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6th Congress of the Balkan Geophysical Society
- Conference date: 03 Oct 2011 - 06 Oct 2011
- Location: Budapest, Hungary
- Published: 03 October 2011
1 - 100 of 158 results
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Comparison of the Dispersion Curves of Different Geological Units using MASW Method
By B. EkinciGround that is subjected to dynamic loadings behaves in differing ways even over short distances. This study examined the effects of firmness of ground on wave dispersion using multichannel analysis of surface waves. Surface waves in different grounds were recorded in the same layout order using the Multichannel analysis of surface waves method (MASW). Seismic recordings, dispersion images and 1-D shifting wave velocity of surface waves were compared for different geological units. The first stage in analysis of surface waves is to obtain preliminary information about the firmness of the environment of surface wave recording. The arrangements in order to increase S/N (Signal/Noise) proportion in forming the dispersion curve allows more accurate calculation of shifting wave velocity. This enables accurate and efficient calculation of seismic base depth.
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Rock Mass Classification using Seismic Velocities
Authors Z.S. Prónay, E. Törös and P. TildyAccording to their case study the authors recommend to use seismic velocities, especially shear wave velocity to characterize the rock mass instead of classical rock mass classification systems. Their experimental work includes a case study comparing the RQD, RMR and Q-value with seismic velocities in a tunnel excavated in granitic rock. The best correlation of shear-wave velocity with RQD was about 90%. Using seismic transmission the rock properties are predictable by non-destructive methods. Furthermore the hydrogeological parameters of rock masses are predictable by vp/vs as well.
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Determination of Geologic and Seismic Rock Mass Properties of Eastern Pontide Eocene-Neocene Volcanic Rocks
Authors A.E. Babacan, K. Gelisli and H. ErsoyShear wave velocity, obtained from surface wave analysis and distribution of longitudinal wave velocity, obtained from refraction tomography is constantly used to determine dynamic elastic properties of the underground layers and soil response. In recent years, many investigations have been carried out to determine the response of the subsurface structure to dynamic strengths in areas where multi-storey buildings are thought to be constructed. This study was performed in the county of Trabzon, Cukurcayır, in the Eastern Black Sea region. It was tried to determine the geological and seismic properties of the Eocene- Neocene aged volcanic rocks in the region. In the study area, seismic data were collected at 10 profiles for refraction tomography and surface wave analysis. Velocity distributions and depth of bedrock were determined from seismic data. In addition, six boreholes were drilled in the study area, and 23 core samples were collected to conduct laboratory tests. The laboratory study was conducted to determine ultrasonic velocities, uniaxial comprehensive strength, and porosity values for each core. Thus, Rock Quality Designation (RQD) values were calculated from borehole cores. The data, obtained from field and laboratory tests, were interpreted in terms of construction.
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Evaluation of Seismic Hazard of Hpp Ashta, Albania
Authors F.G.M. Silo, A.S.A. Bushati, A.S.A. Aliaj and F.G.M. SiloBased on the objectives for the evaluation of HPP Ashta seismic hazard, the purpose of study should comprehend: a) Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) values on rock site conditions for a return period of 475 years (this equates to a 10% probability of a value being exceeded in a 50 year period) for all three sites under investigation, using Cornell-McGuire Probabilistic Seismic Hazard Assessment (PSHA) methodology. b) Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) values on specific site conditions, based on the data of geotechnical profile, Vs30, and SPT-N, using soil correction factors of the National Earthquake Hazard Reduction Programme. c) Peak Ground Velocity (PGV) values on rock and specific site conditions, for all three specified sites under investigation. It is important for such kind of critical structures, as HPP Ashta is, to estimate the greatest possible seismic hazard, based on fault types, which are the source sites of earthquake generation in or near the area under study. The extensional region, into which the normal faulting earthquakes are generated, is located in eastern Albania. The compression region, into which mainly thrust faulting and much rare strike-slip faulting earthquakes are generated, is located in western part of it.
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New Data on CO2 Storage Capacity of Poland
By A. WojcickiCO2 storage potential for Poland has been assessed under FP6 EU GeoCapacity project and these works were initiated in FP6 CASTOR project. Then domestic research has been carried out, especially ongoing National Programme(2008-2012). In the National Programme both regional studies based on all archive data available and six detailed case studies are conducted. The studies include laboratory analyzes on drill core samples. The goal is to produce "high" realistic storage capacity estimations together with matched capacity estimations. As a result information necessary for future exploration permits for potential CO2 storage sites is expected. The realistic storage capacity for Poland is certainly above 10 Gt which makes a few times bigger value than calculated in EU GeoCapacity. On the other hand matched capacity (injection scenaria) values for particular structures might be a small fraction of realistic capacity. In case of hydrocarbon fields the discrepancy is not so high but in case of saline aquifers, where safety precautions additionally might force us to make strict constraints due to insufficient knowledge about the structure in question or possible conflicts of interest, only a small fraction of storage capacity might remain. Same rule refers to storage in un-mineable coal beds (CO2-ECBMR).
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Thermal Waters Origin and Temperature Signals from Albanides Depth
By A. FrasheriGeological information’s from the thermo-mineral waters origin and the temperature signals from the depth are presented in the paper. Albania represents a country with rich in geothermal resources of low enthalpy and thermo-mineral waters. Geothermal energy of low enthalpy resources is located in different areas of Albania. Thermal waters are sulfate, sulfide, methane, and iodinate-bromide types. Thermal sources are located in three geothermal zones. Location of the geothermal springs, their reservoirs, and water physical-chemical properties are analyzed in detailed in the paper. This analyze is performed in complex with geothermal regime of the geological structures of the Albanides based on temperature at different depths, geothermal gradient and heat flow density. All geothermal information for the depth of the Albanides there is study as integrated part of the geological settings interpretation. Geothermal studies of the Albanides have their contribute in two directions: first, regards on some regional geological aspects of the Albanides, as depth ruptures, etc. Secondly, collection of knowledge in regional and local plane on the thermal and mineral water resources potential and geothermal market of the Albania. Both of directions are presented and analyzed in the paper.
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Tectonically Conditional Zones with an Occurrence of Deep Magnetic Anomalies
By L. KucharicThe Slovak Republic territory is from the abyssal geological structure point of view built by several tectonic mega units of various age. From the North it is the Proterozoic unit Brunia with overlying the Flysch; the next is the Klippen belt; than the partial tectonic crust unit of Cretaceous age (Tatricum, Veporicum, Gemericum) and superficial nappes system; and finally the South Alpine units (Pelső).In the areas of the Neogeneous development markedly hits into the deep structure influence of the lower crust and the upper mantle as a consequence of crust thinning and the ascent of the asthenolite what eventuated into creation of potential geothermal areas.
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Application of Seismic Attributes and N N Log Properties Prediction for Markada Fm. Sandstones, Palmyra Gas Field, Syria
More LessPalmyra is a dry gas field located northeast of the town of Palmyra in central Syria, in the eastern part of the Hayan Contract Area. Palmyra structure belongs to the tectonic province of the southern Palmirydes. The field is covered by 340 km2 3D survey. The main target is Markada Formation. Markada sandstones, as part of Carboniferous Markada Formation, are main Paleozoic gas bearing reservoirs in Palmyrides. In clastic depositional system, nearshore, deltaic distributary mouth bar and/or channel sandstone were intercalated with shale. Markada formation is subdivided into several reservoir/layers A, B, C and D. Target reservoirs have been hardly traceable on conventional seismic and common seismic attributes were difficulty related to any certain lithology or possible gas saturation. Due to good production results on Palmyra gas field it was decided to better explore nearest area and to find location for a new Well-C. In order to evaluate and explore possibility of additional hydrocarbon accumulation, it was necessary to perform additional analyses such as seismic attribute analyses and Neural Network logs properties prediction to better characterise Palmyra reservoirs.
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Seismic Visualization of Thin Sand Bodies in a Mature HC Basin
By L. PollnerWith successfull seismic visualization of channel evolution we strongly supported geological model building and helped in revealing new potentials in a mature HC basin.
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Investigation of the Fethiye-Marmaris Bay using Multi-beam Bathymetric and Seismic Reflection Data
By N. OcakogluMulti-beam bathymetric and seismic reflection data from Fethiye-Marmaris Bay at the SW corner of the Anatolia are interpreted to determine morphological features in the bay. This area connects the Pliny Trench, which constitutes the eastern portion of the subduction zone between the African and Eurasian plates in the eastern Mediterranean with the Fethiye-Burdur Fault Zone in the Anatolia. On bathymetric data, a very narrow shelf of the Anatolian coast, a sub-marine plain between the Rhodes Island and Marmaris Bay, and a large canyon connecting the abyssal floor of the Rhodes Basin with the Fethiye Bay are observed. Of these, the submarine plain and the canyon were named here as Marmaris Plain and Fethiye Canyon respectively. Several active and inactive faults are seen in the study area. Inactive faults with normal character developed a buried basin beneath the Marmaris Plain, called as Marmaris Basin. Active faults with strike-slip character are mapped in NE-SW direction in Marmaris Plain and in Fethiye Canyon. Character of these faults are correlated with transtensional left-lateral Fethiye-Burdur Fault Zone on land and compressional character of the trenches in the Rhodes Basin and its vicinity.Several active channels and submarine landslides are also mapped in the study area.
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Structural-tectonic Interpretation of 3D Seismic Data on Ježevo Oil Field
Authors K. Staniša, F. Šumanovac, J. Velić, A. Bljakčori and R. RajićUsing the programme package Petrel, the three-dimensional seismic interpretation of the Ježevo oil field has been made, in order of defining the structural-tectonic relations and developing new hydrocarbon reserves. Based on the well logs and the data from the cores, the lithology log plot have been made and both the top and bottom of the Gama sandstone series have been identified. E-log marker Rs7 (Sarmatian/Pannonian), Rs5(Lower/Upper Pannonian), Z'(Pannonian/Pontian), Rφ(Lower/Upper Pontian), and the structural-tectonic interpretation of the 3D seismic data have also been made. For reliable settings of lithological limits on the seismic section, the one-dimensional modeling (synthetic seismogram) has been used. We have created a new model that is based on 3D seismic interpretation and contains the tectonic complex limiting the reservoir. In order to achieve a more accurate interpretation of seismic horizons and fault complex, we have used seismic trace and horizon attributes, as well as continuity/discontinuity attributes. The seismic attributes analysis helped define improved collector characteristics, so that, new hydrocarbon reserves could be developed in the future.
