Ground Penetrating Radar Sounding Research Articles

Real-time dual-parameter full-waveform inversion of GPR data based on robust deep learning

SUMMARY Ground penetrating radar (GPR) is becoming an increasingly important tool for understanding the shallow electrical structures of the Earth and planets due to its adaptability to harsh detection environments, efficient data acquisition and accurate detection results. GPR full-waveform can simultaneously constrain the permittivity and resistivity of the medium, providing more comprehensive geophysical information and reducing the non-uniqueness of inversion. However, given the highly non-linear inverse problem and the massive data resulted from high temporal and spatial samplings, traditional full-waveform inversion algorithms are prohibitively costly. Inspired by Google's vision semantic segmentation system, we develop a robust deep learning-guided network that integrates geology and geophysics knowledge to support the real-time translation of zero-offset GPR data into dual-parameter electrical structures. We test our proposed network using synthetic data, which demonstrates that the algorithm can provide an accurate dual-parameter electrical model from a GPR sounding in milliseconds on a common laptop PC, exhibiting high robustness and adaptability to noise interference and extreme values of model parameters. We also apply our network to field data gathered for pollutant investigation in the United States. The resulting dual-parameter structure provides a more comprehensive and realistic depiction of subsurface electrical properties and reveals the migration and ageing of pollutants. Our algorithm's real-time and accurate advantages are expected to further unleash the potential of GPR technology and enable it to play a more significant role in earth and planetary exploration.

Ground Penetrating Radar Survey of Arctic Polygonal Wedge Structures

Ground Penetrating Radar Survey of Arctic Polygonal Wedge Structures

GPR snow cover investigation to determine its spatial and temporal variability

The paper presents data on the meteorological features of the 2023/24 winter season in Moscow and the results of observations of snow cover at the MSU meteorological observatory site, as well as a comparison of these meteorological conditions and the characteristics of snow accumulation in the winter of this year with previous years. The paper also presents the methodology and data of ground penetrating radar sounding of snow cover at the site of the Moscow State University meteorological observatory, their analysis and comparison with the given direct measurement data, which allows us to draw conclusions about the structure of the snow layer and its spatio-temporal variability based only on geophysical methods.

Интерпретация результатов георадарного зондирования скального массива пород с использованием цифрового образа

A methodological approach to interpreting the results of georadar sounding of a rock mass using a digital image is considered. The studies carried out have established that during the georadar probing of the rock masses, distortion of the induced electromagnetic field is observed in areas with different physical properties of the rocks (such as the rock mass heterogeneity, rock fracturing, zones of increased water saturation). The creation of a digital image of the electromagnetic field caused by ground penetrating radar sounding using computer modeling made it possible to significantly reduce the uncertainty in interpretation of the obtained field data through understanding the mechanism of formation of the wave characteristics and comparing synthetic data with the in-situ data. Regularities in formation of the wave patterns of the ground penetrating radar model data (changes in the in-phase axes and amplitude characteristics of the signal) of a rock mass containing structural heterogeneities have been identified. When sounding such a rock mass with the georadar, reflections from the edges of heterogeneities appear in the wave patterns in the form of hyperbola branches. The intensity of the wave field distortion is determined by the contrast of the physical properties of rocks, as well as by the spatial orientation and depth of the heterogeneity, which is a key parameter of georadar sensing. It has been established that the variability of the physical properties of rock masses near disturbances introduces significant distortions into the parameters determined by georadar sounding, including the angle of incidence of disturbances. The considered methodological approach provides the basis for creating a digital image of georadar probing of a rock mass.

