inclination towards the utilization of groundwater resources. Conducting a geophysical survey is a widely employed method for subsurface mapping and the detection of groundwater. A geophysical study was conducted in Nanshan township, Huarong County, located in the Hunan province of the South-Central region of China. The investigation involved the utilization of a 2D electrical resistivity imaging technique employing forward and inverse pole–dipole electrode arrays. A total of six survey lines were established, each with an electrode distance from the nearest measuring point exceeding 800 m. The maximum current electrode separation was utilized in this setup. The spacing between the electrical resistivity sounding points was established at regular intervals. The findings from the exploration indicate the existence of multiple faults within the surveyed region. The study additionally identified two regions of structural failure, which occurred due to the convergence of faults oriented in different directions. This convergence led to the fracturing of rocks, an increase in water content, and a decrease in resistivity. The findings from the exploration were utilized in the formulation of five verification target boreholes. The results of this study offer significant insights that can inform future investigations into groundwater exploration endeavors within the region. [ABSTRACT FROM AUTHOR]

Developing a geophysical test site (GTS) to a full target requires a lot of work in sequential order. This article presents the construction procedures and requirements for developing a GTS, field measurements, geophysical response analyses, and site descriptions. A GTS is an experimental site that contains several targets of known properties, materials, and parameters, buried at different locations, depths, and orientations. The 55 m × 55 m multi-purpose GTS was developed within the Ahmadu Bello University Geophysics Test Site (ABUGTS). The site was developed on a lateritic-clay soil within a shallow depth of 0.6–3 m to study the geophysical signature of various burial scenarios and replicate situations usually encountered in geophysical surveys, engineering, and environmental investigations. A pre-buried investigation with integrated geophysical methods was conducted to provide adequate information about the site condition. The integrated geophysical methods were also explored on a few buried targets for test runs alongside a laboratory test to determine the electrical and magnetic properties of the buried targets. The pre-burial study indicates that the site's electrical resistivity (ER) values decrease significantly from 1081 Ωm to 47 Ωm with depth due to the regional groundwater effect. The post-burial investigations show positive results, corresponding to the laboratory results. The post-burial results show that the subsurface resistivity of the burial terrain decreases from 200 to 0.1 Ωm due to the influence of the buried metallic target and increases from 1081 to 110,000 Ωm due to the influence of the buried non-metallic target, while the total magnetic intensity of the site increases from 44,500 to 48,000 nT. Seismic result shows distortion in subsoil layers after the buried target, confirming a significant influence of the natural geophysical signature of the site by buried targets. The implications of the GTS on economic growth and educational activities were discussed. Geophysicists, researchers, and institutions can now take advantage of the site to explore the existing and new geophysical techniques routinely employed in geophysical investigations. Geophysical equipment manufacturers and individuals can also use the site for instrument configurations. The site can provide an experimental site to appreciate the nature of subsurface anomalous generated by different buried targets. It can serve as a guide for modelling new GTSs while bridging the gaps between hypothetical teaching and real-life problems through effective field-based exercises. [ABSTRACT FROM AUTHOR]

The newly constructed Bois d'Arc Lake Reservoir in Fannin County, Texas, USA, inevitably flooded a large ground surface area (67.34 km2) when the reservoir began impounding water in April 2021. Inside this (now) flooded area, land-based archaeological data recovery investigations discovered and documented several archaeological sites, now registered in the state of Texas; though, only two neighboring sites, namely, 41FN178 and 41FN244, are examined here. The first phase of archaeological testing at these sites included shovel testing, test unit excavations, and geoarchaeological trenching that yielded archaeological artifacts suggesting that Middle Caddo Indian peoples (AD 1200–1400) might have occupied this landscape. As the sites were recognized before the reservoir's impoundment phase, this merited a non-invasive, non-destructive, high-resolution near-surface geophysical study to map strategic areas within sites 41FN178 and 41FN244 that might yield potential shallow targets of archaeological context. The adopted geophysical survey comprised 3D direct current electrical resistivity imaging (ERI) and land horizontal magnetic gradiometry (HMG), each mapping a total surface area of 2133 and 15,640 m2, respectively. The combination of 3D ERI and land HMG surveys was instrumental in rapidly mapping the horizontal and vertical extent of shallowly buried anomalies within a large area prior to the completion of the dam and the beginning of water impoundment. Based on the geophysical insights, the outline of several Caddo houses with functional internal and external features (e.g., burnt cooking surfaces, storage pits, refuse pits, fired soil, ditches, a dump site, and a compound fence) are thought to exist within the uppermost 2 m of the Quaternary stratigraphy at both sites. At site 41FN244, 3D ERI found numerous resistive anomalies surrounding a conductive anomaly, collectively interpreted as a group of post-holes surrounding the remains of a Caddo house's inner clay floor. It also found a cluster of several resistive anomalies interpreted as midden or middens. The HMG survey carried across areas from which archaeological test units also yielded positive findings, at sites 41FN178 and 41FN244, identified numerous scattered monopolar and dipolar anomalies interpreted as post-molds of Caddo houses, compound enclosures or fences, and adjacent middens. Archaeological excavations guided by the geophysical results yielded significant cultural material and post-mold features at site 244, which validate the geophysical interpretation in a preliminary context. Additionally, several dispersed magnetic anomalies are thought to be shallowly buried hearths, burn cooking surfaces, storage pits, and ditches. The mapped magnetic anomalies agree with the location and distribution of previously found archaeological artifacts and the extent of resistive and conductive resistivity anomalies. Follow-up archaeological excavations of these geophysical anomalies have preliminarily confirmed interpretations. [ABSTRACT FROM AUTHOR]

This work proposes the development of a software module for studying historical and cultural heritage objects using remote and non-invasive research data. The module aims to integrate modern technologies such as image processing, data analysis, and visualization to provide access to heritage information for researchers, conservators, and the general public. Utilizing non-invasive data, such as geophysical surveys, enables the collection of information about heritage objects without causing damage. The module facilitates the analysis and visualization of this data as well as the creation of interactive object models, thereby promoting further research, preservation, and popularization of cultural heritage. The module consists of three blocks: defining areas for ground-based research using interferograms; constructing a comprehensive 3D model based on ground and underground research data; and refining the boundaries of historical-cultural heritage objects and establishing protective zones. The program is developed in the object-oriented programming language VisualBasic with additional modules. This developed module could become a significant tool for studying and preserving historical and cultural objects in the modern world. [ABSTRACT FROM AUTHOR]

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. Therefore, comprehensive geophysical research is necessary to locate and predict regional metallogenic potential and the spatial distribution of veins beneath the cover. This study conducted a combination of ground magnetic method (GM), induced polarization (IP) surveys, portable gamma-ray (PGR), portable X-ray fluorescence analyses (PXRF), and audio Magnetotelluric (AMT) to conduct comprehensive exploration. The IP and GM effectively identified concealed ore-bearing space distributions and ground PGR- and PXRF-constrained mineralization anomalies, while AMT surveys constructed deep electrical structure models for ore deposits. This approach delineated concealed fluorite deposit locations as well as potential magmatic–hydrothermal migration pathways. Engineering verification confirmed the effectiveness of this method combination. This study established a comprehensive geological–geophysical positioning prediction technique that can serve as a reference for locating and predicting fluorite deposits in shallow-covered areas within the Gobi Desert. [ABSTRACT FROM AUTHOR]

