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In this study we show the successful deployment of Ground Penetrating Radar (GPR) together with Electrical Resistivity Surveys (ERS) in guiding the archeological excavations at Ashdod-Yam (southern coast of Israel). This approach enabled the precise identification of excavation targets relating to an Early Byzantine ecclesiastical complex located in a residential neighborhood of the modern city of Ashdod. Applied over the course of five years, the combined use of GPR and ERS, interspersed with phases of archeological excavation, not only facilitated an efficient exploration but also ensured the preservation of valuable historical structures. The geophysical data, corroborated by drone images of the post-excavation site, revealed a striking correlation between excavation and non-intrusive survey data. This study not only charts a successful excavation journey but serves as a methodological blueprint for future archeological explorations. The techniques and strategies detailed here have broader implications for the preservation and public presentation of historical sites. [ABSTRACT FROM AUTHOR]

Effective engineering design of structures requires a thorough understanding of the groundwater conditions of the substrate. In some situations, a three-dimensional survey is necessary. Landslides are examples of such cases. They are complex phenomena, and the main factors significantly influencing their behaviour over time are changes in slope geometry, inclination and water conditions. The article discusses the reconnaissance of the substrate structure in an area threatened by mass movements along a modernized section of a railway line. The analysed area is located in the marginal zone of the North Polish glacial moraine. The geological structure of the substrate consists of: glacial tills, glaciofluvial sands, lacustrine clays, and organic soils found in periodically waterlogged areas and depressions in the terrain. Colluvial deposits, mainly consisting of clayey formations, occur on the slope of the escarpment. Surface geomorphology was interpreted using LIDAR data and field observations. Two-dimensional and three-dimensional electrical resistivity tomography (ERT) was used to obtain a detailed subsurface image, which was verified by borehole drilling and laboratory analysis of soil samples for physical properties, including grain size distribution and plasticity, as well as mechanical properties of soils. This research enabled the creation of a three-dimensional substrate model, showing the spatial distribution of colluvium and areas at risk of active landslides. The results indicate that an integrated approach, combining geophysical imaging and geotechnical reconnaissance, allows for a detailed understanding of the structure and lithology of landslide areas.

Copyright of Archives of Civil Engineering (Polish Academy of Sciences) is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geophysical monitoring of CO2 geological sequestration represents a critical technology for ensuring the long-term safe storage of CO2 while verifying its characteristics and dynamic changes. Currently, the primary geophysical monitoring methods employed in CO2 geological sequestration include seismic, fiber optic, and logging technologies. Among these methods, seismic monitoring techniques encompass high-resolution P-Cable three-dimensional seismic systems, delayed vertical seismic profiling technology, and four-dimensional distributed acoustic sensing (DAS). These methods are utilized to monitor interlayer strain induced by CO2 injection, thereby indirectly determining the injection volume, distribution range, and potential diffusion pathways of the CO2 plume. In contrast, fiber optic monitoring primarily involves distributed fiber optic sensing (DFOS), which can be further classified into distributed acoustic sensing (DAS) and distributed temperature sensing (DTS). This technology serves to complement seismic monitoring in observing interlayer strain resulting from CO2 injection. The logging techniques utilized for monitoring CO2 geological sequestration include neutron logging methods, such as thermal neutron imaging and pulsed neutron gamma-ray spectroscopy, which are primarily employed to assess the sequestration volume and state of CO2 plumes within a reservoir. Seismic monitoring technology provides a broader monitoring scale (ranging from dozens of meters to kilometers), while logging techniques operate at centimeter to meter scales; however, their results can be significantly affected by the heterogeneity of a reservoir. [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]

Around 40% of the world's population depends on coastal aquifers for freshwater supply but natural and anthropogenic drivers threaten groundwater availability. Of these drivers, saltwater intrusion (SWI) is one of the most critical and is increasingly affecting coastal areas worldwide. Interest in coastal aquifers has significantly increased, as demonstrated by the growing number of publications in which researchers describe various approaches to illuminate the importance of coastal aquifers, specifically with regard to SWI. The state of research and knowledge of the coastal SWI issue has been reviewed herein. The review includes a discussion of select geophysical and field methods and tools which can inform the numerical modeling of coastal aquifers. MODFLOW was identified as the most often used numerical modeling platform. Further, while many research sites, particularly in the United States, were identified where field studies and geophysical methods, mostly geoelectric ones, added important value to the numerical modeling of the SWI process in the coastal zone, in some regions of the world, data scarcity was identified as the main challenge. Overall, numerical modeling, combined with geophysical methods, is a valuable tool for studying SWI and managing coastal water resources. [ABSTRACT FROM AUTHOR]

