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Near Surface 2004 - 10th EAGE European Meeting of Environmental and Engineering Geophysics
- Conference date: 06 Sep 2004 - 09 Sep 2004
- Location: Utrecht, Netherlands
- Published: 06 September 2004
1 - 50 of 132 results
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Correction of Buildings, Basements and Bridge Influences in an Urban Microgravimetry Survey
Authors P. Chasseriau, P. Radogna, P. Logean and R. OlivierA001 CORRECTION OF BUILDINGS BASEMENTS AND BRIDGE INFLUENCES IN AN URBAN MICROGRAVIMETRY SURVEY 1 Summary A microgravity survey was carried out in summer 2002 and 2003 for modelling the molassic bedrock in Lausanne a high-urbanized city in Switzerland. The project of a new underground determined the availability of continuously updated mechanical loggings data that permitted us to check our models and to find out a routine procedure. We could evaluate influence of basements and large buildings. Firstly we had to ameliorate the digital elevation model (DEM) to have precise near topographical corrections and exact interfaces between basements and topography. Roads
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The Use of Microgravity for the Detection and Characterization of Sinkholes and Historic Extraction Features in the Chalk
Authors P. Styles, S. Toon, E. Thomas and M. SkittrallA002 THE USE OF MICROGRAVITY FOR THE DETECTION AND CHARACTERIZATION OF SINKHOLES AND HISTORIC EXTRACTION FEATURES IN THE CHALK 1 P. STYLES S. TOON E. THOMAS and M. SKITTRALL 1 Applied and Environmental Geophysics Research Group Keele University Keele Staffs. ST5 5BG UK 2 Geotechnology 3 Mouchel Parkman GB Ltd Chalk has been extracted extensively in the United Kingdom for more than 4 000 years with excavations for flints at Grimes Graves near Thetford in Norfolk probably being the earliest instance. From as early as Roman and Saxon times the flint contained within the chalk was initially quarried and mined
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Multichannel Spectral Induced Polarization (Sip) – Application to Geotechnics and Construction Materials
Authors E. Niederleithinger, S. Kruschwitz, M. Behrens and A. BrinkA003 MULTICHANNEL SPECTRAL INDUCED POLARIZATION (SIP) - APPLICATION TO GEOTECHNICS AND CONSTRUCTION MATERIALS Introduction 1 Geoelectrical methods are applied in many fields of civil engineering. They are used for building ground inspection hydrogeological investigations or moisture determination in building materials. Both instrumentation and interpretation software are commercially available and relatively simple to use. But the measured parameter (electrical resistivity) is often ambiguous. For example there is no unique correlation between resistivity and moisture. Many other parameters in particular salt content have great influence on the measurements. So other methods (geophysical or not) have to be used to calibrate the results.
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Microseismic Monitoring of Abandoned Salt Mines beneath Northwich, Cheshire, UK
More LessA004 MICROSEISMIC MONITORING OF ABANDONED SALT MINES BENEATH NORTHWICH CHESHIRE UK Introduction 1 S.M. TOON AND P.STYLES Applied and Environmental Geophysics Research Group Keele University School of Earth Sciences & Geography Keele Staffordshire ST5 5BG United Kingdom The Cheshire Salt Field has been the site of salt mining and wild brine pumping from Roman times for industry on Merseyside and Cheshire. Whilst mining under Northwich ended in 1928 there has been a history of continuing subsidence. Salt and brine extraction formed the basis of mid-Cheshire's chemical industry the primary economic force for the area up to the 1960's. Since then
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Borehole-to-Surface ERT Inversion
Authors P. Tsourlos, R.D. Ogilvy and C. PapazachosA005 BOREHOLE-TO-SURFACE ERT INVERSION Introduction 1 Increasing use is being made of cross-hole ERT to scan between two or more boreholes (Daily and Owen 1991; Daily and Ramirez 2000). However cross-hole tomography cannot be used successfully if the boreholes are too widely spaced. In such cases combined use of surface and single-hole electrodes (Bevc and Morrison 1991) or even single-hole ERT measurements can be considered (Tsourlos et al. 2003). Although the cross-hole ERT case has been studied extensively only limited information about the borehole-to-surface ERT measuring mode exists in the literature. In this work we examine the case of inverting
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Interpretation Enhancement by Combining SIP and NMR
Authors M. Müller and U. YaramanciA006 INTERPRETATION ENHANCEMENT BY COMBINING SIP AND NMR Introduction 1 The nuclear magnetic resonance (NMR) technique is mainly known in geophysics for well logging and laboratory measurements of cores. Therefore most publications in geophysics deal with the NMR properties of hard rocks. NMR is observed with nuclei of certain atoms which are immersed in a static magnetic field and exposed to a secondary oscillating magnetic field. The advantage of NMR is based on its direct sensitivity to hydrogen (water) protons ( 1 H). Furthermore structural parameters as porosity pore size distribution or permeability of porous media can be determined by
