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1st EEGS Meeting
- Conference date: 25 Sep 1995 - 29 Sep 1995
- Location: Torino, Italy
- ISBN: 978-94-6282-129-3
- Published: 25 September 1995
1 - 100 of 142 results
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Applied Geophysics Code of Good Practice
More LessThere is a need for clients for the evaluation of geophysical servicing companies. The French companies, which untill too years ago did not possess any professional organization, have set a group to work in the direction of a better quality insurance geophysical service.
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Monitoring Creep Movements by Seismic Refraction
Authors I. Campagnoli and G. SantaratoThe Italian Apenninic area is a well known example of hydrogeological and landslide hazard, due to recent largely incoherent shallow formations like clay, sandstone, flysch. When artifacts must be built as roads, bridges, dams..., a very careful study of buried geology and lithological properties must be performed in advance, resorting to intensive geotechnical and geophysical surveys, to evaluate both geometry and mechanical properties of the shallowest formations.
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Monitoring a Landslide in Baiso by GPS Survey
Authors E. Baj and A. ColombettiThe extent to which landslides are monitored before and after the stabilisation work is limited by the high costs involved. Furthermore the more common measuring instrument, the inclinometer, is rendered useless when movement begins again and must therefore be replaced.
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Acoustic Emission and Landslide Investigation
By P. BlahaThe geoacoustic method is one of the less known geophysical methods. This method tracks natural elastic waves that are generated due to rock mass disturbances. The method is sometimes known in literature as "acoustic emissions" or the "rock noise method".
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Determination of Water Flow at the Base of a Large Landslide by Resistivity Methods
Authors A. Carbo‘Gorosabel and A. Casas PonsatiLarge Engineering works caused a 1.5 -m3- landslide on a valley slope. The material consist of coluvium: sand, silty sand overlying folded carbonifeous mudstones and sandstones. The slip plane underlies the coluvium where a clayey bed derived from the weathering of the basement favoured the landslide. The major movements are produced after raining periods. The objective is to figure out the slip plane location and the main water flow areas.
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GPR Investigations to Evaluate Geometric Features of Rock Slides and Bucklings in a Limestone Formation in Northern Italy
Authors S. E. Beaubien, F. Galadini, P. Tommasi and E. PettinelliIn recent years the application of ground penetrating radar (GPR) has been extended to a large number of geotechnical and engineering geology problems (see 5th Int. Conf on GPR, Kitchener, Canada 1995).
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VLF Measurements Applied to Landslide Investigations
Authors W. Stiefelhagen, I. Muller, H. Raetzo and O. LateltinVLF measurements are playing already some important role in the field of urineral exploration, waste deposit investigation and investigations of kanstic media. In more porous media the application of the VLF method seems to be more difficult. Nevertheless we tried to evaluate this method for the investigation of land slides in Switzerland. Surprisingly we could clearly identify some borders of the biggest recent land slide (Falli Hölli, Canton Fribourg) in Switzerland.
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Broad Band Complex Conductivity Tomography for Environmental Applications
Authors F. Borner, M. Gruhne, L. Halleux, A. Kampke, A. Weller, J. Kulenkampff and T. RichterThe properties of porous rock and soils , i.e. fluid flow permeability, sorptivity, fluid phase distribution and composition are of great interest in environmental site characterization and hydrogeological applications. Additionally, recent environmental research include the - representative determination of input parameters for groundwater and migration modelling, - noninvasive evaluation of the condition of the multiphase system subsurface - monitoring the remediation of contaminated groundwater and soil zones
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Limits of Surface Resistivity Methods in Determining Transient Parameters by Mathematical Modelling
Authors O. Mazac, I. Landa and W. E. KellyKnowledge of transient parameters (e.g., direction and velocity of groundwater or pollution flow, dispersive parameters) is necessary for analyzing pollution procesces in an aquifer. For determining the parameters, many traditional and well elaborated methods have been applied.