The use of geophysical techniques can contribute considerably to the advancement and optimization of subsurface surveys, due to the low costs and time effectiveness. Ground penetrating radar (GPR) has great potential to rapidly and non-invasively evaluate soil in sites affected by the Fundão dam collapse, Southeastern Brazil. The objective of this work was to investigate the thickness of the iron ore tailing layer deposited in a stretch of the Gualaxo do Norte River, besides identifying the most efficient electromagnetic frequency for analysis of this type of material. Three antennas (200, 400 and 900 MHz) were used for GPR surveys in three transects. The radargrams were processed with filtering and gain techniques, aiming to improve the signal quality. We could detect three ground reflection zones with different electromagnetic properties, representing, sequentially, the topsoil, the tailing layer, and the C horizon of the original soil, separated by two reflectors representing the boundaries layers. The tailing layer presented an average thickness of approximately 1 m. 200 MHz presented the best results, whose signal reached the greatest penetration depth and detected the entire tailing layer thickness, besides the others layers present. Using field control points, we could observe that the depths obtained with radargrams had 93% of concordance with the actual depths, which is very satisfactory. The results indicate that the 200 MHz antenna is a better option in surveys involving stratification on Technosols constituted by tailings and GPR should be more explored in the evaluation of soil and sediments. [ABSTRACT FROM AUTHOR]

Abstract With the exploration, development, and research of deep‐sea resources, there is an urgent need for long‐term and continuous observation data of the deep‐sea seabed boundary layer. The traditional method of deep‐sea seabed survey and sampling based on scientific research vessels has the discontinuity of observation data in space and time scales. There are some problems in the seabed in situ observation method based on the seabed observation network for low mobility and high operation and maintenance costs, restricting the in‐depth understanding of the dynamic change process of the deep‐sea floor. To solve the above problems, an open and modular data acquisition control system was designed based on an embedded system and signal processing technology. In terms of the physical, chemical, geological, and ecosystem characteristics of the seafloor or near the seafloor boundary layer, various functional sensors and instrumentation were matched to form an independent underwater integrated measurement or experimental device, eventually realizing in situ multiparameter and long‐time series observations of the seafloor. The system data acquisition and control test were completed through laboratory experiments, which verified the feasibility of the system design. The research showed important theoretical and technical reference significance for the exploration and development of resources in the submarine boundary layer and the promotion of deep‐sea scientific research.

With the exploration, development, and research of deep‐sea resources, there is an urgent need for long‐term and continuous observation data of the deep‐sea seabed boundary layer. The traditional method of deep‐sea seabed survey and sampling based on scientific research vessels has the discontinuity of observation data in space and time scales. There are some problems in the seabed in situ observation method based on the seabed observation network for low mobility and high operation and maintenance costs, restricting the in‐depth understanding of the dynamic change process of the deep‐sea floor. To solve the above problems, an open and modular data acquisition control system was designed based on an embedded system and signal processing technology. In terms of the physical, chemical, geological, and ecosystem characteristics of the seafloor or near the seafloor boundary layer, various functional sensors and instrumentation were matched to form an independent underwater integrated measurement or experimental device, eventually realizing in situ multiparameter and long‐time series observations of the seafloor. The system data acquisition and control test were completed through laboratory experiments, which verified the feasibility of the system design. The research showed important theoretical and technical reference significance for the exploration and development of resources in the submarine boundary layer and the promotion of deep‐sea scientific research. [ABSTRACT FROM AUTHOR]

Around 40% of the world’s population depends on coastal aquifers for freshwater supply but natural and anthropogenic drivers threaten groundwater availability. Of these drivers, saltwater intrusion (SWI) is one of the most critical and is increasingly affecting coastal areas worldwide. Interest in coastal aquifers has significantly increased, as demonstrated by the growing number of publications in which researchers describe various approaches to illuminate the importance of coastal aquifers, specifically with regard to SWI. The state of research and knowledge of the coastal SWI issue has been reviewed herein. The review includes a discussion of select geophysical and field methods and tools which can inform the numerical modeling of coastal aquifers. MODFLOW was identified as the most often used numerical modeling platform. Further, while many research sites, particularly in the United States, were identified where field studies and geophysical methods, mostly geoelectric ones, added important value to the numerical modeling of the SWI process in the coastal zone, in some regions of the world, data scarcity was identified as the main challenge. Overall, numerical modeling, combined with geophysical methods, is a valuable tool for studying SWI and managing coastal water resources.

