- Home
- Conferences
- Conference Proceedings
- Conferences
7th Congress of the Balkan Geophysical Society
- Conference date: 07 Oct 2013 - 10 Oct 2013
- Location: Tirana, Albania
- ISBN: 978-90-73834-55-2
- Published: 07 October 2013
1 - 20 of 110 results
-
-
Detection of Fractures Stoneley Waves - Application - Example on a Oil Sinks in Algerian Sahara
By D. MabroukIn this paper, it is applied to acoustic data processing to study the fracturing tank oil on a well drilled horizontally using Stoneley waves the different stages of treatment allowed to detect, in a first step, areas of high attenuation energy .. The study of the Stoneley wave reflections has finally detect the fracture zones of the reservoir
-
-
-
Gravity and Geo-Electric
More LessThere are so many complex geological appearances having been discovered by professional Geoscientist in Bayat. This research aims to investigate the contact of igneous rock and metamorphic rock.
-
-
-
Geo Electric Three-Dimension Surveys for Detection of Subsurface Structures
More LessResistivity electrical changes in vertical, horizontal and in the direction that is perpendicular to the survey line, is measured in 3D surveys. 3D electric data illustrate a 3D image from subsurface layers, therefore combination of3D electric results and surface geology is appreciated as helpful technique in electric data interpretation. What Is carried out for performing a 3D survey is as follows: first a 2D survey is carried out in the survey field and then collected data are interpretated. When the subsurface layers are defined clearly, an area is selected and a suitablegrid for 3D survey is designed. After data acquisition, by using a 3D interpretation software, data points areinterpretated. Finally, the results are compared with the result of 2D configuration. In this study, the mainobjective is the detection of a fault trend by using pole–pole electrode array which is commonly used for 3Dsurveys. This survey method by using a 3D interpretation model gives accurate results of subsurface structures. In order to confirm the abilities of this method for fault detection, after checking the final results of 2D Shlumbergerarray on a fault trend in Anarak area in Esfehan province, an square grid with a 60 meters long, .
-
-
-
Investigation of Sabalan Geothermal Field Structure Magnetotelluric Method(MT)
More LessSabalan geothermal field is a high potential geothermal system in Ardebil province N-W of Iran that is now under investigation for the electricity power generation .In this paper the fourteen MT stations of 1998 MT data set were used along a profile perpendicular to the main geological structures in order to assess the three main elements of Sabalan geothermal field namely cap-rock, reservoir and heat source. TE and TM mode data and skew parameter show that the earth dimensionality differs from site to site, so we examine the joint 2D inversion along the profile. The two-dimensional inversion has been done by using a code from Siripunvaraporn and Egbert (2000).The resulting model show a pattern of high–very low–low resistivity with depth. The high resistive layer at the surface is governed to a great extent by basalt, andesitic and old trachyandesitic flows and other impermeable rocks that have thermal conduction and acts as the cap-rock of the system. The second layer is a very conductive layer and interpreted as the reservoir with thermal convection and hot fluids contained in its fractured and pores.
-
-
-
Geophysical Overview on Contact between the African and Eurasian Plates Transverse Folded Belt of the Albanides
Authors A. Frashëri, S. Bushati, N. Frashëri and S. DemaThe article presents an attempt to generalize the integrated geophysical data: Gravity, Magnetic, Paleomagnetic, Geothermal, Seismological and Remote Sensing images of zone, where it crosses the deep transversal fracture Shkodër – Pejë. Analyses of the geophysical data are based on regional geological setting data of Shkodër-Pejë sector of Mediterranean Alpine Folded Belt, which presents the existence of important disjunctive deep tectonics element. Shkodër-Pejë tranversal fracture represent the contact between the African and Eauasian plates contact transverse territory of folded belt of the Albanides. The geological mapping at the scale 1:25.000 up to regional ones at the scale 1:200.000, does not have traced at the Earth’s surface the outcrop of this thrust. Consequently, have brought about the different concepts on it, from “scharung” (1901) to “transform transversal fault” (1970-2012), and to silence about its existence, even to denial of its presence. These changes in the course of a century, not just in terms of use, were related to different geological schools over the geological setting of the Albanides. The integrated geophysical information has cast light on the depth of the area, where it crosses the transverse Shkodër-Pejë that represent a deep transverse vertical fracture, which affects the Moho Discontinuity.