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Slope Stability Evaluation and Monitoring using Petrophysical Data
By A. FrasheriAlbania is a mountainous country and Albanides are represented geological structures with possibilities of instable slopes and landslide development (Fig. 1). Based on the geological formations and landslide body mass, can be present following landslide classification in Albania: - Instable slopes and intensive landslides developed in weathered bedrocks and in overburden bed at the lakeshores of hydropower plants. - Instable slopes and intensive landslides developed in Oligocene flysch formation. - Instable slopes and landslides developed in Neogene’s molasses formations. - Landslides developed in loose Quaternary deposits. - Downfalls in the weathered rocks Developing of new landslides or re-activation of the old ones is mainly due to construction works. Special constructions, such as hydrotechnical works, civil, industrial, urban and rural constructions and constructions in the infrastructure, particularly during last years, as well as destroyed equilibrium in ecological systems through deforestation etc., all these events have contributed to landslide development. Landslides are located in the deluvial deposits, and in the altered-bedrocks. The slipping bodies of some landslides have very big volume, more 50 than million cubic meters. The biggest ones are observed near of hydrotechnical works.
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Determination of Cracks in Road Rock Slops using Ground Penetrating Radar
By C. KurtuluşHighway rock cuts are potential risk for the vehicles and passengers. Remediation is required for all road cuts not to cause any damages. For this purpose, mapping of discontinuity orientations is a requirement. Most discontinuities may be observed once the cut was exposed. However, the discontinuities in the rock mass are not observed, and their detection plays important role for preventing damages. Ground Penetrating Radar (GPR) has the ability to detect these discontinuities and provide information to reduce damage and lost of lives.
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Application of the Electrical Resistivity Tomography Method (2D) for Study of Slides in Albania
More LessThis presentation introduces the results from geophysical methods application during the geological-engineering study of Bagoja landslide (Kavaja). Geophysical method used for this study is the Electrical Resistivity. The Electrical Resistivity method has been applied in the respective study , was for achieving Tomography with the dipole-dipole sceme and SEV method. By applying these electrometrical methods, the thickness of the sliding body as well as the depth and angle of the slipping plane, are determined
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Slip-sweep Seismic Technique at GES: On the Way from Theory to Practice
Authors A. Ragalyi-Kovacs Ltd. and E. SzantoSuccess of hydrocarbon exploration principally relies on seismic prospecting. Rush for more detailed image with higher resolution and reliability is not only a technical question. In the industrial seismic explorations cost efficiency always has been and remained to be an essential issue. We have investigated the possibilities of application of slip-sweep seismic technology in the Pannonian basin. Our goal was to optimize acquisition parameters and processing on synthetic data and design special filters to remove noises and draw an economic conclusion.
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Field Testing Sesimic Phase and Polarity - Vibratory Source Signature and Recording Systems
More LessThere have been many field testing methods to check the phase and polarity of the recording system and vibratory source on seismic surveys. Applications of different test techniques lead have led some confusion due to crews having different manufacturer’s geophones, accelerometers and vibrators. The aim of phase and polarity testing in the field is to ensure that recording system and vibratory source polarity conventions are properly implemented and polarity of the data correctly being recorded. In order to avoid any confusion, phase and polarity of the final product should be discussed in the initial project start-up with the company representative and crew supervisor. The full system of data acquisition and processing must be considered to make meaningful statements of the phase and polarity of final products. In this paper, phase and polarity field testing of the two types of vibratory sources use of two different vibrator accelerometers will be explained, implementation of the field quality control for the recording system and source polarity will be discussed and established definitions of the polarity “Normal and Reverse Polarity” real raw data examples will be presented.
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3D Seismic Data Merging: A Case Study in the Croatia – Hungary Border Area
Authors M. Radovcic, S. Cumbrek, I. Nagl and T. RuzicOver the last two decades, numerous small 3D seismic campaigns with varying objectives have been conducted in the Croatia – Hungary border area. For the purpose of better understanding the subsurface relations, the need to merge existing surveys emerged. The most recently acquired project of Novi Gradac-Potony 3D was designed to allow merging with the previously processed adjacent 3D projects (Barcs Southeast, Barcs West and eastern part of Molve South). According to the test results, it was decided to merge those surveys in pre-stack stage, i.e., from the original field tapes. In such way, plenty of tricky issues encountered, like different original processing flows, mismatches of static shifts, phase and amplitude variations, discrepancies in velocity fields, etc. were directly addressed. The final result was a single consolidated 3D data volume with a near perfect match across the four projects which allow more confident seismic interpretation.
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Some Survey and Interpretation Problems on IP Method
Authors A. Frasheri, P. Alikaj and N. FrashëriProblems of IP mining exploration are analyzed and solutions presented in the paper. The dipole-dipole array configuration is considered as a symmetrical array in terms of the reciprocity principle. In the paper, is demonstrate that the IP/Resistivity configurations of the anomalies in pseudosections depend from the location of transmitting and receiving dipoles related to target, there are left C1C2-P1P2 and right P1P2-C1C3 arrays. IP physical modeling and field surveys have demonstrated that exist differences between real medium and mathematical models. In IP sections of mathematical models, anomalies remain open in the depth. It is due to the fact that in used mathematical formulas, the IP chargeability is considered as a linear phenomenon. The use for the inversion of formulas based on the linear IP phenomenon implies errors, which may be comparable with the instability of the inversion itself. To achieve the quality of IP surveys, it is necessary to well evaluate the non-linear character of IP phenomenon. An accurate interpretation of data with dipole-dipole array should consider the information on dipoles orientation on the survey line. The same recommendation is valid for the inversion interpretation. IP Realsection represents the best solution for the representation of the underground anomaly medium.
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Geoelectrical Model Calculations on Investigation of Subsurface Nuclear Explosion
By Z. PlankThe Comprehensive Nuclear-Test-Ban Treaty (CTBT) is an international treaty outlawing nuclear explosions in aH environments.If CTBTO data indicates that a nuclear explosion might have taken place, an on-site inspection can be dispatched to the suspected area. The group of inspectors will search the ground for more concrete evidence of a recent nuclear test. At this stage application of geophysical survey methods are focused. Subsurface nuclear activities cause such irreversible changes in the geological structure and rock properties that make the surface geoelectric methods suitable for inspection. Geoelectric models of the undisturbed and after explosion earth have been created for the purpose of investigating the possibilities of applying resistivity methods. Forward and inverse model calculations were carried out to find the most appropriate array parameters of the geoelectric survey.
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Electrical Tomography for Studies of the Inner Structure of Dumps (Open-pit “Ellatzite”, Bulgaria)
Authors S. Shanov, I. Vasilev, A. Mitev, V. Hristov and B. MihailovaThe study presents the results of electrical tomography profiling (electrical resistivity and induced polarization) on external dumps at the vicinity of the open pit “Ellatzite” for copper ore mining (Central Balkan Mountain area, Bulgaria). The aim of the performed geophysical works was a clarification of the dumps structure, because increased instability of the dumps slopes, visible as a surface rupturing on the artificial terrain. The study is of importance for the engineering designing and decisions for the dumps stability. In order for more detailed mapping of subsurface structures the method of electrical profiling using the advanced technical capabilities of the electrical tomography on the base of multi-electrode schemes was applied. Two presented cross-sections, both crossing at the best way the western dumps, because of their positioning perpendicularly to the artificial, secondary sliding structures, are very informative and can be used for finding the necessary approaches to stop the processes of gravitational destroying of the dumps.
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Inversion of First Breaks on Multilayered Media
Authors A.N. Paripas and T. OrmosIf we assume layered models, usually such methods have been developed before that can calculate 2-layered models - with one layer boundary in the structure. Recent development and utilization follows the direction of tomographic methods using diving waves that can deal with multilayered structures as well. A method has been developed in the Department of Geophysics, University of Miskolc, which is able to invert more than one layer at a time in case of a properly chosen measuring system. However, inversion evaluation in a multilayered case can lead to uncertain ambiguous results – similar to equivalence problems. Thus, for having more reliable inversion results, adequately set inversion parameters and a measuring configuration is needed that results in appropriate quantity and quality of information. Investigation results and examples are shown in this study.
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First Arrival Picking in Seismic Refraction Data by Cross-Corelation Technique
Authors M. Senkaya and H. KarsliThe quantified interpretation of the seismic refraction record depends on correct and confident picking first arrival times. However, if the refraction data are poor, traditional first arrival picking techniques are not enough. For this reason, novel techniques are necessary to obtain first arrival times from such data. In this study the cross-correlation technique (CCT), commonly used in reflection data processing, was applied to determine first arrival times. By means of the technique, the process of the first arrival time picking is realized semi-automatically and erroneous picking to be arise from noises was decreased and picking procedure was attributed to mathematical base. Also, effectiveness of semi-automatic picking was especially evaluated with seismic refraction tomography.
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Seismic Wave Velocity and Anisotropy of Devonian Limestones, Nw Turkey
By C. KurtuluşDevonian limestones crop out at various places at northwestern part of Turkey. In situ geophysical and geotechnical studies were conducted to determine their dynamic engineering parameters such as: P-and S-wave velocities, Poisson’s ratio, shear modulus, elasticity modulus, and natural period. Geophysical and geotechnical laboratory tests were performed: ultrasonic measurements of compressional pulse velocity (UPV), uniaxial compressive strength (UCS), point load index (Is(50)), were carried out on cylindrical specimens cored across and along the foliation planes; effective porosity (n), Bulk density (d), and absorption of water by mass (Wm) sets of the rock specimens were determined. Finally, statistical correlations were performed by regression analysis to evaluate the relationships between UCS , Is(50),d, n, Wn and UPV.
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Deghosting of Seismic Data Based on Adaptive Subtraction Algorithm
Authors A.A. Bocharova and M.A. Poluboyarinov.Ghost-waves is a traditional problem for seismic processor, however there is no efficient solution of this problem until now. It is considered, that ghosts are less obvious then long-path multiples and are less easily removed by seismic processing. This paper propose a new approach for ghost-wave removal. It is based on adaptive subtraction of a ghost-wave model from the original wave field. The method was applied to synthetics seismic data and field seismic data recorded in several areas. Results show that the described approach is effective in all cases.
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Regional Magnetic Field Model for Croatia and Hungary
More LessWithin the framework of a Croatian-Hungarian bilateral project, joint field surveys were carried out and common geomagnetic field data base was compiled with the aim of constructing a reference geomagnetic model for the two countries. The magnetic maps were obtained by polynomial expansions in latitude and longitude (PA) and by adjusted spherical cap harmonic analysis (ASHA). It was shown that good fit between model and observations could be achieved by the traditional PA method. However, it was argued, that since PA could not satisfy the physical condition of curl-free property of the field, ASHA was superior to it. With ASHA, the determination of at least 25 coefficients or the selection of big half-cap-angle was required to achieve similar residuals than obtained in PA. We showed also that the residuals of the global IGRF11 model were comparable to that of the PA and higher-degree ASHA models. It is suggested that this is resulted in by the fact that the RSs of Croatia and Hungary are located in non-anomalous area. We think therefore that the real power of ASHA technique can be exploited in local anomaly studies carried out on the basis of the observations of country surveys rather than RS campaigns.
