- Home
- Conferences
- Conference Proceedings
- Conferences
23rd European Meeting of Environmental and Engineering Geophysics
- Conference date: September 3-7, 2017
- Location: Malmö, Sweden
- Published: 03 September 2017
21 - 40 of 157 results
-
-
Crosshole Seismic Testing on Pressure and Shear Waves - An Example of Effective Usage of the Method
Authors A.I. Konkov, A.N. Oshkin, N.A. Ragozin, V.I. Ignatev and R.Y. ErmakovSummaryThe paper describes an example of the implementation of crosshole seismic testing for pressure and shear waves at the site of proposed construction of Nuclear Power Plant “Paks-2” (Hungary). Based on the comparision of summary seismograms it was concluded that method demonstrates the best results at distances between wells of 25 27 m.
-
-
-
Application of ERT to Identify Buried Covered Karst Features in the Design of Linear Constructions
Authors D.V. Makarov, I.N. Modin, A.A. Pelevin, A.D. Skobelev and K.D. EfremovSummaryThe impact of sinkholes can be extremely severe so that mapping buried karst in the karst areas is of primarily concern to construction of engineering infrastructure. Initially, potentially karst hazardous sites should be determined by geological and geomorphological approaches. Then electrical resistivity tomography (ERT), a well-established method for investigating near-surface geological and geotechnical conditions, is performed on selected sites. At the last stage, drilling is performed, confirming the presence or absence of sinkholes at a particular site. We see this sequence of steps as the most economical and efficient and show some results of ERT as applied to the karst risk assessment when designing linear engineering structures like roads, pipelines, power lines.
-
-
-
Potential of Ground-penetrating Radar for Imaging Active Layer and Ice Wedges in Permafrost Areas
Authors S.S. Schennen, S.S. Bricheva and J.T. TronickeSummaryIce wedges are prominent phenomena of permafrost landscapes and cause a characteristic polygonal patterned ground. However, the existence of ice bodies in the subsurface is not always delineable based on surface data. Detection and imaging of these ice bodies is of interest to identify regions of increased subsidence potential and for scientific field work such as drilling programs. We demonstrate for two synthetic datasets of increasing complexity, that ground-penetrating radar can be used to determine ice wedge structures and to image their lateral extension. However, a structural imaging of complex ice-wedge geometries (i.e., steep dipping flanks) is beyond the potential of typical acquisition-strategies (surface-based, common-offset). While for simple wedge models synthetic data can be used to delineate information about the wedge geometry, this is not suitable for our more realistic synthetic data. However, for surface-based data acquisition more sophisticated techniques such as multi-offset-strategies may be a solution.
-
-
-
Conceptual Model for Exploring Geothermal Resources in La Seva Basin (NE Spain) from Integrated Geophysical Data
Authors M. Torrens, R. Lovera, M. Himi, A. Sendrós, J.C. Tapias, X. Font and L. RiveroSummaryAn integrated geophysical interpretation has been conducted around La Selva basin that show strong geochemical and geologic evidences of hydrothermal with the intent of define a conceptual model for exploration of low and intermediate enthalpy geothermal resources. The geophysical data involved in this study consist of gravity, magnetic and geoelectrical, supplemented by geological and hydrogeochemical information. The interpretation of gravity anomalies has been useful for defining the main structural discontinuities, magnetic map show the existence of several anomalies related to mafic intrusions while geoelectrical prospecting let delineate more conductive areas which could correspond to an increase in thermal fluid circulation. The results obtained by the different geophysical methods are in good agreement and allows defining a reliable geostructural model of the subsurface of the studied area.
-
-
-
The Use of Slingram Method to Map the Marine Water Intrusion: A Case Study from the Trabzon, Turkey
Authors K.H. Çoban, A.E. Babacan, E. Durmaz and S. CeylanSummaryGeophysical methods are successful in identifying of possible marine water intrusion in coastal regions. The marine water intrusion may have unfavorable effect on agricultural soil and freshwater quality. A geophysical electromagnetic survey was performed to mapping possible marine water intrusion effect along the Değirmendere River in coastal regions of Trabzon, Turkey. The survey consists of Loop-Loop electromagnetic method (Slingram). The two different study area were selected along the Değirmendere River, the first one included 3 parallel profiles from north to south (the length of one profile is 52m and the interval between profiles are 6m from west and east direction) and the second study area consist of 2 profiles from north to south direction 147m and 82m respectively. Also the study areas were about 640m and 100m distance from the marine respectively. The data were collected by EM-34-3 instrument with vertical dipole mode (VD) and horizontal dipole mode (HD) for 10m and 20m interval between transmitter and receiver coils along profiles. The marine water intrusion zones were determined by the help of apparent conductivity values in studied area. In addition, the general structure of the underground has been tried to reveal with Slingram method.