-
-
-
Geosciences - The Contest Has Change
Authors G. Kallfa, J. Hinzer and L. KapllaniA nation's prosperity will be enhanced by the discovery and exploitation of economically viable natural resources within its borders; processes that are more than ever subject of rapid changes and increasingly dependent to the political, financial and marketing factors. In the last two decades the natural resources industry worldwide experienced dramatic irreversible changes. In the oil and metallic ores sector, countries, including Eastern Europe, emerged in global financial and economic markets. The big state-owned mining companies collapsed and/or transformed into private companies, many mines were closed. On the other hand, private sector is talking over the financial part of managing, developing and exploiting natural resources, consequently the new emerging in market countries have to compete in order to attract the attention of major financial institution and companies. The scope of presentation is to explain some of major changes in natural resources industry last decades that directly influenced or will influence the future of geosciences and business models in emerging markets. The authors, based on their long international experience in mining sector, will try to identify some of most influential factors and how the geoscientists must respond to the new era of managing, developing and marketing countries’ natural resources.
-
-
-
Time-dependent Aftershock Seismicity Patterns and Their Propagation - The Van Earthquake (7.2), 23 Oct. 2011, E-Anatolia
By M. TokerThe Van earthquake (ML 7.2, 23 October 2011) occurred in E-Turkey, typically “intraplate” earthquake. Aftershock seismicity pattern of the Van earthquake indicates the most prominent type of compound-complex earthquakes due to its multifractal dynamic complexity and uneven compressional nature, ever seen all over Turkey. Aftershock seismicity of the Van earthquake can’t be explained with linearly uniform, elastic fracture mechanics, because the time delays between the observed individual clusters are too long to result from elastic processes. The Van earthquake dynamically loads the surrounding volcanic region, such a compound earthquake can result from viscoelastic relaxation in the immediate postseismic period, resulting in nonlinear and heterogeneous redistribution of loads. Van earthquake as a composite system has input parameters more than one and strongly characterized by composite sequences of event instabilities. This brings an idea that is intraplate seismicity of accretions, giving a possibility of the extensive investigation of post-collisional rheology of accretionary complexes. We conclude that, in Lake Van, the deep-reaching zones of weakness allow magmatic intrusions into upper crustal layers, where magma-fluids or unstable fluctuations of the magma chambers themselves may cause the generation of unstable evolution and propagation of earthquake sequences.
-
-
-
Petrology of the Eastern Taurus Ophiolite (Turkey)
Authors A.F. Bingol and M. BeyarslanThere are many ophiolitic massifs, situated either northern or southern flank of the EW-trending Pütürge-Bitlis Metamorphic units, that they inform a good tectono-magmatic model for the Neotethyan ocean during Mesozoic in Taurus Oriental. They are, from west to east, Kızıldag, Koçali, Göksun, İspendere, Guleman and Gevaş. They consist of mantle peridotites, oceanic crust units, such as mafic cumulats, isotropic gabbros, sheeted dyke complex which are covered by the basaltic pillow, massive lavaş, and isolated diabase dykes. Some ophiolitic massifs as Koçali, Göksun, and Gevaş and tectonically overlying metamorphic units were intruded by tonalitic and granodioritic intrusions. The mantle peridotites are generally harzburgite and less lherzolite, mafic rocks consist of layered and isotropic gabbros cutting by wehrlitic intrusions. Geochemical data indicate the presence of two different types of volcanics, MORB and suprasubduction. The age of the volcanic rocks have been assigned to Late Triassic-Upper Cretaceous based on the radiolarian data from the associated pelagic rocks units. On the basis of petrography, geochemistry andage data, we conclude that the evolution of the eastern Taurus ophiolites involved at least two stage episodes. The first stage is presented by MOR type rocks and the second stage is characterized by SSZ type rocks.
