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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
21 - 40 of 110 results
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New Arrays in the Geoelectric Prospection
Authors S. Szalai and K. SzokoliThe g11n arrays, which were until now outside of the interest of the geophysicists will be introduced. These so called quasi null arrays can be more effective in detection and characterisation of anomalies have just a small impact on the potential (due to their small size, resistivity contrast to the host rock, and/or their large depth) than the traditional arrays. In many investigations they proved to be even better than the Stummer array which was constructed by an optimisation procedure from the set of the traditional arrays. The g11n arrays proved to be moreover significantly better in horizontal and vertical resolution investigations and in some more models, as well, than even the optimised array. According to our theoretical and numerical investigations the usefulness of these arrays can be expected in numerous other geophysical research areas, as well. It is however already seen that the g11n arrays can be valuable tools for solution of many problems similar to the investigated one, like e.g.: in the research of tunnels, caves, cables, abandoned riverbeds, or discontinuities in the clay layer below a waste deposit. The applications of these arrays require moreover less time to carry out the measurements than those of the traditional arrays.
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Applying Edge Mapping Functions to the Magnetic Anomaly of the Philippi Granitoid in N. Greece
Authors G.N. Tsokas, A. Stampolidis, P.I. Tsourlos and G. VargemezisAirborne magnetic surveys provide a cost effective, quick and accurate way to map the subsurface distribution of magnetization for large, usually inaccessible, areas. Differences in magnetization of rock units are related with differences in the content of magnetic minerals within rock units (i.e. their magnetic susceptibility) and their remanent magnetization. Assuming that these properties are discernible between the various rock units, magnetic field anomalies could provide valuable information for the texture of lithological units and even be correlated with distinct lithologies. Here, we evaluate a number of edge mapping techniques applied on a part of the magnetic map of Macedonia and Thrace (N. Greece) in order to delineate the edges of the magnetic sources. The magnetic field anomaly which is studied is created by the so called Philippi granitoid. The mappers used comprise functions of the anomaly and its derivatives. The aimed in locating the lateral limits of subsurface magnetized granitoid.
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Some Main Aspects and Features of Seismic Activity in Albania During 2012
By Rr. OrmeniAlbania is characterized by intense microseismic activity and small and medium-size earthquakes and only seldom by large event. We present here the results of the analysis in parameters of events and some features of Seismicity that have occurred in the Albania and surrounding area during 2012 year. On that territory 39°00’-43°00’ N and 18°50’-21°50’E there are 869 located earthquakes with magnitude M≥1.5 (Richter), 196 with magnitude M≥3.0, 19 with magnitude M≥4.0. The most of local earthquakes about 92% are distributed in depth between 0 and 25 km, with maximum concentration between 4 and 12 km. The earthquake foci are concentrated mostly along the some active faults: 1) In the Vlora-Elbasan-Dibra transversal fault zone. In the vicinity of Fieri was registered a small series of earthquakes that have the same level of of magnitude and supposed to be an inducted seismicity. 2) In The Korca-Leskovik seismogenetic zone. 3) In the Ionian seismogenic zone. 4) In the Lezha-Ulqini seismogenic zone. Increased seismic activity was registered on the Greece territory, nearby of southern Albania.
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Crust and Upper-mantle Structure in Anatolia from Analysis of Love Wave Group Velocity
By N. SayilThe environmental noise, the noise related to signal, the equal sharing of seismic energy between the components and the other factors effect discrimination of surface waves forms on seismograms. The differences between polarization properties of surface waves and microseismic noise permit to filtering a desired surface waves kinds on three components records. Dispersion property of surface waves, i.e. changes in seismic velocities and absorption as depending on frequency, has been used to investigate the Earth crust and upper mantle structure. In order to investigation of the Anatolian crust structure, it has been selected the profiles across east-west trending the Anatolia. To create these profiles, long period three component digital records at six stations (YLVX, MRMX, MLSB, ISP, ISK,EDRB) of KOERI network having about 10 epicentral distance of an earthquake (EZM) were taken. Surface wave discrimination filter based on the polarization has been applied to three component records of all stations for making more convenient the surface wave records. Multiple filter technique has been applied to discriminated surface waves and detected the group velocities. A five layered crustal model having total thickness of 38-40 km and Pn-wave velocity of 8.00 km/sec in the upper-mantle have been determined by inversion process.