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Magnetic Anomalies of Central Volcanics in Slovakia
Authors Ö. Bektaş, A. Büyüksaraç and K. RozimantThe Central volcanics, located in Central part of Slovakia, is characterized by andesitic volcanic activity, andesite stratavolcanoes, dome complexes dating Middle and Late Miocene. Magnetic anomalies of the region exhibit a highly complex pattern. A 3-km upward continued magnetic anomalies do not appear to be correlated with topography and reflect anomalies of the deep-seated magnetized bodies. Pseudogravity transform was performed on the upward continued anomaly. Then, pseudogravity anomalies were modeled as a three-dimensional. The top and bottom of the body are at 4.4 km and 8.5 km, respectively. Volcanic structures, which are known and some lineaments, are presented on the maxima of the horizontal gradient of pseudogravity anomalies. They are well correlated with structural map of Central Slovakia Volcanic Field (CSVF).
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Electromagnetic Imaging with Tensor Invariants and Classical Magnetotelluric Interpretation along the CEL-07 Profile
More LessBesides the traditional electromagnetic data processing, nowadays one can see more and more transformation solutions (especially for very large data systems), which provide images about deep geological structures and their dimensions free of the orientation of the measuring system. The key parameters of these transformations are called tensor invariants. In this paper the detailed information about the quality, joint interpretation possibilities and applicability of the most used tensor invariants in electromagnetic investigation is presented. Comparison of various invariant results (together with dimensionality analysis) with results of classical magnetotelluric interpretations (inversions) to a 2D datasets in a research area in West-Transdanubia (Hungary) was applied and the main tectonic lines could be identified. In the contact zone of three tectonic units (Pannonian Basin, Eastern Alps and Dinarides), in a complicated – basin and range – geological situation magnetotelluric deep soundings were carried out along a 140 km long profile with a site distance of 2 km. The MT sites followed the Hungarian part of the CELEBRATION-07 (CEL-7) deep refraction profile, and the MT spacing was the same as the seismic one.
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A new analytical modeling of Asphaltene-Induced Formation Damage under Ultrasonic Stimulation
Authors A. Rabbani, M.H. Gazanfari and I. NajafiAlthough there are evidences on efficiency of the ultrasonic waves in asphaltene damage removal, a little is known about the modeling of permeability enhancement due to ultrasonic waves radiation towards the asphaltene-induced damaged formations. This study presents a novel analytical stimulation on formation asphaltene damage with an approach to the ultrasonic stimulation. By attending the hydraulic radius concept, filtration theories in porous media and ultrasonic effects on asphaltene particle size, a theoretical and relative statics model has been developed. In addition to examining the effects of asphaltene particle size distribution on permeability impairment, a Sensitivity Analysis has been presented to clarify the relationship between asphaltene adsorption parameters and permeability alteration. Literature experimental results confirm the permeability damage predicted by the current modeling for five volume injection of Asphaltenic oil. Furthermore, it has been proved that sonicated samples of crude oil cause less asphaltene-induced damage in the porous media due to solvent injection.
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Developing of Dynamical Evolution Model of Rock Massif State as a Response on a Changing of Stress-deformed State
By O.A. HachayThe first feature of the state evolution is: the local volume massive does not immediately respond on the changing of the surrounded it stress state. Therefore it stores the response energy and then extracts it through a high energy dynamical effect. It is very significant to define the time of reaction lagging, in spite of the influence on the massive can be assumed as elastic. The unique model which can explain that effect is a model of the massive with a hierarchic structure. We developed a mathematical algorithm using integral and integro-differential equations for 2-D model for two problems in a frequency domain: diffraction a sound wave and linear polarized transverse wave through a arbitrary hierarchy rank inclusion plunged in an N-layered medium. That algorithm differs from the fractal model approach by a more free selecting of heterogeneities position of each rank. And the second the problem is solved in the dynamical approach. The higher the amount of the hierarchic ranks the more is the degree of nonlinearity of the massive response and the longer can be the time of massive reaction lag of the influence.
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Structural Investigation of the Western Transdanubian Hills – a Transition Zone between the Alps and the Pannonian Basin
Authors G. Kovács and T. TelbiszThe investigated study area is situated in the transition zone between the still uplifting Eastern Alps and the subsiding Little Hungarian Plain (Joó 1992). The contrasting forcing of the differentially uplifting neighbour regions created here a distinctive low relief, hilly surface morphology and a characteristic drainage network pattern. Our study aimed at the reconstruction of the surface evolution. First, we determined the geomorphic domains based on their geomorphometric characteristics. Second, we proved neotectonic origin of some specific area. Last, we analyzed the connection between the surface morphology and the deeper structure.
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Travel Time Residuals at the Contact of the Dinarides and Pannonian Basin
Authors F. Šumanovac, D. Dudjak and E. HegedűsTeleseismic earthquake records from a passive array of 15 short-period and 4 broad-band seismometers are used to estimate traveltime residual patterns at the contact of the Dinarides and Pannonian basin. Estimation of relative residuals is achieved with fast and powerful stacking procedure through iterative alignment of traces. Global ak135 propagation model is used for achieving initial alignment by selecting the time window around the desired phase. Final alignment is obtained by rapid convergence of introduced time-shifts between reference trace and traces from each station. Similar residual patterns are caused by events arriving from the same region, but patterns differ if the events originate from various locations. Stations situated in the south-western part of the array show positive residuals, and stations situated in the north-eastern part of the array show negative residuals. Stations that show positive residuals are situated on thick Dinaridic crust, which explains later arrivals. Early arrivals correspond to stations situated on much thinner Pannonian crust, hence the negative residuals. Residual pattern that occurs between these two distinctive groups is characterized by alternating negative and positive residuals. This feature corresponds to ophiolitic Transitional zone characterized by strong lateral heterogeneities in the lithosphere.
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The Crustal Structure Beneath the Marmara Region, Turkey using Receiver Function Method
Authors T. Tezel, B. Kaypak and T. ShibutaniWe determined the Moho depth and velocity discontinuities in the crust and uppermost mantle using receiver function method in Marmara region, Turkey. We used teleseismic earthquake data recorded between 2005-2010 by the national broad band seismic stations operated by Earthquake Department of Disaster and Emergency Presidency of Turkey and Boğaziçi University Kandilli Observatory (KOERI). In this study, we selected 21 broadband stations that are located in the Marmara region in Turkey. The Moho depth changes from 28 to 39 km and upper mantle velocities varying between 4.0-4.5 km/s in the study region.
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Dynamic Topography in Europe
More LessAccording to the classical theory of isostasy topography is controlled by the variations of crustal thickness on a regional scale because the crust floats on the mantle. However, the existence of over- and undercompensated areas indicates that the classical isostatic theories are not enough to explain the topography. Mounting evidence indicates that a significant proportion of Earth’s topography results from the viscous stresses created by flows within the underlying mantle. This portion of the topography is commonly referred as dynamic topography. In a case study on the European continent I analyzed the coherency between topography and free-air anomaly and it was found that dynamic topography may play an important role in the Pannonian basin.
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The Effect of Different Geometries on the Thermal Mantle Convection
More LessA leading tool for understanding thermal convection in the Earth’s mantle is numerical modeling. To solve Boussinesq equations a finite element code has been applied. This is the first time this method has been used in Hungary, namely, modeling mantle convection on the Cartesian coordinate system. The simulations have been run in 2D Cartesian and cylindrical coordinate systems as well as in a “mantle-like” cylindrical-shell. The mantle dynamics are controlled by the Rayleigh number, which is the ratio of the buoyancy to viscous forces. The effect of Ra has been studied in the range of 1e4 to1e7. The significance of the cylindrical geometry is that at a given rms velocity the convection can carry the most heat to the surface and the results were close to the three dimensional case. This may imply that the upwelling part of the 3D mantle convection is cylindrical (mantle plume). In the cylindrical-shell domain an impressive approximate picture of the chaotic structure of the mantle convection has been shown. With the comparison of the three geometries it could be said that the cylindrical coordinate-system seems to be the most appropriate geometry to investigate the physical properties of an individual mantle plume.
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Facies Variations Detected by Well Log Correlation in a Geothermal Reservoir (Újfalu Formation) around Debrecen, Hungary
Authors T. Buday and Z. PüspökiA sequence stratigraphy based well-to-well correlation was performed as part of a regional geothermal project to determine the geometry and hydrogeology of a reservoir from which two famous spas produce thermal water. The most important thermal reservoir in Cenozoic formations in Hungary is the Újfalu Formation, which was mainly deposited in a delta front environment. In this paper a facies variation is presented in the Újfalu Formation, above a thrust wedge of the basement. Parasequences were determined by well log correlation, the appearance of parasequences is different in the sub-basins (sandy) and above the thrust (silty with sand layers). The silt and clay deposits in the reservoir decrease the hydraulic conductivity, modify the water movement. The difference could be formed by the relative vertical movement of the thrust during the deposition and local character in the surroundings of it. This information refines the sub-regional solid and hydrogeological model, thus helps the sustainable, economic and various utilization of geothermal energy in a famous thermal bath area.
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Vibration on the Surface Due Underground Mining in Karviná Region, Czech Republic
Authors Z. Kaláb, R. Kořínek, E. Hrubešová and M. LednickáKarviná region, part of the Upper Silesian Basin (Czech Republic and Poland), where intensive mining induced seismic events have been documented for a long time, is the area with underground exploitation of black coal. This exploitation manifests also as negative effects on the surface, mainly deformations of surface, changes of hydrogeological conditions and induced vibrations. Experimental investigation documents intensive vibrations that for more intensive mining induced seismic events exceed the value of 10 mm/s. One example from interpretation using time-frequency map of measured digital signal is included.
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Possibilities of Potential Mapping for BHE Heat Pump Systems
By E. PulayThis study is aiming to develope a mapping method that can be used as an aid for designing smaller borehole heat exchanger geothermal heat pump systems. This is yet a not widely researched, undeveloped topic. For the mapping method assessment a study area near Budapest was used. The results showed that besides rock composition mapping and guideline-based heat extraction calculations, the thermal conductivity estimations are the most precise and the most informative way to complete this task. With these maps favorable and less favorable areas can be distinguished within a study area. These maps allow for more precise estimation of necessary borehole lenghts for given projects. Also, after consulting with companies, this information can be used for payback time analyses.
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Trends of Wastewater Discharge and Pollutant Content in Rivers of Shanghai
By J. C. KangWater Environment in Shanghai got more and more attentions. The hotspots are wastewater discharge and pollutant content in Changjiang and Huangpu rivers. From 1981 to 2009, the city wastewater discharge was fluctuated between 18*108 ton and 24*108 ton. Inside, the gross of industrial wastewater was trendily decreasing from more than 13*108 ton at 1980s to about 7*108 ton recently years. The gross of living wastewater was increasing trendily, it related with increasing of city population. The month flux of chemical pollutant discharged by Changjiang River was between 25.9*104 ton to 209.6*104 ton in recently years. The average pollutant gross carried by Changjiang River in year, was about 593.45*104 ton among 2002 to 2009; about 83.68% was COD. Other pollutants were nutrients, oil, heavy metal and arsenic, the variability was larger with year. The month flux of pollutant carried by Huangpu River was 2.56*104 ton, more than 63% was COD averagely. The pollutant gross had an increasing trend year by year. Generally, the percent of pollutant from Huangpu River was about 3.6 to 4.4% compared with that in Changjiang River.
