Location of Archaeological Structures using GPR Method: Three-dimensional Data Acquisition and Radar Signal Processing

The aim of this study is to show applications of the ground penetrating radar (GPR) method to the monuments and the cultural heritages in order to maintain and evaluate the progress of treatments. In this framework, we involved transparent 3D half bird's eye view visualization of the GPR data. Our study area was on the Midas Monument remained a Phrygia civilization, lived between the 9th and 7th centuries BC in the Eskisehir region of Central Anatolia-Turkey. The monument has covered with miscellaneous geometric designs and hyerogliphics. During the Phrygian period religious ceremonies used to be held here. The Midas Monument has taken the shape of a giant rock-cut facade measuring over 16.5 meters in width and some 17 meters in height. The rock of the facade is nature rock heightened from surface. There are a lot of rock cut chambers seems as a multi-storey apartment in the North of the monument. We used the GPR method to evaluate the existence of internal discontinuities such as micro fractures and cavities of Midas Monument in order to control stability condition. 800 MHz shielded antenna was used to acquire GPR data on parallel profiles on the monument and 250 MHz shielded antenna was used on parallel profiles spaced 1m apart to research stability conditions around the monument and rock cut grave chambers. We obtained 2D/3D image of the GPR with half bird's eye view visualization of depth slices and their transparent 3D sub-volumes and pictured fractures on the Midas Monument and buried cavities representing rock cut tombs between monuments and the rock cut necropolis.

'The project''s goals are threefold: (1) to examine the complementary site-characterization capabilities of modern, three-component shallow-seismic techniques and ground-penetrating radar (GPR) methods at depths ranging from 2 to 8 m at an existing test site; (2) to demonstrate the usefulness of the two methods when used in concert to characterize, in three-dimensions, the cone of depression of a pumping well, which will serve as a proxy site for fluid-flow at an actual, polluted site; and (3) to use the site as an outdoor mesoscale laboratory to validate existing three-dimensional ground-penetrating radar and seismic-reflection computer models developed at the Univ. of Kansas. To do this, useful seismic and GPR data are being collected along the same line(s) and within the same depth range. The principal investigators selected a site in central Kansas as a primary location and, although the site itself is not environmentally sensitive, the location chosen offers particularly useful attributes for this research and will serve as a proxy site for areas that are contaminated. As part of an effort to evaluate the strengths of each method, the authors will repeat the seismic and GPR surveys on a seasonal basis to establish how the complementary information obtained varies over time. Because the water table fluctuates at this site on a seasonal basis, variations in the two types of data over time also can be observed. Such noninvasive in-situ methods of identifying and characterizing the hydrologic flow regimes at contaminated sites support the prospect of developing effective, cost-conscious cleanup strategies in the near future. As of the end of May 1998, the project is on schedule. The first field work was conducted using both of the geophysical survey methods in October of 1997, and the second field survey employed both methods in March of 1998. One of the stated tasks is to reoccupy the same survey line on a quarterly basis for two years to examine change in both the seismic reflection data and the ground-penetrating radar (GPR) data over time. Two factors drive these changes: First, the soil-moisture conditions vary on a seasonal basis at the site. Second, the water table rises and falls on the order of one meter in response to changes in the level of the Arkansas River and in response to the many irrigation wells found nearby. At the test site in the Arkansas River alluvial valley near Great Bend, Kansas, surface material consists of unconsolidated medium- to coarse-grained sand interspersed with clay stringers and lenses deposited by the Arkansas River. A hand-augered test hole 5 meters from the seismic line revealed sand to a depth of about 1.5 meters, where a hard pan was found presumably a clay layer. At the time of the seismic and GPR surveys, the water table was at a depth of 2.1 meters, based on a measurement in a test well located 25 meters from the seismic line. A well drilled about 40 meters away from the seismic line encountered bedrock (a fine- to medium-grained Cretaceous-age sandstone) at a depth of 29 meters.'