The Parecis Basin, one of Brazil's most extensive intracratonic basins, holds significant potential for hydrocarbon exploration. Despite its vast size, Parecis has yet to be extensively explored, with only five wildcat wells drilled. So far, no commercial discoveries have been announced. Regional studies have suggested Paleozoic sedimentation, while recent analyses have revealed a Neoproterozoic infill. Its tectonic model is still a matter of debate, and to date, no detailed structural map for the whole basin has been published. The present work proposes a new detailed structural map of the Parecis Basin based on a four-step interpretation workflow integrating seismic and gravimetric data. The first step includes converting the public 2D seismic lines to the depth domain. The second step is estimating the residual Bouguer anomaly, where the computed residual anomalies should relate to the basin's tectonic features. The third step comprises the 2D forward modeling of the gravimetric anomalies using the 2D seismic interpretation as a constraint. The final step compiled all the interpreted features into our new structural map. This map reveals the top of the basement, forming a complex framework of horsts and grabens. Normal faults define the main structural style in the basin. Further, we could recognize thick, high-density bodies embedded in the crystalline basement. These bodies consist of Orosian–Calimian (1.8–1.6 Ga) mafic and ultramafic rocks, which may be a potential source for hydrogen exploration in the basin. Subsequent geophysical and geochemical surveys will assess the hydrogen potential in the area. [ABSTRACT FROM AUTHOR]

Scientists are always interested in improving the efficiency of geophysical methods. In particular, one of the critical stages is the processing of data measured in geophysical surveys. This study aims to develop a new data processing algorithm of the improved multi-electrode electrical exploration method, and then apply it to investigate groundwater in Vientiane province, Laos as a case study. Our new proposed algorithm has two data processing options (option 1 and option 2) depending on the object to be studied. The results show that both options can determine the boundary of groundwater table. The proposed algorithm can provide the better results compared to the traditional algorithm. The results obtained at profile 1, site 1 in the study area suggest the presence of a potentially high-quality groundwater layer at depths ranging from 22 to 100 m. This finding aligns with the data from Borehole 1 in Phonhong District, situated directly above Profile 1, which similarly indicates a groundwater level at a depth of approximately 22 m. However, with option 2, the groundwater table has a wide variation, not as flat as the treatment results under option 1. The use of the improved Petrovski parameter ρ pm ct (option 2) helps to bring the results with high resolution, which in turn helps to show point/block objects more clearly. Thus, depending on the research object and purpose, it is possible to use only one of the two options and still obtain good results. [ABSTRACT FROM AUTHOR]

Hydraulic tomography (HT) is a promising technique for high-resolution imaging of subsurface heterogeneity, which addresses the limitations of traditional methods, such as borehole drilling and geophysical surveys. This study focuses on the application of HT to detect and characterize fractured zones in bedrock and addresses the gap in the understanding of the role of distributed flux data in the joint inversion of hydraulic head and flux data. By conducting synthetic injection tests and using sequential successive linear estimators for inversion, the study explores the effectiveness of combining limited head data with distributed temperature sensing (A-DTS)-derived flux data. The findings highlight the fact that integrating flux data significantly enhances the accuracy of identifying fracture permeability characteristics, even when head data is sparse. This approach not only improves the resolution of hydraulic conductivity fields but also offers a cost-effective strategy for practical field applications. The results underscore the potential of HT to enhance our understanding of groundwater flow and contaminant transport in fractured media, which has important implications for carbon capture, enhanced geothermal systems, and radioactive waste disposal. [ABSTRACT FROM AUTHOR]

The analysis of ground-penetrating radar (GPR) data is of vital importance for detecting various subsurface features that might manifest as hyperbolic peaks, which are indicators of a buried object or grayscale variation in the case of contrast in the soil texture. This method focuses on identifying exaggerated patterns through a series of image-processing steps. Two GPR images are initially read and preprocessed by extracting channels, flipping, and resizing. Then, specific regions of interest (ROIs) are cropped, and the Fourier transform is further applied to turn them into the frequency domain. With the help of their frequency signatures, these patterns are extracted from the images, and binary masks are constructed to obtain features of interest. These masked images were reconstructed and merged to make hyperbolic features visible. Finally, Local Binary Pattern (LBP) analysis is used to emphasize these hyperbolic peaks, thereby facilitating their recognition across the whole image. The proposed approach improves the detection of performance subsurface features in GPR data; hence, it is an important tool for geophysical surveys and other related applications. The results prove the high performance of the proposed procedure in improving GPR image characteristics. [ABSTRACT FROM AUTHOR]

Seismology is increasingly used to infer the magnitude and direction of glacial ice flow. However, the effects of interstitial meltwater on seismic properties remain poorly constrained. Here, we extend previous studies on seismic anisotropy in temperate ices to consider the role of melt preferred orientation (MPO). We used the ELLE numerical toolbox to simulate microstructural shear deformation of temperate ice with variable MPO strength and orientation, and calculated the effective seismic properties of these numerical ice‐melt aggregates. Our models demonstrate that even 3.5% melt volume is sufficient to rotate fast directions by up to 90°, to increase Vp anisotropy by up to +110%, and to modify Vs anisotropy by −9 to +36%. These effects are especially prominent at strain rates ≥3.17 × 10−12 s−1. MPO may thus obscure the geophysical signatures of temperate ice flow in regions of rapid ice discharge, and is therefore pivotal for understanding ice mass loss. Plain Language Summary: Ice on Earth is pulled toward the sea by gravity, contributing to global mean sea level rise. To better understand the flow, or movement, of ice at the continent scale, geophysical surveys are increasingly being used to measure the microscopic alignment ("fabric") of ice crystals, since ice with a strong fabric flows more readily. However, in temperate regions close to the ice melting point, melt pockets may also become aligned, creating additional macroscopic geophysical signatures. Here, we use numerical simulations to examine the combined effects of ice crystal fabric and melt alignment on the geophysical (seismic) properties of ice containing small amounts of melt. We show that melt can change the seismic fast direction (related to the inferred flow direction) of ice by up to 90°, particularly as the volume of melt exceeds 3.5%, and that different melt orientations can either enhance or diminish the anisotropy‐based estimates of flow that some studies use to predict ice mass loss. These effects are especially prominent in faster‐flowing ice, highly relevant to ice mass loss in warming regions. Geophysical studies that do not account for melt orientation may therefore produce incorrect estimates of flow, leading to inaccuracies in future climate models. Key Points: We used simulations of deforming temperate ice to show that the alignment of interstitial meltwater changes bulk seismic propertiesThe amount of melt required to significantly modify seismic properties is at least 50% lower than previously reportedMelt should be considered when using seismic and radar anisotropy to interpret viscous ice deformation and enhancement [ABSTRACT FROM AUTHOR]