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Geoelectric Monitoring of a Tracer Experiment at Haslemoen, Norway, during the Winter of 1995
Authors M. Morris, O. B. Lile and J. S. RonningRecent studies have focused on the use of the geoelectrical method to monitor tracer experiments (Bevc and Morrison 1991, Karous 1993, White 1995). Geoelectrical monitoring is suggested as a replacement or as a supplement to traditional tracer experiments, which require taking actual samples of groundwater. The aim of tracer experiments is to determine hydrological parameters such as e.g. groundwater flow direction or velocity of flow.
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Detection of Contaminated Groundwater by Geoelectrical Methods
More LessHeavily contaminated groundwater usually contains quite large amount of dissolved salt. It can be expected that porous materials saturated with water of higher concentration can be characterized by lower electrical resistivity than those saturated with clean (fresh) water. Therefore different resistivity methods may be good indicators of contaminated groundwaters.
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Investigation and Simulation of Free Phase Hydrocarbon Subsurface Flaw
More LessProblems due to groundwater contamination by hydrocarbons emerged in the eighties in Hungary, similarly to the rest of the world. Contamination of subsurface water cannot be easily detected, delineation of a hydrocarbon pollution is an even more difficult task because complex problem encountered. To solve these we have to use many different methods and operations and we have to extend our scope to further disciplines and branches of science.
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Hydrocarbon Contamination around Soviet Military Bases
More LessIn the spring of 1990 the Hungarian and Soviet ministers of foreign affairs signed a protocol on the withdrawal of the Soviet troops from the territory of Hungary. According to this protocol the damage to the environment caused in almost 35 years could be assessed in 171 bases prior to the complete withdrawal. Methods of assessment were selected by a joint Hungarian-Soviet expert team.
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Electrical Effects of Pollutants in Earth Soils and Sedimentary Rocks
Authors G. Losito, M. Muschietti and A. TrovaThis work is the development of a laboratory study carried out during the last years to investigate pollution effects in sedimentary rocks. The used method is an extention of the geolelectrical method and is based on the spectral analisys of the output signals (Losito and Trova; 1981).
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Engineering Geophysics in the New German Governmental Area in the Centre of Berlin
Authors C. Gelbke, E. Raekers, B. Lehman and P. AlthausAfter reunification of Germany in 1989, the government decided that Berlin instead of Bonn will be the capital of Germany. Therefore new governmental buildings as well as underground road and railways shall be erected in the centre of Berlin until 1999. The specific area had to be surveyed with engineering geophysical and geotechnical methods. This was certainly the largest area for investigations with engineering geophysics in Germany, maybe in Europe (Fig 1 only shows half of the total surveyed area)
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Seismic Tomography in Shallow Geology
By P. BlahaTomography is a new method for processing the data obtained by radiography. Tomography has gradually found its way into the processing of geophysical measurements. The first tomographic applications were made for the processing of seismic measurements.
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Geotechnical Applications of Seismic Tomography: Case Histories
Authors E. Toros and L. HermannThe essence and the main advantage of tomographic methods are that they able to map the distribution of physical parameters inside a volume from the sequence of measurements performed on the perimeter of the domain.
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Preliminary Experiments with Radar Tomography for Civil Engineering
More LessPreliminary tests on laboratory models enable us to provide guidelines for traveltime ray tomography with G.P.R. applied to civil engineering problems, specifically to find voids in pillars, walls and structures. The width of the Fresnel zone and the source and receiver locations are the limits to resolution capabilities. For crosshole geometry a criterion to know resolution capabilities, based on detectable wavenumbers, is analytically derived.
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On Site Sonic Tomography Data Processing and Analysis for Dam Investigations
Authors P. Angeloni, G. Bettolo, S. Superbo and A. ZaninettiIn Italy, sonic methods (using elastic waves in the sonic frequency range) for monitoring dams have been in use for about 30 years, in the framework of ENEL's project regarding the systematic monitoring and restoring of old dams. The investigated dams are made of both reinforced concrete and masonry.
