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Near Surface 2005 - 11th European Meeting of Environmental and Engineering Geophysics
- Conference date: 04 Sep 2005 - 07 Sep 2005
- Location: Palermo, Italy
- Published: 04 September 2005
81 - 100 of 180 results
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Numerical Modeling of Magnetic Resonance Signal from Water-Filled Cavities
Authors J.-F. Girard, M. Boucher, A. Legchenko and J.-M. BaltassatB037 Numerical Modeling of Magnetic Resonance Signal from water-filled Cavities Summary 1 For the Magnetic Resonance Sounding method (MRS) a water-filled karstic cavity is a typical example of 2D/3D target. For practical purposes these cavities should be localized with very high accuracy. However due to a strong dependence on the geomagnetic field MRS performance is in turn dependent on the geographical location of investigated area. Efficiency of actually available MRS system with coincident transmitting/receiving loop applied to localization of 2D/3D structures with a size smaller than MRS loop size was studied numerically. It was shown that MRS results are sensitive
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Groundwater Inspection in Coastal Aquifers Using MT and AMT Methods
Authors M. Di Mauro, A. Manzella, G. Ranieri, G.P. Deidda and A. CasasB038 Groundwater Inspection in coastal aquifers using MT and AMT Methods Summary 1 In the framework of the SWIMED Salt Water Intrusion European Project the coastal aquifers of Muravera south-western Sardinia have been studied. Intensive agricultural and tourist activities have exploited these aquifers in the past. Since few years a salt-water intrusion happens mainly caused by a recurring lasting drought by aquaculture system and by intensive rice growing. Geophysical studies performed in past in the same area showed deep geological structures and placed questions about 300 meters deep groundwater conditions. In Muravera plain Gravimetric Seismic and TDEM Electromagnetic surveys have
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River-Bottom DC Resistivity for 3-D Imaging in Seoul Subway Tunnel Site
More LessB039 RIVER-BOTTOM DC RESISTIVITY FOR 3-D IMAGING IN SEOUL SUBWAY TUNNEL SITE Abstract 1 For site investigation related to planning Seoul subway tunnel construction river-bottom dipole-dipole resistivity survey was conducted in Han-River. In this case we need more precise subsurface information compared with bridge or mountain tunnel construction. We designed high density 3-D water-bottom resistivity exploration. In addition gradient cesium magnetic survey with DGPS-RTK boat system was also conducted. Before field survey we tried several numerical modeling to test the ability to detect two hidden parallel fracture in the 100Ωm rock body. The 3-D resistivity inversion results showed clear low
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High-Resolution Acoustical Site Exploration in Very Shallow Water – A Case Study
Authors J. Wunderlich, S. Müller, S. Erdmann, P. Huembs, T. Buch and R. EndlerB040 High-Resolution Acoustical Site Exploration in Very Shallow Water – A Case Study Abstract 1 Sub-bottom profiling in very shallow water areas is difficult by using conventional equipment. Sonar systems based on nonlinear acoustics offer many advantages: They have a narrow beam in spite of small transducers and virtually no side lobes. It is possible to realize mobile low-frequent sub-bottom profilers which transmit very short sound pulses. Excellent vertical as well as horizontal resolutions at reasonable penetrations are proven benefits by using this technique. In this paper results from a field trial are presented to illustrate the successful application of
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A Mathematical Basis for an Algorithm for the Modeling of Electrokinetic Sounding Data and Interpretation
Authors V. Hallbauer-Zadorozhnaya, E. Stettler and M. Haugerpressure by time then we convolve the two functions: transient pressure of the delta function by time and displacements of particles of sediments Finally we convolve the obtained results and the transient pressure of the delta function by the pore length. The process of transient of pressure in pore when a step function of pressure is applied to the beginning of that pore was described by Chandler (1981) as: ⎡ ∞ 1 2 1 ⎛πnl ⎞ ⎛ n π C t ⎞⎤ P l t) = P ⎢1 − − ∑ sin⎜ ⎟ ⋅ exp ⎥ = P ⋅ ⎢⎣