Archaeological prospection is continually expanding into new frontiers, examining increasingly large areas, diverse environmental contexts and varying site types. One area that has received only limited focus is historic battlefields. This paper presents results from large‐scale geophysical surveys (> 100 ha) at the Napoleonic battlefield of Waterloo (1815) in Belgium, using fluxgate magnetometry and frequency‐domain electromagnetic induction. Despite its international historical significance, professional archaeological research at the battlefield is still in its infancy. We demonstrate how important insights can be gained by using geophysical methods for identifying features and artefacts related to the battle and for developing an understanding of the various influences acting on the present landscape. The largest survey of its kind undertaken on a single battlefield site, this approach holds particular potential for battlefield archaeology, given the subtle and low‐density nature of the sought‐after targets and the extensive area of the site. Such an approach can mitigate (though not entirely resolve) challenges of resolution and scale associated with other methods of investigation. Using a representative range of examples from Waterloo, we consider successes and challenges in undertaking geophysical surveys on battlefield sites. An integrated approach that incorporates targeted sampling and other forms of ancillary data is emphasized for a more robust interpretation of noninvasive sensor data. [ABSTRACT FROM AUTHOR]

Low-frequency electromagnetic induction (EMI) is a non-invasive geophysical method that is based on the induction of electromagnetic (EM) waves into the subsurface to quantify changes in electrical conductivity. In this study, we present an open (design details and software are accessible) and modular system for the collection of EMI data. The instrument proposed allows for the separations between the transmitter to be adjusted and up to four receiving antennas as well as the acquisition frequency (in the range between 3 and 50 kHz) to permit measurements with variable depth of investigation. The sensor provides access to raw data and the software described in this study allows control of the signal processing chain. The design specifications permit apparent conductivity measurements in the range of between 1 mS/m and 1000 mS/m, with a resolution of 1.0 mS/m and with a sampling rate of up to 10 samples per second. The sensor allows for a synchronous acquisition of a time stamp and a location stamp for each data sample. The sensor has a mass of less than 5 kg, is portable and suitable for one-person operation, provides 4 h of operation time on one battery charge, and provides sufficient rigidity for practical field operations. [ABSTRACT FROM AUTHOR]

The Bjerkreim–Sokndal (BKS) intrusion in southern Norway has been studied for decades due to the presence of magnetic remanence creating anomalies 12 000 nT below background as measured by airborne magnetic surveys. The strong magnetic remanence also makes the BKS intrusion a good Earth analogue for remote studies of planets that have prominent magnetic signatures, such as Martian geological environments. Although numerous geophysical surveys and samples have been collected in the area, there are limited 3-D geological interpretations of the subsurface. Here, we used existing geophysical data to conduct forward and inversion modelling of the Bjerkreim lobe to investigate the subsurface geometry of the BKS intrusion. An extensive petrophysical property compilation was used as input data for the models, in combination with airborne magnetics and digital elevation models. This petrophysical compilation was initially analysed using principal component analysis to understand which variables would have the greatest impact on the models. Forward and inversion modelling show that cross-cutting jotunite bodies, and small anorthosite blocks within the Bjerkreim lobe have a limited depth extent of 1 km. Massive and foliated anorthosites to the west of the Bjerkreim lobe extend to depths greater than 4 km indicating that the BKS intruded into these anorthosites. Complications in magnetic field fitting during the forward modelling of megacyclic units with strong magnetic remanence and the results from a new ground magnetic survey support the need to revisit mapped contacts of the cyclical units. [ABSTRACT FROM AUTHOR]

Nanhong agate, esteemed for its vivid color and natural shine, is experiencing a scarcity in supply despite its high demand. The primary deposits of agate, typically found near the surface, have not been extensively explored due to the predominance of traditional manual excavation methods. This research examined the Nanhong agate deposits in the Zhaojue–Meigu region of Liangshan, China, employing the integration of geological and geophysical surveys. Field geological surveys allowed us to outline the general areas where agate is found. Following this, using magnetic surveys, vertical electrical sounding, and controlled-source audio magnetotellurics, agate deposits were located within the conglomerate layer of the second member of the Feixianguan Formation from the Lower Triassic period at depths of less than 100 m. Our results identify mineralized layers, Xuanwei Formation mudstone, and the underlying bedrock, thus supporting the creation of a mineral prediction map. This research provides essential insights and guidance for agate exploration and the development of associated mineral resources. [ABSTRACT FROM AUTHOR]

Attributing the sources of legacy contamination, including brines, is important to determine remediation options and to allocate responsibility. To make sound remediation decisions, it is necessary to distinguish subsurface sources, such as leaking oil and gas ("O&G") wells or natural upward fluid migrations, from surface releases. While chemical signatures of surface and subsurface releases may be similar, they are expected to imprint specific dissolved noble gas signatures, caused by the accumulation of terrigenic noble gases in subsurface leaks or re‐equilibration of noble gases following surface releases. We demonstrate that only a historic surface release influenced the dissolved noble gas signature of groundwater in monitoring wells contaminated with brine near an abandoned O&G well, rather than subsurface leakage from the well. Elevated brine concentrations were associated with lower terrigenic helium concentrations, indicating re‐equilibration with atmospheric helium at the surface during the release. Geophysical surveying indicating elevated salinity in surficial soils upgradient of the wells further supported the interpretation of the noble gas data. Eliminating the possibility that subsurface leakage was the source of the plume was critical to selecting the proper remedial action at the site, which otherwise may have included an unnecessary and costly well re‐abandonment. This study demonstrates the use of noble gas analysis to compare potential sources of brine contamination in groundwater and to exclude subsurface leakage as a potential source in an oilfield. [ABSTRACT FROM AUTHOR]

Parwan Gravity Dam is under construction stage in the Jhalawar district of Rajasthan, India. A thin sub-vertical surficial fracture trending N 75°W to S 75°E has been observed in the foundation area of the dam. Geophysical techniques such as electrical resistivity tomography (ERT), seismic refraction tomography (SRT), and multichannel analysis of surface waves (MASW) are utilized extensively in the field of civil engineering, exploration geophysics for the assessment and construction of large-scale infrastructures such as dams. These methods provide critical information about the subsurface conditions without the need of extensive drilling and excavation. The combination of electrical resistivity tomography (ERT), seismic refraction (SR), and multichannel analysis of surface waves (MASW) techniques with the different acquisition parameters have been used to image the extent of shallow subsurface geological structures. Various geophysical Surveys have been carried out along several profiles in the longitudinal direction and along the transverse direction to the fault axis. A total of 13 refraction and resistivity profiles were conducted of which 9 were transverse profiles and 4 were longitudinal profiles. A total of nine MASW profiles were conducted of which 8 are transverse profiles and 1 is a longitudinal profile. In this paper, the subsurface distribution of seismic wave velocity and electrical resistivity have been studied to identify any possible anomalous zone in bedrock and to detect the downward extension of surface fracture of brittle fault using the afore mentioned methods. The vertical and lateral extent of the surface fracture of the fault has been investigated by the analysis of these survey results. The analysis of the results indicates that a very tight and narrow fracture is present in the shallow subsurface. [ABSTRACT FROM AUTHOR]