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Environmental and Structural Dynamic Monitoring Using High Dynamic Seismic Acquisition Systems
Authors P. Angeloni, G. Gardini, M. Mucciarelli and A. ZaninettiThe need for a wider and even more efficient monitoring for the safety of important civil works like dams has been a key element for stimulating the development and evolution of investigation methodologies and more and more sophisticated monitoring systems.
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The Application of Shear-Wave Reflection Seismics in Shallow Subsurface Investigations
Authors J. Brouwer, V. Nijhof and F. LuitenIn the past decades we have seen the introduction of shallow reflection seismic investigation techniques for application in engineering projects. Although some papers report the use of Shearwave techniques for engineering purposes (e.g. Suyama et al, 1987), the P-wave method has obviously been more attractive. P-wave seismics, however, suffer from a number of fundamental problems that cannot easily be solved: • the P-wave method only indirectly (through AVO) addresses the shear-strength of the soils whereas this parameter is usually of major interest in engineering projects; • within the depth-range of interest (< 50 m) the P-wave method is relatively insensitive to changes in lithology that are significant from an engineering point of view; • within the depth range of interest the P-wave data can be 'blurred' by weathering layer effects (multiples, attenuation, etc.) thus limiting recognition and interpretation of deeper information.
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Shear Wave Velocities of Campanian Tuffs (Southern Italy)
Authors F. M. Guadagno, R. Mele and C. NunziataShear wave velocities of Campanian tuffs were measured both in the laboratory (ultrasonic pulse and resonant column) and in the field (Rayleigh wave spectral analysis). It resulted that it is not sufficient to recognize the tuff basement for computing the site amplification effects, but the dynamic parameters have to be measured because of hardening variation and fracturing.
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Transient Electromagnetic Soundings Applied to Hydrogeology: Some Case Histories in Central Italy
Authors S. Floris, A. Menghini and G. PaganoThese short notes report the results we collected for over four years in geophysical investigations, applied to hydrogeology on various geologic situations in Central Italy, by timedomain electromagnetic method (TDEM). Detailed stratigraphic knowledges, by drillings, allowed a direct comparison with geophysical data.
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High Resolution Seismic Imaging of a Shallow Aquifer
Authors Z. Hajnal, C. D. Hooge and B. SchreinerTwo intersecting high resolution surveys, designed with the support of advanced modelling results, mapped shallow ground-water aquifers. The project was intended to determine optimal data acquisition and processing parameters to image fluids in shallow glacial till deposits. The survey not only imaged the expected target but recognized previously unknown stratigraphic variations within the aquifer. In addition, a study built on geophysical information was initiated to enhance a better understanding of the mechanical properties of till deposits. The test site for the investigation is located north of Saskatoon, Saskatchewan, Canada (Figure 1).
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Applicability of Shallow Cross-Well Tomography in Ground Water Investigations
Authors M. van Kempen, K. Roy-Chowdhurry and W. SpakmanGround water flow is known to be affected by presence of thin, impermeable clay layers. In an area near Ede in Holland, reflection seismics could not be used to detect continuity of such clay layers, due to the presence of a low velocity lid. The applicability of cross-well tomography to this situation was then investigated.
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TDEM Soundings for Locating Aquifers inside the Caldeira of Fogo Active Volcano, Cape Verde Islands
Authors M. Descloitres, M. Ritz and P. MourguesFogo is the highest island of the archipelago of Cape Verde situated 500 km west from Senegal (West Africa). It is an active volcano with a diameter of 27 km and geological outline can be describe as follow: in the beginring, a predominantly effusive vólcanic activity has formed the lower cone overlying a carbonatitic basement.
