- Home
- Conferences
- Conference Proceedings
- Conferences
5th Congress of Balkan Geophysical Society
- Conference date: 10 May 2009 - 16 May 2009
- Location: Belgrade, Serbia
- Published: 10 May 2009
41 - 60 of 134 results
-
-
Sequence monitoring
By J. Knezevic6283 Sequence monitoring J. Knezevic* (Union University) SUMMARY 5 th Congress of Balkan Geophysical Society — Belgrade Serbia 10 – 16 May 2009On the basis of relation between period of sampling and period of fluctuation observed phenomenon geophysical monitoring could be: a)continual monitoring b)sequence monitoring. Natural phenomenon are of continual character so the signal of that phenomena is continual time function -continual signal. The ideal case for continual monitoring would be when velocity of sampling is at least 100 times bigger then Nikvist frequency. In real case continual monitoring contains acquisition made by the sampling velociti with frequency that is
-
-
-
Application of the Geosolar Method in Purpose to Define Hydrogeological Characteristics of the Ground
Authors A. Novitović and A. Šestak6284 Application of the Geosolar Method in Purpose to Define Hydrogeological Characteristics of the Ground A. Novitovic* (Eko Solar d.o.o.) & A. Sestak (Eko Solar d.o.o.) SUMMARY 5 th Congress of Balkan Geophysical Society — Belgrade Serbia 10 – 16 May 2009This paper describes some results of hydrogeological characteristics such as depth of ground waters and lithology achieved with GEOSOLAR method. The basics of method and mechanism of practical implementation are also exposed. INTRODUCTION Having in mind increased use of alternative methods in different fields of science objective of this paper is to show use of GEOSOLAR method as a
-
-
-
Landslide and its investigation by the geotechnical and electrical resistance tomography (ERT) methods in Tirana area, Albania
More LessThis paper present some consideration on the landslides phenomena occurred closed to Tirana capital city, Albania, from which is destroyed the main water supply pipe line and road, that connected several villages with Tirana. It is located in the north east part of Tirana. Landslide is mainly controlled by the interaction of numerous factors, both natural and human-induced. They are the geomorphology, lithology, geodynamic phenomena (tectonics), hydrogeologym physical-mechanical properties of rocks and soils,as well as, manmade works related to excavation and exploitation of raw material as stone-quarry.
-
-
-
Geotechnical and geophysical investigations in problematic soils of Sukthi area, Albania
More LessBetween Tirana and Durresi town in Albania is planed to construct a cement grinding plant with silos, mill construction magazino, compressors room and office. The studied area consist of soft-firm soils with a thickness that varies from 85.0m up to 105.0m. In this paper we wrote some considerations according to geotechnical characteristics, Shallow Seismic and Vertical Electrical Sounding (VES) measurements of the studied area. Finally we would like to give some conclussions and recomendations. Seeing, that constructed site consist of soft-firm soils and great thickness, it was necessary to know the bedrocks, because of the foundations of engineering's objects. At first we carried out the geotechnical study, where are done 24 boreholes with depth range from 30.0m up to 60.0m, taking 35 undisturbed samples and 10 disturbed samples to analyses in laboratory for determination of mechanical and physical parameters by ASTM standards and 227 SPT. From the designers of the project was calculated for several engineering object a minimum bearing capacity from 6.0 kg/cm2. Therefore, we need to know the depth of bedrocks for any solution of using of deep foundations (pilot). That's why we completed the geophysical measurements-Apparent Resistivity method with Vertical Electrical Sounding (VES), which determinate the litological situation of bedrocks. Finally, from completion laboratories and in situ test, fields works, as well as, geophysical measurements we determined 12 geotechnical layers of soils and bed rocks as well.
-
-
-
A Revised Parametric Model of Local Magnitude for Albanian Seismological Network
By E. Dushi6287 A new local magnitude parametric relation for Albanian Seismological Network E. Dushi* (Polytechnic University of Tirana) SUMMARY 5 th Congress of Balkan Geophysical Society — Belgrade Serbia 10 – 16 May 2009Seismicity of Albania is characterized by small and medium size earthquakes with mainly shallow hypocenters hardly passing 35 km of depth. Heterogeneity of the crust leads to a greater scatter witch is the main reason for seismic wave amplitudes decrease and consequently of radiated seismic energy attenuation with variation of distance and azimuth. Using the correction coefficients δ = 0.1 for ∆=0-80 km and δ=0.4 for ∆ up
-
-
-
High Resolution Acoustic Mapping of Gassy Sediments and Gas Related Structures in Izmir Gulf, Aegean Sea
Authors D. Dondurur, M.G. Drahor, G. Çifçi, H. Mert Küçük, S. Coşkun, S. Gürçay and P. Özer6288 High Resolution Acoustic Mapping of Gassy Sediments and Gas Related Structures in Izmir Gulf Aegean Sea D. Dondurur* (Dokuz Eylül University) M.G. Drahor (Dokuz Eylül University) G. Çifçi (Dokuz Eylül University) H. Mert Küçük (Dokuz Eylül University) S. Coskun (Dokuz Eylül University) S. Gürçay (Dokuz Eylül University) & P. Özer (Dokuz Eylül University) SUMMARY 5 th Congress of Balkan Geophysical Society — Belgrade Serbia 10 – 16 May 2009The Gulf of İzmir is a semi-enclosed basin which extends E-W direction to the East and N-S direction to the West. Water depth changes from 20 m in the inner gulf
-
-
-
Geological-gephysical study of landslide on Drini Valley, Albania
Authors V.A. Azizaj, S.D. Dema and S.K.K. KasapiThe study is concentrated in: 1. To determine the fissure over "Balance Shafts" of Koman Hydropawer, direction of the fissure and its dip. 2. To determine colluviums thickness of landslide over turbine room.