Geophysical surveying in water-covered and swampy areas is particularly challenging. This paper presents a new survey strategy for such surveying that integrates ground penetrating radar (GPR) and resistivity image profiling (RIP) methods at the water surface to investigate geologic structures beneath rivers, ponds, and swamps. Two test sites, a pond and a lake, have been selected to evaluate this new survey strategy. Experiments in both areas have been successful in delineating the structure of underlying gravel layers. The depth of water and shallow structures obtained from GPR data provided an effective constrain during processing of RIP data. Deeper structures were delineated using RIP data. The integration of GPR and RIP methods conducted at the water surface was successfully applied to map the Hsincheng fault crosscutting the Tourchyan River in Hsinchu County. This paper shows that the use of GPR and RIP at the water surface is efficient in mapping geological structures beneath water. The proposed approach suggests the potential for conducting geophysical surveys along rivers and drainage canals in urban areas, places where roads and buildings impede other methods designed to detect active fault.

In this paper, the Ground Penetrating Radar (GPR) method was used to characterize concrete tubes and steel/plastic tanks buried in IAG/USP test site. The microwave tomography was used to improve the GPR images, aiming to retrieve the geometry of the targets. The numerical modeling studies also were done in order to predict the GPR results of the buried targets and to give more reliability to the results interpretation. The targets were installed in the first shallow geophysical test site of the Brazil located at Institute of Astronomy, Geophysics, and Atmospheric Science (IAG) of the University of São Paulo (USP). GPR profiles of 200 MHz (shielded bistatic antennas) were acquired along three lines containing concrete tubes and steel/plastic tanks buried in subsoil. The concrete tubes show a hyperbolic reflector for the top, and the vertical tube also presented a reflection on its bottom. The horizontal steel tanks were characterized by a strong GPR reflection on their top. The empty plastic tank shows a strong reflector for the top with normal polarity. On the other hand, the plastic tank filled with water shows a weaker reflector for its top characterized by the inverted polarity of GPR signal when compared with empty plastic tank. The plastic tank filled with water also went characterized by the strong reflection to its bottom, being a good indicative to interpret GPR data on target in subsoil with some types of fluid inside of tank. The results of polarity difference for the top of tank can be used as guide pattern to identify buried tank empty or filled with water. The application of microwave tomography to the GPR data permitted to determine the position and get a good identification of the edges of the targets studied. The numeric modeling presented a good accordance with real data reducing the ambiguities in interpretation of results. These results can be used as a reference, and they can be extrapolated for areas where there is no subsurface information.

The Hagia Sophia Museum has an important place in both Byzantine and Turkish history, which was constructed by Emperor Justinian in 532 – 537 AD. After get over many large earthquakes and disasters, the Hagia Sophia Museum has maintained its existence until nowadays with repairs and renovations at various times. In this study, the crack in the Gallery floor ground and the condition of the vaults, which are located between Gallery floor and the main hall of the Hagia Sophia Museum were investigated by GPR (Ground Penetrating Radar) method with 1 GHz HF (High Frequency) antenna. The obtained data revealed quite clearly, the deterioration in the vault structure located under the Gallery floor. In the same time it has also revealed the work to strengthen the reinforced metal system made at this level. GPR results showed that, the strengthening work larger than the strengthening work mentioned in many older sources at the Hagia Sophia Museum, and these new results contribute to the future static studies. After this successful GPR study, the new project on the walls and the basements of the Hagia Sophia Museum was started with GPR and GPR-CX (Ground Penetrating Radar – Concrete Exploration) methods.

The suitability of common‐offset ground‐penetrating radar (GPR) to detect free‐phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one‐ and two‐dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air‐filled and hydrocarbon‐filled fractures generate low‐amplitude reflections that are in‐phase with the transmitted pulse. Water‐filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air‐filled or hydrocarbon‐filled fractures.The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water‐filled fracture reflections from air‐ or hydrocarbon‐filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common‐offset GPR reflection methods for detection of hydrocarbon‐filled fractures will be problematic. Ideal cases will require appropriately processed, high‐quality GPR data, ground‐truth information, and detailed knowledge of subsurface physical properties.Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.