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Dilution Technique in the Logging Variant: State of the Art
More LessIn an aquifer with confined as well as unconfined groundwater level, the movement of groundwater is usually observed in the direction of the hydraulic gradient. This movement can be described quantitatively by a vector of the filtration velocity Vf with a prevailing horizontal or subhorizontal component, which can be determined reliably in a well penetrating the aquifer.
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Contribution of Geophysical Well-Logging Techniques to Evaluation of Water Resources
More LessCarrying out borehole geophysics measurements applicable to ground-water studies repeatedly in time we can monitore both the dynamics regime of underground water and technical parameters of the borehole. Geophysical logs can be reinterpreted in a post mortem investigation of some geologic or hydrologic factor that was not considered while the hole was being drilled.
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Fluid Logging: the Dilution Technique
Authors D. Chapellier, V. D. Le, A. Re, V. Iliceto and S. MaresRecourse to timed borehole fluid logging after tracer tests (dilution technique) makes it possible to determine, in a mathematical manner, the flow rate and filtration speed up to values of 10-5 m/sec in the case of an induced or natural flow. It also makes possible the continuous recording of variations in these parameters according to the depth. With the help of a tracer, usually NaCI, the variation over time of the electrolytic borehole fluid is studied.
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Maximum Likelihood Object Location Employing Magnetometer and Radar Surface Data
Authors I. Johansen and L. J. GeliusEnvironmental projects concerning site characterization or remediation may also include the problem of locating known objects such as buried drums, unexploaded ordnances, etc.
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Prediction of Rock Temperatures and Water lnflow Zones in Deep Tunnels
Authors A. Busslinger and L. RybachIn deep tunnelling/mining the knowledge of in-site rock temperatures is of paramount importance, e.g. for planning of the underground operabons or for the design of ventilation. During construction large water inflows from karstic or fracture zones can lead to disastrous geotechnical problems. In the following, examples will be presented to predict rock temperatures and water inflow zones.
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Geophysical Imagery of Small-Scale Fracturing
Authors J. C. Gourry and G. GrandjeanInsufficient knowledge of fractured rock represents a common problem in many fields of the Earth Sciences such as the environment, storage, hydrogeology, etc. The study presented here was undertaken in ornamental stone quarries, which offers the main advantage of being able to verify geophysical interpretation after cutting of the working face (meso-scale) or the blocks (micro-scale). As far as the meso-scale is concerned, the aim is to make an inventory of fracturen of an order of approximately 1 m in length, whereas for the micro-scale, it is to identify fractures of up to ten centimetres.
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Advanced GPR Exploration in Karstic Areas
Authors I. Finetti, M. Pipan and G. CandottiMultifold GPR techniques and 3D common offset GPR grids were used for a high resolution geophysical exploration programme in the karstic area surrounding the town of Trieste (Italy). The objective of the programme is the identification of natural cavities and fractures, of interest for applications rangmg from quarry exploitation to civil engineering.
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Use of Geophysical Methods in Old Coal Mine Site Investigations: Some Case Studies
Authors S. C. J. Dawson, K. R. Onions and P. J. JacksonSince the early 1980's, the UK coat industry has declined in size from 200 to its current level of 20 major collieries. Whilst this has meant a reducing demand for Goal exploration geophysics, a new market is emerging: that of site investigations prior to the reclamation of abandoned colliery sites.
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Borehole Radar Survey Applied to a HST Tunnel Investigation
Authors L. Corin, L. Halleux, B. Dethy and T. RichterConsidering the high cost of boreholes, any technique providing additional information on the rockmass around the borehole is extremely useful. Geotechnical tests and geophysical logging techniques are widely used, but the information they provide is only representative of the immediate vicinity of the borehole.
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Earth Resistivity Tomography (ERT) and Cavity Investigation
By F. JacobsTomographic inversion methods appeared in geophysics about ten years ago. In general, they are based upon the principle of transmission of geological bodies by means of elastic or electromagnetic waves, especially in seismology and in engineering geophysics.