Coniolo and Brusaschetto, are two small towns located in the Monferrato area of the Alessandria Province, northern Italy. These communities have similar histories related to development and subsequent abandonment of marl quarry activity that began more than a century ago and continued until recently. Quarrying occurred until soil conditions, water infiltration, and excessive depth made cost of extracting and7 lifting material prohibitive. Quarries consisted of tunnels located directly beneath the towns at about 150 m below ground surface. Collapse of the tunnels led to surface subsidence and destruction of overlying homes and much of the municipal infrastructure. In the early Twentieth Century, regulations pertaining to mine and quarry safety were typically deficient, entirely absent, or not followed. Extractive activities of non-energy mineral resources from quarries and mines were and continue to be widespread in Italy, which currently ranks fifth among what are now countries of the European Union (EU). Mining sites are present in all regions of Italy, particularly in the northern part of the country and along coasts, often in areas of geohydrogeological risk. Consequences of anthropogenic pressures that alter the natural environment, such as the physical size of aquifer drawdowns, are linked to issues for a number of extractive sites across the country. This report analyzes historical and technical documents, conducts a geomorphological analysis of hilly slopes surrounding these communities, and examines urban planning and geophysical surveys to determine the impact of subsurface quarrying activities on the overlying ground surface. The study highlights significant problems that are applicable to other localities globally. This research demonstrates: (a) the importance of geological considerations to development and abandonment of mining activity in inhabited areas; (b) the importance of establishing and following safety protocols; and (c) the manner in which economic interests can take precedence over the well-being and lives of those employed to extract resources. [ABSTRACT FROM AUTHOR]

This study utilizes domain adaptation to enhance the integration of diverse geoscience datasets, aiming to improve the identification of ore bodies. Traditional mineral exploration methods often face challenges in merging different geoscience data types, which leads to models that do not perform well across varying domains. Domain adaptation is a deep learning strategy aimed at adapting a model developed in one domain (source) to perform well in a different domain (target). To adapt models trained on detailed, labeled drilling data (source) to interpret broader, unlabeled geophysical data (target), Domain-Adversarial Neural Networks (DANNs) were applied, chosen for their robust performance in scenarios where the target domain does not provide labels. This approach was indirectly validated through the minimal overlap between regions identified as candidate ore and borehole locations marked as host rocks, with qualitative validation provided by t-Distributed Stochastic Neighbor Embedding (t-SNE) visualizations showing improved data integration across domains. [ABSTRACT FROM AUTHOR]

North Panajam Paser Regency, Kalimantan Island, which is traversed by the Kutai Basin has very high coal fuel potential. The geological structure, depth and seam model of coal-bearing rock formations in the research area can be investigated through geophysical surveys using satellite gravity methods. Gravity field data is downloaded from the TOPEX website which comes from Geodesy Satellite (GeoSat) and European Remote Sensing Satellite-1 (ERS-1). The number of gravitational field data downloaded was 785 sets with an area of around 250 km2. The satellite gravity field data processing procedure includes several data corrections and reductions, as well as modeling and interpretation. The modeling and interpretation results show that the coal-bearing rock is estimated to be at a depth of 0 - 2,593.95 m for the AA' section; 0 - 1,877.89 m for the BB' section; and 0 - 1,558.59 m for the CC' section. [ABSTRACT FROM AUTHOR]

Calabria and the Peloritan Mts. of NE Sicily are exotic terranes predominantly formed by Hercynian rocks interrupting the Meso‐Cenozoic sediments exposed along Apennine‐Maghrebide chains. Dual‐polarity pre‐tilting magnetization direction retrieved from 5 Jurassic, 5 upper Cretaceous‐Eocene, and 4 upper Oligocene sedimentary sites from external‐intermediate Peloritan nappes yield 99° ± 12°, 131° ± 15°, and 138° ± 12° (respectively) clockwise (CW) rotations with respect to Europe. Upper Cretaceous‐Oligocene values are similar to the ∼130° CW late Miocene‐Early Pleistocene rotation previously documented on internal Maghrebian nappes of W Sicily. Jurassic data imply a ∼30° Early Cretaceous counterclockwise (CCW) rotation, similar for sign, magnitude, and timing to Iberia rotation, proving that the Peloritan crust was part of Greater Iberia before its <30 Ma fragmentation and dispersal. Furthermore, 20 Jurassic‐Oligocene sites yield post‐tilting overprint direction (later rotated up to 60° CW) that was acquired synchronous to late Miocene‐Pleistocene rotation. The Peloritan rotation is completely different from the 160° post‐late Jurassic CCW rotation documented on NE Calabria, and demonstrates that the two terranes underwent independent drift histories. Lack of a Sardinian rotation fingerprint (90° CCW between 30 and 15 Ma) suggests that the Peloritan terrane lied S of the Calabria‐Sardinia CCW rotating system, at the non‐rotational apex of an Oligocene‐early Miocene "Paleo Apennine‐Maghrebide Arc." The Peloritan terrane was stacked onto the African margin and incorporated in the Maghrebian chain in mid Burdigalian (18–17 Ma). Afterward, it formed the S limb of the "Neo Apennine‐Maghrebide Arc," and was passively carried on top of CW rotating Maghrebide nappes during late Miocene‐Early Pleistocene (12–1 Ma). Key Points: The Peloritan terrane rotated 30° CCW during Early Cretaceous (similar to Iberia), and 130° CW since the late Miocene on top of MaghrebidesPaleomagnetism proves that Iberia, S Sardinia and AlKaPeCa blocks formed "Greater Iberia" before Oligo‐Miocene (<30 Ma) dispersalPaleomagnetic data indicate that after 30 Ma the Peloritan and Calabria terranes underwent different drift and rotation histories [ABSTRACT FROM AUTHOR]

In deep mineral exploration, it is difficult to constrain the complex geological structures using a single geophysical method. To tackle the difficulty, integrated geophysical surveys and joint data interpretation are essential. Machine learning (ML) provides more accurate predictions than traditional methods, especially when dealing with complex data from multiple sources or varied statistical distributions. However, a major challenge in using ML for deep mineral exploration is the scarcity and imbalance of labeled samples, mainly due to budget constraints and the complexity of ore deposits. This issue reduces the accuracy of predictive models and introduces bias. Additionally, limited labeling can lead to difficulties in predicting previously undefined classes in training datasets. To address these challenges, we introduce a robust semisupervised ML framework that integrates diverse geophysical and geological datasets to improve model reliability with limited labeled data. Our approach uses a semisupervised ML variational Gaussian mixture model (SsL-VGMM) to handle issues related to insufficient and imbalanced data. We enhanced the model's predictive capability for unseen data by introducing a novel penalty factor in the 'cannot-link' function. Moreover, we employed Bayesian optimization, focusing on the mean-mixture weight, to avoid local optima during model training. Our model demonstrated high accuracy and efficiency, with classification and prediction accuracies of 95.33% and 87.4%, respectively, in numerical and electromagnetic simulation scenarios. Its effectiveness was further validated by locating Pb–Zn–Ag deposits in Inner Mongolia, supported by actual drilling data. This paper highlights the model's potential in complex mineral exploration and its significant practical and innovative value for deep mineral exploration. [ABSTRACT FROM AUTHOR]

