GPR Data Research Articles

Sedimentary cover structure of fresh water lakes of Kindo peninsula near the White sea Biological station of Moscow State University according to georadiolocation and drilling data

The geological structure of two freshwater lakes (the Verkhneye and the Vodoprovodnoye) located near the White sea biological Station of the Moscow State University (the Kandalaksha Bay of the White sea) is considered for the first time according to the GPR data. The morphology of the top of the Archean basement, the structure of the Quaternary sedimentary cover and bottom relief were studied. Shallow marine sediments overlying the rocks of the Archean and a sequence of lacustrine-marsh sediments were identified using the drilling data in the Quaternary cover. Structural schemes were constructed for the main reflecting horizons, while isopach schemes were generated on the basis of the main sequences. The values of electrical resistivity and absorption coefficient are calculated and the possibilities of their use for the delineation of GPR facies are considered.

Automation of contrast media boundary detection when processing GPR data

The paper presents the field results of the inspection of transport facilities, in which the contrasting media in terms of radio wave propagation velocities are found. The possibility of high-precision determination of interface boundaries for such media at shallow depths (for example, the contact of asphalt concrete pavement and crushed stone and sand mixture), as well as at high depths (for example, the determination of the bottom of water bodies) is discussed. In addition, the possibility of using artificial neural networks to identify contrasting boundaries on the GPR data and the transition to less contrasting boundaries is justified.

Detection of a thin layer by seismic reflection with different geophones at a site in Liangzhu, Southeastern China

Geophone properties are important factors for high-resolution seismic exploration and greatly influence the quality of data. In this study, we will address the problems of ultra-shallow seismic data acquisition and processing. The purpose of our study is to evaluate the applicability of using different seismic geophones and processing techniques to detect a thin soil layer that is approximately 20 cm in thickness at a depth of approximately 2 m in the Liangzhu archaeological site in southeastern China. We collected seismic data using two types of geophones: normal geophones with different natural frequencies inserted into the ground and towable cable geophones contacting the earth’s surface. We considered combining the frequency advantages of these two different types of geophones to broaden the effective bandwidth of the acquired data. To achieve this, we designed a partial frequency match filtering method for data processing, which helps to improve the resolution of the reflected seismic data. The stacking profile results show that match filtering is effective in detecting a thin layer compared to drilling samples and GPR data the velocity of the thin bed is 350ms while from seismic section interval velocity of the contact between clayey soils and rammed sandy soils about 600 ms.

Seepage investigations of heterogeneous soils beneath some buildings using geophysical approaches: example from southwestern Nigeria

Buildings along the flood plain of River Osun, southwest Nigeria, are usually thought of as been a safe haven for residence over the years. But in recent times with vast (increasing) population and growing urbanization, some of the buildings currently experience structural damages not related to constructional designs but rather ground conditions around building foundations. The ground conditions (seepages in this case) and how it influences properties of soils (water moisture, permeability etc.) to support the foundation of buildings. This paper attempts to map out seepages in heterogeneous soils around buildings in Erinle, southwest Nigeria where building cracks probably as a result of water seepages from subsurface through fissures and fractures where noticed. These cracks are a probable manifestation of a weakened foundation that could overtime result to a collapse, hence the need to investigate seepage prone zones. To achieve this, electrical resistivity (ER) and Electromagnetic Ground Penetrating Radar (EM-GPR) surveys were made along affected buildings to map out possible causes of deterioration. Geo-sections (analyzed ER data) shows high resistivity layer (topsoil) underlain by low resistivity layer (weathered basement) confirmed by planer reflections (topsoil) and fairly smooth to smooth reflections (weathered basement) in Radargrams (analyzed GPR data). An integration of the geo-section and radargram produced from ER and GPR data shows that buildings along traverses 1, 2, 3 and 5 is most prone to seepages especially as it exhibits very low anomalously resistivity values (< 25 Ωm) but this is not the case for buildings along traverses 4, 6, 7 and 8.