-
-
-
Thin Bed Contourite Seismic Imaging
By S. SunjayWavelet (Mathematical Microscope) analysis of seismic data is made fashionable for thin bed precise subsurface imaging and interpretation. 3D seismic data interpretation for subsurface imaging of thin bed contourite systems is integral part of research work . Seismic expression of bottom current deposits from that of other related deepwater sediments (turbidites, hemipelagites, debrites, etc.), and to maximising the information that can be derived from seismic data. A wide variety of seismic facies are common in contourites, most of which are equally present in turbidite systems. Seismic facies associations that may be typical of contourites are still to be defined. Seismic characteristics also depend very closely on the methods of seismic acquisition and processing. Sediment waves and channels are very common both in contourite and turbidite systems, and not specifically diagnostic of either system. Slope deformation, sediment creep, and large-scale water-escape may cause a hummocky seismic facies that can be misinterpreted as sediment waves. The identification of hydrocarbon reservoirs from seismic data is a key issue in the oil industry. Texture Segmentation of a 3D Seismic Section with Wavelet Transform is employed for pattern recognition.
-
-
-
The Use of ERT, Magnetic and EM High Resolution Methods in Archeological Sites - A Case Study in Apollonia, Albania
Authors H. Reci, I. Jata, S. Bushati and M. HaxhimihaliDuring the period 2011-2012, high resolution geoelectric surveys using Electrical Resistance Tomography (ERT), Magnetic and Electromagnetic surveys, has been carried on three archeological sites of Bylis, Apollonia and Tirana Castle, Albania. The geoelectric surveys of squares, was carried out with 2D ERT parallel profiles with distance between them 1.5m or 2m and the distance between electrodes 1m where a multicore cable with 30 takeouts was used. The squares have been surveyed using two geometric configurations, Wenner and Schlumberger arrays. The EM survey grid is 1x 0.5m, whereas the magnetic grid is 1x1m. A 3D interpretation of resistivity profiles has been carried out and the resistivity distribution maps of different depths have been taken. At the same time the 2D map of magnetic anomalies is taken after the appropriate diurnal corrections. The EM 3D maps, show the ground scanning of the conductivity of the underground. From this study we conclude that the ERT method delineates very well the thickness of cultural layer and the buried archaeological objects inside it where the anomalies taken correspond with magnetic anomalies, whereas the EM method delineates very well the conductive clays from the other surrounding formations.
-
-
-
Radioactivity of Phosphorites and Some Opinions on Their Genesis
By A. SerjaniAbstract In Albania there are discovered phosphorite mineralization of the Upper Cretaceous (Coniacian) and Middle Jurassic. The application of radioactive methods have had concrete results and have solved concrete problems (Dafa F., Serjani A., 1994): theoretical solving of the character of distribution of useful components U and P2O5; determination of the mutual correlations between U, P, F and Gamma intensity, discovering the coefficients for the main chemical and radio metrical constituents etc. The differences of the uranium content between Coniacian Phosphate Horizon and Middle Jurassic uranium-bearing mineralization can be explained by their differences in genetically aspect. The formation of phosphate-carbonate-siliceous horizon happened into the pelagic, deep sea, reduced environment of Ionian Trough, where the clastic, terrigenous matter is totally missing, and phosphate beds are very clean, constituted only by phosphate and calcite minerals. Middle Jurassic uranium-bearing phosphorites were formed in photic zone, in shallow water environment, on submarine mountains (high parts) of break in sedimentation. Phosphate mineralization is accompanied by high content of organic matter, dolomite, pyrite, quartz and some other detritus minerals. The high content of uranium can be explained due to above mentioned accompanied constituents and by the absorption during digenetic processes.
-
-
-
Sunspot-dependence of the Geomagnetic Daily Variation in Turkey
Authors C. Celik, E. Tolak-Ciftci, M. Zobu, H. Ozener, S.B. Tank, A. Kizmaz and N. SarikayaIn this study the hourly mean values of the geomagnetic data available in Turkey are analyzed to determine principal harmonics of the solar daily geomagnetic variations. Available data are grouped according to sunspot relative number to determine and analyzed for solar and lunar harmonics. The most disturbed five calendar days of the each month are removed in order to minimize the effect of current systems in the outer magnetosphere regions. Very good sunspot dependence found between solar harmonics and sunspot number.