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GPR Mapping of a Dissolved Metals Plume Inside an Old Dyeing Plant at Leuze – Belgium
Authors J. Deceuster and O. KaufmannB042 Abstract 1 A two antennas (250 and 500 MHz) constant offset GPR field experiment was conducted on an industrial waste land (an old dyeing plant) to evaluate the technique potential in locating underground storage tanks (expected to be sources of a soil and water contamination by dissolved metals). Data were acquired along 52 parallel profiles inside the main hangar. 2Dsections analyses show areas with many diffractions and gaps. They also pointed out a zone of higher attenuation of the signal linked with higher soil conductivities probably due to the presence of dissolved metals. Finally 3 rectangular structures were showed
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Model Experiments Using AC for the Electrical Detection of Leaks in Landfill Liners
Authors R.F. King, D.H. Griffiths and P.R. AtkinsB043 Model experiments using AC for the electrical detection of leaks in landfill liners 1 Before a landfill site is brought into use it is necessary to check the liner for leaks which show as conductive paths through it and so can be detected by an electrical survey of the pattern of current flow in the thin layer of damp sand above the liner between a current electrode in this layer and one below the liner outside the site. This paper explores the use of AC for such a survey using an electrical network a laboratory model and a miniature
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Induced Polarization Measurements Applied to Irrigation Canals Freshwater Seepage Detection
Authors A. Viezzoli and J.P. CullB044 Z-99 Induced Polarization measurements applied to irrigation canals freshwater seepage detection Summary 1 Near Surface 2005 — Palermo Italy 4 - 7 September 2005 AUTHOR ANDREA VIEZZOLI* JAMES P. CULL Address *Monash University School of Geosciences Wellington Road Clayton 3800 VIC Australia IP data can be easily acquired during a standard galvanic survey on superficial fresh-watercourses. Standard and normalized IP parameters together with conductivity data greatly help the interpretation of the hydrology of the area below the watercourse bed. They are especially useful when variations in lithology and hydrology are concurrent. The few conductivity and IP cross-sections here presented
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Pre-Reclamation Geophysical Test Surveys on a Municipal Solid Waste Landfill
Authors R. Balia, M. Bianco, B. Littarru and G. RanieriB045 PRE-RECLAMATION GEOPHYSICAL TEST SURVEYS ON A MUNICIPAL SOLID WASTE LANDFILL 1 Summary In the framework of the surveys aimed at characterizing an old municipal solid waste landfill prior to its reclamation we carried out gravity both refraction and reflection P-wave seismic and electrical resistivity measurements along one test profile. Apart from the seismic refraction and the electrical resistivity methods rather commonly used for landfill detection and assessment interesting results were obtained from gravity and shallow reflection not so widely used for this kind of application. Gravity was useful at least for delineating the horizontal extent of the landfill while
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An AEM Survey of a Leaking Landfill
By D. BeamishB046 Z-99 AN AEM SURVEY OF A LEAKING LANDFILL 1 Abstract This study presents results obtained from a remarkably small-scale helicopter airborne electromagnetic (AEM) survey of a closed landfill. The landfill occupying a former quarry is situated among shallow worked-out coal seams (pillar and stall workings) and was located over at least two mineshafts that occupied the quarry floor. The landfill was known to be leaking from an extensive borehole investigation that took place in the 1970’s when the landfill was active. Redevelopment issues and associated proposed surface extraction of coals have renewed interest in the possible pollution threat of
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Imaging Seawater Intrusion in Coastal Aquifers with Electrical Resistivity Tomography – Initial Results from the Lower Andarax Delta, SE Spain
