Search Results (39)

Ground-penetrating radar surveys on structures have a wide range of applications, and they are very useful in solving engineering problems: from detecting reinforcement, studying concrete characteristics, unfilled joints, analyzing brick elements, detecting water content in building bodies, and evaluating structural deformation. They generally pursued small investigation areas with measurements made in direct contact with target structures and for small depths. Detecting deep piles presents specific challenges, and surveys conducted from the ground level may be unsuccessful. To reach great depths, medium-low frequencies must be used, but this choice results in lower resolution. Furthermore, the pile signals may be masked when they are located beneath massive reinforced foundations, which act as an electromagnetic shield. Finally, GPR equipment looks for differences in the dielectric of the material, and the signals recorded by the GPR will be very weak when the differences in the physical properties of the investigated media are modest. From these weak signals, it is difficult to identify information on the differences in the subsurface media. In this paper, we are illustrating an exploration on plinth foundations, supported by drilled piles, submerged in soil, extensive, deep and uninformed. Pulse GPR prospecting was performed in common-offset and single-fold, bistatic configuration, exploiting the exposed faces of an excavation around the foundation. In addition, three velocity tests were conducted, including two in common mid-point and one in zero-offset transillumination, in order to explore the range of variation in relative dielectric permittivity in the investigated media. Thanks to the innovative survey on the excavation faces, it is possible to perform profiles perpendicular to the strike direction of the interface. The electromagnetic backscattering analysis approach allowed us to extract the weighted average frequency attribute section. In it, anomalies emerge in the presence of drilled piles with four piles with an estimated diameter of 80 cm. Full article

Mining waste management is a significant environmental challenge that requires effective technical and economic solutions. In this context, the use of underground storage systems is sometimes a viable option to isolate this type of mining waste from the outside (especially when it poses a risk of environmental contamination). Despite the applicability and advantages of these structures, it is crucial to conduct thorough monitoring of the isolation and containment measures implemented during their construction. This study demonstrates how ground penetrating radar techniques can provide valuable insights into subsurface insulation layers with the aim of detecting potential water accumulation at depth and verifying the integrity of the seal and the state of buried materials. The results of the georadar survey applied on a mining case study demarcate the areas that should receive more attention in the near future and contribute to defining the most urgent actions to be implemented at the mining site. Beyond the evaluation of the 2D profiles, the research culminates in the creation of a 3D visualization tool for the entire mining site and its insulation layer, enabling users to inspect the structure’s condition at any location and obtain accurate depth measurements. Full article

Quaternary carbonate strandplains serve as archives of land–sea interaction, including the impacts of storms and tsunamis. Incipient lithification, especially of compound beach/dune ridges within the action zone of salt spray, presents challenges to geological research, which is often limited to exposures. This study combines aerial image analysis with geophysical datasets to assess the morphostratigraphy and internal structure of the Freedom Beach Strandplain along southern Eleuthera Island, The Bahamas. Color-intensity analysis of field photographs and satellite images revealed general patterns that can be used to distinguish between areas with different grayscale parameters (sand-covered surfaces, lithified ridges, vegetation, etc.). Cross-shore (dip-section) high-resolution (800 MHz) georadar images across ten ridges (A-J) documented the internal architecture of swash-aligned ridge–swale sets. Signatures attributed to storms include truncations in shore-normal radargrams, scour features in alongshore (strike-section) images, and an extensive accumulation of large mollusk shells along one of the oldest ridges (ridge J). Preliminary radiocarbon dating yielded ages of up to 600 years, suggesting intense storms with 50–60-year periodicity as a possible mechanism for ridge formation. Full article