Copyright of Boletín Geológico y Minero is the property of Instituto Tecnologico Geominero De Espana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the Electrical Resistivity Tomography (ERT) A geophysical investigation involving Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES) for groundwater potentials in Erhoike Community, Delta State, Nigeria, using standard geophysical methods. Six (6) lithologies including the topsoil, dry sand, saturated sand, clayey sand, sandy clay and clay were delineated within the area. The top soil with resistivity and thickness of 547.5 - 8348.6 ohm-m and 0.7 - 1 m respectively represent the first delineated geoelectric layer. This overlies the dry sand having geoelectric parameter of 3.9 - 19.7 m and 761.4 - 8248.6 ohm-m respectively. The dry sand layer underlain by the saturated sand having resistivity ranging from 114.3 - 1380.6 ohm-m. The resistivity of the clayey sand oscillates between 47.6 - 85.3 ohm-m. This layer represents the last layers at the locations where it was delineated, as such the thickness could not be estimated. The clay layer underlies sandy clay in places while in other cases, it succeeds the topsoil. The resistivity and thickness of the clay layer were 11.4 - 48.9 ohm-m and 25.8 - 56.1 m respectively. The sandy clay was found to have resistivity of 50.6 - 115.3 ohm-m and thickness of 2.9 - 8.8 m. The results of the study showed that the saturated sand layer represents the aquiferous layer within the area where groundwater can be tapped for the community. The thickness of this layer is found to be more than 58.2 m which is quite significant for groundwater development. The study concluded that there is abundance of groundwater accumulation beneath the area. It further reinforced the applicability of combined ERT and VES in groundwater potential mapping in an area underlain by similar geology. [ABSTRACT FROM AUTHOR]

This study investigated the Electrical Resistivity Tomography (ERT) A geophysical investigation involving Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES) for groundwater potentials in Erhoike Community, Delta State, Nigeria, using standard geophysical methods. Six (6) lithologies including the topsoil, dry sand, saturated sand, clayey sand, sandy clay and clay were delineated within the area. The top soil with resistivity and thickness of 547.5 – 8348.6 ohm-m and 0.7 – 1 m respectively represent the first delineated geoelectric layer. This overlies the dry sand having geoelectric parameter of 3.9 – 19.7 m and 761.4 – 8248.6 ohm-m respectively. The dry sand layer underlain by the saturated sand having resistivity ranging from 114.3 – 1380.6 ohm-m. The resistivity of the clayey sand oscillates between 47.6 – 85.3 ohm-m. This layer represents the last layers at the locations where it was delineated, as such the thickness could not be estimated. The clay layer underlies sandy clay in places while in other cases, it succeeds the topsoil. The resistivity and thickness of the clay layer were 11.4 – 48.9 ohm-m and 25.8 – 56.1 m respectively. The sandy clay was found to have resistivity of 50.6 – 115.3 ohm-m and thickness of 2.9 – 8.8 m. The results of the study showed that the saturated sand layer represents the aquiferous layer within the area where groundwater can be tapped for the community. The thickness of this layer is found to be more than 58.2 m which is quite significant for groundwater development. The study concluded that there is abundance of groundwater accumulation beneath the area. It further reinforced the applicability of combined ERT and VES in groundwater potential mapping in an area underlain by similar geology.

Metal detection (MD) has traditionally been viewed as a limited geophysical survey method for the identification of metal objects below the surface. However, this pilot study examines techniques utilizing the “ground balance” function, common to most modern metal detectors, to identify subsurface magnetic anomalies. The results of surveys have yielded inconclusive results on the use of metal detectors for feature identification. However, the results of this study suggest a high potential for more efficient and more productive archaeological reconnaissance surveys. The ground balance function, when combined with systematic sampling and geographic information systems interpolation methods, yields low-resolution subsoil magnetic susceptibility maps. Compared to other geophysical methods, such as gradiometry or electrical resistivity, the depth range of MD is limited. However, this technique, in upland contexts with shallow subsoils or sites with high potential for recent ground disturbing activities, can reveal subtle changes in the subsurface that traditional MD techniques would miss. Further studies are recommended to explore the many situations in which a metal detector can provide an informative alternative, though not a replacement, for other geophysical survey methods. This pilot study was funded by the National Geographic Society’s Early Career Grant program.

In determining a suitable path and depth for immersing gas pipeline for power generation at Obada Oko, Ogun State Nigeria, a geophysical survey was carried out to assess the characteristics of the subsurface underlying formations for soil corrosivity. The corrosivity of the soil was ascertained by using the soil resistivity values, soil moisture content, and soil pH values. Five Wenner electrical resistivity tomography (ERT) traverses were carried out with twenty soil samples and twenty-four Schlumberger vertical electrical sounding (VES). The result reveals an asymmetric resistivity deviancy along the proposed gas pipeline route, which indicates a mixture of sandy clay to clayey sand deposition laterally and vertically. The soil pH value reveals that the study area was slightly acidic to alkaline and high soil moisture content was observed at traverse four due to its proximity to the Ogun River. The electrical resistivity model reveals that a suitable depth of buried gas pipe must be within the depth of 2.5 to 3.5 m at Traverse (1, 2, and 3) and a depth of 3.5 to 5 m at Traverse (4 and 5). The ERT model reconciles with the soil moisture content at all the traverses chaperoned with the soil pH test. It was concluded that corrosion risk to buried metallic structures at the study zone is almost non-existent and the subsurface is highly competent, yet without proper maintenance, external coating, and cathodic protection, the immersion of gas pipeline could eventually fail. [ABSTRACT FROM AUTHOR]