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6th EAGE/EEGS Meeting
- Conference date: 03 Sep 2000 - 07 Sep 2000
- Location: Bochum, Germany
- ISBN: 978-94-6282-118-7
- Published: 06 September 2000
21 - 40 of 42 results
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Geological problems of the "Bobov Dol" coal mine (Bulgaria)
By D. AngelovaThe "Bobov Dol" coal mines are situated in the Bobov Dol graben (SW Bulgaria). The coal is produced using 5 underground and lopen-pit mine. The graben is a part of the Kyustendil- Saparevo kettle group. The Bobov Dol graben was formed in its contemporary outlook during the Quaternary between the Konyavo mountain, the Gologlav heights and the Pogled mountain. It was separated from the Saparevo kettle by the Razmetanitsa horst. The average altitude is 830 m. The graben is drained by the Bobov Dol, Babinska, Razmetanitsa and other smaller rivers that mouth in the Dzherman river. All the settlements situated in the area (Bobov Dol, Babino, Golyama Fucha, Mlamolovo, etc.) represent an indivisible part of the Bobov Dol coal basin in an economic-geographical aspect.
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Econeotectonics of the East Maritsa Coal Basin (Bulgaria)
By D. AngelovaThe East Maritsa Coal Basin is situated in the eastern part of the Zagora lowland and includes three open-pit mines for the output of lignite coal. This basin has a priority status since its coal output amounts to 84 % from the total coal output of the country and to 92.5 % of the total lignite coal output in Bulgaria.
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ELF-electromagnetic exposure in urban areas: Preliminary results at two sites in Genova (Liguria, north western Italy)
Authors E. Armadillo, G. Branchesi, E. Bozzo and S. BertiniIn the last twenty years electrical energy consumption in Italy is almost doubled and it is growing at a higher rate than in the other European countries. Associated with the generation, transmission and use of electrical energy, usually delivered as 50 Hz alternating current, is the production of weak electromagnetic fields (EMF) in the extrernely low frequency range (ELF, from 3 to 3000 Hz).
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Testing the resolution of very shallow geophysics: Data from the EIGG test site, Leicester UK
By J. A. HillThe Environmental and Industrial Geophysics Group of the Geological Society of London (EIGG) constructed a shallow geophysical test site on ground donated by Leicester University in 1995. The test site was left for a year for the construction disturbance to decay. Since 1996 it has been used for the collection of a broad array of geophysical data. This paper presents results and comparisons of aselection from the various geophysical data collected to date to illustrate the resolution of the measurements.
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Geophysical and environmental interdisciplinary surveys surveys along Viterbese archaeological areas interested by a large landfill project
Authors G. Finzi-Contini, R. Giaccari, G. Losito, P. Minerbi, A. Marini, M. Montevecchi and A. SpadolaThe Viterbo Province, located in the Northern area of the Lazio Region is mainly characterised by an exceptional heritage given by centuries of Etruscan culture, well known all over the world. Beside that, many also Roman and Middle Age monuments - like e.g. Via Francigena: a Pilgrimage medieval rout to Rome - distinguish its landscape, which support both quite rich agricultural activities and high level tourism; also antique spas are enjoyed not only by population, owing to their historical and up-to-date reputation. Despite all this singular background, a Provincial landfill has been planned in this area, possibly also used by close Rieti Province. This paper is planning a number of actions to counteract such an ecological and environmental disaster.
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Glacial sediment resistivity anisotropy measurements (Kaluga region, Russia)
Authors A. A. Bobachev, D. K. Bolshakov, I. N. Modin and V. A. ShevninThe Aleksandrovskoye Plato, having the area of about 1 km2, is situated on the border of Kaluga and Smolensk Regions (Central Russia) on the left bank of the Ugra River (left tributary of the Oka River) near the mouth of the Vorya River. The glacial sediments properties on the Plato are peculiar in some in some features. The grains of sediment rocks are oriented differently in different rock varieties and in different locations in the geological cross-section (Lavrushin, 1992). This results in physical properties difference depending on the spatial direction, particularly, in resistivity anisotropy.