In Antarctica, SAR interferometry has largely been used in coastal glacial areas, while in rare cases this method has been used on the Antarctic plateau. In this paper, the authors present a digital elevation and ice flow map based on SAR interferometry for an area encompassing Talos Dome (TD) and the Frontier Mountain (FM) meteorite site in North Victoria Land/Antarctica. A digital elevation model (DEM) was calculated using a double SAR interferometry method. The DEM of the region was calculated by extracting approximately 100 control points from the Reference Elevation Model of Antarctica (REMA). The two DEMs differ slightly in some areas, probably due to the penetration of the SAR-C band signal into the cold firn. The largest differences are found in the western area of TD, where the radar penetration is more pronounced and fits well with the layer structures calculated by the georadar and the snow accumulation observations. By differentiating a 70-day interferogram with the calculated DEM, a displacement interferogram was calculated that represents the ice dynamics. The resulting ice flow pattern clearly shows the catchment areas of the Priestley and Rennick Glaciers as well as the ice flow from the west towards Wilkes Basin. The ice velocity field was analysed in the area of FM. This area has become well known due to the search for meteorites. The velocity field in combination with the calculated DEM confirms the generally accepted theories about the accumulation of meteorites over the Antarctic Plateau. Full article

The current paper is dedicated to the documentation of the characteristics of vertical connectors (gomfoi) in ancient columns and to the observed pathology. The gathering of the relative information aims to provide the data necessary for decisions related to an experimental program, investigating the behaviour of columns provided with connectors between successive drums. The investigation has been carried out in monuments where the use of connectors is already known, as well as in monuments for which there is insufficient information. Monuments for which it is assumed that there are no connectors have also been studied to confirm the hypothesis. Literature review, in situ observation, and the application of non-destructive investigation methods (geo-radar) have led to the documentation of the use and location of connectors in the monuments under study. Full article

Sorghatmesh mosque is a historical structure that was constructed in Cairo, Egypt, by Prince Saif El-Din Sorghatmesh in 1356. A dual-frequency ground-penetrating radar (GPR) with 250–700 MHz was used to investigate the subsurface of the Sorghatmesh mosque for restoration purposes. A total of 37 lines were surveyed on the ground floor of the mosque. The subsurface utilities were detected, and the status of the concrete base and the medium of the ground floor were assessed. A set of subsurface anomalies were detected and interpreted within the ground floor area of the mosque. In order to validate the interpretation, a trial pit was drilled on the ground floor, allowing for the visual inspection of the subsurface, and a Georadar numerical simulation was carried out to study the responses of the subsurface materials and conditions. For a better comprehension of the results, the ground floor area was categorized into five zones where the GPR interpretations between survey lines are almost similar. This work not only demonstrates the effectiveness of GPR as a non-invasive investigation tool but also highlights the potential of integrating advanced technologies into cultural heritage preservation by offering refined methodologies and insights for future research and restoration efforts. Full article

Modern climatic changes have an impact on the bearing capacity of permafrost soils at the base of the foundations of buildings and structures in the urbanized territories of the Arctic and Subarctic. The activation of cryogenic processes leads to the destruction of infrastructure and to social, economic, and environmental consequences for the population. Based on the results for the geothermy of frozen and thawing soil, and on the georadar profiling of the city of Anadyr, it was concluded that the main risks of permafrost degradation are associated with the spread of hydrogenic melting zones. Maps of the soil temperature in imaginary cross-sections with depths of 3, 5, and 10 m were compiled, along with maps of the capacity of thawing soils, the permafrost aquifer, and the dangerous spread zones for exogenous cryogenic processes. The total area of talik zones with a depth of 6 m or more in the urban area was 2.34 km², or 67% of the built-up area. The system of permafrost monitoring in the territory of Anadyr was substantiated, and is based on monitoring the boundaries of talik zones. It consists of an automated network of observations of the ground temperature in 35 wells at the boundary and in the center of 20 zones of the dangerous development of exogenous cryogenic processes, as well as 12 control GPR profiles at the intersection of linear hydrogenic taliks. Full article

Determining precise boundaries and protective zones for historical and cultural objects enables their effective preservation. This article presents the framework for establishing protective zones around historical and cultural heritage sites existing in Ukraine, using the example of the Citadel defensive complex located in Lviv (Ukraine). It proposes general and detailed conceptual models for the combined application of remote and non-invasive methods for investigating historical and cultural heritage sites. It introduces the theory of integrating radar satellite imaging with ground-based georadar imaging. Additionally, it presents a software module that has been developed to analyze collected data on two-dimensional historical and cultural heritage objects, refine their boundaries, and establish protective zones around them. The result of the work is the determination of extremum points of vertical displacement on the territory of the historical and cultural heritage site “Lviv Citadel” in Ukraine using SAR, and the construction of a map of vertical displacements. A classification of these points was carried out, after which two of them were investigated using GPR for anomalies. Artifacts from World War II were discovered at each of these points. Using the developed software module, updated boundaries of the site were constructed, taking into account the underground artifacts and protective zones. Full article

