MHz Antenna Research Articles

Potential Identification of Root System Architecture Using GPR for Tree Translocation as a Sustainable Forestry Task: A Case Study of the Wild Service Tree

Sustainable economic development serves society but requires taking over space, often at the expense of areas occupied by single trees or even parts of forest areas. Techniques for transplanting adult trees used in various conflict situations at the interface of economy and nature work as a tool for sustainable management of urbanized and industrial areas, as well as, in certain circumstances, forest or naturally valuable areas. This study aimed to evaluate the effectiveness of ground-penetrating radar (GPR) in determining the horizontal and vertical extent of tree root systems before transplantation. Employing this non-invasive method to map root system architecture aids in the appropriate equipment selection and helps define the dimensions and depth of trenches to minimize root damage during excavation. This study specifically focused on the root systems of wild service trees (Sorbus torminalis (L.) Crantz) found in a limestone mine area, where some specimens were planned to be transplanted, as the species is protected under law in Poland. The root systems were scanned with a ground-penetrating radar equipped with a 750 MHz antenna. Then, the root balls were dug out, and the root parameters and other dendrometric parameters were measured. The GPR survey and manual root analyses provided rich comparative graphic material. The number of the main roots detected by the GPR was comparable to those inventoried after extracting the stump. The research was carried out in problematic soil, causing non-standard deformations of the root systems. Especially in such conditions, identifying unusually arranged roots using the GPR method is valuable because it helps in a detailed planning of the transplanting process, minimizing root breakage during the activities carried out, which increases the survival chances of the transplanted tree in a new location.

Detection of subsurface archaeological features using the GPR method with a 250 MHz antenna in Borsippa site, Babylon, Iraq

The GPR method was used to determine the depth and extent of the subsurface archaeological features at the archaeological site of Borsippa. The extensions of the archaeological walls were identified through the creation of three-dimensional maps. The LMX200 device conducted the survey using a 250 MHZ antenna. sixty parallel profiles were collected and processed by GPR Slice software. Several reflections of possible archaeological walls buried at different depths and extensions of 2, 4, 6, 11, and 20 m were identified. The 250 MHz antenna gave clear reflections of the archaeological walls, with a penetration depth of up to 4 meters. The time slice map identified a buried archaeological structure at 1–1.1 m deep, consisting of many rooms with thick walls up to 2-3 m.

Integrated GPR analysis and numerical modelling for discovering archaeological mysteries at Kom Ombo temple

ABSTRACT Archaeological research is made accurate and detailed by non-invasive geophysical techniques. Hence, the thorough utilisation of GPR data sets alongside numerical modelling is imperative for reducing uncertainty surrounding archaeological sites. This study aims to assess the practicality and efficacy of GPR numerical modelling in analysing concealed archaeological elements within the renowned Kom Ombo temple in southern Egypt. Using 80 MHz and 270 MHz antennas to detect any buried structures on the temple grounds. From the processed 2D GPR sections, two distinct anomalies (deep and shallow) were identified, possibly indicating hidden archaeological structures. Given the likelihood of these features possessing complex geometries, four synthetic models were devised, maintaining consistent electrical properties while varying in buried body geometry, to evaluate the GPR response. Convolution perfectly matched layer (CPML) absorbing media was designed to absorb waves within the modelling grid, alongside a transverse magnetic (TM) mode formulation, were utilised. The findings suggest that the deep anomaly could potentially represent a tunnel or significant geological formation, while the shallow anomaly may correspond to an extension of the Turkish fort. Overall, numerical modelling emerges as an enhanced mapping tool for uncovering hidden archaeological features in areas worldwide where excavation via traditional methods is not feasible.