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A joint inversion method to solve problems of layer boundaries, differently defined by seismics and geoelectrics
More LessOne of the most important possibilities to reduce or abolish the uncertainty of measured VES data, occurring in a single inversion, is known as the joint inversion method. Joint inversions can he realised in different ways. i): with simultaneous inversions if geophysical methods, based on the same physical principles, (e.g. geoelectrical) are used; ii): using parameters of geological models derived from data based on different physical principles (e.g. geoelectrics, seismics) [Vozoffand Jupp 1975, Dobróka et. al.1991, Misiek et. al. 1997, Gyulai and Ormos 1999]. The most frequent problem using that joint inversion which is based on different physical principles occurs because different methods define different layer boundaries. It means that sometimes different geophysical parameters change at different layer boundaries in a different way.
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Combination of radartomography, geomagnetics and geoelectrics in archaeological prospection
More LessThe Geophysical Service of the Archaeological Division of the State Antiquities Department in Baden- Wuerttemberg, Germany employs various methods for the prospection of archaeological sites, such as geomagnetics, geoelectrics, electromagnetic induction and ground penetrating radar. These techniques are used not only for the preparation of excavations but also and mainly for the documentation of sites, which should remain untouched and thus be preserved for the future.
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Airborne EM surveys applied to environmental mapping in the UK
Authors D. Beamish, A. Mattsson and M. KurimoThe first high resolution airborne electromagnetic surveys to address specific environmental issues in the UK were carried out jointly by BGS and GTK in 1999. The dual frequency, fixed wing EM system operated by GTK was used in a series of trials to acquire detailed (low elevation, small flight separation) EM data sets in addition to magnetic gradiometer and radiometric information. Targets for the surveys included colliery spoil tips and domestic and industrial landfills (both active and closed). This paper discusses the ability of the EM data to provide reliable environmental diagnostics from airborne data obtained across populated areas.
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An innovative interpretation of a challenging helicopter electromagnetic survey
Authors L. Pellerin and V. F. LabsonIn 1991 a helicopter electromagnetic (HEM) survey was acquired at the U.S. Department of Energy Idaho National Engineering and Environmental Laboratory (INEEL). Data were collected by Ebasco Inc., an environmental consulting company, using the Aerodat HEM system. The strategy was to increase the resolution by reducing the flight height. In principle, a good idea, but standard interpretational procedures are not applicable at flight height approximately twice the transmitter-receiver coil separation. Hence the dataset was released to the U. S. Geological Survey for interpretation. The survey targets were buried waste sites of trenches and pits containing drums, ordinance and other objects, which are very conductive and highly three-dimensional (3D) in nature. An additional complication was the magnetic signature of the waste, basalt and soil that hosts the waste.
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An analysis of airborne transient electromagnetic data for hydrogological investigations
More LessTraditionally, frequency and time domain airborne electromagnetic (AEM) systems have been used for mineral prospecting, often in parts of the world with little environmental electromagnetic disturbance. However, the increased focus on hydrogeological investigations in many parts of the world has led to a growing interest in the possibility of using airborne systems for such purposes, even in densely populated areas (Sengpiel and Siemon 1998). This raises many interesting questions as to the resolution capabilities of AEM systems and their sensitivity to disturbing influence from ambient electromagnetic noise, and the presence of man-made structures such as power lines, buried cables, and fences.
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Assessing AEM method in mapping contaminated soil - A pilot project in eastern Germany
Authors M. Lahti, M. Kurimo and H. VanhalaAn environmental project evaluates application of airborne multisensor survey for assessment of various contaminated sites. Combination of magnetic, radiometric and dual frequency electromagnetic methods mapped in detail contaminated targets at a test area in eastem Germany. The radiometric data mapped effectively the impacts of uranium mining. Magnetic and EM data described well the landfills and tailing ponds even when they were buried. Additionally the measurements revealed new information of previously unknown possibly contaminated sites, The airborne EM method proved to be useful for assessing groundwater contamination in the vicinity of environmental risk targets. The interpretation of AEM data is validated by geophysical ground measurements and improved using numerical modelling with detailed and precise modeIs.