-
-
-
Assessment of the Seismic Impact from Grouped Quarry Blast Using Standard Seismic Survey Equipment
Authors S.B. Shanov and M. IsaevThe study presents a methodology for using standard seismic survey equipment for assessment of the impact of grouped blasts from quarries. Example from а limestone quarry situated at more than 1.5 km from the thermal spring “Merichlery” in South Bulgaria is discussed. After the two strong earthquakes from 14.04.1928 (М=6.8, Chirpan Earthquake) and from 18.04.1928 (М=7.0, Popovitsa Earthquake) the water from the spring disappeared. A survey was executed for assessing the impact of the blasts on the houses and the discharge of the mineral water from the exploitation borehole. The results are compared to the national and international criteria for the safety limits of accelerations and velocities of the ground in relation to the seismic frequencies. Reference to the maximum expected ground accelerations from earthquakes on the concerned site is also presented. The maximum vertical acceleration from the quarry blasts was calculated to be between 32.81 and 57.62 cm/s2, and the horizontal one – between 37.51 and 233.95 cm/s2 (single high frequency picks). These results indicate that no one record overpasses the normative level of accelerations from earthquakes for the area - 0.27 g (265 cm/s2). In average the recorded accelerations were 2.5 times lower than the normative.
-
-
-
Pre-stack Depth Migration (PSDM) Using Tomography Based Velocity Model
More LessNowadays, the requirements for obtaining high resolution seismic sections lead to searching different approaches to processing and interpretation of the data. Creating depth sections by Pre-Stack Depth Migration (PSDM) is a key issue for obtaining more reliable and informative seismic sections, which in turn enable more confident and more reliable interpretation of seismic data. Depth imaging of seismic data is used to map the complex subsurface geology in areas that have steeply dipping structures, faults or in any areas with a rapidly changing geological environment. The main aspect for achieving high quality depth imaging is the ability to build detailed and accurate velocity model. The model building process involves making an initial estimate of interval velocities for each layer in the model, followed by iterative refinement of the model velocities and layer thicknesses until residual moveout has been minimized on depth migrated gathers. Accurate velocity estimation and depth imaging provides the key to understanding the subsurface.
-
-
-
Detection of Zones Characterized by Different Degree of Water-saturation and Mapping of Landslide Surfaces by Application
Authors S. Dimovski, N. Stoyanov, A. Kisyov and M. YankovaGenerally, the landslides study is aimed towards determination of their physical- geological characteristics and the peculiarities of their structure. The main tasks are detection of zones characterized by different degree of water-saturation, mapping of landslide surfaces and contact zones, along which is performed the rock mass movement, determination of the shape, the dimensions, and the spatial situation of the landslide body. The possibilities, provided by the non-invasive geophysical methods, for solving the above-defined problems depend mostly on the landslide physical-geological model. Usually the geo¬logical section of a landslide site is well differentiated according to electrical resistivity. For this reason geoelectrical techniques applied for obtaining high-resolution images of the underground resistivity have leading role in geophysical investigations of landscapes. In this study are presented results obtained from the application of electrical tomography for investigation of a landslide site on the territory of Bulgaria - near the town of Varna.
-
-
-
An Overview of Eastern Black Sea Crust Using Single Station Fundamental Mode Surface Wave Method
More LessIn this case study, crustal structure of the Eastern Black Sea (EBS) have been investigated by calculating and inverting group-velocity dispersion data of fundamental mode surface waves (Love and Rayleigh) using single-station method between the periods 4-40 seconds. For this purpose, we have used broad band (BB) recordings of three earthquakes recently occurred easternmost EBS recorded on KOERI (Kandilli Observatory and Earthquake Research Institute) BB stations (BZK, DIKM, KVT, SNOP). Computer Programs in Seismology package version 3.30 (Hermann, 2002) were used to both calculate observed fundamental mode group velocity dispersion curves and inversion of these curves to determine 1D shear wave crustal structure of the region. We have statistically averaged the group velocity dispersion curves for Love and Rayleigh waves. Then, mean dispersion curve of these waves has been inverted to determine 1D shear wave structure represents the region. Consequently, we have determined that there is a low-velocity zone in the upper crust corresponds to Maikop formation. The lower crust consists of oceanic/semi oceanic thickened crust. Moho depth is 31 km.