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Determination of the Site Characteristics from Mictroremor Measurements in Gumushane Campus Area
More LessMicrotremor 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 40 points with the aim of determining ground predominant period and magnification parameters of the Gumushane University and its surrounding area located in Northeast of Turkey. Maps of magnification, predominant frequency and ground classification (Z2 and Z3) according to the predominant period are created by derived values.
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Contribution of the Seismic Method in Structural Modeling of Albanides
Authors P.N. Naço, P.L. Leka, J.S. Skrame, F.V. Vinçani and V.D. Dodaod will illustrate its results in different regions. The studies carried out by seismic method in terms of depth has could to outline the transgressive boundaries, overthrusting tectonic contacts, backthrusting tectonic boundaries, possible structures for petroleum exploration, the new tectonic movements etc., specifically in structural determination of Tirana syncline, outlining of Preza-Ishmi overthrust, which is active to this day, outlining in depth of the contact that separates the tectonic Kruja zone with tectonic Ionian zone. It will also be presented the possible structures for petroleum exploration, outlining in depth the oil-gas –bearing deposits.
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Effects of the Borealis Impact on the Thermal Evolution of Mars
Authors A. Fazelvalipour, Y. Vejdani, E. Fazelvalipour and M. BakhshimazdeThe near hemispheric dichotomy of Mars is attributed to a giant impact called Borealis impact[Andrews-Hanna et al., 2008]. In this work, we investigate the effect of Borealis impact ,happened 4.5 Gyr ago, on the thermal evolution of the Martian planet. We show that the impact increases the rate of crustal production for a period of about 50 m.y. after the impact, reduce score mantle boundary heat flux significantly for a period of less than 5 m.y. after the impact but does not change significantly the total volume of melt production of the Mars. We discuss implications of our results on the postulated equivocal theories on the demise of Martian dynamo and conclude that none of them is capable to explain the demise of the Mars magnetic filed happened about 4 Gyr ago
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Assessing the Seismic Hazard for some parts in Hormozgan Province, Southern Iran
Authors A. Fazelvalipour, Y. Vejdani, E. Fazelvalipour and M. BakhshimazdeAn epicentral map of the region with magnitude 3 till 7 for the period 1930 – 2007 showsthat the region to the Hormozgan Province , Southern Iran (52º 30’ - 59º E, 25º –29º N) is one of themost active region in Iran. In this paper a method is developed to produce for the engineer thedesired relationships between such ground motion parameters as Modified Mercalli Intensity (MMI)and their average return period for some parts (Bandarabbas Zone, Hajiaba Zone and Minab Zone)of that province. In addition we have calculated a relationship between return period and MMI for three parts of Hormozgan province, Southern Iran.
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THERMTEC - Thermal-tectonic Modelling of Orogenetic Processes in the Eastern Alps
Authors S. Hoyer, F. Zekiri, G. Goetzl, M. Bottig, M. Fuchsluger, M. Rockenschaub and N. GegenhuberThe scope of the project THERMTEC is to model thermal-tectonic orogenetic processes in the Eastern Alps. Regional geothermal regimes are influenced by tectonically induced processes in terms of uplift or depression, which in combination with exogene processes like erosion and sedimentation lead to significant geothermal anomalies. This study aims to investigate the influence of two antithetic tectonic processes on the recent geothermal regime for the Tauern Window in order to detect possible zones of positive and negative heat flux anomalies. Geophysical, geochronological and petrophysical investigations as well as 3D geological modeling (using GocadTM) are part of the research. Using the software package COMSOL MultiphysicsTM coupled thermal-tectonic modeling will be carried out during several steps focusing on a regional scale geometric 3D model covering the whole Tauern Window. Starting with a conductive, steady-state model and leading to more complex simulations (transient advection and mass movement). Results will be compared with observed recent terrestrial heat fluxes, palaeothermal conditions gained from geochronological data.