-
-
-
ERT Survey at the Wall of Acropolis of Athens
Authors G.N. Tsokas and P.I. TsourlosA non destructive ERT survey at the south wall of Acropolis at Athens is described. The survey aimed to investigate the area behind the wall mainly to image the ways that the water is drained downwards from the Acropolis hill. This is major threat for the integrity of the monument evidenced already by the distortion of the wall. Several technical issues were encountered performing a survey on a wall. Further, modifications to the inversion algorithm had to be implemented. The results comprise images of the water ways.
-
-
-
Correlation of Curie point depths, heat flow data and geothermal modeling for Bulgarian territory
Authors P. Trifonova, Z. Zhelev, T. Petrova and N. PetkovThe basal depth of the magnetic layer (Curie point depths) of Bulgarian territory was calculated using interpretation of geomagnetic field observation and a map of the variations of this border was produced for the first time. The magnetic layer bottom thus obtained has “normal” (28-32km) values in the Moesian platform and central part of Bulgaria which are the relatively stable part of Bulgaria. Several second order anomalous regions are delineated. They have small amplitude (2-4km) and in the main correspond to areas with recognized geothermal anomalies. In the southern part, calculated depths gradually reach the minimal values of the derived Curie isotherm (up to 14-16km) with relatively high gradient. Heat flow anomalous regions are placed mostly above the CPD gradient zones rather than CPD minimums which could be explained with the complicated neotectonic structure of that region. According to the results from geothermal modeling and Paleomagnetic investigations, magnetic layer’s bottom of the Bulgarian territory corresponds to different Curie temperatures. They vary from about 300oC around Kazanluk, 425oC around Dospat up to 550-600oC in the Moesian platform, West and east Balkan unit.
-
-
-
Geobiological Approaches in Assessment of Tsunami Deposits
Authors B. Alpar, S. Unlu, Y. Altinok and N. OzerThe scope of this study is 1) to understand further the historical tsunamis which affected the study area using paleotsunami trenches and mechanic cores, 2) to provide clues to the question which of the earthquakes in the Rhodes Pass are tsunamigenic, and 3) to provide new data inputs to the next important aspects such as modelling or characterization of the tsunamigenic sources which make the main tasks for tsunami hunting in the Eastern Mediterranean. Yet there have been relatively few studies of the processes associated with tsunami sediment transport, their deposition and nature.
-
-
-
Electrical survey for detailed characterizing of underground karst: Example from Iskar River (Western Bulgaria)
Authors S. Shanov, A. Mitev, A. Benderev, K. Kostov and B. MihailovaThe study was done using the method of Vertical Electrical Sounding (VES) for determination of the space characteristics of the underground karst in the gorge area along Iskar River in Western Balkan Mountain (Bulgaria). The method is very flexible to be use for measurements on difficult terrains, where is not possible to make the standard drilling. For the present investigation the computer program IPI2WIN has been used. One of the advantages of IPI2WIN software is the possibility to export as a file for 2D processing and interpretation the VES records from sites along a profile. In this manner the interpretation using the software RES2DINV can be done. The results obtained by the geophysical studies have confirmed the hypothesis for the existence of karst cavities that are not known and not discovered on the relelef.
-
-
-
Seismofacial analysis – new trends in Geophysical Institute, Belgrade (Serbia)
By D.J. CiricIn oil&gas industry today analyzes of seismic facies are standard procedure as part of interpretation in oil & gas exploration. Test example which is made in Geophysical institute, will be present some of new possibilities which we can do in new workflow. According to the case-study for 3D block Kikinda-varoš, palleo-channels presence was justified, as well as seismo-facial analysis of the reservoir performed. That is of particular importance for planning horizontal boreholes at this area. On the basis of all mentioned issues, it can be concluded that this procedure has to be developed in the future and used at various projects, in order to define reservoirs and locate boreholes more precisely.
-
-
-
Inversion of the Corrected Resistivity Pseudosections of the Near Surface Targets
By S. YilmazThe resistivity pseudosections due to the influence of terrain surface variations can be resulted by erroneous interpretation of the subsurface structure. In this study, to take into account the topographic effects in resistivity surveys is used the normalization process that uses the correction factors for a homogeneous earth model in the forward modeling manner. For this purpose, the finite element method is used to determine terrain effect in dc resistivity data. Thereafter, resistivity pseudosection data are inverted using the damping least-squares technique to estimate the resistivities of blocks in an inversion model. The normalization process used to remove the terrain effects in resistivity pseudosections reveals the response of the real subsurface structure. The inversion of the data produces reliable results in the final inversion model.