Applying Ground Penetrating Radar and Electrical Resistivity Tomography for the Detection of Archaeological Structures in a Pre‐Tarascan Classic‐Epiclassic Site, Tingambato, Michoacán, Mexico

ABSTRACTA survey was conducted to investigate buried archaeological remains at Tingambato, a pre‐Tarascan classic‐epiclassic archaeological site located in the north‐central part of the State of Michoacán in western Mexico, using ground‐penetrating radar (GPR) and electrical resistivity tomography (ERT). The aim of this study was to detect the foundations (ancient buried walls) and cavities (tombs), define the geometry of the foundations and correlate construction style and depth with relative chronological buried structures. The survey was carried out on two grids of 15 m × 37 m (Zona Verde) and 10.25 m × 36.5 m (Ballgame court), using a 200 MHz antenna for GPR and Schlumberger‐Wenner arrays for ERT. GPR 3D acquisition was carried out along parallel lines spaced 0.25 m apart in a single direction. In the first area, considering the geometric shape found at a depth of 1.35 m, we can assume the existence of a buried structure, probably wall remains. In the second area, a very diffractive zone coincides with a resistive anomaly (> 2000 ohm·m). In order to refine the GPR results, synthetic modelling and a comparison with real traces were carried out. The 1D GPR modelling allows us to precise the presence of a cavity with a rectangular cross section. Since the type of volcaniclastic avalanche deposits of the subsoil do not allow the formation of cavities of that size, we infer that it may be the remains of a tomb or an anthropogenic cavity.

Comparing the Frequencies of 450 Mhz and 750 Mhz using GPR in Investigating Archaeological Features in (Borsippa) Site, Babylon, Iraq

Mala GX (Ground Explorer) conducted the survey using two different antennas: 450 MHz and 750 MHz. Data for the 450 MHz antenna were collected in a grid, while data for the 750 MHz antenna were collected in parallel profiles at the same location above the 450 MHz profiles. After processing the data using GPR slice software, possible reflections of archaeological walls buried at different depths and with different extensions of 13 m, 7 m, 6 m, 5m, 3 and 2 m were identified. The reflections were clear and high in the 450 MHz antenna with a depth penetration of 3 meters and unclear and weak in the 750 MHz antenna with a depth penetration of 1 meter. When comparing the two antennas, it is possible to notice a match in the reflections of the walls, and some reflections are not identical in the 750 MHz antenna due to the high noise.

Inspection of reinforced concrete structures using ground penetrating radar: Experimental approach

This study aims to the practical detection of sub-meter scale voids located inside reinforced concrete structures with different diameters and depths using different frequency antennas of 800, 1000, 1200, and 1600 MHz. The experiment was performed on two concrete blocks with medium-sized voids between 70 and 100 mm diameter, and small-sized voids between 10 and 25 mm diameter. A GPR survey was conducted by dividing each block into two grids of profiles with 50- and 100-mm profile spacing. Then, GPR data was collected along both the horizontal and vertical directions of each block with multi-frequency antennas. The gathered data was processed in 2D and 3D to detect the exact location, dimension, and brightness of these voids. The results showed that GPR has the potential to be quite effective in automating the identification and location of embedded voids within concrete blocks. The accuracy with which the system was able to identify void locations depended mainly on the frequency of the antenna used and the diameter of the void, while the depth of penetration was inversely proportional to the frequency of the used antenna, with estimated depths ranging from 25 cm (using a 1600 MHz antenna) to 1.5 m (using 800 MHz antenna). Moreover, a GPR survey was conducted to evaluate two sites inside residential buildings before and after the rehabilitation process. The radar scan exhibited a notable proficiency in identifying the positions of rebar sites, whether they were situated at a single level or two levels, inside certain areas of construction. The study revealed the ability of GPR to identify the depth of the reinforcing steel within the cement material, particularly in areas where the soil has experienced subsidence.

Simulation of Image-Guided Microwave Ablation Therapy Using a Digital Twin Computational Model.