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Transport of Pollutants around a High Building: Integrated Magnetic, Mineralogical and Geochemical Study
More LessWe studied the degree and distribution of traffic induced pollution at a 40 m high building at the side of a major road in Budapest by making magnetic, mineralogical and geochemical analysis on settled dust samples collected at different levels and at the front and back sides of the building. We observed strong seasonal dependence of the amounts of anthropogenic pollutants, which were highest during summer. This season was also characterized by strong vertical variation of the amounts of dust, of the magnetic susceptibilities (reflecting best the traffic induced pollution) and of the concentrations of Pb. All these have maximum values at 9 m, on both sides of the building. The pattern of the distribution does not correspond to what is predicted by an air flow model published for high buildings with similar morphology and wind conditions.
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Monitoring Water Quality in Open Basins of Non-operating Mines and Dumps
Authors D. Borisova, H. Nikolov and B. BanushevWithin this research we explore time and seasonal behavior of multispectral satellite data with middle to high spatial resolution in order to estimate the content of metal particles in the water basins formed by non-operating copper mine and dumps. The aim is to test if regression model could be created between metal polluted water and the spectral response of the basins. As basis the spectral response of the embedded rocks of the copper mine and sands on the beaches of the dump site have been investigated. Similar to the well known vegetation indices such as NDVI several spectral indices are suggested, analyzed and the results are reported. The obtained results showed that the analyzed data and the implemented approach are proved to be useful in environmental monitoring process for the mining company responsible for the ecological state of the region. Also the successful implementation of method could be considered as basis for establishment of airborne monitoring of the ecological state of these areas.
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Electromagnetic Profiling for Pollution Studies on Land Contiguos with a Landfill Facility in Kumasi, Ghana
By V.S. AsareThis study aimed principally to ascertain if any, and to what extent, leachate has communicated into the adjoining lands from the operation of the landfill facility. In this investigation an EM ground conductivity survey was done using Geonics EM34-3 instrument. The EM34-3 has three intercoil spacings of 10, 20 and 40 m to vary the effective depth of exploration from 7.5 m to a maximum of 60 metres. Traverse lines were located at both sides of a creek into which the treated effluent is discharged. The equipment was set at 10 m, 20 m and 40 m interval spacing in both the vertical and horizontal dipole modes. At each station the horizontal dipole (HD) mode reading was taken first, followed by the vertical dipole (VD) mode, to probe different depths based on the respective intercoil spacing. Regions close to the banks of the stream were found to have high terrain conductivity but only limited to roughly 30 m on both sides of the creek. The apparent conductivity values are however, mitigated at depths. The results of the study, for now, do not project an eminent threat to the groundwater system.
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Integration of Geological and Geophysical Data in Thrace Basin, Turkey and Modeling of Gravity Anomalies
Authors A. Aydemir, D. Demir, F. Bilim and A. AtesThe Thrace Basin located in the European part of Turkey is the most important basin for natural gas production. In this work, the geology and geophysical data of Thrace Basin are integrated in respect of natural gas potential and to determine the possible “kitchen areas” for hydrocarbon generation. Although the region has been investigated by the petroleum geologists and geophysicists for a long time, the thickness of the sedimentary units is still under debate. In this study, the basin was modelled from the gravity data and it was correlated with the available seismic data. In the conclusion, a good consistency between two different data sets was obtained and depth of the sedimentary basin was found changing from 3 km to 7 kilometres.
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Geopgysical Investigations in Cankiri-Corum Basin, Turkey
Authors A. Aydemir, Y. Aslan, A. Buyuksarac, N.Y. Erik and A. AtesThe Cankiri-Corum Basin is one of the most important Tertiary basins located in the central Anatolia, Turkey. This basin is situated on a complex region and it can be classified as an “unexplored” basin. In this study, gravity anomalies, seismic and borehole data were used to investigate sub-surface structure and thickness of the sedimentary units in the Cankiri-Corum Basin. 2D modelling results of the gravity anomalies with the correlation of the seismic sections indicate that there is good consistency for a basin-fill composed of sedimentary units with thickness of 5 km. This thickness is enough for the hydrocarbon generation in case of having possible source rocks in the deeper parts of the basin that could be accepted as the “kitchen area”.
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Geophysics Entering INSPIRE
By L SőrésGeophysics is going to be involved in the INSPIRE process as part of the Geology theme of Annex II. The first public version of the data model (v2.0) was released in June 2011 (INSPIRE Thematic Working Group Geology [2011]). Consultation and testing period will be closed in October 2012. The core data model will become part of the European legislation and will control the data provision of Legally Mandated Organisations (LMO). To support the INSPIRE framework directives with a coherent data model an application schema for geophysical feature types were specified. The Data model is based on ISO and OGC standards and the INSPIRE General Concept Model. It supports two schemas, a simple one for legal data provisioning obligations and an other one for more detailed data descriptions.
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Enhancement of Linear Features from Gravity Anomalies by Using Curvature Gradient Tensor Matrix
By B. OruçIn this study, a new edge enhancement technique based on the eigenvalues and determinant from the curvature gradient tensor matrix (CGTM) has been described. The performance of the technique has been tested by using theoretical examples. It has been shown that the zero values of smallest eigenvalue of CGTM are suitable for mapping in source boundaries with a high resolution. The method has been applied to CGTM computed from the gravity anomaly data from Aydın-Germencik geothermal area in the western region of Turkey. The small eigenvalue provides a detailed image of the edges of basin and uplift and therefore give the results which tend to structural trends. I have also compared the Euler deconvolution (ED) position estimates with the small eigenvalue map obtained from the CGTM of residual gravity anomaly. Both techniques have agreed in detecting the basin and uplift edges in the subsurface.
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Last Decade Gravity Data Processing in the ELGI
Authors J. Kiss, E. Prácser, L. Vértesy and Á. GulyásThe Bouguer anomaly map shows an integrated image of the geological structures of the given area which depends on the density distribution of the rocks. It means that Bouguer anomaly map gives a summarized gravity effect of all geological formations to be found from the surface until a depth of several tens of kilometres. The different depths of the Moho in Central-Europe is determined by different crust thicknesses of the Carpathian Basin and its surrounding mountains (Alps, Carpathians and Dinarides) which are connected, first of all, to the isostatic roots of the mountain regions. A formula to calculate the isostatic effect of oceanic antiroots — or in case of Hungary the effect of deep sedimentary basins which cause the same effect — is known for a long while. So we realized full isostatic correction to get gravity Bouguer anomaly maps of Hungary without regional isostatic effects. We can get more information about the depths of gravity sources using spectral analysis and spectral depth estimations. The longest wavelengths are connected to crustal anomalies, while the shortest ones to the near surface gravity sources. We can separate gravity effects of different depths by spectral (matched) filtering of the Bouguer anomaly map.
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Major Principles in Spectrometric Studies of Vegetation
Authors D. Borisova and R. KanchevaAn essential application of remote sensing with significant importance for practice is vegetation monitoring. In agriculture for instance regular and timely information is needed about crop state and development, about the occurrence of stress situations for undertaking of respective measures, and etc. This paper has the goal to summarize issues related to vegetation peculiarities as a biological system and as an object of spectrometric studies, and on this ground to analyze a number of specific problems typical in vegetation monitoring, to point out some difficulties that data interpretation runs on, to suggest some approaches for their overcoming. Spectral reflectance specifics of the soil-vegetation cover as a dynamical system and a mixed class is scrutinized, the use of reflectance properties as an indicator of plant state is substantiated basing on their adequate relationship with plant bioparameters.
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Geoelectric Survey of the Hypotetchical Mithras-temple in Porolissum
Authors D. Raáb, K. Kelevitz and L. LenkeyIn this paper we present the results of a direct current geoelectrical surveying made for exploring an underground building in the Roman age fort of Porolissum. It was assumed that the building was a Mithras-temple. It was made of volcanic rock surrounded by clayey soil. We carried out the measurements along two sets of sections perpendicular to each other. We made two surveys: first using Wenner-Schlumberger array and second time a dipol-dipol array. We inverted the apparent resistivities as a 3 dimensional dataset with the software RES3DINV. The boundaries of the building could be easily identified, and we got information about the building’s inner structure, too. The reisistivity distribution showed where bigger rocks, the former archeological trenches, the walls and the collapsed parts of the building were located. There were no significant differences between the results of Wenner-Schlumberger and dipole-dipole arrays, the lateral distribution of the resistivity was almost the same. Later the archeological excavations proved the results of the geophysical measurements in detail.
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Combined geophysical investigation for the detection of ancient metallurgical installations near Keratea City, Greece
Authors G. Apostolopoulos, P. Karalis, G. Amolochitis and K. LeontarakisThe area of Lavrion, south part of Attica, is important in Greece for its mining and industrial history. Ancient times mining activity and metallurgical processing has left galleries and circular laundries for enrichment, tanks for the water used and forges for melting. A geophysical survey has the target to detect walls and tanks in an area near Keratea city some ancient installations have been revealed by archaeological excavation. Electromagnetic measurements with a conductivity meter have found elongated features of low conductivity (walls) and circular features of high conductivity (tanks full of conductive material). ERT and GPR sections have approved these results giving additional quantitative information. The results can be used as guideline in future archaeological excavation.
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Correlation of Geophysical Methods to Investigate an Archaeological Site at Bujang Valley, Kedah, Malaysia
Authors S.Y. Moussavi Alashloo, M. Moussavi Alashloo, R. Saad, M.N.M. Nawawi and R. AsadpourAn integrated geophysical survey using electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and magnetic techniques was performed with the purpose of locating buried artifacts and defining shallow structures at the Bujang Valley archaeological area, Kedah, Malaysia. Bujang Valley is considered to be the earliest commercial and religious center in Malaysia. The geophysical investigation was conducted in three steps. First, a magnetometry survey was performed using a G-856 proton precession magnetometer over 15 profiles. Then, a resistivity survey was designed in 6 profiles utilizing a pole-dipole array. Later, 2 lines of seismic refraction were measured and correlated with resistivity survey results. The magnetic survey revealed six anomalies which two anomalies had a high magnetic value, related to buried structures. The ERT and SRT techniques displayed three main layers of alluvium soil mixed with sand and clay, saturated zone and the bedrock layer. A joint analysis of results showed that the obtained information well suited to determine the archaeological remains and subsurface geological properties. An excavation test confirmed the geophysical results. Consequently, the results of this study reconfirmed that the integrated geophysical techniques yield satisfactory results and useful information upon which archaeologists can base further investigations of the site.