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Applicability of the Linear Model to Interpretation of Magnetic Resonance Soundings
By A. LegchenkoA007 APPLICABILITY OF THE LINEAR MODEL TO INTERPRETATION OF MAGNETIC RESONANCE SOUNDINGS Summary 1 Interpretation of Magnetic Resonance Soundings (MRS) is based on a correct modeling of the magnetic resonance response from groundwater. It is known from nuclear physics that for small flip angles (also called tilt angle) of the nuclear magnetization the spin system is linear and for larger flip angles it is not. Within investigated by MRS volume an alternating magnetic field produced by the surface loop varies by a few orders of magnitude thus producing a large variety of the flip angles of the nuclear magnetization of
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Laterally Constrained 1D-Inversion of 3D TEM Data
Authors E. Auken, A.V. Christiansen, L. Jacobsen and K.I. SørensenA008 LATERALLY CONSTRAINED 1D-INVERSION OF 3D TEM DATA Summary 1 In this presentation we show that the interpretation of spatial densely sampled TEM data over 2D earth structures is greatly enhanced by inverting the data using the 1D-LCI algorithm (Laterally Constrained Inversion). In the 1D-LCI algorithm neighboring models are constrained laterally on layer resistivities and interfaces. Introduction E. AUKEN A. V. CHRISTIANSEN L. JACOBSEN AND K. I. SØRENSEN The HydroGeophysics Group Department of Earth Sciences University of Aarhus Denmark Finlandsgade 8 8200 Århus N Transient EM (TEM) is commonly used in hydrogeophysical investigations as a fast and relatively cheap method
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Characterization of Ashes in a Landfill with Magnetic and Electrical Methods
Authors J.C. Gourry, V. Laperche and A. BitriA009 CHARACTERIZATION OF ASHES IN A LANDFILL WITH MAGNETIC AND ELECTRICAL METHODS Abstract 1 Thermal power plants waste ashes containing heavy metals have been stored and covered by domestic wastes in a landfill near Trieste (Italy). The objective of this study is to locate these ashes polluting the environment with geophysical methods. SASW 3D electrical resistivity tomography (ERT) and vertical magnetic gradient data were collected on a small test area where ashes were suspected. Niton X-fluorescence data were also collected at surface of the landfill to measure metallic compounds concentrations. SASW profile provided a high resolution S-wave velocity vertical section
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Ground-Truthing Airborne EM – Hydrochemical Characterization of a Coal Mine Plume
Authors D. Beamish, B.A. Klinck and J. TrickA010 GROUND-TRUTHING AIRBORNE EM – HYDROCHEMICAL CHARACTERIZATION OF A COAL MINE PLUME 1 Abstract A trial airborne EM (AEM) survey was carried out across a 13 x 9 km area of the northern Nottinghamshire (UK) coalfield. One of the objectives was to examine the influence of collieries situated above the Triassic Sherwood Sandstone aquifer. The conductivity models obtained from the AEM survey revealed extensive zones of enhanced subsurface conductivity in the vicinity of all the collieries in the survey area. The purpose of the present study is to provide information regarding subsequent investigations (ground geophysics and borehole) to confirm the
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Charactrization of the Landfill Using Ves Data Inversion
Authors M. Mirzaei and F. GhadimiA011 CHARACTRIZATION OF THE LANDFILL USING VES DATA INVERSION 1 INTRODUCTION The pollution of aquifers by landfills can contaminate valuable and scarce water resources in most overcrowded communities. The pollution in freshwater can be due to flow of leachate into the aquifers. Pollution investigations can involve determining hydro-geological lithological and structural characteristics at a site; assessment of relations and connections between the land surface and groundwater; detection of the presence of pollutants in the vadose and groundwater zones; and estimation of pollutant concentrations and patterns of movement. Surface geo-electrical methods have been used to image groundwater contamination for a number
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Investigation of a Former Quarry and Landfill Site Using Electrical Resistivity Tomography
Authors J.E. Chambers, P.I. Meldrum, O. Kuras, R.D. Ogilvy and J. HollandsA012 INVESTIGATION OF A FORMER QUARRY AND LANDFILL SITE USING ELECTRICAL RESISTIVITY TOMOGRAPHY 1 J. E. CHAMBERS 1 P. I. MELDRUM 1 O. KURAS 1 R. D. OGILVY 1 AND J. HOLLANDS 2 1 British Geological Survey Keyworth Nottingham NG12 5GG UK 2 North Lanarkshire Council SUMMARY A study of 2D and 3D electrical resistivity tomography (ERT) surveys of a landfill in a former dolerite quarry situated in the Midland Valley of Scotland is described. The main objective of the ERT surveys was to characterise the landfill geometry in terms of lateral extent and depth. In addition it was anticipated