As part of the NAWA-EMMAT project, geophysical surveys were carried out on selected sites in Poland, i.e. on the flood dike and in the surrounding of the concrete water dam. The goal of the surveys was the non- invasive detection of loose zones in the flood dike and fractured zones located in the subsoil of the water dam. Terrain geophysical measurements were conducted with the use of electrical and electromagnetic methods as well as applying seismic methods. Due to the limitations of the length of this paper, only selected results recorded on the flood dike using selected geophysical methods, i.e. electrical resistivity tomography (ERT) and ground penetrating radar (GPR) are presented. The presence of several higher hydraulic permeability zones in the dike was suggested by the results of the ERT method. The GPR method allowed, due to its high resolution, to identify small leakage zones in the body of the dike. An attempt at a quantitative interpretation of the geophysical data was made; for this purpose, the synthetic results obtained from numerical modelling of electrical and electromagnetic fields were applied. For proper construction of numerical models and further interpretation, the results of geotechnical sounding, geological drilling and the results of petrophysical measurements were also used.

This study aims to quantify the corrosion of steel reinforcing bar (rebar) in concrete structures using ground penetrating radar (GPR) and image processing techniques. A method to accelerate corrosion of steel rebars in concrete slab to different level of corrosion is applied. The power supply and the electrolyte are used to induce significant corrosion within a short period of time. The 2 GHz GPR is used to assess the corrosion in the reinforced concrete slab after 28 days of standard moist preservation. GPR method has been found to be useful for quantifying steel corrosion on existing concrete slab. The image processing techniques were used to process the GPR data. The results of the analysis of the GPR data shows that corrosion of the rebars could be detected. The subsequent image processing technique exhibits that corrosion of the rebars could be appropriate quantified.

The most effective way to remove ice jams is the explosive method, the use of which is most appropriate during the ice jam formation period. But it is necessary to know the thickness and volume of the jam-making ice in order to put the optimum quantity of explosive for effective destruction of the ice jam. It is not possible to implement the conventional measuring techniques for the purposes of measurement task solution for thin, fractured, and hummocked ice. During the spring flood period when there are advances of ice, it is possible to perform measurements only using the remote ground-penetrating radar (GPR) method. The actual practical results of GPR measurements of an ice jam on the Lena River were obtained in the vicinity of Namtsy Village. From the results of the GPR measurements, new information was obtained on the thickness of the jam-making ice and its distribution in area. The total calculated volume of the jam-making ice is equal to 4950 m3. The obtained value of the jam-making ice volume can serve as a parameter of estimation of the optimum quantity of explosive when performing explosive works with the purpose of removing the ice jam.

Akçakale (Haldandoz) is a historic castle located at the Akçakale town of Trabzon province. It is thought that archeological findings may be this castle for it has a history of 800 years and hosted to many culture. In this paper, we aimed to make an archeogeophysics work by using ground penetrating radar (GPR) for finding any remains in these areas. In accordance with this purpose, GPR data was collected with 250 MHz and 500 MHz shielded antennas on 11 profiles parallel each others directed from east to west in study area. In this study, time slice maps were generated after processing steps applied the data. These images were examined and compared obtained for 250 MHz and 500 MHz antenna at different depths. According to depth changes by using these two antennas, similar high-amplitude anomalies are displayed. Also, three high amplitude anomalies have been found compared to depth of 1.16 m obtained from 250 MHz and 500 MHz antennas in these time slice maps. A test excavation proposed on the part of high amplitude reflection indicated as arrows on the time slice maps in the study area.