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Investigating the Interior of Tumuli in N. Greece (Regions of Macedonia and Thrace)
Authors G.N. Tsokas, P.I. Tsourlos, A. Stampolidis and G. VargemezisTumuli are anthropogenic constructions to host funeral constructions (burial chambers, simple burials, altars, etc). These must be located, unearthed and studied but the tumuli are also monuments of the past that must be not being destroyed. Geophysics comprise the reasonable means for this task since they can provide imaging of the interior of the tumuli and guide the subsequent excavation. The geophysical techniques used for this purpose are reviewed in this paper. Examples of successful operations are also given dealing with tumuli in the Regions of Macedonia and Thrace (N. Greece).
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GPR Imaging at Aptera Archaeological Site
Authors N.S. Spanoudakis, M. Manataki, V. Niniou-Kindeli and A.P. VafidisA Ground Penetrating Radar (GPR) survey was conducted at the Aptera archaeological site in order to map the buried relics in two main areas. Cisterns and baths to the north and a theater to the south were located during archaeological excavations. The GPR survey indicates anomalies attributed to a small cistern south of the monastery and a small well west of the Roman cistern.
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Magnetic Surveying in the Roman Age Fort of Porolissum
More LessThe researchers and students of the Department of Geophysics and Space Sciences, Eötvös Lóránd University have been carrying out geophysical surveying in the Roman age town Porolissum. Porolissum is located 20 km east to Zalau, Romania. Magnetic surveying is one of the most frequently used geophysical methods in archaeological prospecting. We used GSM-19 Overhauser magnetometers. When the soil is disturbed its susceptibility also changes. That is why we can see these structures in the magnetic anomaly map. We were able to map the structure of the fort in Porolissum with magnetic surveying. The results and their interpretation are in agreement with the results of the former archaeological explorations.
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Magnetic and Electric Surveying in the Medieval Fortress of Moresti and in the Deserted Village of Csittfalva
More LessIn spring 2010 we carried out geophysical surveying in Moresti and Csittfalva. These former medieval villages were located in Transylvania along the river Mures. In Moresti we prospected the medieval fortress, and in Csittfalva we searched the ruins of the temple, which was demolished in the XVIIth century. We carried out magnetic surveying, and then based on the results we made electric measurements. We identified the location of the medieval fortress of Moresti and the ruins of the temple of Csittfalva with magnetic surveying. In Moresti the magnetic surveying revealed the detailed structure of the fortress. The geoelectric measurements in Moresti did not provide further information, but in Csittfalva they gave a more detailed structure of the temple, and the depth of the foundation was established, too. In both places the results of the geophysical prospectings are in agreement with the former archaeological information. Additionally, some new features, e.g. the inner trench in the fortress of Moresti and the tower of the temple of Csittfalva were discovered.
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One Solution for Hardware Realization of Probe for Measuring Temperature and Conductivity of Liquids in Boreholes
Authors M. Brkic, Đ. Dragojević, D. Živković, M. Živanov and V. DoganShort description of borehole tool for measurement of temperature and conductance of liquid is given. Borehole tool is measuring these two parameters in same time. Conductance of liquids is important water quality parameter. Measurement of temperature is useful for normalization of conductivity readings and for locating at which depth liquids flows into the borehole. Principle applied is known as “four wire measurement” where maintaining of constant voltage on inner electrodes is accomplished by regulating of current through outer electrodes. Current flowing through liquid is proportional to its conductivity. Measurement of temperature is realized with platinum resistance thermometer PT100. In this paper description of the tool and mechanical realization of measurement elements are given.
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Estimation of carbonates permeability using numerical image processing
Authors A. Rabbani and S. JamshidiCarbonate rocks heterogeneity and anisotropy has always caused an uncertainty in the permeability estimation methods. In many cases the actual permeability of this rock type cannot be exactly specified just by performing experiment. In the present study a new numerical method has been used in analyzing the results of image processing on scanning electron microscope (SEM) images. Here, estimation of permeability has been presented by developing a modification on effective medium theory in consideration the phenomenon of dead end pores. Random numbers play a prominent role in this simulation corresponded on the randomized nature of carbonate fabrics. Mont Carlo simulation has led to presenting a distribution function of medium permeability. Results of simulation has been confirmed by two literature data which had been obtained by computational fluid dynamics (CFD) methods on a three dimension scanned samples.
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Inversion of Well Log Data with Apriori Information
More LessIn the hydrocarbon exploration the well is a complex source of information, beside the well logs the results of coring, mud logging and well test also can be used in the petrophysical interpretation. In the traditional procedure only the log values are used in the parameter estimation, which based on the maximum likelihood principle. The additional information is only used after the inversion, for confirming the results. The additional information also can be used in the inversion if they are regarded as an apriori information related to the rock parameters. In my work, the apriori information – core porosity data - was built in the inversion procedure by Bayes principle. The estimated probability distribution of core data involves the measurement error and also the effect of vertical inhomogenity of layers. In order to increase efficiency of Bayes type procedure, quality control has been built in. The log data and core data are compared statistically before the inversion, and in the case of significant differences the apriori data are not used. The efficiency of the modified inversion procedure is demonstrated by synthetic and field examples as well.. In both cases the modified inversion gives more accurate results than the traditional.
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Utility of the Gravity Method for Resolving the Conflict over a Mine Panel Claimed to Infringe a Permit Boundary
Authors A. Karaman, T. Seyhan and M.F. IşıkCoal mine panel claimed to infringe a permit boundary, or mine subsidence inflicting damage to buildings has been the subject of lawsuits in several countries. We study at Soma, Manisa, the footprint of a lignite coal mine panel at a depth of about 170 m by mapping all of the surface fractures we could observe, and developed a post-subsidence conceptual density model that we verified through gravity measurements with positive Bourger anomaly. With the utility of the gravity method, we were clearly able to detect the anomalous mass that was created with denser overburden material filling up the space after the extraction of less-denser lignite. The orientations of the fractures we mapped at the ground surface, the Bourger gravity map, and a test borehole all together left no doubt about the existence and the dimensions of the mine panel. This presented approach is expected to find application at sites with similar disputes, and for abandoned mines.
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Evaluation of SP Anomalies in Mine Field
By M. AsciIn this study, an example is given about the approach to SP maps prepared in sulfurous mining areas. For this purpose, a way was determined about how to arrive a real earth model examining through the results of different SP models. The solutions indicated that the examination of 2D SP map obtained in the mining area do not reflect the real earth model all the time. A prediction related to sulfurous metallic mining area was done. At first, although four sources had been thought to produce SP anomalies, later it was understood that seven sources produced SP anomalies in the map.
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GPR Measurements for Engineering Damaged Zone (EDZ) Investigation
More LessAs a part of underground research of intermediate and low level radioactive waste disposal site in Bátaapáti geophysical measurements were carried out after the excavation immediately and one year later for determination of extension of the EDZ (Excavation Damaged Zone) evolved in the granite. The measurements of borehole radar have given very good, while the measurements on the wall (radar, acoustic and tomography) have given good results. The GPR method has proven itself to be the most usable obtaining valuable information about the rock. Several typical differences can be observed that have been arisen on the sections of the two (base and repeated) measurements. These are appearing and strengthening of new reflections and diffractions. New processing techniques were developed for examination of amplitude and phase changes of different wave types on the borehole radar sections. The physical changes of the surroundings of tunnel can be mapped by these results. These changes can be explained only by realignment of stress and enlargement of classical EDZ.
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Comparative Gephysical and Mining Forensic Analysis in exploration of Building Damages in Area of Mine „Lipnica
Authors E.D. Delic, Z.K. Karadzin and E.H. HusejnagicGeophysical explorations enable determination of causes to damage or inflicted injuries, understanding of initiation mechanism of accident and proofing of hypothesis beyond reasonable doubt in court proceedings thus leading to material evidence that will either confirm or deny initial hypothesis. Mining operations in Lipnica underground mine were conducted for about 50 years and were stopped at the begging of the war in 1992. Main openings of the mine, as well as the former mining panels in roof coal seam, are located directly under the settlement Lipnica. After more than two decades of mine closure a number of court proceedings are still pending. It concerns claims for compensation of evident damages inflicted on houses. Conventional calculation methods of subsidence dynamics and time frame of consolidation process that were defined in planning of mining operations and previous forensic investigation were mainly stressing the fact that the giving time distance is to long to expect effects of mining operations. The paper gives overview of a comparative analysis of mining-geological conditions and geophysical explorations in the case of forensic investigation into damages inflicted of houses, including analysis of possibilities to apply geophysical forensics in investigation of underground mining operations impacts.
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Continuous Wavelet Transform – A Study in Enhancement of Signal Amplitude Spectra
More LessAnalytic transformations of complex signals provide new perspectives of the intrinsic properties of these observations. Continuous Wavelet Transform (CWT) permits spatial presentation of the frequency and amplitude properties of the signal. This specific feature of the method allows investigation of non-stationary signals, which is not possible with Fourier Transform. The signal enhancement process requires selection of a mother and subsequent daughter wavelets, which depend on the spectral conditions of the data of interest. Examples illustrate that CWT enhances the upper end of the frequencies of even vintage seismic reflections from the sedimentary basin environments. Distinct structural architecture of local tensional fractures zones, barely recognizable on the original data sets, are revealed by the implementation of CWT. Similar implementation of the technique to recent field data, from the same locality, significantly broadens the spectral band of the reflection waveforms improving both the vertical and horizontal resolution. Mapping of complex fractures are more detailed after CWT processing of records from crystalline basement environments.
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Mutiscale Analysis of 3D Analytic Signal using the 2D Continuous Wavelet Transform
Authors S. Ouadfeul and L. AliouaneIn this paper we have analyzed the aeromagnetic data using the 3D analytic signal technique combined with the 2D continuous wavelet transform (CWT). The objective is to delineate structural boundaries using the spatial distribution of maxima of modulus of the CWT of the analytic signal (AS). The proposed idea has been applied at the geomagnetic data of In Ouzzal area, it is located in the western of Hoggar(Algeria). Obtained results are compared with geological map and analytic signal solutions. It shows that with this approach we are able to resolve the problem of noise effect on the analytic signal solutions, and the reduction to the pole in the contacts identification by the CWT. Our method shows a good precision where geological contacts are known. Keywords: aeromagnetic data, analytic signal, boundaries, CWT, maxima.
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Near-surface Earth Parameter Estimation via Recompressive Filtering
Authors P. Scholtz, C. Saragiotis and P. TildyUtilization of dispersive surface waves is a promising technique for velocity model building of the near-surface. To analyse the dispersive properties of surface waves in case of a 3D reflection seismic acquisition, where surface waves are usually regarded as noise, we consider a recompression technique. Recompressive filtering collapses the long wave-train of dispersive waves into an impulse-like signal. This feature of the filtering method proved to be useful in wave type and wave mode separation, which is highlighted in this paper. When recompressive filtering is incorporated into an optimisation procedure the wavelet shape can drive the parameter estimation (dispersion curve and/or model parameters). We have developed a processing sequence, where traces of reflection records containing dispersive arrivals can be used to get information on the near-surface. On synthetic data we show how well the results of the recompression based Simulated Annealing optimisation works even in noisy conditions. The near-surface earth parameters which can be estimated with the help of recompressive filtering, presented in this paper, can support noise removal techniques, help the standard static calculations, intra-array perturbation correction, depth-velocity function estimation near the surface, etc. even in the latest 3D single source and/or single receiver field acquisition methods.