Monitoring the spontaneous combustion zone of a rock-coal massif using the ground-penetrating radar method

Introduction. Endogenous fires are common and one of the most complex types of accidents in the mining industry. The main cause of endogenous fires is oxidation of combustible rock by oxygen. Existing fires significantly complicate mining operations, lead to the loss of coal reserves prepared for excavation, expensive coal-mining equipment, and cause huge economic losses associated with firefighting operations. Fired areas are sources of emissions of gases harmful for breathing into the atmosphere, so the environmental damage is also very significant. Due to the fact that endogenous fires are difficult to predict and forecast, especially in their initial stages, their study is relevant to scientists of the leading research institutes of the mining industry. Research objective is to investigate and analyze the effectiveness of the ground-penetrating radar (GPR) method for diagnosing the spontaneous-combustion zones of the rock-coal massif. Methods of research. In order to assess the effectiveness of the GPR method, field experimental studies on the recognition and localization of underground fires were carried out. In order to determine the informative value of this method, wells were drilled and geological data was compared with the GPR survey results. Results. The site of an active underground fire was visually inspected to predefine the combustion areas; inspection results were presented in the paper. Using the method of GPR sounding and based on the typical anomalous zones location on fire radiograms, the fire sources were diagnosed by depth and on the plan. Boreholes were drilled to study the lithological structure of the rock mass. Additional GPR sounding was aimed at defining the width of the fire in plan more precisely. Conclusions. The GPR method makes it possible to obtain on-line data on the location of coal massif spontaneous-combustion zones and their sizes. This technology contributes to timely measures for preventing the development of underground fires in the territories of mines and open pits surface plants.

Modeling FMCW Radar for Subsurface Analysis

Determining subsurface properties through ground penetrating radar sounding can be challenging, especially in planetary exploration, where little is known about the terrain and additional observations are limited. Analysis and interpretation of data acquired with the Radar Imager for Mars’ Subsurface Experiment (RIMFAX) could therefore be improved by in-detail comparison with forward modeling. RIMFAX transmits a frequency modulated continuous waveform and utilizes a stretch processing receiver, and we demonstrate how accurate modeling can be achieved through finite-difference time-domain simulations. As the simulation scheme do not allow for direct implementation of such radar system, this study presents the necessary steps in order to replicate the same transmitter and receiver characteristics. In particular, we investigate how the method holds for modeling sounding in a realistic subsurface medium with attenuating and dispersive properties, by comparing the results with analytical estimates. The modeling approach is also assessed through comparison with RIMFAX field test measurements.

Integration of the GPR and radio-impedance techniques in studies of the Baikal rift zone

R adio wave propagation techniques have been very rarely applied to investigate tectonic fault zones and geoelectric profiles of the Baikal rift zone. In our study, we used a combination of g round-penetrating radar (GPR) and radio impedance techniques in order to identify and investigate tectonic crustal fault zones in the study area. Using soundings in the super-long, long and ultra short radio wave ranges (from tens of KHz to few GHz ) , we detected the tectonic fault zones in t he seismically active Baikal rift zone , specifically in the Tunk a depression and the areas of South ern Baikal and Kotokel lake s. Faults and fault zones were identified from impedance variations and changes in the geoelectric profiles by analyzing the radio impedance profiles and soundings in the super-long and long radio wave ranges . The georadi o location of fault structures in the ultra-short wave range made it possible to differentiate the patterns of tectonic disturbances up to individual seismic dislocations in sedimentary and crystalline rocks and to determine the kinematics of movements in the fault zone s . The techniques used in this study complement each other and ensure obtaining adequate quantitative descri ptions of the study object s . By i ntegrati ng various techniques of radio wave diagnostics , it is possible to obtain more detailed information on the structure s of the tectonic fault zones . The results obtained in this study and the radio impedance and GPR sounding and profiling techniques developed to investigate a heterogeneous underlying medium can be used in seismological and geological engineering surveys of the eastern and northern regions of Russia.