-
-
-
Application of Autoregressive (AR) Extrapolation Technique to Enhance the Deconvolution of Seismic Data
By H. KarsliAutoregressive (AR) extrapolation technique has been widely used to replace missing or corrupted samples in signal processing. In a similar fashion, it can be used to enhance quality of results from deconvolution which is main step in seismic data processing. It is well known that deconvolution is a process universally applied to seismic data to extent bandwidth of seismic data. However, lower and higher frequencies of the seismic data are missing even if it is deconvolved. In this paper I apply AR extrapolation technique to recover missing frequencies of deconvolved seismic data. This technique described is performed in spectral domain and is useful to successfully retrieve a broad-band seismic data. Synthetic and field data examples show that it increases resolution and yields a more interpretable seismic section.
-
-
-
Stress induced azimuthally anisotropic reservoir - AVO modeling
Authors M. Brajanovski, B. Gurevich, D. Nadri and M. UrosevicThe analysis of rock anisotropy in terms of seismic velocities and within the context of rock physics (Biot-Gassmann theory of poroelasticity) provides important information for the evaluation of the stress state (tensors) of rocks, detection of the directions of formation weaknesses, helps in the estimation of overall permeability and failure prediction. Understanding the influence of stress and pore pressure on seismic velocities is important for 4-D reflection seismic interpretation, AVO analysis and reservoir modeling. Laboratory measurements were carried out on spherical shale samples from the overburden under confining stress up to 400 MPa, by means of ultrasonic soundings in 132 independent directions. Such an approach enables the estimation of 3-D elastic anisotropy. Since the sandstones were partly unconsolidated, it was not possible to take ultrasonic measurements. To overcome this, we developed a method for stress induced azimuthal anisotropy estimation using only cross-dipole logging data. These results give the possibility for anisotropic correction in AVO analysis.
-
-
-
Modelling the anomalous gravity effect in the range of the Mirovo salt diapir and the surrounding area
Authors R. Radichev, S. Dimovski and E. Zaneva-DobranovaThe performed study of detailed gravity survey data in the range of the Mirovo salt diapir and the surrounding area and the analysis of various possible anomalous effects caused by different combinations of synthetic models lead to the conclusion that the specifics in the gravity field distribution can be justified by the presence of a second anomalous source (the so-called Manastir salt body). This possibility is well-grounded from a genesis point of view.
-
-
-
Seismic attenuation in partially saturated fractured aquifers
Authors M. Brajanovski and T. MüllerA conceptually simple superposition model is presented for dispersion and attenuation of compressional waves in fractured porous rocks that are saturated by a mixture of two pore fluids. These two different types of heterogeneities are described by four parameters: The fracture spacing (fracture density) and fracture weakness characterizing the fractured medium; the correlation length and degree of saturation characterizing the fluid patches that are embedded between the fractures. This model is employed to explain the relatively strong P-wave velocity dispersion found for a limestone reservoir. We conclude that the mechanism of wave-induced flow may well explain large P-wave dispersion and attenuation in heterogeneous porous media.
-
-
-
Deterministic deconvolution for GPR data in t-f domain
Authors N. Economou and A. VafidisA deterministic deconvolution for of GPR data is implemented using the S-transform. This method utilizes narrow time windows in t-f domain and sets spectral balancing as a precondition. The algorithm, tested on synthetic and real data, produces very promising results. Its application on GPR data from a sandbox experiment showed that temporal resolution of GPR data can be equally increased to reveal reflected waves travelling in high and/or low loss media.
-
-
-
Geological and geomorphological potentials of development of eco-tourism on the south-western slopes of the Old Mountain
Authors A. Mladenovic and M. VanicResearch has been conducted on this part of The Old Mountain in order to establish geological characteristics, using geological mapping method combined with remote sensing, paleontological, hydro geological and structural geology method. The terrain is characterized as complexly composed regarding its geological setting. Higher part of the terrain is made of metamorphic rocks, where the most frequent of them are schist and phyllite, rarely amphibolite and gneiss. Diorites can be seen like eruptive breach in these rocks. The terrain up to the Visocica River is made of limestone, marl and sandstone from Mesozoic. The lowest part of the terrain is made of red sandstone from Permian. In tectonic view three bigger parts there can be seen. Sprouts of diorites, phyllite and amphibolite, which are rare there, and sprout of limestone where fold form can be seen, are represented as especially interesting geological objects on this terrain. Except this, deposit of marine fossils from Jurassic, and gorges of the Visocica and the Rosomacka River are represented as interesting. The most interesting hydro geological objects are the most generous fountainhead and karst depression Ponor, with specific underground flows. This map gives a simple review of geological characteristics of this terrain.
-
-
-
Geophysical Investigation for Finding Out the Causes Leading to the Degradation of the Tunnel Structure
Authors V. Ciszkowski, M. Georgescu, L. Bogateanu, A. Ienciu and N. DanThis paper shows the possibility of using the geophysical methods (seismic and electrometric) for ground investigation in order to establish the causes leading to the degradation in time of the structure of railway and road tunnels.
-