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Groundwater Research Within the Estancia Basin, New Mexico
Authors J. Dimick, V. Mitchell, D. Klepacki and M. WennogleA013 GROUNDWATER RESEARCH WITHIN THE ESTANCIA BASIN NEW MEXICO Introduction and Background 1 The Colorado School of Mines Geophysics Summer Field Camp (GPGN 486) is a required course for the Mines undergraduates; however this unique opportunity to apply course theory with practical academic investigation has also attracted graduate students and students visiting from other schools for more than 50 years. Traditionally the course has been taught in Colorado and consists of a week of geologic mapping two weeks of geophysical data acquisition and a week of data processing with interpreting before a final presentation. In the fall of 2002 the
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Relationship Between Biodegradation and Bulk Electrical Conductivity
Authors E. Atekwana, E.A. Atekwana, F.D. Legall, R.V. Krishnamurthy and W.A. SauckA014 RELATIONSHIP BETWEEN BIODEGRADATION AND BULK ELECTRICAL CONDUCTIVITY Abstract Groundwater chemistry data were used to assess the relationship between high bulk conductivity zones and biodegradation of hydrocarbon. Biodegradation was verified using terminal electron acceptors (nitrate sulfate and iron) dissolved inorganic carbon (DIC) and the isotope ratio of DIC (delta 13 CDIC). The bulk conductivity was measured using in situ vertical resistivity probes. The results show that peak values in the bulk conductivity occurred in zones in the aquifer where total petroleum hydrocarbon were high and nitrate sulfate and iron reduction were occurring. Also in the zones where bulk conductivity was
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Constrained Inversion of Helicopter AEM Data for Managing Irrigation Salinity
More LessA015 CONSTRAINED INVERSION OF HELICOPTER AEM DATA FOR MANAGING IRRIGATION SALINITY ANDY GREEN 1 ROSS BRODIE 2 TIM MUNDAY 3 Abstract 1 The RESOLVE frequency domain HEM system has been used to map the distribution of near-surface clay-rich sediments in and around the Riverland irrigation districts of South Australia. The data were recalibrated with measurements from down-hole induction logs and then inverted using a 1-D layeredearth model. The inversion was constrained with as much geological and hydrogeological information as possible. The resulting detailed map of the distribution of the Blanchetown Clay is being used to model the recharge behavior of
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Towards Three and Four Dimensional Data Collection for Electrical Resistivity Data
Authors D.J. La Brecque, R. Sharpe and M. StubbenA016 TOWARDS THREE AND FOUR DIMENSIONAL DATA COLLECTION FOR ELECTRICAL RESISTIVITY DATA Summary 1 Advances in hardware and software have made the collection of fully three-dimensional and four dimensional resistivity data not only possible but practical. To fully utilize these new capabilities requires new approaches to collecting data. We compare more traditional one- and two- dimensional data collection strategies with fully three-dimensional strategies that include array patterns such as horizontal subsurface dipoles not possible in older two-dimensional schemes. Finding optimal arrays requires tradeoffs in resolution acquisition time and signal levels. A new statistical based approach is shown that can be
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Using Resistivity Measurements for Dam Safety Evaluation at Enemossen Tailings Dam
Authors P. Sjödahl, T. Dahlin and S. JohanssonA017 USING RESISTIVITY MEASUREMENTS FOR DAM SAFETY EVALUATION AT ENEMOSSEN TAILINGS DAM 1 SJÖDAHL P.* DAHLIN T.* JOHANSSON S.** * Dept. of Engineering Geology Lund University Box 118 221 00 Lund Sweden [email protected] [email protected] ** HydroResearch Sam Johansson AB St. Askens väg 6 183 65 Täby Sweden [email protected] INTRODUCTION Internal erosion is one of the major reasons for embankment dam failures. Resistivity measurements may have the possibility of detecting internal erosion processes and anomalous seepage at an early stage before the safety of the dam is at stake. The technique is essentially non-destructive which is particularly important when working with
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Quantitative Inspection of Sewer Systems Using Geophysical Methods