The transition area between the Pannonian Basin and the East Carpathians is the subject of considerable tectonic research in Central Europe because of its geological diversity, especially for Lithosphere–Asthenosphere Boundary determinations. The major objective of this study is to investigate the Earth’s lithospheric structure and in particular to determine the Lithosphere–Asthenosphere Boundary from the Pannonian Basin, through the Transylvanian Basin to the Carpathian Bend area. We recorded six new deep magnetotelluric soundings and used two archive measurements to complete the information and to put additional constraints on the depth of the Lithosphere–Asthenosphere Boundary. In the part of the discussions we provide a brief overview of the existing various methodologies and Lithosphere–Asthenosphere Boundary determinations for the wider Carpathian–Pannonian region and Europe and comparison with new magnetotelluric results. The lowest Lithosphere–Asthenosphere Boundary depth was detected in the Pannonian Basin (~50 km). Our results indicate in addition that the Lithosphere-Asthenosphere Boundary beneath the Transylvanian Basin (~70–80 km) is not thick and much thinner than those of the European and Moesian Platforms. The additional geophysical information (geomagnetic data and phase tensor results) detected the presence of deep well conductive zones towards the Pannonian Basin, the Bogdan Vodă–Dragoș Vodă fault and the East Carpathians. This could be explained by the elevated position of the well conductive asthenosphere in the Pannonian Basin and deep and presumably fluid rich tectonic zones associated with the Bogdan Vodă–Dragoș Vodă fault and the East Carpathians. The phase tensors highlighted that the most complex tectonic zones are present in the vicinity of the East Carpathians (where the average Lithosphere–Asthenosphere Boundary depth is >100 km), which is in line with the relatively young age of the mountain belt and the very complex nature of collisional orogens. [ABSTRACT FROM AUTHOR]

Regions densely populated with archaeological monuments pose significant challenges for construction investors and archaeologists during the planning stages of major construction projects. Recognising the archaeological potential of these areas is crucial for planning effective rescue excavations, which have become a standard procedure in construction. This study explores the utility of non-invasive prospection techniques, including artefact field surveys, multispectral imaging, and magnetic surveys, in assessing the area chosen for the I/16 Slaný–Velvary road construction. We specifically focused on the contributions these methods make towards understanding the archaeological context of the proposed construction site. The findings from the magnetic survey were compared with the results of actual archaeological excavations. Through manual visual analysis and statistical spatial correlation, we assessed the effectiveness of the magnetic survey. The ability of magnetic survey to locate different types of archaeological objects proved to be dependent on various factors. The variability of the environmental setting, particularly pedological and geological conditions, is essential. However, the modern anthropogenic impact and the very nature of individual archaeological objects, especially their dimensions, also play an essential role. [ABSTRACT FROM AUTHOR]

We expound on a hydrographic and geophysical survey in the south of the Archipelago of San Andres, Providencia, and Santa Catalina (ASAPSC) in the Colombian Caribbean Sea. In 2017 and 2018, high-resolution data were acquired from the Caribbean Center for Oceanographic and Hydrographic Research (CIOH). The hydrographic data were processed and filtered per International Hydrographic Organization (IHO) standards and the geomagnetic data were processed, corrected, and filtered to improve the interpretation. We could then characterise the submarine relief, analyse the geomagnetic anomalies in the area, and identify different relief forms of volcanic origin. Regarding geomagnetic work, a spectral analysis of the anomalies revealed highly magnetic bodies in deep water and residual magnetic anomalies strongly related to the seabed morphology. Magnetic highs associated with the basement highs and volcanic cones were detected. Complementary spectral analysis showed that the shallowest magnetic sources were in the first 500 m, whereas the deepest magnetic sources were between the depths of 4 and 5 km. The geomagnetic data were also validated using Euler deconvolution analysis, which confirmed these magnetic anomalies. Thus, a direct relationship between the magnetic anomalies and bathymetry of the seafloor was confirmed, reinforcing the theory of the volcanic origin of these islands. [ABSTRACT FROM AUTHOR]

The Wayand‐Nilambur granulite terrain in Kerala (India) is well‐known for vein‐type gold mineralization within the quartz veins. Based on the previous geological, petro‐physical and geophysical characteristics of Wayand‐Nilambur gold deposit, the integrated geophysical survey was carried out to delineate the favourable prospecting zones. In the present study, detailed ground geophysical surveys, that is, magnetic, electrical resistivity/chargeability surveys were carried out in an area of 2 km2 in Kattikallu and Kalkulam blocks to delineate the ore deposits in terms of depths and extensions through the structural shear zone, locate the anomalous sources and the geometry of the Au‐rich sulphide zone and its depth continuity in the subsurface. These surveys brought out prominent resistivity and chargeability zones over known magnetite‐quartz veins that are associated with low‐grade sulphide bands at the central part of the Kattikallu block. The prominent potential zone is characterized by strong bipolar magnetic anomalies over the quartz veins. Based on the 2D inversion of resistivity data, the resistivity low zone of order 80–600 Ω m and chargeability of 21–25 mV/V are observed at a depth range of 5–20 m. In Kalkulam block, the magnetic survey has also brought out high intensity anomaly zones over quartz veins, the same quartz veins are mapped by high chargeability of 10–35 mV/V and low resistivity of 185–400 Ω m. The dipole‐dipole configuration produces two parameters, that is, resistivity and chargeability, these methods distinguish the anomalies along the two selected profiles in the study area. An attempt was made for combining the resistivity and chargeability values to identify the anomalous zone boundaries. The results of inversion indicated that the conductive bodies are located at the subsurface, with depths ranging from 5 to 25 m. Based on this integrated geophysical study, we suggested two borehole sites for further geo‐scientific studies in view of mineralization. [ABSTRACT FROM AUTHOR]

In the Bushveld Complex, South Africa, open pit mines are faced with a challenge of rock slope stability due to geological structures (fractures, faults and dykes) that compartmentalize the rock mass. Geophysical surveys (seismics, magnetics and electrical methods) were conducted in a 0.2 km2 area at Tharisa mine, with the goal to delineate fractures that may be potential conduits for water migration into the pit. Special processing techniques were applied to the dataset to obtain good quality seismic, magnetic and resistivity models. The P‐wave velocity models show distinct low velocities in the centre of the seismic profile, indicating the presence of weak zones associated with faulting or fracturing. Seismic reflection method was used to image the deeper discontinuities and mineralization contacts. Near surface reflections are observed throughout the profiles and are correlated with the contact between the chromitite and host rock. Ground magnetic surveys were conducted to delineate dykes and fractures. De‐trending and de‐culturing techniques were applied on the magnetic data for correcting regional and temporal variations. The low magnetic regions indicate the presence of fracture systems in the subsurface, whereas the high magnetic region is correlated with the dolerite dyke that crosscuts the pit. The electrical resistivity tomography exhibits linear low resistivity contrast zones that differentiate between the fractured and undisturbed hard rock at an estimated depth of 4–10 m. Resistivity shows discontinuities that suggests the presence of fracturing and dyke‐host rock contacts. Correlation among magnetics, P‐wave velocity models, resistivity section and seismic data is evident when overlaying the different datasets, implying that the low magnetic regions are highly weathered and prone to fracturing. The integration of geophysical data is encouraging, because it was able to image the depth to the bedrock, fractures within the host rock and dyke in a complex mining environment. [ABSTRACT FROM AUTHOR]