Authors O. Kuras, P.I. Meldrum, R.D. Ogilvy, J. Gisbert, S. Jorreto and F. Sánchez MartosB047 IMAGING SEAWATER INTRUSION IN COASTAL AQUIFERS WITH ELECTRICAL RESISTIVITY TOMOGRAPHY: INITIAL RESULTS FROM THE LOWER ANDARAX DELTA SE SPAIN Introduction 1 O. KURAS 1 P. I. MELDRUM 1 R. D. OGILVY 1 J. GISBERT 2 S. JORRETO 2 F. SÁNCHEZ MARTOS 2 1 British Geological Survey Electrical Tomography Programme Keyworth Nottingham NG12 5GG United Kingdom 2 Department of Hydrogeology University of Almería Spain The Lower Andarax river basin in the Andalucía region of southeast Spain is an alluvial valley of about 250 km 2 situated in one of the most arid regions in Europe. Its infrequent and irregular precipitation
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Characterization of Unconsolidated Coastal Aquifers with Magnetic Resonance and Electrical Soundings
Authors J.M. Vouillamoz, B. Chatenoux, F. Mathieu, J.M. Baltassat and A. LegchenkoB048 Characterization of unconsolidated coastal aquifers with Magnetic Resonance and Electrical Soundings Abstract 1 VOUILLAMOZ J.M. 1 2 CHATENOUX B. 2 MATHIEU F. 3 BALTASSAT J.M. 3 LEGCHENKO A. 1 1 IRD LTHE BP53 38041 Grenoble Cedex9 [email protected] 2 Action contre la Faim 4 rue Niepce 75014 Paris. 3 BRGM BP 6009 45060 Orléans Cedex France Summary Unconsolidated coastal aquifers can be characterized using surface geophysical methods. In presence of salty water use of electrical resistivity methods makes the reservoir identification difficult. It was demonstrated by field example that electromagnetic (EM) or direct current (DC) methods and Magnetic Resonance Soundings
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Geophysical Assesment of Water Dynamics in Urban Soils – Interurban
Authors J. Schmalholz, M. Müller, O. Mohnke and U. YaramanciB049 Z-99 GEOPHYSICAL ASSESSMENT OF WATER DYNAMICS IN URBAN SOILS - INTERURBAN Abstract 1 Near Surface 2005 — Palermo Italy 4 - 7 September 2005 AUTHORS M. MÜLLER O. MOHNKE J. SCHMALHOLZ AND U. YARAMANCI Dept. of Applied Geophysics Technical University of Berlin Ackerstr. 71-76 13355 Berlin Germany E-mail: [email protected] www.interurban.de In order to monitor long and short term changes of the electrical resistivity due to soil moisture variations two permanent electrode in-line arrays were installed. Each array consists of 50 electrodes with an electrode spacing of 0.2 m. We started to monitor long term dynamics of the electrical resistivity
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3D-Imaging of Shallow Fractured Aquifers along the Scansano-Amiata Ridge (Tuscany, Italy)
Authors R. Francese, A. Bistacchi, F. Mazzarini, G. Morelli, H. Robain, N. Wardell and A. ZajaB050 Z-99 3D-Imaging of shallow fractured aquifers along the Scansano-Amiata ridge (Tuscany Italy) Summary 1 ANDREA BISTACCHI 1 ROBERTO FRANCESE 2 FRANCESCO MAZZARINI 3 4 GIANFRANCO MORELLI 5 HENRY ROBAIN 6 NIGEL WARDELL 2 AND ANNALISA ZAJA 7 1 Dipartimento di Geologia e Geotecnologia Universita’ di Milano Bicocca – Milano Italy 2 Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS – Sgonico (Trieste) Italy 3 Istituto Nazionale di Geofisica e Vulcanologia INGV Pisa section – Pisa Italy 4 Istituto di Geoscienze e Georisorse Consiglio Nazionale delle Ricerche CNR – Pisa Italy A series of high-resolution geophysical surveys including 3D
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Geophysical Investigations for Evaluating Water Storage Potential on Agricultural Soils
Authors G. Kurz, M. Müller and U. YaramanciB051 Geophysical investigations for evaluating water storage potential on agricultural soils INTRODUCTION 1 The knowledge of the soil water retention is one basis for developing flood protection concepts. The research objectives of this project are: Investigation of the water retention (storage) potential of agricultural soils examining the hydraulic conductivity and the noninvasive determination of the near-surface water content (down to 3 m). For flood preventation a decrease of the surface drain rate and therefore a decrease of the erosion should be achieved. The known methods in soil physics to determine the water retention potential are timeconsuming and expensive and they