-
-
-
Integration of Geophysical Studies in Near Coastal Lowland of Albania with Technology Gis
Authors F.V. Vinçani, P.L. Leka, P.K. Kosho and P.N. NaçoDuring the period of 20 years in near coastal Lowland of Albania, many geophysical studies have been carried out with Electrometric, Magnetometric, Gravimetric and Radiometric methods. Important place in these studies has taken Electrometry, mainly the method of resistivity. Results obtained in the most important regions of near coastal Lowland provide the supporting basis for all infrastructure projects and major works. Geophysical studies have provided research-scientific information to the surface and in depth, helping in solving geological, geoenvironmental, civil geology, geological-sedimentological, geological-engineering, hydrogeological and archaeological tasks in varying degrees. To standardize the information collected over the years, to coordinate and to annex it to any other type of support information for performing processing, further riinterpretations, it was necessary to use technology GIS (International Geographical System) in order to integrate them. Geological-geophysical studies included in these region resolved tasks: determining of the thickness of Quaternary deposits, the study of land for social buildings, exploration of minerals, researchs for waterbearing and the microzone of some regions. Based on existing technology (hard-software) was achieved to build GIS for geophysical studies at this region of Albania. Process has passed some phases like as: data preparation, informatization and processing etc.,
-
-
-
Determination of the Neotectonic Movements through Geophysical Methods in the Elbasani-Kruja-Lezhe Region
Authors P.L. Leka, P.N. Naço, F.V. Vinçani and P.K. KoshoThe article presents the analyze of geophysical surveys: Geoelectric, Seismic for the determination of the neotectonic movements in the Elbasani-Kruja-Lezhe region. 2-D geoelectrical image of the profile “Vidhas-Gjergjan”, related to the neotectonic system of faults is characterized complicated, creating graben structure in the central part of this profile due to the normal slides situated with neotectonic system of faults in the valley of Shkumbini’s River time to time. 2-D geoelectrical image of the profile “Krastë-Shushicë” related with extensional neotectonic regime.The separation of geoelectrical layers of Mirdita’s zone with sub-zone Krasta and aftermost with Kruja’s zone represents the extensional neotectonics of these zones with different dip from the upper part to the depth. Obtained data from the interpretation of seismic profile have helped in the conception of geotectonic model of Elbasan’s water basin. In such conditions is formed graben or cumulative depression of Elbasan, also expressed through seismic facies 0.6 to 0.2 sec. Geophysical-engineering study in Kruja region has identified the sliding plan and their active areas, helping in the selecting of construction sites. Active areas of the sliding are located usually in parts with steep terrain and this phenomenon is distinctly observed in the eastern part of neighborhood Kasme.
-
-
-
Fracture Detection and Determination Its Orientation Using Different Geoelectric Null-arrays
More LessA comparative study of the behaviour of three null-arrays, midpoint null-array (MAN), Wenner-g null-array and Schlumberger null-array in response to a fracture, both in profiling and in azimuthal mode is presented. The term “geoelectric null-array” is used for direct current electrode configurations yielding a potential difference of zero above a homogeneous half-space.The main objective is to determine which array(s) best localise vertical structures or best identify their orientation. Forward modelling of the three null-arrays revealed that the Wenner-g and Schlumberger null-arrays localise vertical fractures the most accurately, while the midpoint null-array combined with the Schlumberger null-array allows accurate orientation of a fracture. Field test measurements were carried out to verify the theoretical results above a quarry in Les Breuleux with the three null arrays and many classical arrays. The results were cross-validated with quarry-wall geological mapping. In real field circumstances, the Wenner-g null-array showed to be the most efficient and accurate in localising fractures. The orientations of the fractures in accordance with the numerical results, were most efficiently determined with midpoint null-array, however Schlumberger null-array adds accuracy to the results. This study shows that geoelectrical null-arrays are better than classical arrays for the characterisation of fracture geometry.
-
-
-
Seeing Deeper by ERT Measurements
Authors S. Szalai, A. Novák and K. SzokoliDepth of investigation is studied here, because nowadays more and more research should be carried out in built-up areas where space is limited, that is this question becomes more and more important. Since we think that the depth of investigation is basically determined by the detectability of small-size inhomogeneities, the so-called depth of detectability (DD) values, this parameter is investigated in this presentation for the 2D ERT. In the case of the studied prism and dyke models the not-yet investigated g11n arrays gave systematically higher DD values than the pole-dipole and dipole axial arrays which were the best conventional arrays from this point of view. This makes possible to obtain useful information even where the measuring area is limited, eg. in settlements, in less time and from greater depth. Moreover, due to the imaging properties of arrays having larger DD values are generally better it is easily possible that these arrays have also better imaging properties than those of the traditional arrays.
-