Emerging computational tools such as healthcare digital twin modeling are enabling the creation of patient-specific surgical planning, including microwave ablation to treat primary and secondary liver cancers. Healthcare digital twins (DTs) are anatomically one-to-one biophysical models constructed from structural, functional, and biomarker-based imaging data to simulate patient-specific therapies and guide clinical decision-making. In microwave ablation (MWA), tissue-specific factors including tissue perfusion, hepatic steatosis, and fibrosis affect therapeutic extent, but current thermal dosing guidelines do not account for these parameters. This study establishes an MR imaging framework to construct three-dimensional biophysical digital twins to predict ablation delivery in livers with 5 levels of fat content in the presence of a tumor. Four microwave antenna placement strategies were considered, and simulated microwave ablations were then performed using 915 MHz and 2450 MHz antennae in Tumor Naïve DTs (control), and Tumor Informed DTs at five grades of steatosis. Across the range of fatty liver steatosis grades, fat content was found to significantly increase ablation volumes by approximately 29-l42% in the Tumor Naïve and 55-60% in the Tumor Informed DTs in 915 MHz and 2450 MHz antenna simulations. The presence of tumor did not significantly affect ablation volumes within the same steatosis grade in 915 MHz simulations, but did significantly increase ablation volumes within mild-, moderate-, and high-fat steatosis grades in 2450 MHz simulations. An analysis of signed distance to agreement for placement strategies suggests that accounting for patient-specific tumor tissue properties significantly impacts ablation forecasting for the preoperative evaluation of ablation zone coverage.

Multisensor and Multiscale Data Integration Method of TLS and GPR for Three-Dimensional Detailed Virtual Reconstruction.

Integrated TLS and GPR data can provide multisensor and multiscale spatial data for the comprehensive identification and analysis of surficial and subsurface information, but a reliable systematic methodology associated with data integration of TLS and GPR is still scarce. The aim of this research is to develop a methodology for the data integration of TLS and GPR for detailed, three-dimensional (3D) virtual reconstruction. GPR data and high-precision geographical coordinates at the centimeter level were simultaneously gathered using the GPR system and the Global Navigation Satellite System (GNSS) signal receiver. A time synchronization algorithm was proposed to combine each trace of the GPR data with its position information. In view of the improved propagation model of electromagnetic waves, the GPR data were transformed into dense point clouds in the geodetic coordinate system. Finally, the TLS-based and GPR-derived point clouds were merged into a single point cloud dataset using coordinate transformation. In addition, TLS and GPR (250 MHz and 500 MHz antenna) surveys were conducted in the Litang fault to assess the feasibility and overall accuracy of the proposed methodology. The 3D realistic surface and subsurface geometry of the fault scarp were displayed using the integration data of TLS and GPR. A total of 40 common points between the TLS-based and GPR-derived point clouds were implemented to assess the data fusion accuracy. The difference values in the x and y directions were relatively stable within 2 cm, while the difference values in the z direction had an abrupt fluctuation and the maximum values could be up to 5 cm. The standard deviations (STD) of the common points between the TLS-based and GPR-derived point clouds were 0.9 cm, 0.8 cm, and 2.9 cm. Based on the difference values and the STD in the x, y, and z directions, the field experimental results demonstrate that the GPR-derived point clouds exhibit good consistency with the TLS-based point clouds. Furthermore, this study offers a good future prospect for the integration method of TLS and GPR for comprehensive interpretation and analysis of the surficial and subsurface information in many fields, such as archaeology, urban infrastructure detection, geological investigation, and other fields.

Utilizing Ground-Penetrating Radar for Water Leak Detection and Pipe Material Characterization in Environmental Studies: A Case Study

Detecting and mapping subsurface utilities in urban areas is crucial for identifying defects or damages in drinking and sewage pipes that can cause leaks. These leaks make it difficult to accurately characterize the pipes due to changes in their reflective properties. This study focused on detecting leaks originating from underground pipes and distinguishing between these various types of pipes. It also aimed to create a visual fingerprint model that displays the reflection characteristics of these pipes during different leak conditions, enabling efficient maintenance and handling procedures on the pipes. To achieve this, a finite-difference time-domain (FDTD) method was used to simulate two types of pipe materials with and without leak areas to construct different scenarios. Additionally, a ground-penetrating radar (GPR) field survey was conducted using a 600 MHz antenna in a part of the El Hammam area on Egypt’s northwest coast. The simulated images produced with numerical modeling were compared with the radar profiles obtained using GPR at particular locations. The numerical simulations and radar profiles demonstrated the noticeable influence of water leaks from the different pipes, wherein the reflection of saturated soil waves was interrupted due to the presence of saturated soil. Envelope and migration techniques were employed in a new application to accurately distinguish between different pipe types, specifically focusing on leak areas. The strong correlation between the real radar profile and the specific signal of a water pipe leak in the simulated models suggests that GPR is a reliable non-destructive geophysical method for detecting water pipe leaks and distinguishing between the different pipe materials in various field conditions. The simulated models, which serve as image-matching fingerprints to identify and map water pipe leaks, help us to comprehend reality better.