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Offset-Dependent Predictive Deconvolution
Authors R. Güney, H. Karsli and D. DondururPredictive deconvolution depends on the two important parameters, prediction distance (alpha) and operator length (N), and is commonly used to attenuate reverberation, short path and also long path multiples in seismic data. These parameters are generally used as constant along offset in routine processing. In this study, an offset-depended application procedure is developed in choice of the two parameters. It was observed that the use of the parameters based offset increased the performance of the predictive deconvolution rather than the constant parameters, leading to better stack and interpretable sections.
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Evaluation of Earthquake Hazard Parameters for the Different Regions in the Western Anatolia for Whole Time Periods
More LessThe earthquake hazard parameters are estimated for different regions of the Western Anatolian (WA). The whole examined area is divided into 15 seismic regions based on their seismotectonic regime. The database used in this work was taken from different sources and catalogues such as TURKNET, International Seismological Centre (ISC), Incorporated Research Institutions for Seismology (IRIS) and The Scientific and Technological Research Council of Turkey (TUBITAK) for historical and instrumental periods. The technique of maximum likelihood method is applied. The procedure allows the use of either historical or instrumental data or even a combination of them. By using this method the earthquake hazard parameters, which are the maximum magnitude, Mmax, mean seismic activity rate, λ, and the b-value which is the slope of the frequency-magnitude Gutenberg-Richter relationship, are estimated. Also, probabilities (Pr) for the occurrence of earthquakes of a specified size in a each region are evaluated. According to earthquake hazards parameters computed for each region Aegean Sea, Aegean Arc and Gölhisar-Çameli, Acıgöl and Tatarlı Kumdanlı Faults and Dinar Graben have highest hazard potential.
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Investigation of seismcity of the Marmara region with statistical approaches
By N. SayilEarthquake prediction researches keep an important place among the studies about the minimizing of earthquake damages. Great earthquakes in a characteristic region where is defined as seismogenic source take place recursively, but the time interval among these events varies from a seismogenic source to another. These changes do not only depend on a ratio of plate motions. Rupture length along the strike, the downdip width and the dip of the plate boundary are also effective factors on earthquake recurrence intervals. If a certain pattern is identified concerning changes in seismic activity in the hypocentral region after a large earthquake and leading up to the next large earthquake, an examination of the course of seismic activity will provide a lead to long-term forecasting of the occurrence of the next large earthquake. In order to estimate the recurrence intervals for large earthquakes occurred in the Marmara Region, this region limited with the coordinates 39°-42°K, 25°-32° has been separated into six seismogenic sources on the basis of certain seismological and geomorphological criteria. Poisson and exponential distribution methods have been applied for each source and recurrence times and seismic risk of earthquakes have been determined in the period of one hundred years.
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Statistical Assessment of Seismicity Pattern in Muğla and Rhodes Region, Turkey: Current Seismic Quiescence
More LessAn assessment of current seismic quiescence for Muğla and Rhodes region of Turkey using ZMAP software are studied. For this purpose, a quantitative study of the spatial distribution of the seismicity rate in the beginning of 2011 has been performed using standard deviate Z-value. Two regions with an apparently significant seismic quiescence are observed in the beginning of 2011. These areas are found centered at 37.32ºN-27.812ºE (around Milas and Yatağan) and 36.84ºN-28.712ºE (between Dalaman and Köyceğiz). These areas of seismic quiescence are recently observed and nearly started in the beginning of 2005. For this reason, special attention should be given to these regions where the seismic quiescence is observed. If such features could be recognized as a constant and reliable character of the seismicity, they could eventually contribute to the forecast of impending main shocks in future circumstances.
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Recent Seismotectonic Implications of the East Anatolian Fault Zone, Eastern Turkey
Authors A. Tan, H. Eyidogan, V. Gecgel, O. Tan, Z. Pabuccu and A. YorukAbstract One of most prominent and active faults in eastern Turkey is the NE-SW oriented left-lateral strike-slip East Anatolian Fault Zone (EAFZ) with a length of approximately 500 km. In this study, we have examined the recent seismicity of EAFZ that was obtained from the records of 34 3D broad-band earthquake stations established around the fault zone within TURDEP project since 2006. Further the seismicity and fault mechanism solutions of EAFZ, eastern Turkey have been examined. The new fault mechanism solutions in addition to previously published 220 earthquakes that occurred on the EAFZ between 1951 and 2010 were studied to understand the principal stress field and the seismo-tectonic characteristics along the fault zone. The new mechanism solutions of the earthquakes, with a magnitude of ML=2.0 or more were determined by a local moment tensor solution and P-wave first motion data. It is suggested that the recent tectonic deformation of EAFZ south of Turkoglu is taken up by the left-lateral strike-slip active faults in between Amik and Adana Basins where young trans-tensional stress regime is also active.
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Different crustal structures of the Istra and SW Pannonian basin from receiver functions modelling
Authors J. Orešković, F. Šumanovac, E. Hegedűs, S. Kolar and A.C. KovácsWe have used teleseismic events recorded at temporary seismic stations from the ALPASS-DIPS experiment to estimate the crustal structure of Istra peninsula and SW Pannonian basin. The data were analysed by P receiver function method based on the converted P-to-S phase generated at significant velocity discontinuities in the crust and upper mantle. Forward modelling of receiver functions was used to construct crustal shear-velocity models under the stations. The receiver function results can be compared with results from wide-angle seismic experiment in this area. The receiver functions analysis at stations deployed in Istra have showed that crustal velocity models fit to Dinaridic type with three major discontinuities within the crust. Whereas, models with single-layered crust could fit well observed receiver functions in the Pannonian basin. The crustal thickness for stations in the SW Pannonian basin is 25.5 – 28 km, and for Istrian stations it is in the range from 37 to 43 km.
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Some Seismotectonic Consequences of The W Black Sea Opening as Inferred from Geophysical Data
By L. BesutiuThe paper presents some crust to upper mantle geophysical imprints of the W Black Sea opening and seismotectonic consequences of this large event on the NW inland. Potential fields and seismic tomography are used as a tool
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Structural Impacts on Crustal Seismicity of Lake Van Basin (Eastern Turkey): Seismological Constraints for Crustal Defor
Authors M. Toker, S. Krastel, F. Demirel-Schlüter, E. Demirbağ and A.M. ŞengörOrogenic and seismically active lakes constitute only a few of the world’s lakes and do not produce the largest earthquakes. However, strike-slip lacustrine basins point to sharp mechanical changes at the bends along their faults, with specific implications for lacustrine earthquakes. Increasing attention has been paid to the micro and intermediate seismic events on the Highlands lacustrine environment “Lake Van basin” of Eastern Anatolia High Plateau (Eastern Turkey), creating solid base of seismic reflection and seismogram data for the estimation of structural characteristics of intra-plate earthquakes based on tectonic and sedimentary observations. Anomalous distribution of earthquake patterns and fault focal mechanisms in Lake Van underscore the need for better use of seismological and seismic structural information from the lake to understand its Highlands crustal seismicity and contribute to thin-skinned crustal deformation. Seismogram data clearly support overall deformation patterns shown by seismic sections and comparatively characterize them with the evolution of earthquake waveforms during magma migration and brittle faulting at volcanic stress conditions of the lake. This study has strong structural and seismological impacts on the surficial manifestation of volcano-seismicity and physical mechanism of tectono-magmatic processes all over Lake Van, significantly giving an evidence of “the Highlands lacustrine seismicity”.
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Water and its Effect on the Lithosphere-asthenosphere Boundary
By I. KovacsThe water in the Earth's upper mantle considerably lowers the melting temperature and this was investigated experimentally with the application of a novel experimental and analytical approach. It was shown that the instability of pargasite at depths greater than ~90km and at temperatures higher than 1000-1050 ºC leads to a sharp drop in the upper mantle's solidus temperature. It is speculated that this effect may define Earth's lithosphere–asthenosphere boundary at many geodynamic settings characterised by relatively high heat flow (>60 mW/m2).
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Stress Condition Determination based on Focal Mechanism Data: A Case Study on Kraljevo Earthquake
Authors A. Mladenovic and D. PetrovicThe aim of this research was to perform stress condition analysis in the area of Kraljevo, based on focal mechanism data of an earthquake from November 3rd 2010, as well as it’s three strongest aftershocks. Focal mechanisms of these earthquakes have been formed based on polarity of first arrivals of P-waves on seismic stations. Also, structural inversion of these data was performed. It was determined that, during investigated earthquakes, strike-slip faults of WSW-ENE were reactivated.
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Metamorphic Reactions as Indicators of Lower Crustal Processes during Formation of the Pannonian Basin
More LessThe Pannonian Basin is famous of its xenolith localities hosted by late Tertiary alkaline basalts, from different depths of the lithosphere. In this work we present the petrography, mineral chemistry, and geothermobarometry study of lower-crustal mafic garnet-granulite xenoliths from the central Pannonian Basin, namely from the Bakony-Balaton Highland Volcanic Field (BBHVF). Based on geothermobarometric calculations, the estimated pressure of the peak metamorpishm was about 1.0-1.6 GPa, at temperatures of about 800-1050 °C. Several reactions have been recognized in both the mafic garnet granulite and the metapelitic granulite xenoliths from the BBHVF, involved. The breakdown reaction of the garnet is the only reaction which can be observed both in metabasics and in metapelites. Experimental works and thermodynamic calculation show that the breakdown reaction of the garnet occurs at relatively low pressures of about 0.6-0.8 GPa. This pressure value is equivalent to 20-30 km depth which is equal with the present day depth of the lower crust. Reaction of garnet in metapelitic granulites shows similar or even slightly lower pressures. The metamorphic reactions show not only the thinning of the crust during the formation of the Pannonian Basin, but also make it possible to estimate the quantification of crustal thinning.
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Recent Tectonic Model of East (Iranian) Azerbaijan
By B. Zamani G.The stress analysis results in this study (by analytical method, for seismic and field data) have shown that there are two compressional stresses (NE-SW and NW-SE directions) in E-Azerbaijan Microplate. First stress system by NE-SW direction causes development of three tectonic grains, Arasbaran, Ahar and Bozkosh thrust sheets (fig. 3a). While, the second one (NE-SE direction stress system) causes the development of thrusts in N-S direction. Results show that thrusting leads to the development of tear faults in N-S and NE-SW directions with dextral strike-slip mechanisms. Also, development of young geological structures has good consistency with stress state in this area. These results could be developed as recent tectonic model of E-Azerbaijan. In this model materials are compressed in four sides of the E-Azerbaijan lozenge, while structures and materials escaped from north and Southern parts of this lozenge (fig. 3). The state of multiple stress system and the escape of material impose a left-lateral rotation to the E-Azerbaijan microplate (Fig. 3-b).