This paper explores some challenges of archaeological interpretation and classification through an enclosure at Inchnadamph in Sutherland, northwestern Scotland, a site that has proven difficult to interpret. Despite a small number of archaeological interventions, including topographic and geophysical survey and excavation, the site remains enigmatic. We discuss the different interpretations suggested for the site in turn, concluding that the enclosure does not fit readily into existing classification schemes. This raises issues surrounding the use of classification systems, prior assumptions, and the need for critical thinking in interpretation. These are universal issues, applicable beyond the Scottish example chosen, and this paper highlights concerns and difficulties encountered by all who deal with the classification of sites and monuments. Ultimately, this challenges some of our preconceptions and sheds light on the limits of our knowledge, as well as the limits of our classification systems. [ABSTRACT FROM AUTHOR]

This article presents the findings of a geophysical survey conducted on the Khachkovi gold-polymetallic occurrence in Georgia. The study aimed to evaluate the geological prospects through comprehensive investigations. Three methods - electrometry, magnetometry, and gamma spectrometry - were employed in the survey, covering approximately 3.5 square kilometres. Analysis of the survey data revealed high magnetic field anomalies and variations in the gravity field, indicating gabbro-diorite intrusive bodies at depth. The Khachkovi occurrence was structurally associated with faults, fractured zones, and hydrothermally altered zones. Electrically conductive minerals within the hydrothermally altered zones were confirmed through induced polarization values and anomalous potassium content. The study area exhibited low potassium, thorium, and uranium levels, potentially due to Quaternary sediments and weak alterations. Hydrothermally altered sulfide mineral-containing zones were primarily linked to fault zones, intrusive bodies, and brecciated zones. The surface hydrothermally altered zone consisted mainly of pyrite-bearing rocks. The geophysical survey provided valuable insights into the geological characteristics and prospects of the Khachkovi gold-polymetallic occurrence, offering guidance for further exploration activities. These findings contribute to understanding the mineralization potential and future mining efforts. [ABSTRACT FROM AUTHOR]

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This study delves into the fusion of ground-based and drone-based ground-penetrating radar (GPR) technologies in archaeological exploration. Set against the backdrop of the Hulata solar panel construction site in Israel, the research confronts daunting obstacles such as clayey soil, accurate detection of small objects, and the imperative of timely reporting crucial for construction management. The drone-based GPR, a testament to technological innovation, showcases remarkable adaptability to challenging terrains, dispelling doubts about electromagnetic wave decay in clayey soil. Methodologically, the study employs detailed orthophoto mapping and grid-type surveys. The correlation of the results significantly bolsters the reliability of archaeological discoveries, uncovering scattered artifacts buried approximately 1–1.5 m below the surface. Meticulous excavations validate the geophysical surveys, affirming the presence of structures constructed from boulders. The application at the Hulata site validates the adaptability of drone-based GPR in challenging terrains. It provides a swift, cost-effective, and minimally invasive alternative to traditional excavation techniques, thereby transforming the field of archaeology. [ABSTRACT FROM AUTHOR]

The archaeological zone of Izapa was an important pre-Hispanic settlement of probable Mixe-Zoque affiliation in the Soconusco region, southeast of the current state of Chiapas, whose occupational sequence extended from the Early Preclassic (1800 BC) to the Early Postclassic (1200 AD). Throughout its long habitation, various population movements occurred within the settlement. During the Classic period, in the complex known as Group F, of which only 2.88 ha are currently protected, monumental structures were built that integrated a civic-ritual compound. Previous research identified a prolonged constructive sequence, specifically in the main pyramid (Structure 125-A). To identify possible construction moments prior to those currently appreciated and determine the state of conservation of some of its monumental structures, a geophysical survey was carried out by means of georadar and electrical resistivity tomography techniques in various areas of Group F. Through these, it was possible to detect several anomalies that can be interpreted as archaeological structures, including platforms, channels and walls. Some of these elements were verified by archaeological excavations. The different depths at which these possible structures are located speak of a prolonged occupation of Group F, with various modifications to its architectural configuration. [ABSTRACT FROM AUTHOR]

We applied an interdisciplinary approach to analyze the late Quaternary activity of the Sava Fault in the Slovenian Southern Alps. The Sava Fault is an active strike-slip fault, and part of the Periadriatic Fault System that accommodated the convergence of Adria and Europe. It is one of the longest faults in the Southern Alps. Using high-resolution digital elevation models from lidar and photogrammetric surveys, we were able to overcome the challenges of assessing fault activity in a region with intense surface processes, dense vegetation, and relatively low fault slip rates. By integrating remote sensing analysis, geomorphological mapping, structural geological investigations, and near-surface geophysics (electrical resistivity tomography and ground penetrating radar), we were able to find subtle geomorphological indicators, detect near-surface deformation, and show distributed surface deformation and a complex fault pattern. Using optically stimulated luminescence dating, we tentatively estimated a slip rate of 1.8 ± 0.4 mm/a for the last 27 ka, which exceeds previous estimates and suggests temporal variability in fault behavior. Our study highlights the importance of modern high-resolution remote sensing techniques and interdisciplinary approaches in detecting tectonic deformation in relatively low-strain rate environments with intense surface processes. We show that slip rates can vary significantly depending on the studied time window. This is a critical piece of information since slip rates are a key input parameter for seismic hazard studies. [ABSTRACT FROM AUTHOR]

In the territory of Dushanbe city, the capital of Tajikistan, detailed geological and geophysical data were collected during geophysical surveys in 2019–2020. The data comprise 5 microtremor array measurements, 9 seismic refraction tomography profiles, seismological data from 5 temporary seismic stations for standard spectral ratio calculations, 60 borehole datasets, and 175 ambient noise measurements. The complete dataset for Dushanbe was used to build a consistent 3D geologic model of the city with a size of 12 × 12 km2. The results of the seismological and geophysical surveys were compared and calibrated with borehole data to define the boundaries of each layer in the study area. The Leapfrog Works software was utilized to create a 3D geomodel. From the 3D geomodel, we extracted six 12 km long 2D geological cross-sections. These 2D geological cross-sections were used for 2D dynamic numerical modeling with the Universal Distinct Element Code software to calculate the local seismic response. Finally, the dynamic numerical modeling results were compared with the amplification functions obtained from the seismological and ambient noise data analysis. The 2D dynamic numerical modeling results allowed a better assessment of the site effects in the study area to support seismic microzonation and the determination of local peak ground acceleration changes in combination with regional seismic hazard maps. In addition, our results confirm the strong seismic amplification effects noted in some previous studies, which are attributed to the influence of local topographic and subsurface characteristics on seismic ground motions. [ABSTRACT FROM AUTHOR]

