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8th Congress of the Balkan Geophysical Society
- Conference date: October 5-8, 2015
- Location: Chania, Greece
- Published: 05 October 2015
21 - 40 of 124 results
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Application of Machine Learning Method in Classification of Rock Types in Open Pit Mines
By H.S. NikolovSummarySupport vector (SV) method for classification originates from supervised machine learning methods. Although theoretically developed in the 70-ties of the 20-th century it was significantly improved in theory and practically implemented in the late 90-ties. Originally intended and elaborated as two class separation procedure it was latter transformed in robust multiclass classification technique. In this research the SV based technique for classification has been used for discrimination of rock types found in and around the open pit mines of Asarel-Medet mining complex located in the Srednogorie copper-porphyry mining region. The data used for the experiments are from the multispectral instruments TM/ETM+ onboard Landsat satellites from the same season of two different years. For ground trutning polygons having nomenclature under CORINE EU project were taken and adapted to the needs of this research. The results after classifying the area under study confirmed that the method selected is robust and offers good alternative to other approaches used for this task. In conclusions it is mentioned that for improvement of the outputs better spatial resolution is essential, but also more and narrower spectral bands would be offer an advantage.
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Remote Sensing Methods in Studying Stone Quarries
Authors D. Borisova, H. Nikolov, D. Petkov and B. BanushevSummaryIn Engineering and Environmental Geophysics different methods and techniques are applied. In this paper a remote sensing method has been tested in the segmentation of human made land covers such as open pit mines and stone quarries. The idea is to exploit to larger extent the possibilities offered by multispectral imagers having mind Thematic Mapper /TM/ onboard satellite series Landsat. The method has been used in the framework of our research is to find consistent statistical dependencies between multispectral data gathered in-situ and the corresponding ones in the images offered by airborne-based sensors. After correct identification of the pixels the subsequent segmentation forming the shape of the artificial feature is determined much more reliable. We have been combined ground spectrometry of stone quarry near Smolsko village, Landsat images of region of interest /RoI/, and in-situ condition surveys for assessment of the quarry area. For the purpose of the study geological observations, petrographical investigations, photo documentation and in-situ spectrometric measurements have been performed.
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Prospection of Wind Farm Site Using Geophysics
By P.S. SoupiosSummaryThe last decade, the use of geophysical surveys prior to completion of the initial subsurface monitoring and characterization for constructing wind parks, is very common. Geophysical models can provide critical, valuable, accurate and reliable information concerning the status of the ground on the site where the wind turbine are going to be founded and such information can be used by the engineers in the most appropriate and cost-effective way. This paper presents the use of surface wave method for the exploration of the subsurface in order to define the optimum places for wind turbine foundation.
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Strong Motion Network in the Bodrum Peninsula, Turkey
Authors H. Alcik, G. Tanircan, A. Korkmaz, O. Cirag and E. OzdemirSummaryThe Bodrum peninsula with a population of one million in summer season is one of the most populated touristic centers of the southwest coast of Turkey. The region is also located in one of the seismically active regions of the southeast Aegean Sea. Frequent occurrence of historical destructive and of instrumental earthquakes clearly demonstrates high seismic hazard in Bodrum and its surrounding area. Seismic activity has been monitored by three instruments located in the peninsula, however, currently there has been no strong motion network for use in generating parametric information for urban rapid response system after a damaging earthquake. Considering the high seismicity and high population of the region, a strong ground motion monitoring system, called as B-network, consists of 5 accelerometric stations was deployed on 2nd June 2015. Primary aims are to provide input for future earthquake rapid reporting and early warning implementation projects which turn out to be a crucial step and essential tool to mitigate the impact of strong earthquakes on urban environments in the Bodrum peninsula and the surrounding areas. So far the network recorded more than 5 local events (Ml>3.0). Preliminary analyses are underway. Possible future cooperation and coordination of mutual interests through joint projects may obviously give an opportunity to implement an empowered early warning system may serve to the whole region.
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Tsunami Modeling Scenarios for Some of the Seismic Sources in the Black Sea Area, Using Tsunami Analysis Tool Software
Authors R. Partheniu, M. Diaconescu, D. Ioane and A. MarmureanuSummaryAlthough a rare phenomenon, tsunamis in the Black Sea were generated in the past, studies showing more than twenty events observed ( Altinok Y., 1999 ). Earthquakes monitoring in the Black Sea as well as a database with tsunami modeling Scenarios could lead to a better understanding of such phenomena.