High quality pre-stack migrated radar images of several fixed-offset passes along a shore-normal profile on Marambaia Barrier Island

We show high quality images of constructed multi-offset radar data along a shore-normal profile on Marambaia Barrier Island. The multi-offset data is constructed assembling traces from seven collinear fixed-offset passes with a 100MHz bistatic equipment. The traces are binned and stacked as sparse 7-trace common-source gathers along the profile. We deal with the severe alias on each gather through trace interpolation, yielding adequately sampled, unaliased, dense common-source gathers. With the interpolated gathers we have produced a stack section and estimated a 2-D velocity model spanning over the whole profile. All images obtained through from the common-source gathers have a degree of quality far beyond what would be possible to obtain with a usual fixed-offset survey, eventually complemented with a limited number of multi-offset gathers, aiming at estimation of 1-D velocity models. Moreover we show here that a CMP gather is unable to accurately estimate a 1-D velocity distribution at its central point. The multi-offset data yielded not only a 2-D velocity model but also pre-stack time and depth migrated images of the subsurface, products which are well beyond the reach of the usual GPR data acquisition. The pre-stack migrated images provide a clear glimpse on the stratigraphic framework, a result from the interplay of base-level changes and sedimentation at the shoreline of Marambaia Barrier Island. Two unconformities probably correlated to the last process of marine regression, provide chronological markers allowing a qualitative correlation with a sea level variation curve for the last 12,000calyBP on the coast of the State of Rio de Janeiro.

Cloud‐based difference algorithm using big GPR data for roadbed damage detection

SummaryGround‐penetrating radar (GPR) technology is being widely used for urban roadbed damage detection. In this paper, we present the development of a cloud‐based difference detection method using big GPR data for roadbed damage detection. Unlike many processing methods relying on standalone servers, the proposed method can achieve high accuracy and processing efficiency by distributing the computation over a server cluster. The method includes a difference detection algorithm for GPR image enhancement and damage extraction, the Hadoop Distributed File System, and MapReduce distributed parallel computing framework for big GPR data parallel processing and interpretation. Moreover, to automatize roadbed damage classification, a criterion with seven grades is established based on the wave group shape, amplitude, phase, and attenuation characteristics. We validate the proposed method through a detection experiment that was conducted on the Fourth Ring Road in Beijing, China. The detection revealed 187 damage from the efficient processing of big GPR data, thus suggesting the ability of the proposed method to provide timely support for road safety in cities.

Geocryological Analysis of Rocks to Predict Adverse Freeze-and-Thaw Effects

The geophysical investigations are carried out at the Kangalass open pit coal mine using the round penetrating radar and electrical tomography. The main frost effects in rock mass and in water retaining dam are described. The investigation procedure is developed, and the wave fields are characterized. The GPR surveys aimed to reveal water invasion zones in a rock block to be blasted and to trace dynamics of a seasonal thawing layer are presented. The integrated analysis of GPR and electrotomography data is performed to determine adverse freeze-and-thaw processes at the dam bottom. Applicability of GPR in prediction of unfavorable freeze-and-thaw activities is demonstrated.

Pavement-distress detection using ground-penetrating radar and network in networks

This study proposes a nondestructive testing technique for pavement distress detection using ground-penetrating radar and network in networks. Ground-penetrating radar signals are imported into two network-in-network structure as input data directly. The network in networks are used as deep learning models to distinguish abnormal signals, recognize distress types, and measure distress locations and sizes. A database with information from four highways is generated by a ground-penetrating radar with different transmitting frequencies and numbers of samples per trace. Then, the database is used to train, validate, and test the network in networks. The results show that the proposed method detects cracks, water-damage pits, and uneven settlements with 85.17% accuracy, 2.15 mm location errors, and reasonable stability. The proposed method was superior to other state-of-the-art techniques in terms of classification accuracy, location error, and stability. Additionally, the results show that this method overcomes the negative effect of transmitting frequencies in pavement distress detection using GPR data.