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Comparison Between some Borghole Geophysical Methods to Defect Underground Cavities
Authors R. Lagabrielle, P. Cote and N. Lecocq-LeventWhen underground cavities have geometrical characteristics (size and depth) or feature geophysical contrasts which place them beyond the detection limits of surface geophysical methods, borehole geophysics should be used to make sure that they can be detected if they actually exist.
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Single Geophone Profiling (SGRP) Used in the Detection of Lateral Vetocity Changes: Example of Cavity Detection
Authors R. Gauderon, G. Alleman and D. ChapellierThe interest of this new type of research consists in setting up a new method based on the common seismic refraction and reflection methods which are sometimes too expensive and too complex to use. These reasons have led us to develop a new method, the Single Geophone Refraction Profiling (SGRP), which makes possible the rapid and inexpensive interpretation of a chosen site.
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Airborne Geophysics for Geotechnical Applications (Tunnel Location)
Authors W. Seiberl, R. Arndt, A. Romer, R. Supper and G. OberlercherThis papers focusses on the results gained from a hydrogeological study and their geotechnical implications for a tunneling project to be planned in the Inn-Valley (Tyrol).
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Processing of Very High Resolution 3D Marine Seismic Data
Authors T. Missiaen, B. Marsset, M. Noble and W. VersteegVery High Resolution marine 3D seismics offers wide use both in the field of engineering geophysics as well as for geological and environmental site investigations. Considering the frequency content of the data, specific 3D processing techniques have to be applied in order to obtain a correct image of the subsurface. Due to the average wavelength of the "seismic signal and the width of its associated Fresnel zone, CMP-like processing can still lead to a destructive stack of misplaced events. The latter will also be the case if precise time delay corrections are not applied. A first step in the development of such 3D processing techniques was done using a very high resolution 3D data volume previously acquired on the river Schelde in Antwerpen.
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High Resolution, Microseismic Profiling in the Coastal Zone
By A. StefanonThe latest techniques and instrumentation allow to perform successful reflection seismic surveys both at sea and in inland waters, even at very shallow water depth and using small crafts. Such talk is not easily achieved, but the obtainable results are definitely rewarding and pay welf botte for the indispensable effort and for the money involved.
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Geophysical Remote Sensing of Sea Floor Sediment Properties
Authors A. M. Davis and M. D. RichardsonIn the marine environment, geophysical methods have for many years been used to investigate subsurface structure and to map the distribution of sediments at the seabed surface, the latter using a purely qualitative approach.
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Sea Floor Sensing of Sediment Shear Wave Properties
More LessKnowledge of sediment geoacoustic properties is of fundamental importance to marine environmental end engineering applications. For instance, geoacoustic approaches are currently being applied to predictions of marine slope stability, evaluation of the consolidation behaviour and strength of marine foundations, studies of mine burial, assessment of contaminant distribution, and prediction of high frequency acoustic bottom scattering. Within the engineering community the geophysical parameter currently receiving most attention is the seismic shear wave velocity, this being recognised as a definitive soil property indicative of the structural stiffness of the material. Out of this has arisen a requirement for new methods for in-situ evaluation.
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Preliminary Results of Seismic and GPR Surveys on the Hells Gate lce Shelf (Victoria Land -Antarctica)
Authors A. Lozej, I. Tabacco, F. Merlanti and M. PavanIn the course of the ItaliAntartide Expedition of the summer 1993-1995, geophysical surveys, seismic and GPR, were undertaken on the Hells Gate Ice Shelf with the objective of defining the structural and physical characteristics of the ice body. The Hells Gate Ice Shelf (HGIS) is one of the minor glacial structures in the North Victoria Land area, the geomorphology and glaciology of which are described by Baroni & Orombelli (1987) and Baroni (1990), among others.