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Two Dimensional Electrical Imaging of Quaternary Aquifer at Wadi Muraykhat and Wadi Sa’a, Al Ain Area, UAE
Authors A. El Mahmoudi and A. GabrB052 TWO DIMENSIONAL ELECTRICAL IMAGING OF QUATERNARY AQUIFER AT WADI MURAYKHAT AND WADI SA’A AL AIN AREA UAE. Abstract 1 Wadi Muraykhat and Wadi Sa’a are of the main tributaries crossing east of Al Jaww Plain Al Ain area UAE. These wadies originate from the Oman Mountains range and form the catchment and feeding area of the water resources. From the hydrogeological point of view subsurface investigation of these wadis is very important for better understanding of the aquifer system water flow water quality and management of water pumping. Two-dimensional (2-D) electrical tomography survey has been implemented. Eleven (2-D) profiles
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Imaging Structure Using AMT for Hydrological Modelling in the Western USA
Authors L. Pellerin, D.K. McPhee, B. Chuchel and G.L. DixonB053 Imaging structure using AMT for hydrological modelling in the western USA Summary 1 Inversion of audiomagnetotelluric (AMT) sounding data collected in Spring Valley Nevada USA shows significant two-dimensional (2D) structure within the upper kilometre of the valley and helps define the shallow basement surface. The depth-to-basement profile provided by the AMT inversion is in good agreement with an independent determination made from gravity measurements. The survey was conducted as a test to determine the applicability of the AMT method to mapping basin structure to depths of 1 km or more. The results exceeded expectation and future surveys are planned
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Observation of Shear-Wave Splitting in Quaternary Sediments of the New Madrid Seismic Zone (Central USA) – An Indicator of In-Situ Stress Conditions?
By J.B. HarrisC001 OBSERVATION OF SHEAR-WAVE SPLITTING IN QUATERNARY SEDIMENTS OF THE NEW MADRID SEISMIC ZONE (CENTRAL USA): AN INDICATOR OF IN-SITU STRESS CONDITIONS? 1 Introduction Investigating the relationship between seismicity and geologic deformation in the New Madrid seismic zone (NMSZ) the most active earthquake zone east of the Rocky Mountains is one of the most essential areas of earthquake hazards research in the central United States. Evaluating the near-surface continuation of basement faults in the region is limited by the inability of the unconsolidated Quaternary sediments to propagate large coherent fractures making evaluation of the near-surface stress field and associated structural
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Frequency Domain Analyses of TDR Waveforms for Soil Moisture Measurements
Authors C.-P. Lin, C.-C. Chung and S.-H. TangC002 FREQUENCY DOMAIN ANALYSES OF TDR Abstract WAVEFORMS FOR SOIL MOISTURE MEASUREMENTS 1 When time domain reflectometry (TDR) is applied to the field characterization of soil moisture the waveforms have typically been analyzed using traveltime along the waveguide. The apparent dielectric constant (Ka) traditionally determined by the traveltime analysis using a tangent-line method does not have a clear physical meaning and is influenced by several system and material parameters. The frequency domain analysis however can determine the actual frequency-dependent dielectric permittivity and can be performed using a very short probe. The primary objectives of this paper are to (1) examine
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Use of Numerical Simulations to Explain SASW Field Measurements
Authors A. Nasseri-Moghaddam, C. Phillips, G. Cascante and J. HutchinsonC003 USE OF NUMERICAL SIMULATIONS TO EXPLAIN SASW FIELD MEASUREMENTS Abstract 1 ALI NASSERI-MOGHADDAM UNIVERSITY OF WATERLOO Summary This study uses numerical models to explain the results of two MASW field tests in the presence of a void. The Fourier spectra of the field data contain a region with high energy concentration in the proximity of the void. Numerical models are constructed and the responses at the surface of the medium and around voids of different sizes and embedded depths are monitored. The numerical results show that part of the incident energy is trapped in the void region. The trapped
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