Authors D. Orlowsky, B. Lehmann, A. Redmann and T. KabbeA018 QUANTITATIVE INSPECTION OF SEWER SYSTEMS USING GEOPHYSICAL METHODS Abstract 1 To investigate the conditions of accessible underground sewer systems the geophysical methods seismics ground penetration radar (GPR) methods from borehole geophysics ultrasonic and impact-echo measurements as well as gravity geoelectrics electromagnetics and thermography had been applied in a 40 m long artificial underground test track in Gelsenkirchen (Germany). The test sewer track consists of different concrete pipes with diameters of 2.2 m and concrete thickness’ between 20 and 42 cm which are usually used in Germany. The goals of the test measurements were to find techniques which get more
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Non-Invasive Characterisation of Road Subgrade with Towed-Array Capacitive Resistivity Imaging
Authors O. Kuras, P.I. Meldrum, D. Beamish and R.D. OgilvyA019 NON-INVASIVE CHARACTERISATION OF ROAD SUBGRADE WITH TOWED-ARRAY CAPACITIVE RESISTIVITY IMAGING Summary 1 A towed-array Capacitive Resistivity Imaging (CRI) system has been used in a controlled experiment to acquire multi-channel high-resolution ERT data on an asphalt road. Results from a CRI survey on a purpose-built trial road are discussed and compared to corresponding GPR profile data. It is demonstrated that CRI is particularly effective for the assessment of road subgrade condition. The technique is found to be sensitive to variations in moisture content and porosity in the subgrade layer which can be used to distinguish areas of structural weakness in
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Geophysical Investigation of Slow Active Faults in the Provence Area (France)
Authors D. Jongmans, F. Nguyen, S. Garambois, D. Chardon, O. Bellier and D. HermitteA020 GEOPHYSICAL INVESTIGATION OF SLOW ACTIVE FAULTS IN THE PROVENCE AREA (FRANCE) Introduction 1 In regions of low to moderate seismic activity such as Western Europe seismic hazard assessment often requires careful studies of active faults that have very long recurrence intervals and tenuous morphological expressions due to substantial erosion rates vegetation coverage and human activity (Peulvast et al. 1999). Moreover most of Western Europe is characterized by a relatively high seismic risk due to the concentration of human and material properties presenting high-vulnerability. Consequently detecting tectonic structures that may lead to destructive earthquakes (i.e. Basel 1356; Verviers 1692; Lambesc
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Cross-Borehole Resistivity Tomography below Foundations in Covered Karst
Authors J. Deceuster, J. Delgranche and O. KaufmannA021 CROSS-BOREHOLE RESISTIVITY TOMOGRAPHY BELOW FOUNDATIONS IN COVERED KARST AUTHORS Abstract 1 This paper presents a case study conducted below building foundations in a karstic area at Tournai (Belgium). Geophysical investigations were carried out to map the complex geometry of the subsurface. Twenty-three cross-borehole resistivity panels with multiple arrays were performed on the site. Data were inverted with Res2DInv ® software. Tomographies give a good overview of the competent bedrock geometry and also allow to delineating covered weathered limestone. Introduction The investigated building is situated at Tournai in the south-west of Belgium. Several collapses from 2 to 3 meters in
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High Resolution Seismic Experiment within the Low-Noise Underground Laboratory (LSBB) of Rustrel (Province)
Authors G. Sénéchal, D. Rousset, E. Gloaguen and T. LebourgA022 High resolution seismic experiment within the low-noise underground laboratory (LSBB) of Rustrel (Provence). Abstract (1) (1) (2) (3) GUY SÉNÉCHAL DOMINIQUE ROUSSET ERWAN GLOAGUEN AND THOMAS LEBOURG (1) FRE 2639 – Imagerie Géophysique Pau – IPRA Université de Pau et des Pays de l'Adour - 64000 Pau – France (2) Dép. Des Génies Civil Géologiques et des Mines – École Polytechnique de Montréal - Montréal C.P.6079 – Canada 1 (3) UMR 6526 - Géosciences Azur – Sophia Antipolis 06560 Valbonne – France Several high resolution seismic experiments have been performed along underground galleries located 200 meters below the surface.
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Advances in the Interpretation of Geophysical Borehole Logs
Authors M.G.G. de Jong, S.D. Nio, D.T. Biewinga and D.G. SmithA023 ADVANCES IN THE INTERPRETATION OF GEOPHYSICAL BOREHOLE LOGS Summary 1 Modern software packages greatly facilitate the analysis and interpretation of geophysical borehole logs. Standard applications in hydrogeology and petroleum geology such as the evaluation of lithology and reservoir fluids are nowadays carried out routinely with such software. A disadvantage of most packages is that they are developed for the experienced geophysicist. Software tailored to the needs of geologists and hydrologists is now also available. Using flexible scaling options histograms and advanced multiple log display functions the non-petrophysicist can quickly evaluate lithological parameters and the nature of the fluids in
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Random Gridding Decomposition (RGD) in Seismic Tomography