Research on Development 3D Ground Penetrating Radar Acquisition and Control Technology for Road Underground Diseases with Dual-Band Antenna Arrays.

This paper describes the development of a new 3D ground-penetrating radar (GPR) acquisition and control technology for road underground diseases with dual-band antenna arrays. The 3D GPR system can be mounted on a vehicle-loading device and used by vehicles to detect road underground diseases at regular speeds. Compared with existing 3D GPR systems, this new type of 3D GPR has the following design features: it has dual-band antenna arrays, including a 16-channel 400 MHz antenna array and an 8-channel 200 MHz antenna array, which not only improves the detection efficiency, but also effectively balances the detection depth and detection resolution. A novel antenna switching method for time division step multiplexing (TDSM) is realized via field programmable gate array (FPGA), which not only avoids the crosstalk of antenna echo signals of different frequencies, but also ensures the interval of the same antenna working time. By combining the advantages of the FPGA and micro-control unit (MCU), and utilizing the high-speed transmission of the network port, the high-speed real-time transmission of the 3D GPR echo data is achieved. Finally, the integration of all software and hardware verified the correctness of the system, with good results.

Assessment of Combustion Cavern Geometry in Underground Coal Gasification Process with the Use of Borehole Ground-Penetrating Radar

In this study, the shape and size of a combustion cavity with a fracture zone in the gasified coal seam was determined with the use of control boreholes and a ground-penetrating radar (BGPR) test. The underground coal gasification (UCG) field-scale experiment was performed in Carboniferous strata in coal seam 501 at a depth of approx. 460 m in the Wieczorek hard coal mine in the Upper Silesian Coal Basin, Poland. After the termination of the UCG reactor, five coring boreholes were drilled to identify the geometry of the resulting combustion cavity and the impact of the UCG process on the surrounding rock mass. Borehole ground-penetrating radar measurements were performed using a 100 MHz antenna in three boreholes with a length of about 40–50 m. This enabled the identification of the boundaries of the combustion cavity and the fracture zone in the coal seam. The fracture zones of rock layers and lithological borders near the control borehole were also depicted. As a result, the cavity was estimated to have a length of around 32 m, a width of around 7 m and a height of around 5 m. The analyses performed with the control boreholes and the BGPR provided sufficient information to determine the geometry of the combustion cavity and the fracture zone.

Levee Slurry Wall Assessment Using Ground Penetrating Radar, A Case Study

Levees are essential structures in places with high water level events. Therefore, it is important to make periodic monitoring of these structures to assess their condition. Some levees consist of slurry walls built with reinforced concrete. GSSI ground penetrating radar with 200, 400, and 900 MHz antenna was used to assess the rebar and concrete condition of the slurry wall along 300m of the Big Dam Bride levee, Little Rock, Arkansas, USA. GPR profiles indicate the deterioration in rebar and concrete from the reflections of the rebar and the differences in the rebar vertical depths which represent the change in the concrete properties. These vertical shifts in the rebar anomalies indicate that the concrete fractured and the discontinued slabs shifted upward or downward over the years, all field observations did not indicated any vertical shift or fracture in the concrete slabs, or is the presence of deterioration in the concrete above the rebar. Therefore, the deteriorated part will appear at a higher or lower levels related to the non deteriorated part. Also, non-uniform values of reflections for the same depth suggest the rebar deterioration as well. There were about 182m out of 300m of the studied levee are detroierated with various degrees of rebars and concrete deterioration. The GPR was found to be effective to detect the slurry wall's concrete and rebar deterioration. The result of this study indicates that the slurry wall of the levee is possibly unsafe and partially deteriorated.