The physical properties of seafloor massive sulfides are crucial for interpreting sub-seafloor images from geophysical surveys, shedding light on the evolution of seafloor mineral deposits. While some studies have explored the relationship between electrical properties and the volume of conductive minerals in rocks from seafloor massive sulfide deposits, they primarily focused on artificial samples, leaving the characteristics of natural samples less understood. Moreover, there has been no comprehensive study detailing the general characteristics of electrical properties, particularly chargeability and relaxation time, in relation to the volumetric fraction of sulfides in rocks from massive sulfide mounds in typical hydrothermal areas. In this study, we employed complex conductivity measurements, elemental concentration analysis, and mineral content identification on to rock samples from the active hydrothermal zones of the Okinawa Trough in Japan. The complex conductivity observed was remarkably high, with a pronounced imaginary component and a broad frequency range. This is attributed to induced polarization extending beyond our measurement range. The rock samples were rich in conductive sulfide minerals such as pyrite, chalcopyrite, and galena. Using the Cole–Cole rock physics model, we established a correlation between rock chargeability and relaxation time coefficient with the volume fraction of conductive sulfide minerals, which deviated from previous findings. The intensity of induced polarization was notably higher than anticipated in earlier studies using artificial samples. Furthermore, we observed a distinct positive correlation between the coefficient of relaxation time and the increase in sulfide volume, likely due to the geometric characteristics of the sulfide minerals. Our findings suggest that rocks in massive sulfide mounds may generally construct sulfide clusters that lengthen the conductive path of the electrical carrier. [ABSTRACT FROM AUTHOR]

Abstract—As part of the international collaboration of several research groups from Russia, France, and Germany, 77 temporary seismic stations were installed in the summer of 2015 for one-year period to conduct a detailed study of the deep structure of the Earth's crust and upper mantle in the region of the Klyuchevskoi Volcano Group (KVG), Kamchatka Peninsula. One of the results of the KISS experiment (Klyuchevskoi Investigation –Seismic Structure of an extraordinary volcanic system) was the final catalog based on the joint data from the temporary stations and the permanent network of the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences (KB GS RAS). The catalog comprises 2136 events, including 560 for which the permanent network catalog lacked sufficient data for correct processing. The catalog in.xlsx format and the station bulletin in.isf format are presented in the supplementary material to the paper. A comparative analysis is performed of joint solutions of two catalogs, one obtained solely from the data of the KB GS RAS permanent network stations and another from a denser seismic network integrated with KISS stations. [ABSTRACT FROM AUTHOR]

Abstract—The paper presents the results of applying the Discrete Perfect Set (DPS) topological filtering algorithm to analyze the spatial clustering of seismic epicenters in the Baikal region. The study in based on the earthquake data recorded by the seismic network of the Baikal Branch of the Geophysical Survey of the Russian Academy of Sciences in the region between (48° N, 58° N) and (99° E, 122° E) from 1964 to 2018. Clustering characteristics are obtained for (i) the recording period from 1989 to 2018 with different parameters of the DPS algorithm and four levels of the minimum energy class KР of seismic events and (ii) six nonoverlapping time intervals from 1964 to 2018 and seismic events of energy class KР ≥ 8.6 with fixed parameters of the DPS algorithm. The dynamics of the clustering parameters from 1964 to 2018 possibly characterizes the variability of seismicity in the region. Namely, the decrease in the linear size of the identified groups of epicenters from about a thousand km to tens km may indicate a significant change in seismic activity in the Baikal region at the end of the 1990s and the beginning of the 2000s compared to the period between 1964 and 1997. [ABSTRACT FROM AUTHOR]

Geophysical exploration of bauxite deposits has been carried out in the area of Posušje in Bosnia and Herzegovina, which were formed on an Upper Cretaceous carbonate substrate, whereas the hanging wall rocks can be Paleogene limestones and sedimentary clastic rocks. Karst terrains are demanding for geophysical exploration due to the relatively complex geological relationships and exceptional near-surface inhomogeneities that generate large noises and challenging conditions for taking field measurements. The fundamental question is whether geophysical research can detect exceptionally irregular karst bauxite deposits with relatively small dimensions. The basic idea is to combine several geophysical methods and a joint interpretation of several data sets to increase the efficiency of geophysical surveying in detecting complex bauxite deposits in karst terrains. Therefore, fundamental near-surface research methods, electrical tomography and seismic refraction are used. In addition, magnetometry was used to examine whether bauxite deposits yield potential magnetic anomalies that could help in detecting them. Research undertaken in the area of Posušje was carried out in the first step on already discovered and known bauxite deposits to determine whether geophysical responses correlate with the occurrence of bauxite deposits and to evaluate the effectiveness of each of the applied surface geophysical methods. Measurements were taken at several locations, and results for two micro-locations, Krstače and Mratnjača, are shown. Geophysical measurements were firstly performed on discovered bauxite deposits in order to reliably determine the possibility of identifying deposits in geophysical inverse models. Bauxite deposits were clearly recognised as characteristic geophysical responses in inversion models using both methods, electrical tomography and seismic refraction. Although the response of bauxite deposits is expressed in both models, resistivity and velocity, it is much more evident in resistivity models. The characteristic resistivity response was confirmed by the discovery of a new deposit. Therefore, the conclusion is that electrical resistivity tomography should be considered a basic method for exploring karst bauxite deposits. Seismic refraction provides a better characterisation of deposits and reduces the interpretation ambiguity. This solution can generally be applied to the problem of researching bauxite deposits in the Dinarides and similar geological models in the Mediterranean. Magnetometric measurements have shown that no magnetic anomalies could be associated with bauxite deposits, and only magnetometry was not successful in discovering bauxite deposits. [ABSTRACT FROM AUTHOR]

The aim of this research is to imagine the buried antiquities within the fortress of Aghia Maura, on the island of Lefkas in Greece, through the application of geophysical prospection methods. Resistance mapping was applied and reported here. The survey was carried out employing the twin probe array at the nodes of a 1-m grid established on the ground surface. After processing, grey scale maps were compiled showing more or less the ground view of the concealed architectural remains. These are presumably linear and articulated anomalies resembling the ground view of vestiges. The presentation of the results was carried out through the use of Geographical Information Systems (GIS). As a visualization tool, GIS offer the advantage of representing more than one layers at the same time, in this case the different construction phases of the fortress in relation to the results of the geophysical survey. The results include, among others, the high resistance values arranged in clear geometric shapes, such as rectangular, semicircular and linear layouts. Their shape in combination with their dimensions allows their attribution to the existence of foundation remains and therefore the presence of buried antiquities. Additionally, an attempt was made to identify the possible buried antiquities with certain chronological periods based on past available plans of the fortress. The geophysical results are expected to make a decisive contribution to any future archaeological excavation. [ABSTRACT FROM AUTHOR]

The present study was conducted to assess the potential occurrence of coal deposited in the Gamo zone, Kuccha woreda, Daho Kebele. It also aims to determine the quality and quantity of coal through field and laboratory techniques. Nineteen coal samples and five rock samples were collected from outcrops, test pits and trench sites and analysed for major and minor oxides of rock units and coal samples to determine the percentage of moisture, volatile matter, fixed carbon content, ash and calorific value in the laboratory of the Geological Survey of Ethiopia using AAS, adiabatic caloric matter, gravimetric and proximate analyses, respectively. The geologic setup of the study area is predominantly characterized by basaltic rocks and rhyolite interbedded/intercalated with coal seams of different thicknesses ranging from 0.3 m to 2.62 m. A geological map with a 1:25,000 scale and three potential coal occurrence maps with a 1:10,000 scale were prepared based on field surveys and laboratory results. Analysis of the coal samples revealed that the moisture content ranged from 1.62- 12.84%, the volatile matter content ranged from 6.53-32.98%, the fixed carbon content ranged from 0.04-55.78%, the ash content ranged from 10.34 to 90.06%, and the calorific value ranged from 1007.24 to 6873.76Cal/gm. This indicates that compared with the ASTM international standards, the rank of kucha coal lies on the lignite to subbituminous. Fifteen test pits were dug in all potential coal sites, and the average thickness of the coal seams ranged from 1.06 m to 1.14 m. According to the geophysical survey of the vertical electrical sounding results, a coal layer with an average thickness ranging from 0.62 m to 2.62 m was identified. Based on the log results of pits, geophysical results and areal coverage of coal deposits, the study area is estimated to have 744,174.96 tons of coal. [ABSTRACT FROM AUTHOR]