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The Use of Resitivity Methods for the Exploration of Water-bearing Stratums in the the Quaternary Deposits
More LessThis study presents examples of Vertical Electrical Sounding (VES) resistivity methods used for hydro-geological exploration in Albania. There are given examples of VES method, for the exploration of water-bearing reservoirs in Vjosa river valley in Llakatund area. It is presented the geometry of the aquifer in the area according to resistivity data and the correlation between hydrogeological and resistivity data. Also, it is given the geoelectrical cross-section along the Mati River, which gives the opportunity for the study of the water-bearing deposits in all the quaternary deposits of this river.
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Indoor Radon Concentration to Different Lithological Conditions in Shkodra Area, Albania
Authors S. Dogjani, I. Jata, I. Milushi and H. ReciThe studied area is located in the north-west of Albania in urban areas of that area. Radon activity in indoor air was measured by passive and active detectors. Radon concentration survey has been carried out in schools and kindergartens. Depending on the detectors used in measurements, the long term and in a few cases is the use short term methods have been applied. In this research, it is included the results taken only for the 26passive and 15active detectors in schools and kindergartens. In addition, the results of the other 25 detectors are in the procedure of analyzing. The choice of the measured areas is related to the different geological formations. The investigation area shows low- medium – high radon indoor concentration. Keywords: radon, indoor air, soil, red clay, permeability, terra rossa.
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Engineering Geology Mapping for Seismic Microzoning Purpose in Lezha Town Area, Albania
More Lessnds in northwest of Albania, closed to Adriatic Sea. Mostly of the Lezha town is built on flat area on both site of Drini River that are consisted of soils with low geotechnical properties. The other part of town is built on hill’s slopes, which are characterize by unstable state. Also, the Lezha area was defined a high hazardous area in Albania related to seismicity. For that, was carried out the engineering geological mapping on scale 1: 10 000 for seismic microzoning purpose and urban area development. The engineering geological mapping were based on geofactors are lithology, morphology, hydrogeology, geodynamics phenomena and physical-mechanical properties of soils and rocks.
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Pseudo-random Sweep Optimisation for Broadband Vibratory Seismic Measurements
By P. ScholtzBroadband vibratory seismic measurements are suited for deep signal penetration, improving reflector continuity and inversion. Seismic vibrators have serious mechanic and hydraulic limitations in emitting very low frequencies, hence special low-dwell non-linear sweeps are the most common drive signals, but pseudo-random sweeps are also considered to achieve satisfactory results. In this study a global optimisation technique used tailored to include several optimisation targets concurrently to reach a workable solution. Since a simple random sweep generated by vibrator manufacturers’ software has serious disadvantages, our optimisation minimises amplitude fluctuations in frequency domain, correlation side-lobe amplitudes and maximises total seismic energy of the sweep. By controlling maximum amplitudes below a certain vibrator specific lower frequency and by minimising instantaneous frequency changes vibrator mechanic and hydraulic limitations are taken into account. The resulting optimised pseudo-random sweeps have much better correlation and spectral properties than a simple random sweep. Also sweep length could be reduced substantially compared to a simple random sweep and a typical non-linear broadband sweep due to the increased total seismic energy achieved by the optimisation process. As a consequence optimum pseudo-random sweeps could be used in high productivity broadband seismic acquisition where resonance effect reductions are important, too.