A set of 6 past earthquakes were taken into consideration for generating tsunami modeling Scenarios, using the earthquakes Depth, Latitude and Longitude as initial conditions. For preset parameters of fault dimensions and plane solution (Strike, Dip, Rake, Width, Length) a set of 36 different tsunami modeling Scenarios have been run, varying the Magnitude (Mw = 7, 7.5 and 8). These tests using the Tsunami Analysis Tool (TAT) software for modeling tsunamis in the Black Sea resulted in moderate to high tsunami waves, with the highest waves of 3.2 m, for an earthquake with M = 8 in Novorossisk area, generated at 15 km depth. Some of the Scenarios did not generate tsunami waves at all, for a Magnitude of 7 or 7.5.
The computations in this study need more thoroughness, in order to have a better correlation of the results from the tsunami modeling Scenarios and the tsunamis observed in the past.
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Study of Products from Neutrophilic Iron Bacteria by Prompt Gamma/Neutron Activation Analysis and X-Ray Diffraction
Authors K. Krezhov, R. Angelova and I. Sziklai-LaszloSummaryThe Fe(II)-oxidizing bacteria (FeOB) and Fe(III)-reducing bacteria (FeRB) were among the first groups of microorganisms to be recognized for carrying out a fundamental geological process - the bacterial iron redox cycling. The deposition of iron ions by the bacteria from the Sphaerotilus-Leptothrix group of neutrophilic FeOB is extracellular in the form of biogenic products contained in tubular structures (sheaths). We report on the determination of the concentration of elements in these products and the relative amounts of biogenic iron oxides/(oxy) hydroxides resulting from the bacterial metabolism. The Fe (II)-oxidizing organism was isolated from freshwater wetland surface sediments in Vitosha Mountain. Biogenic nanostructured materials were obtained after growing the genus Leptothrix in SIGP and Adler’s nutrient media. Formation of sheaths was observed only in case of dynamic cultivation in SIGP medium. High enrichment level of iron was found by the PGAA and NAA techniques in the products of cultivated isolates as compared to the reference sample (product of nature). Three iron oxide phases were found after cultivation in Adler’s medium: lepidocrocite (γ-FeOOH), non-stoichiometric magnetite (Fe3-xO4) and goethite (α-FeOOH). The cultivation in the SIGP medium yielded a single phase bacterial product — lepidocricite of poor crystallinity.
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Remote Sensing Techniques In Soil Degradation Detection
Authors R. Kancheva, D. Borisova and G. GeorgievSummarySoil salinization as a result of natural or human-induces processes is a serious global-scale problem. Numerous studies and efforts in assessing and controlling soil salinity have been made. Nearly sixty percent of the salt-affected soils around the world are in irrigated farmlands, and this trend is increasing. Salinization is a major reason for degradation of soil resources and decline of soil fertility. From an ecological and economic point of view it is extremely important to establish the occurrence and distribution of soil salinization as well as the intensity of the process. Remote sensing techniques are widely used in soil surveys to detect and map salt-affected areas. However, many constrain in monitoring and evaluating the spatial and temporal variability of the salinization process has been found out. Difficulties also arise in applying remote sensing to the assessment of slightly affected soils. The goal of this paper is to examine the spectral reflectance properties of soils with different degree of salinization and the feasibility of using spectral indicators derived from Vis/NIR data as detectors of salt-affected soils and quantitative estimators of soil salinity level.
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Subsurface Structure of Tympaki Basin (Crete, Greece) Based on Well and Geophysical Data
Authors G. Panagopoulos, E. Manoutsoglou, A. Vafidis, P. Soupios and S. BellasSummaryTympaki basin has been studied in the past years from a hydrogeological point of view. Whatsoever, less are known on the subsurface structure of the plain part of the basin in terms of sediments thicknesses and faults existence. A way of identifying in-ferred faults is the integrated use of geophysical and well-data which finally give an insight of the subsurface within a content of a well-established knowledge of the geo-logical regime of the study area. In this paper the use of 3D geological modelling technique is described as a mean to identify fault structures and horizon depths. The data used include the digital elevation model (DEM) of the area, the boundary sur-face between geologic formations and the litho-stratigraphic data from wells, geo-physical measurements of Vertical Electrical Soundings (VES) and Transient Electro-magnetic Method (TEM). The first step was to develop a 3D stratigraphic model that approximates the subsurface position of the Plio-Quaternary and the Neogene depos-its. The inferred faults came out from this model were cross-checked with the TEM measurements providing an updated subsurface structure. All the newly identified faults and along with the depth of stratigraphic horizons give finally an overall tecton-ic pattern of the Tympaki basin.
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Two Dimensional Joint Inversion of Seismic refraction, Radiomagnetotelluric and DC Resistivity Data: an example from Bafra plain, Turkey
Authors M.E. Candansayar, I. Demirci, A. Vafidis, P. Soupios, N. Economou, N. Andronikidis and H. ArslanSummaryA new two dimensional joint inversion algorithm for Seismic refraction, Radio-magnetotelluric and DC Resistivity data was developed. We used synthetic data to show advantage of the algorithm. The developed joint inversion algorithm found resistivity and velocity model better than the individual inversion of each data set if one compare with the real models. We also tested the algorithm with the field data collected in the Bafra basin to image the saltwater intrusion at this area. The field data inversion is also showed that the joint inversion recovered the resistivity and velocity model better than the individual inversion of each data set.