-
-
-
Groundbased TEM Survey in the Subsiding Mekong Delta
Authors T. Bording, A.V. Christiansen, E. Auken, J.L. Gunnink and G.H.P. Oude EssinkSummaryThe Mekong Delta in southern Vietnam is struggling with intensive use of the groundwater due to intensive irrigation of multicycle rice cultivation and aquaculture in the coastal zone. This has led to groundwater overexploitation and salt water intrusion of the fresh groundwater resources from the coast inwards. However, the picture in this enormous delta is much more complex with many of the groundwater resources still containing residual saline groundwater from previous transgressions. Furthermore, the lowered water table has led to high subsidence rates since the early 1990’s. At present, the condition of the Mekong Delta groundwater system is poorly understood, mainly described by boreholes explaining about geology and salinity, with only few geophysical surveys to connect the geological observations. In this abstract we present the first results from a groundbased TEM survey. We have mapped a large, very conductive area, with depth of investigation reaching down to -200 m. The results can feed into geological and hydrogeological models of the area and provide a better understanding of the connection between groundwater resources.
-
-
-
Probabilistic Inversion of Time-lapse EMI Data for Spatiotemporal Monitoring of Soil Moisture
Authors K.Z. Jadoon, D. Moghadas and M.F. McCabeSummaryLow frequency electromagnetic induction (EMI) systems have proven to be useful in mapping soil apparent electrical conductivity and soil moisture. Nevertheless, obtaining depth profile water content has not been fully explored using EMI. In this study, we performed time-lapse EMI measurements using CMD mini-Explorer sensor along a 10 m transect in a corn farm during a 6 day period. Meanwhile, reference data were also regularly measured at the end of the profile in an excavated pit using 5TE capacitance sensors. In order to derive a time-lapse, depth-specific subsurface image of true conductivity, we applied a probabilistic optimization approach, DREAM(ZS), on the measured EMI data. The uncertainties in measured apparent electrical conductivity, as well as inaccuracies in the inverted data, introduced some discrepancies between estimated and reference values in time and space. Moreover, the difference in measurement footprints of the 5TE and CMD Mini-Explorer sensors also led to the differences between reference and estimated data. The obtained depth profile permitted to accurately monitor spatiotemporal distribution and variation of soil water content encountered because of root water uptake and evaporation. The time-lapse monitoring approach, developed using DREAM(ZS) appears to be pertinent for accurate retrieval of spatiotemporal distribution of soil water content.
-
-
-
Near Surface Geophysical Method Applicable for Water Sensitive Urban Design Projects
Authors O.F. Nielsen and S.W. NielsenSummaryGround Penetrating Radar (GPR) and Sonar has been applied for a Water Sensitive Urban Design (WSUD) project. Detailed information on an urban freshwater lake in Copenhagen was obtained. A complete bathymetric survey of the lake as well as a detailed map of the thickness of limnic deposits on the lakebed was obtained. The GPR was significantly attenuated at water depth below approximately 3.3 m. However, the combination of the methods provided a full bathymetric survey. The combined results served as basis for planning of in-situ sediment samples, for calculating volume capacity of the lake as a potential rainwater storage basin as well as for quantifying the volume of limnic deposits. This will assist in the WSUD project to optimize the solutions and thereby reduce cost and time in future phases.
-
-
-
Data Adaptive Denoising of Magnetic Anomaly Maps
Authors J. Tronicke and E. LückSummaryIn the past one to two decades, a number of data adaptive denoising tools have been proposed in the image processing community. The basic idea of these filter approaches is to establish the filter weights by considering the actual sampling values, their local statistics and similarities. This helps to minimize image blurring and to preserve edges and corners. As such filter characteristics are also desirable for noise attenuation in near-surface magnetic data sets, we propose to adopt these methods for processing magnetic anomaly maps collected across archaeological targets. Here, we test and evaluate two selected methods (a generalized Kuwahara-style filter and the steering kernel method) to denoise a magnetic data set collected across Neolithic ring structure in Germany. Our results show that both methods are successful in removing prominent noise features present in our data. Concurrently, they largely preserve local structures; i.e., blurred images as typically observed after applying filters using a fixed filter mask are avoided. Thus, the methods can be considered as promising and novel approaches for denoising magnetic data sets.
