- Home
- Conferences
- Conference Proceedings
- Conferences
9th EAGE/EEGS Meeting
- Conference date: 31 Aug 2003 - 04 Sep 2003
- Location: Prague, Czech Republic
- ISBN: 978-94-6282-116-3
- Published: 01 September 2003
61 - 80 of 180 results
-
-
Deep layered structure investigation with multielectrode methods
Authors R. Hoffmann and P. DietrichDirect current geoelectrical measurements since several decades are used to investigate geological structures. With the rapid development of computer hard- and software and the advances made in the field of the measurment technology, multielectrode measurements have for many applications replaced the conventional four electrode equipment. 2D and 3D inversion software allows to invert large data sets. But, while lateral structures are usually well resolved, the interpretation of data sets over rather horizontally layered structures often fails-even falling back behind the achievements of a 1D investigation.
-
-
-
Geophysical assessment of groundwater protective layers
Authors R. Heinse and P. SchikowskyGroundwater protective layers covering the groundwater table play a crucial role in protecting groundwater from infiltrating contaminants. The protection depends heavily on the structure and texture of the groundwater covering layers. Sandy layers with low thickness will lead to a fast infiltration of contaminants whereas silty and clayey layers - because of their low hydraulic conductivity -have a higher protective potential.
-
-
-
Hydrogeological aspects of the helicopter borne electromagnetic measurements in the area between Cuxhaven and Bremerhaven, Lower-Saxony, Germany
More LessDuring the years 2000 and 2001 the area between Cuxhaven and Bremerhaven (Figure 1) was covered by high resolution helicopter borne EM (HEM) measurements (Eberle & Siemon 2002, Gabriel et al. 2003). In this area a complex coastal aquifer system comprising Quaternary sediments and deeply incised Pleistocene subglacial valleys is partly endangered by saltwater intrusions. In order to study the hydrogeology of the region in detail several geophysical and hydrogeological measurements are carried out including e.g. reflexion seismics, SIP-(spectral induced polarisation) and VES-(vertical electrical soundings) measurements, investigation drilling, hydrochemistry, and isotope hydrology (Kessels et al. 2000).
-
-
-
Mapping buried glaciofluvial aquifer by airborne EM measurements - A case from Kyrönjoki valley in Southern Finland
Authors H. Vanhala, I. Suppula, P. Lintinen and J. LehtimäkiMany buried valleys contain important groundwater reservoirs. Buried deposits discussed in this paper are glaciofluvial eskers and ice-marginal deposits wvered with lacustrine and glacilacustrine clays and silts.
-
-
-
Characterization of coarse materials using geophysical methods
Authors E. Rey, S. Garambois, D. Jongmans and P. GottelandThis summary deals with geoelectrical properties of coarse soils such as till deposits, rubbleslopes, alluvial fans or debris flow deposits. This type of soils is frequently found in the mountains areas. The presence of decimetric, sometime metric, blocks in these deposits makes them diacult to characterize using classical geotechnical in-situ tests. Being non-inhusive, geophysical measurements affect important volumes, are always possible anti rather rapid to execute. In addition the linear geometry of this type of measurements is interesting for locating lateral variations of the deposits, very frequent in this type of grounds.
-
-
-
Porosity and water saturation degree from combined resistivity and seismic surveys for geotechnical site characterization
Authors R. Mota and F. M. dos SantosPorosity and water saturation degree are some of the physical parameters that are commonly estimated in site characterization studies by laboratory tests in selected samples from geotechnical soundings. This kind of procedure gives discrete results, is time consuming and needs heavy equipment.
-
-
-
Groundwater exploration by use of TEM, reflection seismic surveys and drillings
Authors F. Jørgensen, E. Auken, H. Lykke-Andersen and K. I. SørensenThe Danish water supply is decentralized and based on private, public and municipal water works. Increasing problems with groundwater quality caused by pesticides and nitrate contamination have in recent years forced the county administrations to search for new deepseated and unpolluted aquifers in large parts of Denmark.
-
-
-
Re-establishment of the subterranean canals using VES data inversion
Authors M. Mirzaei and M. YousefiradFor solving hydrogeological and environmental tasks, geoelectrical methods are routinely applied. One of their advantages is their inexpensiveness while another advantage is the high resolution in near surface exploration problems.
-
-
-
Time-lapse azimuthal apparent resistivity measurements for estimating fracture dilatency on the coastal cliff top
Authors J. Busby, M. Raines, L. Nelder, P. Jackson and D. MorganThe erosion of hard rock cliffs is inevitable and to-date it has been considered to be relatively unpredictable. A large proportion of the European coastline is subject to erosion and cliff recession. This dynamic process continually changes the hydrogeological and stress regimes, exposes fresh geological features and materials to changes in environment and stress.
-
-
-
Identification of fracture zones by a travel time-based diffusivity approach
Authors R. Brauchler and P. DietrichRecently the irnportance of understanding fractured aquifers is increasing particular with the relevance to the question of water resources development, groundwater contamination and the search of suitable nuclear waste deposits. For the analysis of engineering, geotechnical and hydrogeological questions is the knowledge about the spatial position of fractures of particular irnportance. Conventional aquifer investigation methods like pumping or slug tests lead to integral information averaged over a large volume. This kind of information is insufficient to develop groundwater models requiring detailed information about the spatial distribution of fractures. To circumvent this problem new investigation methods have to be developed.