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Interpretation of IP Measurements Using an Inversion Based TAU-Transform Method
Authors E. Turai, M. Dobroka, E. Prácser, T. Ormos and Á. GyulaiSummaryThe paper presents the TAU-Transform of the Time-Domain IP curves and gives an approximate solution for TAU-transformation using inverse problem theory. A method for estimation of the type and the measure of soil contaminations will also be introduced. The determination of the contamination type (metallic or chemical) comes from the time constant spectra. The estimation of the soil contamination is based on the waited amplitude values of the time constant spectra. The application of the method is demonstrated in a contaminated industrial area in Hungary.
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An Investigation of Environmental Radioactivity Effects of Moloz (Trabzon, Turkey) Municipal Waste Dump Site
By H. ÇinarSummaryEnvironmental radioactivity level of the former Trabzon municipal solid waste dumpsite were investigated by in-situ gamma-ray spectrometric method. The natural radioelement concentrations on the surface of dumpsite were measured using a portable gamma-ray spectrometer. Spectrometry data were collected on the ground surface at 231 points along 21 profiles, parallel to each other, where the interval for both measurement points and each profile are 10 m. The measuring time was set to be 300 s at each point. The average activity concentrations of 238U, 232Th, 40K and dose rate in the dumpsite are 42.68 Bq/kg, 49.88 Bq/kg, 417 Bq/kg, and 67.91 nGy/h respectively. In addition, radiation hazard parameters were calculated and compared with the international standard values. Consequently, it was found that there is no significant radiologic hazard and risk for humans and the environment in studied area.
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Imaging the Saline/Fresh Water Interface at Bafra, Turkey Using Joint Inversion of Seismic Refraction and ERT Data
Authors H. Hamdan, E. Candansayar, I. Demirci, N. Economou, N. Andronikidis, H. Arslan, P. Soupios and A. VafidisSummaryA geophysical survey was conducted at Bafra, Samsun, Turkey, Greece in order to support the geological and hydrogeological studies of the existing phenomenon of seawater intrusion. This survey employed seismic refraction tomography (ST), time domain electromagnetic (TDEM) and geoelectrical methods.
The later, consisted of Electrical Resistivity Tomography (ERT). The objective of this survey was to image the saltwater intrusion at this area and map possible favorable sea water pathways. We present the interpretation of geophysical data obtained under the research project ClearWater project. We applied both individual and joint inversion of electric and seismic data from Bafra. At Bafra, the geophysical survey provided images of the saltwater intrusion which is present at the north eastern of the study area. These geophysical methods proved useful as prediction and prevention tools in qualitative characterization of water bearing formations for an optimum groundwater management plan for the Bafra basin.
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Application of Self-Potantial (SP) Method for Monitoring Contaminants Movement
Authors P. Soupios and M. KaraoulisSummaryThis paper presents the application of self-potential (SP) method in environmental application. The resulted SP model was compared with the resulted tomographic electrical resistivity models which acquired at the same time period with SP data. Both geophysical methods applied in Western Crete in Chania territory to delineate contaminants movements from a waste disposal site to the main river of Chania basin through the alluvial permeable formation. The main purpose of the SP method was the determination of the subsurface contaminants flow direction. The final resulted images showed a good correlation with geoelectrical resistivity model. The self-potential method has proved to be an important qualitative monitoring tool for assessing the environmental quality in contaminated lands.
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Preliminary Results from Lab Experiments on the Use and Sensitivity of Spectral Induced Polarization (SIP) Method
Authors K. Gerodimou, P. Kirmizakis, P. Soupios and A. VafidisSummaryThis paper presents the application of spectral induced polarization (SIP) method in a controlled laboratory experiment using known fluid concentrations. Specifically, we employed different fluid samples with variable concentration in order to record the temporal change of SIP response over time and test the sensitivity and reliability of SIP method. The SIP method has proved to be an important qualitative monitoring tool for assessing the environmental quality in contaminated lands.