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New Interpretation of the Old ∆Z Anomaly Map of Hungary
More LessThe Hungarian magnetic vertical component anomalies were interpreted first more than 40 years ago by Posgay Since then, no one has conducted a country-wide interpretation and, unfortunately, there has not been any regional magnetic survey. However recent progresses in geological and geophysical knowledge allow a new, more complete analysis of the old magnetic anomaly map. The study of relationship between anomalies and geological structures and model calculations at some selected area resulted in the following interpretation. • Near the Austrian border the Penninicum represents a large-scale high-amplitude anomaly. In the territory of Little Hungarian Plane the visible anomaly is connected in Slovakia with the anomaly north of the Diósjenő line. The anomalies along the Balaton line continuing in direction to Buda and Recsk are caused by Eocene andesites. In South-Transdanubia both anomalies caused by serpentinites and basalts have characteristic curved shape which was formed during the Cretaceous. Anomalies located on the Great Hungarian Plane are caused by Cretaceous basalts and covered Miocene andesites. Miocene andesites and Mio-Pliocene basalts at the surface have intensive, rapidly changing anomalies. However it must be noted that to improve the interpration new magnetic survey and unification with data from the neighbouring countries is essential.
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Basalt Volcanoes under the Lake Balaton
More LessThe oldest volcano in the Bakony – Balaton-highland Volcanic Field is the Tihany Volcano (7,99-7,93 Ma). Due to its phreatomagmatic origin there was no lava flow onto the surface, one can find only tuffs and pyroclasts. In these pyroclasts there are volcanic bombs at multiple levels, derived from the ripped up basement clasts of the Balaton-highland. Reconstructed trajectories of these clasts suggest the existence of a volcanic center towards the East of the peninsula. According to the interpretation of seismic sections, recorded in the eastern part of the Lake Balaton, basalt intrusions can be present at a few places bellow the lake. In September 2010 we carried out magnetic survey in this area to confirm the seismic interpretation. We have acquired 14 north-south directed sections of the total magnetic field, with a complete length of 140 km. Correction of temporal variation of the field strength was performed on the basis of the continuous record in the Tihany geomagnetic observatory. After spatial correction based on the relevant normal formula, we arrived at a magnetic anomaly map. Although the resulting amplitude of the anomaly (30-40 nT) is lower than expected, it occurred exactly where the seismic interpretation indicated basaltic intrusions.
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Determination of Site Characteristics with Single Point Microtremor Measurements at the KTU Campus Area
By Y. BekerMicrotremor method used for engineering seismology is very important for determining of dynamic ground parameters and its variations. Method based on frequency of horizontal and vertical component microtremor records provides to quick and economical estimation of dynamic ground parameters. Most important advantage of Nakamura method defined as single station method isn’t required reference point and it can be applied easily in the area with low seismic density and without base rock. In this study, Nakamura (H/V) method has been applied to microtremor records taken with CMG-6TD three component broad band velocity seismometers in 6 profiles and 75 points with the aim of determining ground predominant period and magnification parameters of the (KTU) campus area of Black Sea Technical University in Turkey. Maps of magnification, predominant frequency and ground classification (Z1, Z3, Z4) according to the predominant period are created by derived values.
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Assessment of the Subsidence in Internal Maliqi Depression using Geophysical Methods
More LessThis study have covered the former Maliqi Swamp which of point view consists of the Quaternary overburden formations (Q1-4) and the Upper Neogene, concretely not differentiated Pliocene and Pliocene-Quaternary (N2-Q1) formations The main objectives (intention) are: - Investigation of the subsidence phenomenon, which may lead to the gradual formation of the Maliqi Swamp. - Locating on eventual second turf layer under the known one and its control with integrated methods. - The monitoring of the subsidence phenomenon To achieve a good result for above the objectives there have been used geodesics, geological and geophysical (VES) methods. The integrated interpretation of geodesic and geogolical-gephysical date allowed drawing the following main conclusion: - VES do not indicate the presence (at least up to70-80m) of e second turf layer; this is not a definitive conclusion. This conclusion can be verified by drilling up two holes 50m deep. - The youngest formations (swampy ones) are about 30-35m thick and composed of two fine grained argillaceous layers and two sandy-argillaceous layers. - The Maliqi Depression has been constantly having subsidence, at least since the swamp started to get dried out. In the period 1952-1977 the monitoring showed a vertical dipping from 0.5-3m
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Determination of Site Response Functions in Yalova City with Microtremor Data
Authors S. Tekebaş and E. YalçinkayaIn recent years, at the determination of the soil response function, microtremor method is a most-preferred one which offers properties such as recording at short time and having no requirement of using any source. While microtremor method is considerably successful at the determination of resonance frequency, it is not successful at the assessment of soil amplification. Within the context of study, the microtremor measurements were taken at 81 total stations at Yalova and around (Altınova, Çiftlikköy and Çınarcık). Measurements were collected with CMG 6-TD seismometer at four different times in October, January, April and July. The horizontal/vertical spectral raitos were computed by using Nakamura (1989) method from these data and HVSR curves were derived. The obtained curves are evaluated with the geology and Yalova’s soil properties are tried to be determined. Few of the measurement points which have a clear peak and complex characteristics of H/V curves in Yalova point out the sediment discontinuties in lateral and vertical direction, resulting in 2D or 3D site effects. No soil-structure resonance were determined in Çınarcık, Hacımehmet, Çiftlikköy where the worst damage occured during the 17 August 1999.
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What is the Information Content of the Near Surface Debris Distribution?
More LessFormation of surface depressions is a significant geological hazard. Prediction of future sinkholes in buried karstic areas needs knowledge about the subsurface. In order to determine the varying topography of the karstifiable bedrock (in Bakony Mts, Hungary), we carried out multielectrode measurements. Due to the hard field conditions, the bedrock depth could not be detected. The resistivity anomalies in some places had a seasonal variation (low-resistivity in springtime, high-resistivity in the end of summer); therefore we interpreted the springtime resistivity lows as indicators of locations with high water content, that is as high porosity, saturated with water. At the same time, when pushing the current- and potential electrodes into the ground, we discovered a regularity in the areal distribution of the soil's rock debris content. Therefore we carried out a systematic electrode-pricking experiment, and categorized the soil's "toughness" corresponding to soft penetration, or blockage within the upper 30 cm. We have found a close relationship between the locations of resistivity- and the soil's toughness extremes. From some epikarstic features we think that high "pricking probe" values indicate smaller depths of the bedrock.
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Different Alternatives of Surface Waves Data Inversion. Applications on Environmental and Geotechnical Case Studies
Authors G.S. Kritikakis and A. VafidisThe inversion of Rayleigh surface waves dispersion curves exhibits the last few years rapid development in geotechnical and environmental geophysics. This study stresses on the demonstration of different alternatives of surface waves data inversion. The implemented algorithms (kriSIS) consist of several inversion techniques such as the usage of Quasi-Newton methods, the minimization of L1 or L2 norms, the application of smoothing, damping and blocky constraints and their combinations, as well as weighting inversion using data errors and/or the values of Jacobian matrix. Furthermore, any a-priori geophysical or/and geotechnical information can be taken in to account during the inversion. Two selected inversion techniques (damping and combination of blocky constraint with L1 norm minimization), were applied at two areas of environmental and geotechnical interest. This study indicates that the choice of the most appropriate inversion technique is crucial for any high resolution study.
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Seismic Geotechnical Site Characterization by MASW-REMI Method: Importance of Higher Modes of Rayleigh Waves
More LessIn the ’90 several researchers have realized that, when dealing with inversely dispersive sites, the MASW method based only on the fundamental mode can really cause erroneous Vs profiles, hence an erroneous seismic site characterization. When dealing with inversely dispersive sites ( i.e. sites where stiffness discontinuities exist, soft layers trapped between stiffer layers or viceversa stiff layers trapped between softer layers) higher modes of Rayleigh waves must be combined together with the fundamental mode to calculate the effective or apparent dispersion curve (Lai 1998, Roma 2001-2002-2006), in order to achieve a reliable Vs profile and a reliable seismic site characterization. It is not sufficient to calculate the numerical higher modes and use them separately for the inversion process, because it is practically impossible to distinguish the experimental higher modes from the field data in the geotechnical scale. It is well known that the apparent experimental dispersion curve that is determined from the field data is the result of a superposition of the several higher modes. In this article the potentialities of a new algorithm (www.masw.it, Roma 2001) that calculates the apparent dispersion curve using all higher modes are shown into an application to a real case.
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Integrated Geological-Geophysical Studies on Regionalization of Cities Mamuras, Lac, Milot and Fushe Kruje
More LessIn this paper we have intention to demonstrate the capacity of geophysical methods (electrical resistivity methods) to help in the more accurate way in these studies. In this case, some results achieved through electric resistance tomography method will be demonstrate, completed for the geological-engineering zonation of Milot, Lac, Mamuras and Fush Kruja, cities.
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Aplication of Geophysical Methods in Investigation
More LessKarstic phenomenon of carbonated geological formations is very developed in some parts of Albania. The results taken from the integrated geophysical methods for the study of karst phenomenon show that the most effective methods are: resistivity surveying with profile arrays, resistivity surveying with array profiles in combination with VES method, SP method, IP(Induced Polarization), gravimetric micro method. These methods have made possible the detection of karstic zones, with fresh water content and the cavities that present risk for private and public building.
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Complex Geophysical Investigation (CPT, Seismic Reflection and Tomograpy) of the Sliding Loess Wall along the Danuber River
Authors A. Cs. Kovács, T. Gúthy, E. Hegedűs, T. Bodoky, R. Csabafi and I. TörökA 30 to 35 m wide slice of a 100m height loess wall sank more than 10 m at the bank of the Danube near Dunaszekcső (Hungary) on 12th of February, 2008. Eötvös Lorand Geophysical Institute (ELGI) was requested a geophysical investigation of the area. ELGI installed a system of six continuously operating seismic stations to detect the seismic micro-emissions. Two main source areas of seismic micro-emission were allocated after the data analysis. We made four points of CPT a depth of 12 m on the bank of the Danube. We have concluded that the movement of the loess wall was caused not by a sliding phenomenon. We used vibrator as a source and 121 units of RefTek 125 single channel autonomous seismic recorder to make two seismic lines beneath and above the loess wall. Based on the structural image from seismic tomography and reflection sections sedimentary layers of different thicknesses can be found on the old basement up to the level of the river Danube. The anomalies of the two profiles mark out a tectonic zone running in an approximately E-W direction.