-
-
-
Investigation of Subsurface Archaeological Remains of Kalecik Castle Using GPR Method (Arakli, Trabzon, Turkey)
Authors A. Seren, Z. Ogretmen Aydin, A.E. Babacan and K. GELISLISummaryKalecik Castle in Kalecik town, a neighborhood connected to the Araklı district of Trabzon on northeast of Turkey, is located on a rock overlooking the sea. The castle is located far away 30 km east of Trabzon. We aimed to investigate whether the underground structure includes any structural elements in terms of archaeological aspect by using the ground radar method (GPR) in this study. For this purpose, GPR data were collected with by Mala GPR system with 250 MHz and 500 MHz shielded antennas on selected south-north directional 36 profiles and east-west directional 12 profiles in the study area. After applying the required data processing steps to these data, 2D/3D views were obtained. In 2D views, high amplitude reflections were observed at different depths with different geometries. The shapes of these reflections are highlighted in 3D slice images by their depth slice maps. Finally, test excavations proposed on the part of high amplitude reflection indicated as arrows on the time slice maps in the study area.
-
-
-
The Use of VLF-EM and Electromagnetic Induction Methods for Mapping the Ancient Fort of Kuta Lubok as Tsunami Heritage i
Authors M. Yanis, M. A Bakar and N. IsmailSummaryThe 2004 Indian Ocean tsunami was not only devastating for human life and their properties but also destroying many cultural monuments in Aceh Province, Indonesia. The presence of traces of the ancient buildings along the coast of Aceh from the past has been the pride of the Acehnese today. However the giant 2004 tsunami has destroyed some historical buildings along the coastal area, for example the 13th century fort of Kuta Lubok. We have applied VLF-EM and EM induction measurements in Kuta Lubok area along 22 profiles. In order to resolve a better image of the subsurface manmade structures, distances between each profile and station were performed as close as possible, i.e. 20 meters and 5 meters. Tilt and ellipse data were measured by VLF-EM, while relative conductivities and susceptibilities data were acquired in the EM induction. We have applied Fraser filtering for VLF-EM data. In the electromagnetic induction, we have performed high pass filter in order to remove regional effect from the data. The expected buried walls were imaged clearly as shown by fraser filtered in VLF-EM data. For the EM induction, the buried wall can be tracked by relative low electrical conductivity values (i.e. -25.6 to 0.75 mS/m).
-
-
-
Analysis Procedures of an ERT Monitoring Network to Assess Mountain Permafrost Degradation Rate
Authors C. Mollaret, C. Hilbich and C. HauckSummaryA long-term ERT monitoring network of mountain permafrost in the Swiss Alps allows the detection of ground ice changes. It enables to compare sites of diverse landforms which are characterized by various ground properties. Electrical resistivity is highly sensitive to unfrozen water content present in the pores and to a lesser extent to temperature change. Data quality assessment of the six sites of the ERT monitoring network involves grounding resistance analysis as well as automatic filtering procedures. The combined analysis of borehole temperature and resistivity dataset reveals spatio-temporal ground property changes. This long-term monitoring network enables e.g. to characterize the extent of permafrost thaw and/or melt of ground ice at Schilthorn, to a lesser extent at Stockhorn, and no or very small changes at rock glacier Murtel.
-
-
-
Monitoring Thickness and Wetness of Snow Sheets at a Catalan Pyrenees Ski Resort Using GPR, TDR and Chemical Analisis Me
Authors J. Medina, L. Rivero, R. Lovera, M. Himi, A. Sendros, A. Urruela and A. CasasSummaryThe different snow sheets have special characteristics in order to different parameters (humidity, temperature, etc.) between the different snow falls and the final fusion in summer. This particular properties will be modified during the snow transformation process along the winter/spring seasons. We try to monitoring these properties using different geophysical and geochemical methods.
-
-
-
2D-SEA Methodology for GPR Reflections
More LessSummaryWe describe a 2D-Synthetic Emitter Array methodology for improving GPR reflections altered by clutter and noise. We show examples in which the proposed methodology is applied to simulated datasets. The results of the methodology are compared to the results of the 1D and Single Offset methodologies. Significant improvement with respect to them is obtained.
-
-
-
Investigation of Erzincan Airport Landing Field with GPR Method
Authors I. Saricicek, Z. Ogretmen Aydin and A. SerenSummaryIn this study, it is aimed to visualize whether the deteriorations observed from surface on the landing surface of the aircraft at the Erzincan Airport floor is continuing horizontally and vertically under the floor with GPR data. It is useful to do modeling exercises to help comment on the soil structure from the radargrams obtained. Primarily, GPR data were collected using a 800 MHz central frequency antenna. GPR modeling studies have been carried out with the finite difference time method (FDTD) in the time by obtaining from the construction project for the ground structure in the inspection area. By comparing the obtained real field data with artificial radargrams theoretically generated, the deteriorations of ground structure was determined. From the results obtained; It is observed in radargrams that ground quality is generally in good condition and ground is composed of four different units although fractures and deterioration are observed in places. It was also observed that fractures observed from the surface at 3 and 15 meters along the measurement line extended to depths of about 35 cm in the ground. In addition, in theamplitude slice maps of different depths, the lateral extensions of the fractures were also determined.