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Advanced R&D of Geosciences on Synergy of Multidimensional RS-EO, Cosmical Geophysics & Space Sciences
By Z.D. AndonovThis research represents advanced 6D R&D paradigms for evolution of Geosciences up to Space Sciences on fundamental synergy of multidimensional RS-EO (Remote Sensing – Earth Observation), Cosmical Geophysics and Space Physics in the light of actual “Public domains of the Geosciences & Space Sciences”, especially: Global Changes of Environment & Climate Stratigraphy; Planetary Geodynamics; Catastrophic Earthquakes and Volcanoes; 6nD Computational Tomography; Development of Multidimensional Exploration Geophysics for Strategic Energetic and Advanced Earth&Cosmos Technology; Development of Multidimensional 6D-6C RS-EO, Cosmical Geophysics & Space Physics to the 6D-6C (6-Dimensions – 6-Components) and 6nD Synergetical Paradigms for Earth & Space Sciences & Technology… Advanced paradigms of Multidimensional 6D-6nD Space-Time Strategy are aimed to innovative S&T objectives included new 6D R&D aspects, covered: 1. Innovative 6D S-T Coordinate System & Methodology adaptive for multi-waved transitions from 4D-4C to 6D-6C Methodology&Systems. 2. Innovative Multidimensional 6D Space-Time Strategy for Earth-Sun Structure and 6D Geo-Sun Dynamics, 6D S-T Transferences and 6D Turbullences using 6nD Synergy of Earth & Cosmos, 6D Kolmogorov’ Turbullentce and 6D Kalman Space-Time States; 3. Multidimensional & Multitemporal 6D-6nD Synergy Research on Earth&Cosmos Evolution - Fundamental for 6nD System of all Earth&Space Sciences & Technology Systems…
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3D Velocity Structure of the Albania Region Obtained by Inversion of Local Earthquake Data
By Rr. OrmeniThe ‘minimum 1-D’ velocity model (Ormeni 2011) was used as initial model and, therefore, a reliable velocity model for the region was derived. Interesting features and details of the Albania upper and middle crust can be recognized in the final tomographic images. The results show that the velocity distribution is influenced from the geology and the seismotectonic regime of the region. At shallow depths (less than 4 km) the velocity increases gradually with respect to the depth without any sharp variation. On the contrary, the lateral variation of velocity seems to be affected from the geological regime of the region. Our new velocity model solving low-velocity features at shallow depths in the basins and some high-velocity features in the uppercrust.
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Application of Coda Q Method on Broad Band Recordings, from Local Earthquakes, in Albania
By E DushiInterpretation of the high-frequency part in seismograms of local micro to moderate earthquakes can provide a wealth of information about the earth structure within a region.First to draw attention, to these continuous wave trains in the tail portion of seismograms, was Aki (1969). These waves appear immediately after the direct seismic phase arrivals and are termed “Coda”. The cause of their appearance is the superposition of the incoherent scattered phases from random heterogeneity within the Earth’s lithosphere (Aki, 1969, 1980; Aki and Chouet, 1975; Roecker W. S., et al, 1982; Chung, et al. 2009). It has been observed that the decay of coda wave amplitudes, of a local earthquake with time, can provide a quantitative estimate of the attenuation. The method based on this observation is widely referred to as Coda Q (QC). Aki and Chouet (1975) assumed coda waves to be single back-scattered S waves. Based on this model and using CodaQ routine in Seisan v. 1.9.1, (Havskov, et al., 2012) we have analyzed 55 earthquakes recoded by broadband seismological sensors of the Albanian Seismological Network (ASN). Dataset contains mainly local earthquakes and several regional ones. Taking into account vertical as well as horizontal components, secondary body waves S (Sg/Sn) are processed, which dominates expressing higher amplitudes. We determined parameters in the expression, , where in this frequency dependent model of the attenuation properties in the medium, express the quality factor determined for the characteristic frequency of 1 Hz, and α is the frequency term of the model (Dushi, 2011). The procedure description and results obtained are the subject of this paper.