-
-
-
Near surface karst structure imaging for hydrogeological inverstigation with the VLF gradient method
Authors F. P. Bosch and I. MüllerConsidering the properties of carbonate rocks and the resulting demands for water management, we can formulate some requirements that geophysical methods applied to karst structure detection need to fulfil.
-
-
-
Seismic velocity anisotropy - measurement and application
Authors J. Dohnal, J. Hrdá, Z. Jáne, R. Prikryl, J. Vilhelm, T. Lokajícek, Z. Pros and K. KlímaTo find out water resources in crystalline rocks or to clean up contaminants in fractured bedrock, hydrologists must know the location of hydraulically conductive fracture zones. Some information about these zones is often obtained with single-borehole hydraulic tests, cross-borehole hydraulic tests, and tracer tests.
-
-
-
Water exploration on small Croatian islands by electrical tomography and refraction seismics
Authors F. Sumanovac, Z. Pekas and T. VlahovicWater explorations were carried out at three Croatian islands: Susak, which belongs to Kvarner islands, Dugi otok and Molat, which belong to northem Dalmatian islands. These explorations were carried out in a framework of a large hydrogeological project of water explorations at numerous Croatian islands.
-
-
-
Development of a new electric conductivity sensor in order to characterize soil solute concentration
Authors C. Frippiat, A. Renard and A. E. HoleymanLaboratory solute transport investigation can be performed using a large panel of tools. On one hand, Same techniques as in the field, including geophysical ones, can be used. However, these are bulk techniques which give an overall image of the soil heterogeneities and of the plume extension.
-
-
-
The description of underground water movement using ERT survey
Authors A. Bratus and D. N. YabarThis is a case history of a pilot test which has been performed in the NE of Italy to detect and monitor the sub-surface behaviour of a salt-water solution within a sand-gravel aquifer. ERT (Earth Resistivity Tomography) was used. The experiment consisted in pumping a of saltwater solution - which presents a low resistivity value - into a well, in order to detect variations of resistivity vs. time during the flow of the solution within the aquifer.
-
-
-
Actual possibilities concerning the determination of groundwater flow with single well methods
Authors T. Feischl and F. KerschnerIn many hydrogeologic applications the determination and monitoring of groundwater flow parameters, especially groundwater seepage velocity and groundwater flow direction are an essential part regarding analyze of groundwater flow. This includes questions like water supply location, ground water plume characterization inter alia for contamination issues, landfill leachate characterization, inflow and outflow analysis, hazardous spill response and also environmental surrounding effects like tidal effects on groundwater aquifers. This paper gives an insight about the advantages and disadvantages of the traditional Multi-Well methods and the less time consuming but sometimes adulterated Single-Well methods. Further on another Single-Well method the Dark-Field-Sonde is introduced. Including field and laboratory tests of this tool in comparison to other methods during a benchmark test gives an impression about the reliability, and possibility of actual groundwater flow measurement.
-
-
-
Interurban - geophysical assessment of water dynamics and solute transport in urban soils
Authors M. Müller, O. Mohnke, J. Schmalholz and U. YaramanciUrban soils are subject to strong variations of environmental conditions, like water flow, solute transport or heat budget. The research project INTERURBAN has been formed to study the dynamics of water and materials at urban locations with special consideration of the spatial heterogeneity, the organic soil substance and soil-biological transformation processes. The objectives of the research group define the target for geophysics: The development of a noninvasive conception to map the water distribution and important structural parameters with high resolution. In addition to standard methods, like Geoelectrics and Ground Penetrating Radar (GPR), Spectral Induced Polarization (SIP) also Surface Nuclear Magnetic Resonance (SNMR) will be used. We have choosen two locations typical for urban soils: The Tiergarten (Berlin, Germany), a metropolitan park with intensive use by pedestrians, sportsmen and big events (Love Parade) and a former sewage farm in Buch at the outskirts of Berlin. The soil in Buch is highly contaminated by organic hydrocarbons and heavy metals. In this paper we show examples of the necessary methodological improvements for the application of high resolution shallow geophysics for high resolution assessment (see Muller et al., 2002).
-
-
-
Long-time monitoring of soil water content and apparent resistivity
By P. NovákThe apparent resistivity of soil is one of the most important parameters of shallow geoelectrical survey. Soil resistivity varies a lot in time and space. Soil resistivity depends on resistivity of soil framework, structure and volume of pore space and soil water content and mineralization.
-
-
-
Mathematical model of land subsidence above fluid-carrying reservoir adjacent to clay layer
Authors A. V. Kosterin and M. M. ToropovaIt has been known that fluid withdrawal from an underground reservoir adjacent from below to a water saturated clay layer can cause land subsidence running up several meters and extending over a considerable area [1 - 3]. The reservoir's decompression due to fluid withdrawal is accompanied by clay layer's compaction under the influence of rock mass weight and as a result water outflow from it into the reservoir. So, land subsidence in this case is governed mainly by clay layer compaction. In the present paper a mathematica] model of such process is proposed. Analytical expressions for pressure distribution, water outflow from clay layer into the reservoir and land subsidence were obtained. These expressions make it possible to analyze the change of their development rate. The connection between maximum subsidence and rheological parameters of clay layer were found in analytical form.
-