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Electromagnetic horizontal-loop-measurements in the salt mine of Bischofferode (Germany)
More LessDry rock salt with resistivity higher than 10-4 Ωm is undetectable with electromagnetic methods and can be considered as an insulator. On the other hand, the resistivity of brine (0.03 Ωm) is low and unlike dry rock salt a good conductor. This high resistivity contrast will be used to locate brine soaked areas or filled fissures, They imply a high risk of brine penetration and can cause fatal tunnel collapse.
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Improvement of aquifer characterisation by joint inversion of surface-NMR and geoelectric
Authors M. Hertrich and U. YaramanciA joint inversion scheme of Surface Nuclear Magnetic Resonance (SNMR) and Vertical Electrical Sounding (VES) has been developed and tested in order to improve the interpretation on aquifer characteristics. Since SNMR and VES did prove a high accordance in sensitivity to water distribution, these methods can easily combined in groundwater prospecting. Their different physical principles offer a promising objective of mutual supplement on structural and hydrological interpretation.
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Inversion of surface NMR amplitudes and decay times - Examination of smooth and block inversion
Authors O. Mohnke and U. YaramanciSurface nuclear magnetic resonance (SNMR) is a new non-invasive groundwater-exploration method allowing direct determination of the water content using relaxation amplitudes and of the effective pore size, i.e. permeability using decay times [1,2,3].
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Interactive acquisition and interpretation of resistivity and EM field data based on laboratory sample behaviour
Authors G. Losito, A. Mazetti and A. TrovaPrincipal purpose of the described work is to implement an integrated and interactive geophysical DC-EM methodology that can optimise both field times and prospecting method, in environmental researches, like archaeological and poIluted soils.
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The sensitivity functions of TEM methods
Authors A. V. Christiansen and N. B. ChristensenTransient electromagnetic (TEM) soundings have proven useful in a variety of geophysical investigations, e.g. hydrogeological investigations and mineral prospecting. In many cases the investigations are carried out from an aircraft (AEM TEM) to cover large areas resulting in vast amounts of data.
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A new distributed acquisition system for ground TEM
Authors R. J. Henderson and B. O‘NeillARTEMIS is a new ground TEM system which employs the concept of distributed acquisition whereby a number of receivers can be deployed to make simultaneous TEM measurements in the same background noise environment. While also the name of a greek goddess, ARTEMIS stands for Array Receiver TEM Intelligent System. Special circuitry has been devised so that each receiver detects the transmitter pulse remotely for synchronisation. This avoids the need to use connecting cables which are logistically inconvenient and, furthermore are a souree of unwanted common mode noise. The lack of cables also makes it quicker and easier for the receivers to be deployed and in any desired array.
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Development of the TEM arbitrary impulse method
Authors I. O. Isaev, M. I. Epov, E. Y. Antonov and A. E. PlotnikovThe TEM arbitrary impulse method (AlM-TEM) is adopted for the solution of various near-surface environmental problems: • water contents, • special features ofthe geological structure, • voids, • metallic objects, etc. The method presented is useful for building and monitoring of different engineering construction: • roads, • residential area, • darns, etc. And it is the sounding pulse spectrum managing which allow one to do a sum successfully. Another important feature is the registration of very early stage of transient process.
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New technology of bases and foundations construction with soil thermal strengthening by a microwave field
Authors Y. I. Spector, O. L. Denisov, A. E. Shchepetov and S. V. ToporovA new way of soil thermal strengthening with a microwave energy has been developed last years. By this way heat is transfered into soil by means of radiation. This essentially differs the way from the traditional thermal ones, by which thermal energy is transfered by heat carrier through the soil macropores by convection. Microwave radiation penetrates into the soil to a sufficiently large depth that can be varied, the process is accompanied with the intensive absorption of electro-magnetic energy and vibration of elemental particles of minerals relative to nodes of a crystaIlic grid. As a result, a threedimensional heating of soil mass for a short time interval takes place.
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