The WARR Machine: System Design, Implementation and Data

In this paper, we describe a ground penetrating radar (GPR) system called the wide angle reflection and refraction (WARR) machine, outline the design and discuss the implementation challenges. WARR and the closely related common-mid-point (CMP) GPR soundings have been standard survey methods to measure velocity since GPR first existed. Earliest efforts demonstrated the variation in ice sheet velocity versus depth. Although GPR multi-offset soundings are valuable survey methods, they have seen little adoption since many systems are not bistatic. In addition, surveys most often use a single transmitter with a single receiver deployed sequentially at varying antenna separations, making data acquisition slow. Modern instrumentation with recent advances in GPR timing and control technology has enabled deployment of systems with multiple concurrent sampling receivers. This development has resulted in the ability to continuously acquire multi-offset WARR data at the same rate as two dimensional (2D) common offset reflection surveys in the past. The concomitant issues of survey design plus organizing the WARR data storage, documentation and analysis present numerous challenges. The extraction of velocity information from the large volumes of GPR WARR/CMP data demands automated analysis techniques. We have explored the use of normal move out (NMO) stacking at creating enhanced zero offset section from multi-offset data. Furthermore, we investigated the use of semblance analysis at estimating move-out velocities in order to apply in the NMO stack. These traditional seismic processing steps have proven to be less effective with GPR. These conclusions point to the differences in data character between seismic and GPR. Results of in-field deployment are used to illustrate advances to date and point the way to further advancements.

Effect of medium electrophysical parameters and their temperature dependences on wideband electromagnetic pulse propagation

The dielectric permittivity of fiery spoil tips (Shakhty town, Rostov Region) is studied with the use of a GROT 12E remote-controlled ground-penetrating radar (GPR). An anomalous zone in a combustion source is shown to be clearly pronounced in GPR data due to the temperature dependence of the dielectric permittivity of these spoil tips. To substantiate this statement, the GPR data are compared with direct measurements of soil temperatures at depths from 1.5 to 2.5 m. The experimental results are compared with the variable spectral range of a GPR sounding pulse. GPR is shown to be a promising tool for the mapping of temperature-contrast underground objects.

Measuring Orientations of Individual Concealed Sub-Vertical Discontinuities in Sandstone Rock Cuts Integrating Ground Penetrating Radar and Terrestrial LIDAR

Vertical or sub-vertical discontinuities striking parallel to rock cuts are dangerous because toppling and spontaneous raveling failures can initiate from these surfaces, creating hazards below. At the same time, the surfaces of these discontinuities are often concealed because they do not “daylight” into the rock, and any trace of the discontinuity that might be seen at the top of the rock cut is obscured by overburden. These hidden discontinuities can often be detected by ground penetrating radar (GPR). Our new method uses GPR in conjunction with terrestrial LIDAR (light detection and ranging) to accurately measure the orientation of these hidden discontinuities. The method presented in this article establishes three control points on the surface of the rock cut. At each control point the global coordinates are remotely measured using LIDAR. GPR soundings at each control point are used to measure “the perpendicular horizontal distance” (depth) from each control point on the rock cut face to any discontinuities hidden behind the rock cut face. The true perpendicular distance is added to the GPR coordinates at each control point to form three new control points on the surface of each of the hidden discontinuities. Using the three-point method, the orientation of the hidden discontinuity is calculated.

Measuring Orientations of Hidden Sub-Vertical Discontinuities in Rock Cuts Integrating Ground Penetrating Radar and Terrestrial LIDAR

Vertical or sub-vertical discontinuities striking parallel to rock cuts are dangerous because toppling and spontaneous raveling failures can initiate from these surfaces, creating hazards below. At the same time these surfaces are often hidden, because they do not daylight into the cut on either side, and any trace of the discontinuity that might be seen at the top of the cut is obscured by overburden. These hidden discontinuities can often be detected by Ground Penetrating Radar (GPR). Used in conjunction with Terrestrial LIDAR (LIght Detection And Ranging), it is possible to accurately measure the orientation of these hidden discontinuities. The method presented in this paper establishes three control points on the surface of the rock cut. At each control point the global coordinates are measured using LIDAR. GPR soundings at each control point are used to measure the perpendicular horizontal distance (depth) to any discontinuities hidden behind the rock face by GPR. The true perpendicular distance is added to the GPR coordinates at each control point to form three new control points on the surface of each of the hidden discontinuities. Using the three point method the orientation of the hidden discontinuity is calculated.