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Radar and Seismic Survey on Temperate Glaciers in Northern Italy, Adamello and Stelvio Glacier
Authors I. Tabacco, P. Pettinicchio and L. VeroneseRadar survey on temperate glaciers is more difficult on respect of the other one on polar, Gold glaciers, because the presence of a scattered layers that usually prevent the transmission of e.m. waves. Bogodorosky (1985) consider that the scattered layer is due to in fraglacial discontinuity and to physical caratheristics of the ice body.
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Investigation of Fine Structures of Buried River Beds
Authors B. Neducza and M. PattantyusThe objective of investigations for buried river beds and alluvial fans might primarily be water or raw material prospecting but it might be of archaeological importance, too. Ancient settlements can frequently be found close to a water supply, e.g. a river, thus, delineation of river beds could help in finding ancient or historical settlements. Analyzis of aerial photographs and topographic maps of proper scale is the best means for this purpose.
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High-Resolution Seismic Mapping of Glacial and Proglacial Sediments in the Swiss Molasse Basin
Authors F. Buker, A. Pugin, H. Horstmeyer and A. GreenQuarternary sediments in the Swiss Molasse Basin contain more than two-thirds of the country's aquifers and large amounts of industrial minerals. Glacial sediments are highly inhomogenous, such that their lithology and hydraulic conductivity may change significantly over short distances. As groundwater flow is influenced strongly by hydraulic conductivity, evaluations of the safety of waste disposal sites and predictions about hazardous contaminant flow require reliable information about the three-dimensional distribution of the near-surface sediments that are highly permeable.
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Geophysical Investigation on Geometry and Internal Structure of the Lago Sackung, Calabria
Authors F. Ferrucci, M. Sorriso-Valvo and C. TansiQuantitative studies of deep-seated gravitational dope deformations, that often represent the longlasting preparatory phase of catastrophic landslides, though seldom carried out are undoubtedly relevant to hazard assessment and to the correct planning of environmental frameworking.
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Transient Electromagnetic Soundings at the Taquari-Vassouras Potash Mine (Brazil)
Authors M. Chouteau, S. Krivochieva and R. FrankTaquari-Vassouras is an underground potash mine exploiting silvinite ore at a depth of approximately 500 metres. The mining method used is room-and-pillars. Of main concern to the mine operation is the presence of an aquifer zone 50 to 100 metres above the potash zone. The danger of water inflow through fractures could result in safety hazards and large remediation costs for the company Vale do Rio Doce. Fractures may result from the collapse of the salt sequence.
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Seismic First Breaks lnterpreted as the Diving Waves
Authors J. D. Laski, F. Kohlbeck and J. SkowyraTime distance curves of seismic first breaks may be looked upon as consecutive straight lines (velocity of refractor and overburden constant) or more realistic as consecutive lines slightly curved (velocity of refractor and/or overburden increasing with depth). In the last case raypaths are curved and the first breaks correspond to diving waves penetrating the refractors.
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To Imaging of Q-1 Model in an Attenuation Tomography on the Creeping Waves
Authors V. N. Troyan and A. P. KrauklisPropagating along concave boundaries P and S waves (creeping waves) can be used in seismics and acoustics to locate a fracture zone, corrosian induced pits, topographic irregularities, etc. For example in last time a lot of circumferential acoustical devices for well logging were constructed which use the creeping wanes for the solution of such problems.
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Body Wave Dispersion in Formations Crossed by Boreholes: Consequences on Velocity Calculation
Authors D. Jeantet and A. RousseauOne of the most important parameters provided by well-logging is the body wave velocity of formations crossed by a borehole. The body wave velocity calculation is based on the difference between the propagation times of the waves which propagated in those formations and which have been recorded by two or more receivers.
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Assessing Systematic Errors in Seismic Crosshole Data
By H. MaurerSmall scale structures with velocity anomalies of a few percent are often the targets of the seismic travel time tomography between boreholes or tunnels. To successfully invert for these velocity structures, accurate knowledge of the source and receiver coordinates and of the shot times is required.