By B. AbbadA024 RANDOM GRIDDING DECOMPOSITION (RGD) IN SEISMIC TOMOGRAPHY Abstract 1 The purpose of this work is to invert crosswell first arrival data on a high resolution velocity grid called the fundamental grid obtained by running several tomographic inversions on grids of smaller size generated randomly. Later the inversion results of these grids are scaled by the ray density and the pixel area to produce a final velocity image with a better resolution. The method has proven a significant gain in computing time for the inversion and has given superior results than those provided using simple grids of similar size especially
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Integrated GPR and Geo-Resistivity Study of Shallow Stratigraphy in Sandy Coastal Environments
Authors M. Pipan, E. Forte, M. Sugan, G. Dal Moro and P. GabrielliA025 INTEGRATED GPR AND RESISTIVITY STUDY OF SHALLOW STRATIGRAPHY IN SANDY COASTAL ENVIRONMENTS Abstract 1 We performed an integrated Multi-Fold GPR and resistivity survey in a coastal area in the northern part of Italy (Adriatic coast) to reconstruct 3D stratigraphy to localize vadose zone and water table and to identify possible man-made structures and excavations. The spatial sampling was sufficiently dense to perform 3-D interpretation of radar data and 2.5-D reconstruction of iso-resistivity surfaces across the grid. Processing of GPR Single and Multi Fold data focused on true amplitude signal recovery in order to preserve information related to electromagnetic impedance
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Soil Moisture Dynamics with Time Lapse GPR
Authors J. Schmalholz, A. Kemna, M. Müller, H. Stoffegen and U. YaramanciA026 SOIL MOISTURE DYNAMICS WITH TIME LAPSE GPR J. SCHMALHOLZ 1 A. KEMNA 2 M. MÜLLER 1 H. STOFFEGEN 3 AND U. YARAMANCI 1 Introduction 1 Tracing the water content in the uppermost soil is of great interest for a variety of different scientific disciplines. Since many processes are linked to the volumetric water content and its dynamics the scale of interest ranges from kilometres to submetres. With the availability of shielded high frequency ground penetrating radar (GPR) antennas a non- respectively minimally invasive geophysical tool valuable information concerning the water content can be obtained with a spatial resolution in
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Monitoring of Water Infiltration Using GPR Data
Authors P. de Beukelaar, S. Mazouz, M. Meinster, A. Saintenoy and P. TucholkaA027 Monitoring of water infiltration using GPR data Summary A Ground Penetrating Radar survey was carried out for water infiltration monitoring and mapping of shallow subsurface conditions. A first measurement allowed high resolution mapping of subsurface conditions and assessment in variations of the GPR reflection response for saline water infiltration in the upper few metres of unsaturated soil. In total three sites with representative lithologies of the Paris Basin were investigated to compare hydrologic behaviour in different types of soil. This paper shows results from both synthetic modelling as well as from measurements carried out over sands nearby Rambouillet. Further
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Fracture Characterisation Using the NA Inversion Algorithm on Synthetic GPR Signals
Authors C. Gregoire, M. Jeannin, M. Wathelet, S. Garambois and D. JongmansA028 FRACTURE CHARACTERISATION USING THE NA INVERSION ALGORITHM ON SYNTHETIC GPR SIGNALS Abstract 1 The geometry and properties of discontinuities are very important in the rock mass stability assessment. The GPR method which is able to yield information about the internal structure of resistive rocks was applied in extreme conditions to image sub-vertical cliffs. The profile interpretation allowed to locate several discontinuities whose characterisation required an analysis based on the frequency content of the radar reflection. The possibilities and the limitations of the reflectivity inversion were previously tested with a grid search within the parameter space. In this paper we
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GPR Measurements at the Site of a German Medieval Imperial Palatinate
More LessA029 GPR MEASUREMENTS AT THE SITE OF A GERMAN MEDIEVAL IMPERIAL PALATINATE SUMMARY 1 Measurements with the ground penetrating radar (GPR) are very useful in exploring archaeological sites. The main features are high resolution and fast data acquisition. In practice there are some problems which have to be overcome: low material contrast of the archaeological objects to the surrounding layers and strong reflective layers near the surface. Several processing steps are presented and discussed which were chosen to improve the signal to noise ratio. The results could be tested because parts of the area had been excavated several years ago
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Fast Imaging of a Romano-Celtic Temple with a Decimetric Resolution – 1 Ha in 2 Hours?
