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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 - 20 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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