The U.S. Geological Survey (USGS) operates a network of about 7,000 streamflow-gaging stations that monitor open-channel water discharge at locations throughout the United States. The expense, technical difficulties, and concern for the safety of operational personnel under some field conditions have led to the search for alternate measurement methods. Ground- penetrating radar (GPR) has been used by the USGS in hydrologic, geologic, environmental, and bridge-scour studies by floating antennas on water or mounting antennas in boats. GPR methods were developed to measure and monitor remotely the cross-sectional area of rivers by suspending a 100-megahertz (MHz) radar antenna from a cableway car or bridge at four unstable streams that drained the slopes of Mount St. Helens in Washington. Based on the success of these initial efforts, an experiment was conducted in 1999 to see if a combination of complementary radar methods could be used to calculate the discharge of a river without having any of the measuring equipment in the water. The cross-sectional area of the 183- meter (m) wide Skagit River in Washington State was measured using a GPR system with a single 100-MHz antenna suspended 0.5 to 3 m above the water surface from a cableway car. A van- mounted, side-looking pulsed-Doppler (10 gigahertz) radar system was used to collect water-surface velocity data across the same section of the river. The combined radar data sets were used to calculate the river discharge and the results compared closely to the discharge measurement made by using the standard in-water measurement techniques. The depth to the river bottom, which was determined from the GPR data by using a radar velocity of 0.04 meters per nanosecond in water, was about 3 m, which was within 0.25 m of the manually measured values.

Geophysics has played a significant and efficient role in studying geological structures over the past decades as the goal of geophysical data acquisition is to investigate underground phenomena with the highest possible level of accuracy. The ground penetrating radar (GPR) method is used as a nondestructive method to reveal shallow structures by beaming electromagnetic waves through the Earth and recording the received reflections, albeit inevitably, along with random noise. Various types of noise affect GPR data, among the most important of which are random noise resulting from arbitrary motions of particles during data acquisition. Random noise which exists always and at all frequencies, along with coherent noise, reduces the quality of GPR data and must be reduced as much as possible. Over the recent years, discrete wavelet transform has proved to be an efficient tool in signal processing, especially in image and signal compressing and noise suppression. It also allows for obtaining an accurate understanding of the signal properties. In this study, we have used the autoregression in both wavelet and f-x domains to suppress random noise in synthetic and real GPR data. Finally, we compare noise suppression in the two domains. Our results reveal that noise suppression is conducted more efficiently in the wavelet domain due to decomposing the signal into separate subbands and exclusively applying the method parameters in autoregression modeling for each subband.

Combined application of GPR and ERT for the assessment of a wall structure at the Heptapyrgion fortress (Thessaloniki, Greece)

Abstract. The aim of the study is to formulate an approach to the monitoring of internal micro discontiniuties in a hybrid 2-D/3-D image of ground penetrating radar (GPR) data gathered on historical monument groups, and to indicate methodologically rearranging amplitude-color scale and its opacity functions to activate micro fractures in monument groups including three colossal women, three men, and 24 lion statues in Mustafa Kemal ATATÜRK's mausoleum (ANITKABIR) in Ankara, Turkey. Additionally, this paper illustrates the use of petrographic research to describe the monument and its groups. To achieve the aim, data measurements were carried out on the monument groups with spaced 10 cm profiles and 1.6 GHz antenna. The 3-D image was transparent 3-D volumes of the GPR data set that highlighted internal micro fractures and cavities in the statues. Rearranging appropriate amplitude-color scale and formulating the opaque of the data sets were the keys to the transparent 3-D data visualizations. As a result, the internal fractures and cavities were successfully visualized in the three women, three men and twenty-four lion statues. Micro fractures were observed particularly at the rim of the vesicular of the rocks under a polarizing microscope.

Improving understanding of Arctic ecosystem functioning and parameterization of models that simulate freeze-thaw dynamics require advances in quantifying soil and snow properties. Due to the significant spatiotemporal variability of soil properties and the limited information provided by point-scale measurements (e.g., cores), geophysical methods hold potential for improving soil and permafrost characterization. In this study, we evaluate the use of Ground Penetrating Radar (GPR) to estimate thaw layer thickness, snow depth and ice-wedge characteristics in polygonal-shaped tundra in Barrow, AK. To this end, we analyze GPR and point-scale measurements collected along several parallel transects at the end of the growing season and the end of winter. A synthetic study is also performed to understand the GPR signal response to ice-wedge characteristics. Results show that GPR data collected during the growing season provide reliable estimates of thaw depth although strong spatial heterogeneity in soil properties can impair the estimates. While previous studies have documented the value of GPR for providing thaw depth estimates during the growing season, results from this study suggest that GPR methods are also useful for estimating active layer thickness during the frozen season, snow thickness and geometry of permafrost features, such as ice-wedges.