More LessA030 FAST IMAGING OF A ROMANO-CELTIC TEMPLE WITH A DECIMETRIC RESOLUTION – 1 HA IN 2 HOURS ? Abstract 1 Archaeological exploration of buried targets with non destructive techniques is becoming more and more important but has to face a specific problem of spatial resolution: most of our heritage is buried in the first meter below the ground surface and in order to obtain a good resolution of images we need a ground resolution of the order of several decimetres. Exploration of areas of more than several hectares with this resolution need lot of time and money and is not
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Rapid and Precise Archaeogeophysical Survey Using a Multi-Sensor Platform (MSP)
Authors I.A. Hill and N. LinfordA031 RAPID AND PRECISE ARCHAEOGEOPHYSICAL SURVEY USING A MULTI-SENSOR PLATFORM (MSP) Abstract 1 I. A. HILL 1 AND N.LINFORD 2 1 Department of Geology University of Leicester Leicester LE1 7RH UK. Email: [email protected] 2 English Heritage Centre for Archaeology Fort Cumberland Fort Cumberland Road Eastney Portsmouth PO4 9LD UK Email: [email protected] Archaeogeophysical surveys are established as vital tools for archaeological investigations. The target physical property contrasts are often small and the anomalies subtle. Magnetic surveys are perhaps the epitome of these surveys where the anomalies sought are only a few nannoteslas in amplitude and of the order of a metre
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MULTISENSOR - A Mobile Geophysical Multi-Sensor System for Archaeological Prospecting
Authors S. Woelz, E. Erkul, W. Rabbel and H. StümpelA032 MULTISENSOR – A MOBILE GEOPHYSICAL MULTI-SENSOR SYSTEM FOR ARCHAEOLOGICAL PROSPECTING Summary 1 We show first results of a new highly mobile multi-sensor system for archaeological prospecting. It has been developed for the geophysical investigation of large kilometer-scale antique settlement areas with high resolution in an economic way. The system comprises a four-wheel drive tractor and a trailer carrying magnetic electro-magnetic and ground penetrating radar sensors. Positioning is performed online using differential GPS. Introduction: New demands for archaeological prospecting E. ERKUL W. RABBEL H. STÜMPEL AND S. WOELZ Institute of Geosciences Geophysics Kiel University Otto-Hahn-Platz 1 24118 Kiel Germany In
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Integrated Inversion of CVES and TEM Data Using Lateral Constraints
Authors A.V. Christiansen, N. Foged, E. Auken and K.I. SørensenA033 INTEGRATED INVERSION OF CVES AND TEM DATA USING LATERAL CONSTRAINTS Summary 1 We present a mutually and laterally constrained inversion between transient electromagnetic (TEM) and geoelectric (DC) data sets. Although both methods measure in some sense the electrical resistivity or conductivity of the subsurface they sample different volumes and have different sensitivities. The different sampling volumes and different sensitivities are exploited by the mutually and laterally constrained inversion algorithm combining the coinciding profile data sets. The output model incorporates the information from both profile data sets to obtain the optimum layered 1D models fitting both data types. All data
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Joint Inversion of TEM and DC Soundings
Authors P.O. Barsukov, E.B. Fainberg and E.O. KhabenskyA034 JOINT INVERSION OF TEM AND DC SOUNDINGS Abstract 1 P.O. BARSUKOV E.B. FAINBERG AND E.O. KHABENSKY Institute of Physics of the Earth RAS Troitsk branch 142190 Troitsk PO Box 30 Moscow region Russia It is well known that DC (direct current) soundings are very sensitive to resistive layers and structures imbedded in section and insensitive to conductive layers. On the contrary TEM (transient electromagnetic method) is sensitive to conductive layers and insensitive to resistive ones. The real paper describes the way of joint inversion both DC and TEM data in 1D class of layered sections providing construction of a
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Interpretation of a Hydrogeophysical Survey – Data from the High-Resolution SkyTEM System
Authors K.I. Sørensen, B. Sørensen, A.V. Christiansen and E. AukenA035 INTERPRETATION OF A HYDROGEOPHYSICAL SURVEY – DATA FROM THE HIGH- RESOLUTION SKYTEM SYSTEM Abstract 1 During the last decade approximately 50 000 ground-based TEM soundings have been carried out in Denmark for groundwater investigations. This number will increase in the future and therefore we have developed a new time-domain electromagnetic (TEM) helicopter system SkyTEM. In the development and design of the SkyTEM system it has been an unchangeable demand that the data quality of the SkyTEM system should be the same or better than the data quality of ground-based systems e.g. the Protem 47 system (40 x 40 m
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Constrained Inversion of Helicopterborne EM Data
By H. ThunehedA036 CONSTRAINED INVERSION OF HELICOPTERBORNE EM DATA Summary 1 Helicopterborne EM data from two surveys in Sweden have been inverted into two-layered models. The surveys were carried out in areas of resistive crystalline rock. The leveling of the data was aided by geophysical measurements on the ground. Ground truth information was also used as constraints during inversion. The data was treated in a regular grid over the survey area and a two-layer model for each grid node was produced. These models were stitched together to give a continuos description of the bedrock resistivity and the soil cover resistivity and thickness
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Empirical Inversion of HEM Data for Sea Ice Thickness Mapping