Glacier thickness estimations of alpine glaciers using data and modeling constraints

Abstract. Advanced knowledge of the ice thickness distribution within glaciers is of fundamental importance for several purposes, such as water resource management and the study of the impact of climate change. Ice thicknesses can be modeled using ice surface features, but the resulting models can be prone to considerable uncertainties. Alternatively, it is possible to measure ice thicknesses, for example, with ground-penetrating radar (GPR). Such measurements are typically restricted to a few profiles, with which it is not possible to obtain spatially unaliased subsurface images. We developed the Glacier Thickness Estimation algorithm (GlaTE), which optimally combines modeling results and measured ice thicknesses in an inversion procedure to obtain overall thickness distributions. GlaTE offers the flexibility of being able to add any existing modeling algorithm, and any further constraints can be added in a straightforward manner. Furthermore, it accounts for the uncertainties associated with the individual constraints. Properties and benefits of GlaTE are demonstrated with three case studies performed on different types of alpine glaciers. In all three cases, subsurface models could be found that are consistent with glaciological modeling and GPR data constraints. Since acquiring GPR data on glaciers can be an expensive endeavor, we additionally employed elements of sequential optimized experimental design (SOED) for determining cost-optimized GPR survey layouts. The calculated cost–benefit curves indicate that a relatively large amount of data can be acquired before redundant information is collected with any additional profiles, and it becomes increasingly expensive to obtain further information.

Identification of eroded sediment layer thickness and depth of Mahakam River at Tenggarong Bridge Area, Kutai Kartanegara East Kalimantan using Ground Penetrating Radar Method

GPR measurements of lines are two lines intersect under the bridge of Tenggarong (southwest to northeast) along the 377 meters (segment-1 Line04) and 457 meters (Line03) and the other is Southeast to Northwest along the 533 meters (segment-2 Line04) with a starting point It is located on the side of the Mahakam River (Southern) to the West of Kumala island. and there is one track in this area, which is to the northeast to the southwest along the south side of the Mahakam River (Line02) with the length of line is 780 meters. This research used the AKULA-9000C, 100 MHz antenna frequencies, and in time mode. The purpose of this research is to know the depth of the bottom of the Mahakam River, and the thickness of sediments eroded around the bridge of Tenggarong. GPR data processing using the ReflexW software ver. 8.5 through static correction, subtract-mean (dewow) filter, gain, background removal, band-pass filters, and fk-filter. To convert two-way time of electromagnetic wave propagation data to depth units, we use velocity adaptation methods by selecting velocity value each layer anomaly. Cross sections of the line from line02 and Line03 showed that the average thickness of the layer of sediment erosion over 15 meters and depth variation ofthe river was 10 to 40 meters. The shallow depth is under the Tenggarong Bridge (10m). In addition, on Line04 shows the deepest depth of the Mahakam River is 35 meters, located in the middle of Line04 or the center of Mahakam river flow.

3-D structure of the discharging zone of the Daginsky hydrothermal system (Sakhalin Island) according to the ground penetrating radar method and well logs

The paper presents the results of a comprehensive analysis of GPR data and geophysical well survey data (gamma-ray logging and self-polarization potentials) to study the 3-D spatial structure of the Daginsky hydrothermal system discharging zone (Sakhalin Island) and its hydrogeological situation. According to the GPR method, the paleo-valleys were identified, the morphology of which indicates the presence of runoff hollows, the accumulation of sandy-aleurite-clay sediments covered with peat formations. It can be concluded that the caprock in this area consists of a pack of water layers and permeable zones. Based on the data of geophysical studies in wells, three zones can be distinguished, each of which is characterized by the corresponding values of gamma activity and changes in the potentials of its own polarization. All this helps in identifying permeable thermally conductive zones. The data obtained are of practical importance.