Investigation of snow-firn thickness and ground in the East Antarctica by means of geophysical radar

Results of field investigations of snow-and-firn thickness and ground structures performed with the use of geophysical radar GPR (Ground-Penetrating Radar) are discussed in the paper. Industrial radar GSSI SIR10B (Geophysical Survey Systems, Inc., USA) with «5106» antenna (pulses frequency of 200 MHz) was used. Its mean wavelength is 1.57±0.18 km. The main purpose of this work was to test this new technique for solution of glaciological and geological problems. The works were done during the austral summer season of 2012 – 2013 (58 th Russian Antarctic Expedition) in the Eastern Antarctica and mainly concentrated in the vicinity of the Lake Vostok, between the Russian stations Vostok and Progress (the Larsemann Hills). The GPR sounding was carried out together with precise geodetic measurements. The electromagnetic wave propagation in the snow-firn layer was analyzed using the data on density obtained from the 5G borehole at the Vostok Station. Investigations near the Vostok Station focused on a huge snow ridge or so-called “megadune” located eastward from the station at a distance of 30 km. About 80 km of the GPR cross-sections were collected there. Eight internal layers were traced. They demonstrated wavy forms with amplitudes of about 10 m high which corresponded to the megadunes. Main result of GPR investigations in the Larsemann Hills was our understanding of the snow-firn and ground structures in this region. The GPR data collected on structures of crevasses near Progress-1, shallow glacier near the Progress-3, and ground not far from Progress-2 are also discussed. Methodological recommendations on using the GPR under conditions of the Eastern Antarctica were developed.

Preliminary results of the ground penetrating radar (GPR) prospection in the area of the prehistoric flint mine Borownia, southeastern Poland

Abstract Preliminary results of GPR field prospection carried out in the area of the prehistoric mining field Borownia (Ćmielów, Ostrowiec Świętokrzyski District) are presented. This mining field forms a belt (30-50 m wide and 700 m long), starting from the valley edge of the Kamienna River southeastwards. Southeastern and western parts of the site have preserved the original post-exploitation relief. Geology of the Borownia mining field was examined and acquired radiograms revealed three distinct zones of anomaly concentrations. The central zone (B) is clearly a fragment of the prehistoric mining field, confirmed not only by the GPR sounding but also by archeological surveys. The other two zones have not yet been investigated in detail yet but their surface and archaeological examination may determine only whether their underground structures are natural or have been created by humans. Data obtained during the GPR prospection at the Borownia archaeological site confirmed usefulness of 100, 250 and 500 MHz antennas. The relatively large depth range and good resolution are due to favorable geological conditions.

Applicability of Ground Penetrating Radar on desert archaeological sites: a case study from the Saqqara necropolis in Egypt

Abstract This paper presents the preliminary results of ground penetrating radar sounding applied at the desert archaeological site in Saqqara (Egypt). The survey was carried out in 2012 within a project realized by Institute of Archaeology, Cardinal Stefan Wyszyński University in Warsaw and the Faculty of Geology, University of Warsaw. One of the key aims of the research was testing the application of ground penetrating radar to non-invasive surveys of desert archaeological sites. Radargrams obtained for area of so called the Dry Moat channel surrounding the Step Pyramid complex have shown the geological structure of its filling. It comprises among others debris-sand conglomerate of diluval origin characterized by a significant content of the clay fraction and clay minerals. Such lithological content strongly attenuate the propagation of EM waves, restricting the depth range of the GPR survey. The conducted geophysical prospection west to the Step Pyramid in Saqqara has confirmed the high applicability of the GPR method in non-invasive studies of vast architectural structures, such as the monumental ditch surrounding the Step Pyramid known as the Dry Moat. It should summarised that high horizontal resolution obtained during GPR survey is a result of local geological structure of the searched area, i.e. strong lithological contrast of the sediments filling the Dry Moat, which, depending on their mineralogical composition