Authors A. Pfaffling, C. Haas and J.E. ReidA037 EMPIRICAL INVERSION OF HEM DATA FOR SEA ICE THICKNESS MAPPING Summary 1 Since 2001 the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven (AWI) has operated a purpose built unique HEM system to map sea ice thickness in the Arctic and Antarctic. To determine the sea ice thickness from the measured EM field we use an empirical curve fitting approach. The master curve is tuned for every flight leg using measurements over open water between the ice floes in leads or polynyas. The level ice thickness which is a key value for sea ice science and climate
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Magneto-Electric Mapping of 3D Electrical Conductivity Distributions – System Design and Resolution Analysis
Authors A. Verweerd, A. Tillmann, E. Zimmermann, A. Kemna and H. VereeckenA038 MAGNETO-ELECTRIC MAPPING OF 3D ELECTRICAL CONDUCTIVITY DISTRIBUTIONS – SYSTEM DESIGN AND RESOLUTION ANALYSIS Abstract 1 In order to map the electrical conductivity distribution in cylindrical soil columns a combined measurement of the electric potential and the three magnetic field components due to a low frequency current injection is proposed. The magnetic field is measured by means of a vertical moving scanning torus with 24 sensor modules capable of measuring in a range of 200 nT with a resolution of 50 pT without the use of extensive magnetic shielding. Numerical simulations prove the additional value of the magnetic dataset when
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Moisture Dynamics in Urban Soils with High Resolution Geoelectrics
Authors M. Müller, O. Mohnke, J. Schmalholz and U. YaramanciB001 MOISTURE DYNAMICS IN URBAN SOILS WITH HIGH RESOLUTION GEOELECTRICS Introduction 1 Urban soils are subject to strong variations of environmental conditions like in water flow solute transport or heat budget. The research project INTERURBAN has been formed to investigate the dynamics of water and solutes at urban locations with particular attention to the spatial heterogeneity the organic soil substance and soil-biological transformation processes in the unsaturated zone. The objectives of INTERURBAN define also the tasks for geophysics: The development of a noninvasive conception to map water distribution water dynamics and important physical parameters on small scales. Approaches to adopt
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Streaming Potentials Associated with Well-Pumping – Analogical and in Situ Results
By F.A. GassB002 STREAMING POTENTIALS ASSOCIATED WITH WELL-PUMPING – ANALOGICAL AND IN SITU RESULTS Summary 1 Water flowing in a porous media causes natural electrical currents called streaming potentials. Thus during pumping the inflow of water to the well causes a positive potential anomaly above the well. Analogical experiments in a tank during well-pumping show that the piezometric surface acts as a dipolar electrical source. Furthermore measurements of the streaming potentials before during and after pumping show that they are linearly dependent of the variation of the water level thus allowing calculation of the coupling coefficient around the well. This opens some
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The Effect of Changing the Salinity of the Groundwater on SIP of Sandstones
Authors A. Weller, J. Scott, N. Schleifer and R. BarkerB003 THE EFFECT OF CHANGING THE SALINITY OF THE GROUNDWATER ON SIP OF SANDSTONES SUMMARY 1 Previous work between the University of Birmingham and Technical University Clausthal examined the basic shape of the complex conductivity spectra of sandstones saturated with a synthetic groundwater solution and compared the two different laboratory measurement procedures. It is known that the Spectral Induced Polarisation (SIP) is also dependent upon the pore fluid so we examined the effect of two different salinity groundwaters on the SIP response. The changes caused by decreasing the salinity of the groundwater varied widely for different sandstones with both increasing
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Hydrogeophysical Study at an Olive Farm, S. Italy
Authors R. Meissner, S.A. al Hagrey and A. IsmaeilB004 HYDROGEOPHYSICAL STUDY AT AN OLIVE FARM S. ITALY Summary 1 We present results of hydrogeophysical experiments at an olive farm with calcareous soils at Canosa S. Italy. Geoelectric subsurface models down to 8 m depth display the main waterfed layer for trees. In infiltration experiments hydroelectrical monitoring images the water penetration into soils in 2D and 3D. From diverse petrophysical (insitu and lab) analyses on soil samples we could establish a reliable empirical resistivity-water content relationship similar to that of Archie. This was applied to derive pore water distributions from electric models. We could find that diverse biological und
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High-Resolution Echo-Sounding and Estimation of Sediment Properties Using Nonlinear Acoustics
Authors J. Wunderlich and G. WendtB005 HIGH-RESOLUTION ECHO-SOUNDING AND ESTIMATION OF SEDIMENT PROPERTIES USING NONLINEAR ACOUSTICS Abstract 1 There are a lot of advantages using nonlinear echo sounders compared to linear ones in particular in shallow water areas. An important problem in sediment acoustics is to determine the thickness of sediment layers. If the sound velocity is known the thickness can be calculated from the travel times. Nonlinear acoustics combined with principles of refraction seismic allow to estimate the sound velocity of selected sediment layers. Nonlinear acoustics has also advantages while obtaining frequency dependent sediment properties like attenuation coefficients. Nonlinear Acoustics JENS WUNDERLICH and GERT
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Two Acoustic Methods for Classification of Near-Surface Sediments