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Viscoelastic Finite-Difference Modeling of Shallow Seismic Data: Formation of Near-Surface Waveguides
Authors J. O. A. Robertsson, A. Pugin, K. Holliger and A. GreenWaveguides are formed in grossly layered media bounded by strong physical property contrasts. In ocean acoustics, the formation of shallow water waveguides is known to have a significant impact on wave propagation (Brekhovskikh and Lysanov, 1991). We suggest that similar waveguides may exist near the solid earth's surface and investigate the effects of such waveguides on high-resolution shallow seismic data.
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The Bedrock in Refraction Seismics as an Inhomogeneous Medium with Vetocity Gradient
Authors S. Hrach, J. Skopec and J. VilhelmSeismic methods have recently been used more and more frequently for studying shallow parts of subsurface media. Their application is increasing in the prospecting for some raw material deposits, in engineering geology and in hydrogeological investigations as well. They have been applied to determine the overburden thickness and the degree of subsurface fracturing of individual rock blocks as well as to study the extent and quality of quarry-stone deposits etc.
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High Resolution Seismic Revised
More LessDuring the last ten years seismic methods have lost much of its interest among all geophysical methods. Shallow investigations related to environmental problems are often made more efficiently using non seismic methods.
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Application of Statistical Pattern Recognition Techniques to Geophysical Data
Authors I. Rosati and E. CardarelliEach geophysical survey is accomplished via a detailed program of sampling. In other words, by choosing the right amount of data to be collected with respect to the type of analysis to be carried out, to the type of anomalies that have to be surveyed, and to the relative costs.
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High Resolution Shallow Seismic Reflection Study for Hydrological Site Characterisation near Acerra (Naples): Preliminary Results
Authors P. P. Bruno, E. Carrara, A. Rapolla and N. RobertiIn the past the Campani an Plane was famous for its fertility and abundance of water. Unfortunately the disorderly industrial, and urban development of the last forty years, especially in the proximity of the city of Naples, has resulted in a strong negative impact on the geological medium in terms of pollution and depauperation of the land and its alluvial hydrological resources. On the other hand the increased population pressure (one of the highest of Italy) has also increased the demand for clean fresh water both for human and agricultural utilisation and consequently new water resources (i.e. alluvial acquifers) must be located.
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Variation of Longitudinal and Transverse Dispersion with Flow Velocity - a Laboratory Study
Authors N. Tosi, C. Calabrò, A. Ghiotto, S. Pisani, G. Beltramelli and G. ZiglioA large series of laboratory experiments have been carried out, utilizing a box of longitudinal dimension of the order of a meter, filled with a highly homogeneous and isotropic artificial porous medium, consisting of glass heads (diameter 0.5 mm), to determine and characterize the eventual dependence of longitudinal and transverse dispersion on flow macroscopic velocity.
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Delineation of Groundwater-Flow with Self-Potential Tomography
Authors M. Hammann, H. R. Maurer, H. Horstmeyer and A. G. GreenSubsurface fluid flow phenomena may under favorable circumstances be described quantitatively on the basis of self-potential (SP) measurements.
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Hydrogeology Supported by Geophysic
Authors J. Kiss, L. Vertesy, G. Csillag, K. Gondar and L. KoloszarThe project aimed to clarify the hydrogeological circumstances of a urineral water well. Nowadays the well produces water from 12m depth, but previously it was known as natural spring. Before the project the origin of the water was unknown, so the planning of the mise of the production rate and the delineation of the protection area could not based on actual data. To provide the needed data, detailed geological mapping, processing archive and new geophysical data, water table determination and chemical analysis were performed. This paper deals mainly with the geophysical aspects of this integrated geologicalgeophysical work.