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Exploration Complex Methods of Copper Ore in the Volcano-sedimentary Formation of Porave Area, Puka
Authors I. Milushi, I. Jata, N. Vukzaj and K. GjeciSummary Volcano-sedimentary formation of Porave - Miliska area is constituted by high titanium basalts and sedimentary intercalations represented of argillaceous and argillaceous – radialarite. This formation is characterized by a very complicated structural construction. The area is highly saturated with copper-pyrite sulfur mineralization and up to now 42 sulphide ore showings are found. Three types of mineralization have been identified: (VMS) volcano massive sulphide ore type with almost sharp contacts with the surrounding rocks, quartz-sulphide mineralization (or vein type) with sharp contacts with the surrounding rocks and hydrothermal-metasomatic mineralization characterized by large mineralized zones within which are meet the massive lenses. All field-spreading of volcano-sedimentary formation is covered with complex geological-geophysical works with 50x20 m grid. These works have identified a number of IP anomalies related to known ore bodies and in sectors with no ore showings. Measurements of IP with Dinpol apparatus provide clear differences between the ore body and surrounding rocks (Porave deposit case). The method of body charged also gives very good results (case of Geraj ore deposit). Key words: volcano-sedimentary formation, copper ore, IP measurements.
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Visibility of the Strands of the North Anatolien Fault in the Topography of Marmara Sea - Bathymetric Surveys
By M. ŞenözThe Visibility of the Strands of the North Anatolien Fault in the Topography of Marmara Sea – Bathymetric and Seismic Surveys The Bosporus is a strait that connects the Black Sea with the Sea of Marmara of northwest Turkey. The Black Sea is in the North and the Sea of Marmara is in the South of bosphorus. The Bosporus (Turkish Boğaziçi) Strait is considered to be the boundary between Europe and Asia, and the large city of İstanbul. Turkey is located on both sides of the southern end of the strait. The Gulf of Izmit is the narrow gulf extending to the east from the Sea of Marmara. The city of Izmit at the end of the gulf was heavily damaged by a large magnitude 7.4 earthquake on August 17, 1999, often called the Izmit earthquake, that killed at least 17,000 people. The Izmit earthquake ruptured a long section of the North Anatolian Fault system continuing under the Gulf of Izmit. Another strand of the North Anatolian Fault system is visible as a linear feature in the topography south of Iznik Lake. The recent Bathymetric and Seismic surveys show that the North Anatolian Fault system extends beneath and has formed the Sea of Marmara, in addition to the Gulf of Izmit and Iznik Lake.
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Contribution of Simplified Surface Waveform Calculation to Separate Dispersion Curves in MASW
Authors H. Karsli, M. Senkaya and R. GüneyAccurate picking of dispersion curves is the most critical stage in Multichannel Analysis of Surface Waves (MASW) method. Although there is several acquisition and numerical techniques for the optimal extraction, sometime, this requirement cannot be valid due to interference, which includes different modes, noises, and also lateral inhomogeneity in the near-surface earth. Hence, the interference between the different modes of surface waves can be so serious that neither fundamental, nor higher mode dispersion curve can be extracted with an accurate and a reliable. For this, we calculate surface waveforms, including geometrical and intrinsic dispersion, based on the summation of the particular seismic impulses corresponding to particular frequency-phase velocity curve points for geophone positions from the seismic source. This methodology is demonstrated by using both synthetic and real shot gathers. Synthetic calculations provide us a simple way to check accuracy of dispersion curve picking on a shot gather, which it is the fundamental or higher mode.
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The Effects of a Landslide on the Habitation Objects and the Results of the Use of Two Dimensional (2-d) Electrical Resistivity
By E. SiloThis paper reports a geophysical study of a recently activated landslide in the village of Proseku, Mirdita (Albania), due to intensive rainfall. The surface of the area involved in the landslide is 10 Ha. However, there are indications that the landslide area could increase and affect also other habitation objects. A geophysical investigation of the landslide, using the electrical resistivity tomography (ERT) method was carried out. The geophysical investigation has established the geoelectric section in several points of the longitudinal profile, improving the detailed geological mapping of the landslide.
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