GPR survey on underwater archaeological site: A case study at Jenipapo stilt village in the eastern Amazon region, Brazil

In this work we present and discuss the results of a pioneering Ground Penetrating Radar (GPR) survey performed at the underwater archaeological stilt village called Jenipapo in the eastern Amazon region. Jenipapo stilt village is located on the Turiaçu River, Maranhão State, Northeast of Brazil. The region is known as the Maranhense wetland where settlements were built by indigenous populations that inhabited this region during the pre-colonial period (∼AD 1 – 1100). These settlements were built on the margin of rivers and lakes, being supported by wooden pillars, corresponding to prehistoric stilt houses. The objectives of this research are to refine the wooden pillars location at the Turiaçu River bottom and guide the search for underwater archaeological artifacts. A total of twelve GPR profiles were acquired with 270 MHz antennas using a rubber boat. The GPR results indicated clear signal reflection from the river bottom and several diffraction hyperbolas suspended over the river bottom related to the top of the wooden pillars. To support the interpretation of the results, a GPR numerical modeling was performed to simulate the diffraction hyperbolas suspended in the water related to the wooden pillars. The synthetic result presented a good agreement with real data. Finally, the location of several diffraction hyperbolas can guide the divers to find and collect archaeological artifacts around the underwater wooden pillars that are the best evidence of the stilt houses of indigenous settlements found in the eastern Amazon region. Several archaeological artifacts were found during previous work, including ceramic materials. The results of this research show the capability of the GPR method to map an underwater wooden pillar and increase the probability of finding archaeological artifacts on the river bottom, which contributes to improve the knowledge of the Amazonian archaeology in Brazil.

Geophysical Prospecting of the Coptic Monastery of Apa Moses Using GPR and Magnetic Techniques: A Case Study, Abydos, Sohag, Egypt

As a result of new discoveries, there is a greater opportunity for development and investment in the Al-Arraba EL-Madfuna region of Abydos, Sohag Governorate, Egypt, which benefits tourism and increases the national economy. The Coptic monastery, which was originally established by Apa Moses, the patriarch of the Coptic Church during the ancient Roman Empire, has vanished inside the current market on this site, along with numerous tombs. As a result, the primary goal of this work is to prospect on this site for these potential archaeological features. Ground magnetic and ground-penetration radar (GPR) surveys were employed for discovering these archaeological issues. This work was done in coordination with the Supreme Council of Antiquities. Ground magnetic and GPR surveys were implemented using the G-857 proton-precession magnetometer and GSSI SIR 4000 with a 200 MHz antenna. The data were processed and interpreted using Geosoft Oasis Montaj and REFLEXW v.5.8 software packages. The magnetic data were filtered to separate the shallower anomalies representing the archaeological remains from those of the deeper ones. Butterworth high pass filter, first vertical derivatives, analytical signal, and tilt derivative were employed to carry out the processing stages. The results were analyzed qualitatively and quantitatively to describe these anomalies and determine their locations, geometrical shapes, and depths. The source parameter imaging technique and 3D Euler deconvolution were used to calculate the depths. The analysis of magnetic maps shows that the study site is characterized by a number of anomalies that occur and have geometric squares and rectangle shapes with depths ranging from 0.7 m to ≈4 m. Some of these anomalies are related to potential archaeological objects. GPR findings reveal considerably scattered hyperbolas along several profiles, which may indicate the presence of potential buried objects. The integration of magnetic and GPR results showed that there is some consistency in the identification of the locations of the likely buried archaeological objects and their depths (0.7 to 3 m) for the majority of the discovered targets. The findings of this study suggest excavating at this location and relocating the market in order to protect the buried antiquities from being lost to be safeguarded as a tourist destination target.