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Investigation of Roadside Pollution Related to Traffic Density by Using Mangnetic Susceptibility Method
More LessSummaryThere is a rapid increase in traffic caused environmental pollution due to increasing population and number of motor vehicles. Especially many detrimental particles emitted by the vehicles reason grave soil pollution in roadsides. In addition, many scientific studies propose that these particles are detrimental for human health. Main purpose of this study is investigation of heavy metal pollution along several roadsides in city of İzmir by magnetic susceptibility measurements are often applied for investigating rock magntic properties, fire sites, landslide deposits, industrial, geothermal and soil pollution studies. Also one of the most frequent geophysical applications is traffic-related heavy metal pollution. In this study, magnetic susceptibility studies were carried out along the roads at Konak, Aliağa, Gülbahçe and Buca districts of İzmir. The measurements were performed by using MS2E high-resolution surface scanning device produced by Bartington Company. The Bartington Instruments MS2 Magnetic Susceptibility System became popular for use in the laboratory and field in universities around the world. The highest magnetic susceptibility value was observed, as 15 times higher than the normal value, along Çanakkale-İzmir highway which has the highest traffic density. Other study areas were Tınaztepe Campus road, Gülbahçe Village road and Konak-Bornova Highway and magnetic susceptiblity values were observed 6,7 and 14 times higher than normal values respectively. Consequently, it was determined that roadside pollution degree can be determined precisely by using magnetic susceptibility measurements.
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An Assessment of Groundwater Seepage beneath Dams Sites in Al-Bahah Region Using Resistivity Imaging
By B. AlhenakiSummaryThis study aims to conduct a hydrological evaluation of the wells located after the dams to estimate the ground nutrition of it through the geoelectrical. four dams are selected. A study is conducted by using electrical resistivity imaging for the study of layers and knowing the resistivity of underground water through dams. Results are shown as follows a semi complete discontinuation of feeding the wells located after the concrete dam and the ground dam which is considered the foundation of cement bases of both of them to reach the base rocks. it has become impossible for the underground water to leak through the dam. as a result, the wells located after the dam are not fed with the underground water. Rockfill dams and the wells located after the dams are not greatly affected due to the penetration of the underground water through sediments under the dam, feeding the wells. We recommend that the concrete dam is periodically and constantly opened to feed the sites located after the dam to avoid the depletion of wells. However, damage of the ground dam is lesser than the concrete dam due to the complete smooth movement of the surface water.
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Field Applicability of the g11n Configuration
Authors S. Szalai, V. Wesztergom, K. Szokoli, A. Frigy and E. PrácserSummaryFirstly a short introduction is given about the theory of the g11n configurations which belong to the group of the geoelectrical quasi null arrays. On the basis of our numerical investigations the application of these arrays seem to be rather perspective. Their field application is however difficult because of the complexity of the inversion of the data of these arrays. These arrays have very large geometric factor, they may change their sign and they can produce very sharp changes. Using an own developed code we inverted field data. The very first results show the field applicability of these configurations.
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Utilisation of Magnetotelluric Sounding for Geological Interpretation of Crustal Structures (Western Carpathians)
More LessSummaryIn the paper we present a geological interpretation of magnetotelluric sounding along the southern part of the seismic 2T profile situated in the southern Central Slovakia (Western Carpathians). The complexes with higher conductivity are imaged in the shallow depths, formed by the Tertiary sediments and volcanics. In the northernmost part of the profile, the influence of non-conductive complexes composed of orthogneisses and overlying Mesozoic carbonates is significant. In the central part of the profile, the low conductive granitoid complexes are superposed over the metamorphic rocks with higher conductivity. This structure is a remnant of the Hercynian middle crust nappes. The most outstanding phenomenon of the profile is the sudden, almost step, change in the conductivity parameters of the crust in the southern part. The significantly high conductivity of the crust in this area is most probably not related to its lithological composition, but by the abundant supply of fluids in the crust after the Neogene tectonic and volcanic processes.
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Aplication of the DC Resistivity Method to Landslide Study; Case Study - Church Ratesti
Authors D. Constantin, D. Constantin, S. Rasvan and P. RazvanSummaryIn the case were made three geoelectrical profiles, the first profile length 20 m, was located at a distance of 10 m west of the monastery direction. For research we used a Schlumberger device with AB = 2m and MN = 1 and I = 20 mA. Here, you see a fairly uniform distribution resistivity resistivity values ranging between 10–60 Ohmm. Area high resistivity depth is in the range AB / 2, between 2 and 6 m. In the interval AB / 2 5 to 30 m, resistivities are smaller, ranging between 2–10 Ohmm.
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Mapping the Bedrock Using ERT for Slope Stability Studies at Mavropigi Lignite Open Pit Mine, Northern Greece
SummaryThe application of the electrical resistivity method in geotechnical investigations is explored through a case study in Northern Greece. This method was employed at a lignite surface mining operation where fracture zones and discontinuities have been recently observed close to the pit boundaries. The main aim of the geophysical survey was to estimate the inclination of the contact between the Neogene and Schist/ Carbonates formations south of the pit. Two configuration arrays proved essential in such conditions, and helped improving the resolution of the geoelectrical section. The geoelectrical sections were then calibrated by boreholes indicating that the bedrock is dipping to the Northeast. Furthermore, the geophysical survey provided invaluable data regarding the geometry of the bedrock which was essential for the slope stability calculations.
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