Authors C.S. Mesdag, P.T.J. Kok, R. Romijn, G. Blacquiere, M. Snellen and D.G. SimonsB006 TWO ACOUSTIC METHODS FOR CLASSIFICATION OF NEAR-SURFACE SEDIMENTS Abstract 1 C. S. MESDAG 1 P. KOK 1 R. ROMIJN 2 G. BLACQUIERE 2 M. SNELLEN 3 and D. G. SIMONS 3 4 1 TNO NITG Netherlands Institute for Applied Geoscience Princetonlaan 6 3508 TA Utrecht The Netherlands The Dutch Ministry of Transport Public Works and Water Management North Sea Directorate (RWS-DNZ) is investigating the amount of extractable coarse sand within the upper 100 m sediment in the Dutch part of the North Sea. Coarse sand is needed for the concrete and mortar industry. The method used to date is
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Shallow Gas in the Baltic Sea from a VHR 2.5-D Seismic View
By C. MüllerB007 SHALLOW GAS IN THE BALTIC SEA FROM A VHR 2.5-D SEISMIC VIEW 1 C. MÜLLER Inst. for Geosciences Dep. of Geophysics Kiel-University Otto-Hahn-Platz 1 24118 Kiel Germany Summary This case history demonstrates the feasibility of acquiring processing and interpreting a shallow marine very high resolution 2.5-D seismic cube. A simple processing sequence (“brute stack cube”) based on only nominal knowledge about acquisition geometry revealed complex small scale geological strucutres on time slices and by interpretation. An extensive shallow gas field hosted in Holocene unconsolidated sediments is mapped Site location and acquisition concept In the Northern German Basin salt tectonics
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Integrated Repetitive Multibeam Bathymetry and Geophysical Surveys of an Offshore Disposal Site
Authors D.R. Parrott, M.B. Parsons, M.Z. Li, V. Kostylev, J.E. Hughes Clarke, A. Duxfield and K.-L. TayB008 INTEGRATED REPETITIVE MULTIBEAM BATHYMETRY AND GEOPHYSICAL SURVEYS OF AN OFFSHORE DISPOSAL SITE Abstract 1 D.R. PARROTT 1 M.B. PARSONS 1 M.Z. LI 1 V. KOSTYLEV 1 J.E. HUGHES CLARKE 2 A. DUXFIELD 2 K-L. TAY 3 The Black Point Ocean Disposal Site has received material dredged from shipping channels and near wharves in Saint John Harbour New Brunswick Canada for over 50 years. The disposal site is located at an exposed position in the harbour approaches where it is affected by strong currents 8 metre high tides and waves from winter storms (Fig. 1). Disposal activities had resulted in
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Applying Seismic Traveltime Tomography in the Exploration of the Foundations of a Byzantine Church
Authors L. Polymenakos and S. PapamarinopoulosB009 APPLYING SEISMIC TRAVELTIME TOMOGRAPHY IN THE EXPLORATION OF THE FOUNDATIONS OF A BYZANTINE CHURCH Abstract 1 This paper discusses the application of seismic traveltime tomography as employed to the exploration of the foundation structure and ground material of a Byzantine church. Byzantine churches are monuments of high historical cultural and artistic value. Moreover they are often important engineering and architectural constructions. Their preservation presents special concerns since it has to cope with specific building and foundation conditions. The investigation of the foundations of these buildings is of great interest since it can provide important information both on subsurface conditions
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High-Resolution Electrical Resistivity Imaging at a Former Industrial Furnace Site, PA, USA
Authors B. Kulessa, S. Haney, P. McCarthy and B. ChiarulliB010 HIGH-RESOLUTION ELECTRICAL RESISTIVITY IMAGING AT A FORMER INDUSTRIAL FURNACE SITE PA USA INTRODUCTION 1 This paper investigates the scope of high-resolution electrical resistivity imaging in resolving man-made and now buried structures at the Shade iron furnace in Co. Somerset Pennsylvania USA. Iron furnaces were widespread in Colonial America between the 17 th and 19 th centuries with 35 such sites currently being registered as historical monuments in Pennsylvania alone. Since many of these sites are aerially extensive reconstruction of former furnace operation presents a considerable challenge to traditional methods of archaeological surveying. Additional application of geophysical methods at the
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Modelling the Meagnetic Field Gradient for Archaeological Structures in Saqqara (Egypt)
Authors A. El-Bassiony and A. WellerB011 MODELLING THE MEAGNETIC FIELD GRADIENT FOR ARCHAEOLOGICAL STRUCTURES IN SAQQARA (EGYPT) SUMMARY 1 The magnetic prospection for archaeological structures in the northern cemetery of Saqqara (Egypt) was carried out with a fluxgate gradiometer. The magnetic image showed an outline of a large tomb complex. An algorithm was developed to model the vertical gradient of the vertical component of the magnetic field for spherical units located at arbitrary locations and depths. We tried to simulate the archaeological structures with spheres of different sizes depths and lateral offsets using the potential equation of a sphere with a volume of an enclosing
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Radar and Electrical Resistivity Data Comparison at Izmir Agora, Turkey
Authors M. Martinaud, R. Chapoulie and M.G. DrahorB012 RADAR AND ELECTRICAL RESISTIVITY DATA COMPARISON AT IZMIR AGORA TURKEY INTRODUCTION 1 Along the seaside of the Anatolian continent at Izmir in Turkey are the vestiges of the ancient agora. As to give back to this agora its archaeological interest and some tourist attraction an important project has been set out. Within this framework an integrated prospection of the present courtyard of the agora has been performed. This study was a part of a more extensive geophysical investigation concerning the inner part and the outer part of the agora i.e. the neighbouring streets of the town. SITE DESCRIPTION The
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