-
-
-
Determination of Horizontal and Vertical Changes of Esiroglu Formation using GPR and ERT Methods (Trabzon, Turkey)
Authors Z. Ogretmen Aydin and A. SerenSummaryIn this study, it is aimed to determine the horizontal and vertical changes of the Esiroğlu formation situated Akoluk distinct within the Trabzon province borders in Eastern Black Sea Region. This site considered as a solid waste site. In engineering geology applications, particularly the depth of bedrock is very important. The location of the massive formation in 2 and 3 dimensions has been determined by multi-electrodes measurements and ground penetrating radar method, while the point measurement can only be determined by drillings. Within this scope, 5 profiles ground penetrating radar and 9 profiles electrical resistivity methods were applied in the study area. After evaluating the obtained data, the subsurface structure in the study area was tried to be revealed in 2D and 3D.
-
-
-
IAG/USP Test Site - II - Construction and Preliminary GPR Results on PVC/Metal Pipes and Ceramic Tubes
Authors J.L. Porsani, V.R. Elis, A.A. Ferreira and B. PoluhaSummaryThis paper shows the construction of the second Geophysical Test Site of the Institute of Astronomy, Geophysics, and Atmospheric Science at University of São Paulo, installed at USP campus in São Paulo city, Brazil. It shows too the preliminary GPR results on buried pvc/metal pipes and ceramic tubes in the subsoil in which they simulate the gas/water pipelines and pluvial water canalization gallery underground of the great cities of the world. The targets installed in subsoil are constituted by metal and plastic tanks, concrete tubes, ceramic vases, plastic conduits etc., and its top depths varying from 0.5 to 2.0 m. The targets simulate geotechnical, environmental, and archaeological studies where its location is the goal. GPR profiles of 900 MHz and 270 MHz were acquired along of line 3 constituted by pvc/metal pipes and ceramic tubes. Preliminary GPR results show typical hyperbolic reflections pattern characteristic for each target. The IAG/USP Test Site-II was constructed with teaching and research purposes in Applied Geophysics. These results can help in location of buried utilities in subsoil of the great cities minimizing the risks of dangerous accidents.
-
-
-
Investigation of Concrete Internal Structures With GPR Method
Authors A. Seren and I. SaricicekSummaryIn this study, during the maintenance of part at the basement of the Department of Geophysical Engineering of the Technical University of Karadeniz, during the maintenance of, It is aimed to investigate by means of the Ground Radar (GPR) method to shows that the damaged reinforcing bar observed in the ceiling continue in the structure. For this, data were collected using 2.7 GHz antenna. After applying the necessary data processing steps to these data, various migration techniques have been applied to move the correct positions of the scattered hyperbole, which is a symptom of reinforcing bars. From the obtained results; from the view of the radargrams obtained from the data collected from the building structure ceiling; hyperbolas are observed at the 20, 50, 70 cm and 1 meter. While hyperbolas are concentrated to more scattering points, when obtained this radargram is applied stolt migration, in kirchhoff migration, hyperbols are also gathered to a scattering point less and deteriorations are more observed in the structure. Furthermore, amplitude-slice maps composed of selected profiles in directions parallel to each other was evaluated. From all these results, suggestions for repair were made by locating solid and damaged parts of reinforcing bar.
-
-
-
Mapping Bedrock Lithology in Urban Environment via Large Scale Time Domain Induced Polarization Tomography
Authors M. Rossi, P.I. Olsson and T. DahlinSummaryThe present work is an example of a Direct-Current resistivity and time-domain Induced Polarization (DCIP) survey, carried out in an urban environment. The main goal of the survey is to map a weak zone in the bedrock, through which a tunnel will be constructed.
Geophysical measurements in urban environments can be very complicated due to the restrictions of available space and the high levels of noise. A way to deal with the latter is careful processing of the recorded waveforms, if they are sampled at a reasonably high frequency (sampling >= 1 KHz). A deeper understanding of raw data leads to a more accurate use of the measured quantities, improving the reliability of electrical resistivity and IP estimations.
-
-
-
BeFo 382 - Detailed Comparison Study of 3D-characterized Rock Mass and Geophysical Models
Authors P.-I. Olsson, P. Jonsson, S. Johansson and L. JohanssonSummaryThis paper presents a study where resistivity and integral chargeability three-dimensional (3D) models, representing a volume in the vicinity of a rock quarry is compared to a quasi-3D characterization of rock mass volume. By repeating geological mapping, i.e. with unmanned aerial vehicles, ground based high resolution photography and sampling, as the quarry operation reaches further into the rock volume mapped with geophysics, we retrieve a semi-continuous geological characterization of the same rock mass volume characterized by the geophysical investigations. This enables a detailed comparison between geophysical results and rock volume, where factors such as fracture and weathering zones or rock type is being considered.
-