Model-based layer stripping FWI with a stepped inversion sequence for GPR data

Model-based layer stripping FWI with a stepped inversion sequence for GPR data

Subglacial sediment distribution from constrained seismic inversion, using MuLTI software: examples from Midtdalsbreen, Norway

ABSTRACTFast ice flow is associated with the deformation of subglacial sediment. Seismic shear velocities, Vs, increase with the rigidity of material and hence can be used to distinguish soft sediment from hard bedrock substrates. Depth profiles of Vs can be obtained from inversions of Rayleigh wave dispersion curves, from passive or active-sources, but these can be highly ambiguous and lack depth sensitivity. Our novel Bayesian transdimensional algorithm, MuLTI, circumvents these issues by adding independent depth constraints to the inversion, also allowing comprehensive uncertainty analysis. We apply MuLTI to the inversion of a Rayleigh wave dataset, acquired using active-source (Multichannel Analysis of Surface Waves) techniques, to characterise sediment distribution beneath the frontal margin of Midtdalsbreen, an outlet of Norway's Hardangerjøkulen ice cap. Ice thickness (0–20 m) is constrained using co-located GPR data. Outputs from MuLTI suggest that partly-frozen sediment (Vs 500–1000 m s−1), overlying bedrock (Vs 2000–2500 m s−1), is present in patches with a thickness of ~4 m, although this approaches the resolvable limit of our Rayleigh wave frequencies (14–100 Hz). Uncertainties immediately beneath the glacier bed are &lt;280 m s−1, implying that MuLTI cannot only distinguish bedrock and sediment substrates but does so with an accuracy sufficient for resolving variations in sediment properties.

Pros and Cons in Helicopter-Borne GPR Data Acquisition on Rugged Mountainous Areas: Critical Analysis and Practical Guidelines

We critically discuss both advantages and limitations of helicopter-borne GPR surveys in rugged mountainous areas by analyzing a pseudo 3D data set acquired over the Marmolada Glacier, which constitutes the largest ice body in the Dolomites (Eastern Alps) and contains several peculiar features both in terms of the internal structures and the surrounding topography. In this paper we analyze several possible issues that can be encountered when performing airborne surveys in mountain regions, related to both the local conditions in the particular survey areas, and the general performance of the data acquisition equipment, which includes the GPR device, the GPS system, and the helicopter itself. Based on our analyses and observations, we propose a few guidelines and optimization strategies in order to address several issues, including the choice of various data acquisition parameters, interpretation problems related to curvilinear or irregular flight paths, and trace positioning errors caused by GPS malfunctioning or oscillating antennas. Such results have general validity and can be used for helicopter-borne survey planning, as well as for data analysis and interpretation.

Groundwater dynamics in fossil fractured carbonate aquifers in Eastern Arabian Peninsula: A preliminary investigation

Eastern Arabian Peninsula represents the main natural groundwater discharge area of the Arabian platform fossil aquifer system. In such settings, connections between aquifers could strongly affect the flow dynamics, water quality and availability as well as karst formation and landscape evolution. Geological structures such as folds and faults are central to aquifer connectivity, yet their role on groundwater flow is poorly understood. Herein, we perform mapping of exposed and buried structural features in the Qatar Peninsula using Landsat, Sentinel-2 and ALOS-PalSAR scenes, correlated with field, GPR and isotopic data to assess their role in aquifer connections and groundwater dynamics. Our results suggest that ENE-WSW oriented fold-related faults act as vertical conduits along which artesian upward leakages from the deep Aruma aquifer take place into the shallower main aquifer unit (i.e. Umm er Radhuma and Rus) in southern Qatar Peninsula. On the other hand, downward leakage from the freshwater lens in the Dammam aquifer take place in northern Qatar Peninsula. The deep, brackish, and gaseous-rich waters ascending along faults in south Qatar Peninsula, in addition to degrading the water quality in the main aquifer unit, enhance dissolution of carbonates and evaporites leading to strong karstification that produces abundant collapse features. Our findings suggest that structure controls can add significant complexity to recharge mechanisms and groundwater dynamics in fossil aquifers. Future large-scale radar subsurface mapping will be essential to resolve the variability of the water heads in such areas and its correlation to structural discontinuities.