Numerical modelling of a ground‐penetrating radar (GPR) has been widely used for predicting and assessing its performance. As the transmitter and the receiver are the most essential components of a GPR system, an accurate representation of them should be included in a model. Simulating a real system is particularly challenging, especially when it comes to commercial GPR systems. A three‐dimensional model based on a 2000 MHz 'palm' antenna from Geophysical Survey Systems, Inc. (GSSI) is presented in this paper. The geometric features of the transducers were modelled via visual inspection, whereas their unknown dielectric properties were estimated using global optimizers in order to minimize the differences between real and synthetic measurements. In particular, the antenna was calibrated in free space and on top of a metal plate. Subsequently, the resulting model was successfully tested in various case studies to assess its performance. Models of two units of the same transducer were developed, showing that units of the same system in general are not identical. The results support the premise that global optimizers can be used to provide information on key aspects of the dielectric structure of the transducer and allow us to accurately model its behaviour in various environments. [ABSTRACT FROM AUTHOR]

The recent landslide at the Tamban site, on 21 December 2021 (23:30 local time), provides relevant information on the trigger mechanisms and their relationship with geological factors. Therefore, the predominant aims of the current study were to identify the lithological units in the rocky substrate and subsoil from geophysical surveys, delineating the thickness of the tuff- and lapilli-supported fall layers. Additionally, we evaluated the deformation dynamics from probabilistic and deterministic analysis, where a plane with well-differentiated discontinuities of normal-type geological fault was evidenced. This deformation feature was associated with a planar-type landslide that reached a debris flow up to 330 m distance, with varied thicknesses. Furthermore, we conducted a probabilistic analysis, which started from the characteristics of the post-slide material analyzed through triaxial trials that were conducted to a retro-analysis in order to obtain the parameters of the moment the event occurred. With the base parameters to perform the landslide analysis and determine its safety factors in compliance with current regulations, a reinforced earth configuration was applied using the Maccaferri's Terramesh method. Hence, it was possible to provide an analysis methodology for further geological scenarios of landslides that occurred in the province of Bolívar, the northern Andes of Ecuador. [ABSTRACT FROM AUTHOR]

The integration of various geophysical methodologies is considered a fundamental tool for accurately reconstructing the extent and shape of a groundwater body and for estimating the physical parameters that characterize it. This is often essential for the management of water resources in areas affected by geological and environmental hazards. This work aims to reconstruct the pattern and extent of two groundwater bodies, located in the coastal sectors of the North-Eastern Sicily, through the integrated analysis and interpretation of several geoelectrical, seismic and geological data. These are the Sant'Agata-Capo D'Orlando (SCGWB) and the Barcelona-Milazzo (BMGWB) Groundwater Bodies, located at the two ends of the northern sector of the Peloritani geological complex. These two studied coastal plains represent densely populated and industrialized areas, in which the quantity and quality of the groundwater bodies are under constant threat. At first, the resistivity models of the two groundwater bodies were realized through the inversion of a dataset of Vertical Electrical Soundings (VES), constrained by stratigraphic well logs data and other geophysical data. The 3D resistivity models obtained by spatially interpolating 1D inverse VES models have allowed for an initial recognition of the distribution of groundwater, as well as a rough geological framework of the subsoil. Subsequently, these models were implemented by integrating results from active and passive seismic data to determine the seismic P and S wave velocities of the main lithotypes. Simultaneous acquisition and interpretation of seismic and electrical tomographies along identical profiles allowed to determine the specific values of seismic velocity, electrical resistivity and chargeability of the alluvial sediments, and to use these values to constrain the HVSR inversion. All this allowed us to recognize the areal extension and thickness of the various lithotypes in the two investigated areas and, finally, to define the depth and the morphology of the base of the groundwater bodies and the thickness of the filling deposits. [ABSTRACT FROM AUTHOR]

Mountains are vital water sources for humans and ecosystems, continuously replenishing lowland aquifers through surface runoff and mountain recharge. Quantifying these fluxes and their relative importance is essential for sustainable water resource management. However, our mechanistic understanding of the flow and transport processes determining the connection between the mountain block and the basin aquifer remains limited. Traditional conceptualizations assume groundwater circulation within the mountain block is predominantly shallow. This view neglects the role of deep groundwater flowpaths significantly contributing to the water, solute, and energy budgets. Overcoming these limitations requires a holistic characterization of the multiscale nature of groundwater flow along the mountain‐to‐valley continuum. As a proof‐of‐concept, we use a coupled groundwater flow and transport model to design a series of numerical experiments that explore the role of geology, topography, and weathering rates in groundwater circulation and their resulting resistivity patterns. Our results show that accumulating solutes near stagnation zones create contrasting electrical resistivity patterns that separate local, intermediate, and regional flow cells, presenting a target for magnetotelluric observations. To demonstrate the sensitivity of magnetotelluric data to features in our resistivity models, we use the MARE2DEM electromagnetic modeling code to perform forward and inverse simulations. This study highlights the potential of magnetotelluric surveys to image the resistivity structure resulting from multiscale groundwater circulation through relatively impervious crystalline basement rocks in mountainous terrains. This capability could change our understanding of the critical zone, offering a holistic perspective that includes deep groundwater circulation and its role in conveying solutes and energy. Plain Language Summary: Mountains are vital water sources for humans and ecosystems, continuously replenishing lowland aquifers through surface runoff and mountain recharge. Quantifying these fluxes and their relative importance is essential for sustainable water resource management. Here, we present a novel approach to characterize the nested nature of groundwater flow along the mountain‐to‐valley continuum by combining flow and transport models and magnetotelluric (MT) geophysical surveys. We assess the approach's potential by creating virtual realities that mimic realistic patterns of subsurface electrical resistivity. Then, using an inverse modeling approach, we test the ability of different MT survey configurations to reconstruct the resistivity fields. Our analysis shows that the accumulation of solutes in subsurface low‐velocity zones (i.e., stagnation zones) results in resistivity fields with enough contrast to image the local, intermediate, and regional groundwater flow cells. While this study is conceptual in nature, we aim to offer a framework for geophysical exploration that can characterize the critical zone without neglecting deep groundwater circulation and its role in conveying solutes and energy. Key Points: We use a coupled flow and transport model to explore the role of deep groundwater circulation in mountain‐to‐valley systemsRegional groundwater circulation conveys significant amounts of water, energy, and solutes through relatively impervious depthsMagnetotelluric surveys can potentially map the resistivity patterns created by the solute concentration patterns within the mountain block [ABSTRACT FROM AUTHOR]