Remote sensing techniques, namely Unmanned Aerial Vehicle (UAV) photogrammetry and t-LiDAR (terrestrial Light Detection and Ranging), two well-established techniques, were applied for seven years in a mountainous Mediterranean catchment in Greece (Ilioupoli test site, Athens), following a wildfire event in 2015. The goal was to monitor and quantify soil erosion and sedimentation rates with cm accuracy. As the frequency of wildfires in the Mediterranean has increased, this study aims to present a methodological approach for monitoring and quantifying soil erosion and sedimentation rates in post-fire conditions, through high spatial resolution field measurements acquired using a UAV survey and a t-LiDAR (or TLS—Terrestrial Laser Scanning), in combination with georadar profiles (Ground Penetration Radar—GPR) and GNSS. This test site revealed that 40 m³ of sediment was deposited following the first intense autumn rainfall events, a value that was decreased by 50% over the next six months (20 m³). The UAV–SfM technique revealed only 2 m³ of sediment deposition during the 2018–2019 analysis, highlighting the decrease in soil erosion rates three years after the wildfire event. In the following years (2017–2021), erosion and sedimentation decreased further, confirming the theoretical pattern, whereas sedimentation over the first year after the fire was very high and then sharply lessened as vegetation regenerated. The methodology proposed in this research can serve as a valuable guide for achieving high-precision sediment yield deposition measurements based on a detailed analysis of 3D modeling and a point cloud comparison, specifically leveraging the dense data collection facilitated by UAV–SfM and TLS technology. The resulting point clouds effectively replicate the fine details of the topsoil microtopography within the upland dam basin, as highlighted by the profile analysis. Overall, this research clearly demonstrates that after monitoring the upland area in post-fire conditions, the UAV–SfM method and LiDAR cm-scale data offer a realistic assessment of the retention dam’s life expectancy and management planning. These observations are especially crucial for assessing the impacts in the wildfire-affected areas, the implementation of mitigation strategies, and the construction and maintenance of retention dams. Full article

This article discusses the methods and results of assessing the angular resolution and sounding depth of enhanced-power ground penetration radars obtained during archaeological and geographical expeditionary works in various natural areas. Elongated local objects were used as test objects to evaluate the horizontal radiation pattern of the Loza–V georadar in the upper- and lower-half spaces. The depth of operation of the Loza–N low-frequency radar was estimated during a geophysical study of a unique natural object in the Siberian taiga. The variability of the GPR antenna radiation patterns in different materials (air, dry, or wet soils) confirms the necessity of quantitative measurements with controlled electrophysical parameters. Full article

Stratigraphy is a fundamental classification tool for archaeology on which modern excavation techniques are based, and essentially consists of a sedimentological, pedological and archaeological interpretation of the multiple cultural layers found while digging; this concept can be adopted when studying monumental buildings and, in particular, their hidden parts or elements. The precious and delicate surfaces of monuments need non-invasive techniques such as geophysical methods and in the present article, the use of GPR technique has been exploited through a dataset collected over the nave of the church of San Leonardo de Siete Fuentes in Sardinia. First, the georadar results have been jointly analyzed by means of the B- and C-scans, in which some most significant patterns were detected and analyzed by looking at their signal features over the investigated volume. Following the analysis, elements from the signal attribute analysis and horizon detection and visualization, with a 3D approach, were used. To strengthen the reliability of the GPR results, a thermal infrared survey was simultaneously carried out. Thanks to the integrated geophysical and historical analysis of the monument, the ancient layout of the church has been reconstructed and other targets of potential archaeological interest identified Full article