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Engineering Geophysical Study of Active Slides in the Mediaeval Castle and Kruja City, Albania
Authors P.L. Leka, F.V. Vinçani, P.K. Kosho and P.N. NaçoThe study region is part of Kruja tectonic zone and represents a syncline structure. City of Kruja has objects with architectural, historical and museum values and is built on Quaternary deposits, on the slopes with inclines 20-100, represented by lithological formations: colluvial, eluvial, deluvial and proluvial. Colluvial deposits represented by slope breccias with values of 30 m thickness are stable in facing of geodynamic phenomena. Deluvial deposits consist of clay and sand combination up to 5 m thickness, unstable and in the presence of groundwaters generate slides, while eluvial ones allow circulation of rainfall waters and weaken the contact of clay basement. Activity of erosion phenomena, neotectonic, tectonic movements in the areas of flisch spreading in this city, has brought the slides, crashes, damage to roads, cracks or demolition of houses as well as detachment of a part of the massive rock, on which lies the museum castle of "George Kastriot Scanderbeg
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Imaging Sand Dunes at Kedrodasos Coastal Area, Crete, Greece
Authors A. Vafidis, S. Zannetidis, N. Economou, H. Hamdan, P. Nyktas, G. Kazakis, D. Ghosn and E. RemoundouIn this work, we present preliminary results from a geophysical survey conducted at Kedrodasos, south Crete, Greece. The scope of this survey is to characterize the subsurface at the Kedrodasos Juniperus trees forest. We used GPR and electrical tomography to map the root system of these trees and to image the sand dunes. We used three methods for the inversion of the resistivity data. We applied deterministic deconvolution on the GPR data and employed a reflected wave from a lab experiment as reference wavelet. The thickness of the sand dunes does not exceed 2 m. Low resistivity regions with abundance of diffracted EM waves are attributed to the juniperous trees root system zones.
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Applied of Electrical Resistivity Method on Concrete Structures
Authors S. Altundaş and N. CoşkunNowadays, non-destructive testing (NDT) methods such as electrical resistivity method plays important role in the evaluation and testing of civil engineering structures. The aim of the study is to give basic principles of electrical resistivity method and their limitations in the structural evaluation programme and provide information about agreed standards that obtained various concrete materials. For this reason, in this study, electrical resistivity method was used to determine that the quality of the concrete and reinforcement within the concrete situation and position. The five different cylindrical concrete models with the same dimension (15x30 cm) are prepared for this study. Iron pieces, sponges and rebar in different size are put into the concrete to determine the resistivity responses of the models. After that, the concrete models are incubated approximately 21 days in a tank filled with water for gaining strength. The resistivity measurements are carried out on each cylinder model in three profiles. On the cylinder models, Wenner and Dipole-Dipole arrays used to obtain data, and interpreted using 2D inversion programme (DC2dTree, developed by Thomas Günther).
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Seismoacoustics in Geotechnical Boreholes for Estimation of Adjoining Soil Properties
By V.P. LisinThe possibilities of seismoacoustic investigations data in geotechnical boreholes using as parametrical for interpretation and increasing of reliability on-land 2D shallow seismic are considered. For these goals the results of a vertical seismoacoustic profiling, obtaining by essentially simple technique in comparison with crosshole investigation, are more preferable.
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Assessment of the Site Effects Based on Earthquake Recordings and in Situ Measurements in Bucharest, Romania
Authors A. Bala, A. Aldea, S.F. Balan and C. ArionWithin the NATO Science for Peace Project 981882 “Site-effect analyses for the earthquake-endangered metropolis Bucharest, Romania” we obtain a unique, homogeneous dataset of seismic, soil-mechanic and elasto-dynamic parameters. Ten 50 m deep boreholes are drilled in the metropolitan area of Bucharest in order to obtain cores for dynamic tests and vertical seismic profiles for an updated microzonation map related to earthquake wave amplification. The boreholes are placed near former or existing seismic station sites to allow a direct comparison and calibration of the borehole data with actual seismological measurements. A database is assembled which contains P- and S-wave velocity, density, geotechnical parameters measured at rock samples and geological characteristics for each sedimentary layer.
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Investigation of the Geological Structures of Kozlupinar and Bentpinar (Bağbaşi-Denizli) Water Source System by Using the
Authors A. Aydin, S. Tasdelen and D. Tanik DenisVery important water sources of Denizli city which are Kozlupınar and Bentpınar springs where take place between Pamukkale University and the Bağbaşı village have been investigated to find the feeding directions of groundwater and to obtain the fresh water for near counties. Those springs are the East part of the Aegean horst and graben systems. In the drainage systems of Gökpınar dams, those springs altitude of topography is high and the Sothern site and along the North Slope of the Bağbaşı village, they take place on the top of the slope debris and some deposited cones. Geoelectric and electromagnetic methods have been used to investigate the affect of drainage and urban area on the fresh water in the county of Sarayköy. Vertical electrical sounding has been performed on 48 points and GPR method was carried out about 6.4 km horizontally using georadar. As a result of hydro-geological and geophysical studies, affective feeding area of the springs is investigated in the area. This study may be the good example to investigate the feeding direction and the location of the springs for similar type of projects.
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Physical - Mechanical and Sanitary Indicators in Drinking Waters and in two Mineral Waters of Lushnja District
By A. DodonaThe study results presented in the paper aimed to deal with drinking water quality of the city and of the district and highlight the characteristics of two mineral water of Lushnja district in the Western Central Albania, according to the “International standards of drinking water” (WHO). The study covering 25 district waterworks, supplying more than 50% of the population. In their waters are determined a large number of indicators, divided into separate groups which are: the odour, taste, colour, temperature, pH, radioactivity and natural radio elements, free carbonic gas, sulphur hydrogen, free chlorine, dissolved oxygen, the total and mineral acidity, total alkalinity, ammonium, biochemical oxygen demand, nitrites, oxidation, nitrates, pesticides, phenols, cyanides, hardness, carbonates, bicarbonates, phosphates, metasilicilic acid, total dissolved solids TDS, anion-cationic composition, fluoride, iodide, iron, zinc, lead, manganese, copper, arsenic and boron. Spectral control have been made for Co, Cd, Hg, Cr, Ni, V, Mo, Se, etc., radiometric and gamma-spectrometric control is made for natural water radio-elements U, Ra, Rn, Th, and bacteriological analyses. Has been observed also the relationship between the chemical composition of groundwater and geological setting of the aquifers.
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Geophysical Detection of Marine Intrusions in Black Sea
Authors F. Chitea, P. Georgescu and D. IoaneCommunities living in coastal areas depend in a great extent on the fresh water resources exploited from aquifers which are usually in a natural hydrodynamic equilibrium with the sea water. The contamination of fresh water with marine salty water determines a significant increase in the aquifers electric conductivity, allowing an efficient application of resistivity methods in detecting and monitoring the marine intrusions. We present case studies from Romania (Costinesti and Vama Veche areas, southern Dobrogea) based on older vertical electric soundings (VES) and recent electric resistivity tomography (ERT) measurements, relevant for the detection and monitoring of coastal marine intrusions. The results of the geophysical investigations are mostly represented as apparent resistivity but also as inverted cross sections, both illustrating by means of resistivity anomalies the spatial development and evolution in time of the marine intrusions.
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Evaluation of Ground Vibrations Generated by Sheet-pile Driving
Authors M. Lednicka and Z. KalabThe article describes basic principles of vibration generation and propagation through the surroundings when vibratory pile-drivers are used in the construction of a sheet pile wall. These vibrations fall into technical seismicity and contribute to the seismic load of engineering structures situated in the vicinity of such walls under construction. Further, the article presents results of the measurement of effects of these vibrations during the making of the sheet pile wall during the construction of a new building of VŠB – Technical university of Ostrava. A result of the measurement is the assessment of the data in time-frequency domain while using special “Spectra analyzer” software. Evaluation of vibration attenuation in the given earth environment and the values of the oscillation velocity amplitudes depending on the distance from the source of vibration for different frequency ranges are also presented.
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The Pressure Dependence of Acoustic Velocity – a New Petrophysical Model
Authors H. Szegedi, J. Somogyi Molnár and M. DobrókaPressure dependence of acoustic waves is an extensively explored rock physical problem. Knowledge of the phenomena of pressure dependence is an important prerequisite for relating laboratory meas-urements to in-situ rock properties, and for interpreting seismic measurements in terms of subsurface petrophysical parameters. Therefore it’s expedient to develop a petrophysical model based on simple physical assumptions which describes the relationship between acoustic velocity and pressure. The model is based on the idea that microcracks are opened and closed besides different pressure states. The model was applied on own acoustic velocity data sets and also data sets measured by Yu et al. as well as Xu et al. The material parameters of the models are determined by using inversion method and the laboratory measurements were compared to the theoretical data. The theoretical data matched accurately with measured data proving that the petrophysical model applies well in practice.
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Interval Inversion of Wellbore Data for Characterizing Metamorphic Hydrocarbon Reservoirs
Authors É.E. Tolnai and N.P. SzaboIn investigating multi-mineral rocks, the nonlinear well-logging inverse problem becomes an underdetermined or at the best a very narrow type of overdetermined problem, which cannot be treated by conventional local (point-by-point) inversion methods with satisfactory accuracy and reliability. In order to determine the unknown petrophysical model composed of many parameters (i.e. volume of matrix components, water saturation, clay content, primer and secondary porosity) with no ambiguity, it is essential using a joint inversion process. The interval inversion method is a special kind of joint inversion technique, which inverts data of a greater depth interval simultaneously in a highly overdetermined inversion procedure. Having used interval inversion method with success for the case of shaly sand environments, now the efficiency of the global optimization based interval inversion method is demonstrated for the case of hydrocarbon-bearing rocks with complex lithology.
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Rock Body Classification made from Geophysical Measurements
By S. HegedűsA very effective and prompt rock body classification can be served from the resistivity and acoustic wave measurements, which complements and highly helps to evaluate the information from the core investigation and pressure tests.
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On the Correlation of Seismic Noise in Izmir City, Aegean Region of Turkey: Preliminary Results
Authors M. Kececioglu, F.J. Chavez-Garcia, E. Gok, U. Ceken and O. PolatSeismic risk in the Eastern part of Turkey is high due to active tectonics in the region. Recently, a new seismic network was installed in Izmir region. Because the objective was to analyze seismic response, not all stations were installed on firm rock. Rather, the different geologic formation at the surface was sampled by the 16 sites. The stations are high quality, digital accelerographs by Guralp, writing continuously. Preliminary analysis of earthquake data recorded to date has been presented in Gok (2011). The results gave some estimate of transfer functions for the different sites. However, no information is available on the subsoil structure. We need to have the structure to compute response and compare with observed seismic response. For this reason, we have taken advantage of the continuous recording at the array. Seismic noise is analyzed in this paper using correlation to estimate Green's function between station pairs. The preliminary results are encouraging. We are able to estimate group velocities between stations, although signal-to-noise ratios are small and the frequency band of the pulses is restricted. In spite of this, we present a preliminary map of velocity variation as a function of path for the Izmir gulf region.
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