Geomorphic mapping and analysis of neotectonic structures in the piedmont alluvial zone of Haryana state, NW-India: a remote-sensing and GPR based approach

The Himalayan Frontal Thrust (HFT) and the surrounding piedmont alluvial region represent a zone of active deformation in the Indo-Gangetic plains. We investigated the Piedmont zone between the Ghaggar and Yamuna River basins in Haryana, India, for geomorphic signatures of active tectonics using remotely sensed data and validated by Geophysical Ground Penetrating Radar (GPR) surveys. The possible locations and the types of active tectonic features such as sub-surface fault, ridges, lineaments and warps were identified based on the presence of geomorphic signatures such as drainage gradient anomalies, abrupt change in flow direction, river offset, compressed meanders, paleochannels and topographic breaks. We used various optical satellite imageries to detect and map the temporal changes in the flow pattern of rivers in the study area. GPR investigations were done at selected test sites to locate and verify the continuity of subsurface fault. The GPR profiles were taken in the North-South direction using the common midpoint technique with 40 and 100 MHz antennae. Low frequency bi-static GPR scanning confirmed a number of dipping reflectors due to fault planes and warp surfaces in the study area. It is concluded that the piedmont zone of Haryana is actively deforming and could become a future seismic hazard zone.

Groundwater Level Variation Analysis Using Hydrogeophysical Methods in an Area of Campo Sujo in Cerrado, Chapada dos Veadeiros Region, Goiás

Cerrado’s campo sujo areas have been one of the main focuses of anthropic occupation in the Chapada dos Veadeiros region, Brazil’s Central Plateau, as they are easily accessible flattened areas with less dense vegetation. They are usually associated with wetlands representing excellent water reservoirs and groundwater recharge zones. The environmental characterization and analysis of water level variation are essential to investigate the impacts of human occupation. Hydrogeophysics represents one of the main subsurface research tools due to its easy application and efficiency in identifying the water level, with emphasis on Ground-penetrating radar (GPR), and electrical resistivity tomography (ERT). An analysis of GPR sections with 200, 400, and 900 MHz frequency antennas associated with the resistivity model was carried out to identify structures, and map the groundwater level. The overlapping data compose a hydrogeophysical model with good correlation to direct measurements of water level in a monitoring well, and soil horizons mapped in a trench. The GPR proved to be efficient in mapping the water level, mainly about to the survey with a 400 MHz antenna, shown as a horizontal reflector associated with attenuation portions of the reflection signal, registering in profile the lowering of the water level from 1.68 m in May to 3.35 m in August. The resistivity model showed a good correlation with the variations between the mapped soil horizons. The analysis shows that constructing a hydrogeophysical model is an excellent alternative for identifying the water level, and characterizing the shallow subsurface by applying non-invasive techniques. The study area represents a preserved area of campo sujo, and the research data can be used for comparison with future surveys, in addition to representing a base hydrogeophysics methodology that showed promising results for the physiographic characteristics of the area, which can be replicated in regions of similar geoenvironmental aspects.

A Pixel-Scale Measurement Method of Soil Moisture Using Ground-Penetrating Radar

Ground validation of remote sensing soil moisture requires ground measurements corresponding to the pixel scale. To date, there is still a lack of simple, fast and reasonable methods for soil moisture measurement at pixel scale between point measurements and remote sensing observations. In this study, a measurement method of soil moisture using ground-penetrating radar (GPR) was proposed for pixel scale. We used a PulseEKKOTM PRO GPR system with 250 MHz antennas to measure soil moisture by Fixed Offset (FO) method in four 30 × 30 m2 plots chosen from the desert steppe. This study used a random combination method to analyze soil moisture measurements acquired by different numbers of GPR survey lines. The results showed that two survey lines of GPR would be sufficient under confidence level of 90% with the relative error of 7%, and four survey lines of GPR would be eligible under confidence level of 95% with the relative error of 5% for each plot. GPR measurement can reproduce the spatial distribution of soil moisture with higher resolution and smaller error, especially when two and four survey lines are designed in cross shape and grid shape, respectively. The method was applied to ground validation for the soil moisture from Landsat 8, showing the advantages of stable relative errors, less contingency and reliable evaluation when compared to point measurements. This method is fast and convenient and not limited to a certain pixel, and thus largely benefits the scale matching of remote sensing results and field measurements in ground validation.