Structural Characteristics of the No.12 Glacier in Laohugou Valley, Qilian Mountain Based on the Ground Penetrating Radar Sounding

The inner-structure of glacier was analyzed from the profile images of ground-penetrating radar at No.12 Glacier in Laohugou Qilian Mountain western China.By calculating the difference of dielectric constants among water,air,bedrock,debris and ice,integrated with changes in radar wave polarity and velocity,the geomorphic character within the glacier was described and caves,caves with water,channels beneath the ice,the interface between glacier and bedrock were identified and positioned,with the comparison of wave patterns introduced in some literatures.The results suggest that there exist debris layers between ice-bedrock interfaces indicating that strong basal erosional processes may even prevail in certain part of a glacier of the continental characteristic,contrary to the early knowledge about this kind of glaciers.

A geophysical investigation of the Late Roman underground settlement at Aydintepe, Northeast Turkey

AbstractThe Aydintepe underground settlement in northeastern Turkey is a series of subsurface galleries carved in Eocene‐aged volcanic tuff. Rescue excavations conducted by the Local Archaeological Museum of Erzurum in 1996 and 1997 uncovered a large settlement with several underground rooms linked by passages. According to the excavators, it may have been built as a hideout and shelter by the first Christians who were banished by the Romans during the 3rd century A.D. Despite its historical and touristic value, parts of the underground settlement at Aydintepe have been destroyed to make room for the construction of new buildings in the modern town. As part of a conservation strategy for this important archaeological resource, a series of ground penetrating radar (GPR) and electrical resistivity measurements were conducted along eight profiles between 2003 and 2005. GPR soundings with a 100‐MHz unshielded antenna yielded reflected hyperbolic signals with high amplitude from tunnel structures. These highamplitude signals corresponded to areas of high electrical resistivity. These anomalies allow us to determine the probable locations of tunnels within the underground settlement and they provide important data that can be used to prevent future damage from modern construction. © 2008 Wiley Periodicals, Inc.

Influence of concrete relative humidity on the amplitude of Ground-Penetrating radar (GPR) signal

In order to improve radar technique efficiency and to offer innovative applications as non-destructive evaluation tools for civil engineering structures, the authors studied the influence of concrete moisture on GPR sounding. The presence of water in concrete leads to modifications of its electromagnetic properties and thus to specific effects upon waveform characteristics. In particular, the paper focuses on amplitude variations during processes which consume free water (hydration, drying). Radar measurements were carried out on laboratory samples using a commercial ground-coupled antenna of 1.5 GHz central frequency, while relative humidity profiles of the concrete were provided by specific sensors placed at various heights through the concrete samples. An increase in the amplitude of signals propagating through the samples was observed during hydration and drying. Moreover, radargrams recorded during the test also show that the direct wave propagating at the surface of the samples, is ereatly influenced by the evolution of concrete moisture. Concrete hygrometric measurements performed at the same time provide quantitative information on the effect of moisture reduction on radar signals.

Ground penetrating radar sounding of a temperate glacier; modelling of a multilayered medium1

AbstractA numerical simulation of electromagnetic propagation through a multilayered medium is performed in order to explain and interpret the signal received from the radar sounding of a temperate glacier. During the winter of 1990, several radar profiles were obtained on the Mont‐de‐Lans glacier in the French Alps with a ground penetrating radar which uses a phase modulation of the transmitted pulse by coded sequences. The pulse compression is obtained by applying the matched filter to the received signal, which provides a range‐resolution of about 8 m in the ice. The profiles recorded on the temperate glacier do not show a single clear reflection from the ice‐bedrock interface, but they exhibit widely distributed energy decreasing with depth. This may be due to the inhomogeneous inner structure of the temperate glacier and we use a simple model of a layered medium to compute a simulation of the propagation. Thus, partial reflection at each layer and scattering from a rough basal interface may explain the observed signal. A computer‐based technique is used to locate on the data the bottom of the glacier in order to estimate the ice thickness. The results from the different radar profiles are consistent and are a good fit to the thickness which has been determined by other geophysical methods.