The georadar method was used to try to find some anthropic structures in a large square inside the Carabinieri barracks in the former military complex of San Giacomo degli Spagnoli in Palermo (Italy). These investigations are part of a broader context of a study of the entire area. The purpose of the investigations is to try to understand if under the ground there are the remains of an ancient horse passage that connected the Royal Palace of Palermo with the sea gate of the city. Furthermore, in the Middle Ages, on the site of the present square, there were most likely two churches, which no longer exist, as evidenced by numerous historical testimonies. One of the two, San Giacomo la Mazara, is known to have was placed right in front of the church of San Paolo, the subject of previous investigations. The investigations carried out on the main square of the military district allowed us to reconstruct a 3D georadar model in which numerous anomalies are highlighted. Some superficial anomalies have been attributed to the presence of sub-services, the deeper ones could be caused by the remains of the medieval underground way or those of the no longer existing medieval churches, but identifying their true nature requires further investigations and archaeological tests. Full article

Coastal archives of changing hydrometeorological conditions include mineralogical anomalies, such as heavy-mineral concentrations (HMCs) of variable thickness and intensity, which contain varying ferrimagnetic (e.g., magnetite) fractions. As an effective alternative to laborious mineralogical and granulometric analysis, we present the first set of bulk-volume low-field magnetic susceptibility (MS) databases from beach and dune lithosomes in the Western Estonian archipelago: Harilaid cuspate foreland (westernmost Saaremaa Island) and Tahkuna strandplain (northernmost Hiiumaa Island). Readings were conducted both in situ from trench walls and on core subsamples. At the Tahkuna site, late Holocene beach ridges reveal substantially lower values: quartz-dominated dune sequences grade from 5–20 μSI downward to diamagnetically dominated (−1–7 μSI) beach facies. Values are higher (20–140 μSI) in historically reactivated parabolic dunes that are encroaching southward over the strandplain. At the Harilaid site, four beach dune ridges (height: 2–3 m) that span the past 250–300 years show a general increase in mean MS from 320–850 μSI with decreasing age, with peaks of 1000–2000 μSI below the dune crests (depth: ~0.3–0.6 m) likely related to contemporary wind acceleration during ridge aggradation. The highest mineralogical anomalies range from 2000–5500 μSI in the historic dune sections and exceed 8000 μSI along the actively eroding upper-berm segments, typical of HMCs generated by moderate storms. MS anomalies are likely correlated with high-amplitude electromagnetic signal responses in georadar records and provide useful information for optical luminescence sampling strategies. Our study demonstrates that magnetic susceptibility trends provide a useful means of rapidly assessing relative temporal changes in overall wave/wind climates, help identify and correlate discrete anomalies related to extreme events, serve as local beach/dune boundary indicators, and represent potentially quantifiable paleo-energy indices. Full article

The effective and safe detection of illicit materials, explosives in particular, is currently of growing importance taking into account the geopolitical situation and increasing risk of a terrorist attack. The commonly used methods of detection are based predominantly on metal detectors and georadars, which show only the shapes of the possible dangerous objects and do not allow for exact identification and risk assessment. A supplementary or even alternative method may be based on neutron activation analysis, which provides the possibility of a stoichiometric analysis of the suspected object and its non-invasive identification. One such sensor is developed by the SABAT collaboration, with its primary application being underwater threat detection. In this article, we present performance studies of this sensor, integrated with a mobile robot, in terms of the minimal detectable quantity of commonly used explosives in different environmental conditions. The paper describes the functionality of the used platform considering electronics, sensors, onboard computing power, and communication system to carry out manual operation and remote control. Robotics solutions based on modularized structures allow the extension of sensors and effectors that can significantly improve the safety of personnel as well as work efficiency, productivity, and flexibility. Full article

The necropolis of El Toro is characterised as a space of prolonged use in northern Oretania. Several important archaeological finds were made in 1975 and 2012, leading to the excavation of six test pits in 2017. Based on the existing legacy data, an extension of the state of knowledge was carried out by combining several geophysical tools. The geophysical tools chosen for this sample consist of a combination of data from two different georadar systems, to which data from a magnetometer survey is added. A series of post-processes are applied to the preliminary results to improve the visualisation and interpretation of the data. The combination of these techniques used at the site is an improvement that helps us to understand these spaces and their interaction with the historical landscape of La Mancha. Full article