Environmental investigation using geophysical data at East Sadat City, Egypt

Three geophysical techniques such as resistivity, seismic refraction, and GPR have been applied to delineate the depth to the groundwater surface, subsurface stratigraphy and subsurface structures which control the configuration and distribution of the groundwater aquifer. Five vertical electrical sounding (VES) were measured by using Syscal-R2 instrument of electrode separation ranging from AB/2 = 1–500 m to reach depth of investigation about 150 m. The results of quantitative interpretation of the VES data indicate that the subsurface sequence composed of six geoelectric units; the first unit is characterized by resistivity values up to 2007 Ohm.m corresponding to sand & gravel and thickness up to 1.2 m. The second geoelectric unit is corresponding to sandy clay which exhibits resistivity up to 235 Ohm.m and depth up to 1.2 m. The third geoelectric unit is characterized by resistivity values up to 1483 Ohm.m corresponding to dry sand which of depth up to 2.6 m. The fourth geoelectrical unit consists of sand saturated with ground water and exhibits resistivity values ranging from 20.2 to 52.9 Ohm.m and depth ranging from 7 to 16.8 m. The fifth geoelectrical unit reveals resistivity values ranging from 7 to 32.6 Ohm.m and consists of sandy clay saturated with groundwater of depth up to 111 m overlaying the sixth unit which reached to depth up to 165 m and characterized by resistivity values ranging from 54 to 91 Ohm.m corresponding to sandstone saturated with ground water. Five shallow seismic refraction spreads of geophone spacing 4 m were measured to investigate the subsurface sequence, where the results of interpretation indicate that the subsurface section consists of three seismic layers; the first layer is unsaturated overburden with seismic velocity range from 280 to 770 m/s and thickness reach about 6 m. The second layer is sand saturated with ground water with velocity range from 760 to 1300 m/s and maximum thickness of about 7 m overlaying the third layer reached to depth up to 24 m and corresponding sandy clay saturated with groundwater with seismic velocity range from 1130 to 2260 m/s. Five GPR profiles are measured using MALA RAMAC GPR System with a Rough Terrain Antenna (RTA) system of central frequency of 100 MHz. The interpretation of GPR data indicate that the expected water table ranging from 8 m to 11 m in the study area. Interpretation of the obtained results and correlation with the available geological and different geophysical data revealed that, the depth to the groundwater table of the investigated area ranges between 7 and 16.8 m.

GPR data interpretation by the deep learning with coloring data

GPR data interpretation by the deep learning with coloring data

Detection of delamination between plane layered media using pulse geodars

The relevance of the problem follows from the consideration of the consequences of such serious road pavement defect as delamination. Also, the validity of the problem stems from the fact that the use of modern pulsed GPR provides low-cost monitoring of roads. This becomes possible when obtaining primary GPR data during the movement of the laboratory car with the speed of the transport stream, and, in addition, due to the exclusion of such labour-intensive operations as coring or cutting sections of pavement. The purpose of the work is to analyze various processing methods for ultra-wideband signals of pulsed GPR to study the capabilities of signal processing methods and algorithms to increase the reliability of detection of delamination. Materials and methods. During the investigation of the processing model and experimental data, first of all, modern theoretical methods of signal processing and computer modelling were used. Results. The factors determining the differences and characteristic features of pulsed signals of GPR, which can be used to detect delamination, as a violation of contact between layers, or to detect the presence of thin layers in a multilayer medium, are established and analyzed. Conclusions. The proposed approach to the formulation of the problem, together with the theoretical analysis and the results of numerical modelling, made it possible to justify the possibility of increasing the reliability of the non-destructive quality control of various structures and the effective detection of critical defects using GPR methods.

Характеристики и интерфейс базы данных сигнала по данным георадара

Характеристики и интерфейс базы данных сигнала по данным георадара

GPR data interpretation in the landslides and subgrade slope surveys

The paper describes results of GPR survey of multi-layered slopes of transport structures. A brief review of this problem by domestic and foreign researchers is presented. The significance of this work is determined by complexity of GPR data interpretation when the GPR survey is conducted in a common offset or common midpoint mode in case of dipping layers. The typical patterns are obtained, the groups of the same reflection events are picked and possible reasons of them are stated by numerical modeling using GprMax software. The technique of ground velocities finding in case of GPR survey of dipping layers is proposed.