Evaluación y Monitoreo de la Variación del Contenido de Humedad en Suelo Tropical Compactado Usando Datos GPR

El rápido deterioro y el desempeño insatisfactorio de los pavimentos, también, están relacionados con la variación y acumulación excesiva de la humedad en la subrasante y en sus capas constituyentes. De ahí que el control de la humedad sea fundamental para asegurar, en parte, la durabilidad y el buen comportamiento de este tipo de estructuras. El Georradar (GPR) ha demostrado ser una potencial alternativa útil para este propósito, dadas sus características no invasivas, preservando la integridad del sitio bajo observación, además de la capacidad de recolectar datos de manera rápida y continua. Este estudio tiene como objetivo evaluar la sensibilidad del GPR a los cambios de humedad e investigar la influencia que tienen los modelos de calibración en la estimación del contenido de humedad en un suelo tropical compactado. Se utilizaron muestras de suelo laterítico deformado y se sometieron a ensayos para la caracterización de sus propiedades físicas y compactación. Se utilizó una antena GPR de 1600 MHz para la adquisición de datos en un ambiente de laboratorio controlado. En general, los resultados mostraron que el GPR es una alternativa promisoria, con precisión satisfactoria en la evaluación de la humedad y sensibilidad al monitorear cambios en el contenido de humedad en suelos compactados.

MAPPING GROUNDWATER CONTAMINATION FROM GAS STATIONS USING GROUND PENETRATING RADAR (GPR) IN AMAZONIA, BRAZIL

The Ground Penetration Radar (GPR/ GSSI-SIR 3000-Common-offset) was used to detect and scale underground structures and hydrocarbon pollution plumes around gas stations in the municipality of Santarém (Pará/ Amazon/ Brazil). Two of them are among the oldest in the city and they are located in a very populated area, which can represent a great risk of subsoil and groundwater contamination because of fossil fuel leaks. The present research used 100 ns and 175 ns time windows, with a 270 MHz antenna, and the received data were processed via Software Reflex Win/ V4.5.5. The results showed that the fuel tanks are best reflected in the 100 ns configuration, while the water table and the hydrocarbon plume were more clearly identified in the 175 ns configuration due to the greater depth range. Therefore, the shallow mapping of the subsoil with the GPR method, using the two complementary configurations, was effective in locating and delineating hydrocarbon plumes up to a depth of 4 meters. Thus, the method proved to be efficient in obtaining important data to guide sanitation and public health services and the elaboration of environmental public policies and licensing of companies dealing with potentially polluting activities.

Electrical resistivity tomography and ground‐penetrating radar methods to detect archaeological walls of Babylonian houses near Ishtar temple, ancient Babylon city, Iraq

AbstractA survey was conducted to investigate buried archaeological walls near the Ishtar temple in the ancient Babylon city using electrical resistivity tomography and ground‐penetrating radar methods. The survey includes applying 12 electrical resistivity tomography profiles using dipole–dipole array and a ground‐penetrating radar grid of 55 m × 50 m using 250 MHz antenna. Although the buried walls are consisting of mudbrick masonry and are embedded in a clayey environment, the electrical resistivity tomography method is still able to differentiate the tiny differences between the host materials and the buried walls, which show distinctive wall‐like features with resistivity values ranging between 9 and 15 Ω m. These features may reflect underground‐buried walls with a general width reaching about 2.5 m. The comparison of ground‐penetrating radar profiles and their corresponding electrical resistivity tomography profiles presents that the main architectures are coinciding well. The analysis of the geometry and composition of the walls around the Ishtar temple suggested that the wall‐like reflections on the ground‐penetrating radar slice at a depth between 140 and 150 cm (may be shallower) are underground‐buried walls. These wall‐like reflections show a special trend and orientation that indicate that they may be the remains of rooms belonging to two small houses or the remains of one big private house.