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Detection of the saline Water Layers beneath the Sea of Galilee by the Time Domain Electromagnetic (TDEM) Method
Authors M. Goldman, B. Rabinovich, Y. Rotstein and H. GvirtzmanThe Sea of Galilee (Lake Kinneret) is the most important surface fresh water reservoir in Israel, providing approximately 500 million m3 of water per year. The Lake is, however, adversely affected by emergent saline springs, only some of which are diverted.
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Bi-dimensional Modelling of Resistivity and IP Data for Hydrogeological Problems
Authors M. Marchisio, L. D‘Onofrio and E. ForlaniIn hydrogeological investigations, when the geological situation looks like a layered condition, the basic geophysical survey technique is of course vertical electrical sounding, VES (possibly, closely spaced along the profiles: in our experience, infact, often also the flattest morphologies can hide discontinuities that can lead to misunderstandings).
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The Assessment of Hydraulic Properties from Geophysical Data: Groundwater Bearing Layers
More LessVanishing resources of high quality groundwater result in the need for careful hydrogeological modelling as a help to prevent overpumping and pollution. Beside the storage capacity the most important parameter for this modelling is the hydraulic conductivity. The yield of well fields as well as the spread of contaminants is governed by this quanity.
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Geoelectric Survey for the Study of the Mineralization and Vulnerability of a Southern Italy Volcanic Aquifer
Authors R. Quarto and D. SchiavoneThe volcanic complex of Mount Vultune (Southern Italy) represents a hydrogeologically relevant area for the presence of urineral waters. The waters are locally bottled by industries for drinking use. The demand of ever-increasing water quantities together with pollution problems call for a detailed knowledge of the geometry and hydrological characteristics of the aquifers as well as their vulnerability.
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On the Resolution of Radar Tomography
Authors A. Godio and G. RanieriThe paper describes a simple procedure useful for modelling GPR tomographic data based on the ray tracing theory; the method achieves to generate synthetic radar traces for 2-D modelling of cross-borehole. The technique is suitable to verify the opportunity and the resolution of a radar survey for tomographic data processing.
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Finite-difference Solutions of Electromagnetic Wave Propagation in Conducting Media
Authors T. Bergmann, J. O. A. Robertsson and K. HolligerTime-domain electromagnetic methods in geophysics include the relatively low frequency transient (TEM) and ground-penetrating radar methods. Problems of time-dependent electromagnetic wave propagation are generally not yet solvable for complex media. Mostly, these problems have been treated theoretically through frequency-domain approaches.
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Quantitative Monostatie GPR Analysis in Interface Profiling: Electromagnetic Inversion
Authors A. Benassi and U. SpagnoliniIn shallow subsurface investigation and non-destructive testing ground penetrating radar (GPR) represents a promising technique that measures short pulse electromagnetic (EM) waves reflections (typical range: 10 MHz-2.5 GHz) due to variations in the electrical properties of medium.
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Quantitative Monostatic GPR Analysis in Interface Profiling: Multisignal Detection-Based Layer Estimation
Authors V. Rampa, U. Spagnolini, G. Stagni and C. TojaDetection-based approach in monostatic ground penetrating radar (GPR) processing is a useful technique for estimation of echoes time of delay (TOD). Its main advantage is simplicity and efficiency in a moderate noisy environment with separate events to be used in any lager stripping roversion approach.
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Use of Transient Electromagnetic and Magnetotelluric Methods for Characterisation and Delimitation of the Santa Catarina Aquifer (Chalco Sub-Basin, Mexico)
Authors S. Krivochieva, M. Chouteau, R. R. Castillo and T. G. MoranLocated in the northern part of the Chalco sub-basin (Basfin of Mexico), Santa Catarina ecological reserve is the main water-catchment point for more than 2 million people living in the southern suburbs of Mexico City.
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Study of Regional Gamma-Ray Data in Central and Eastern Europe and the Radiometric Map of the Czech Republic
Authors M. Matolin and G. SiderisThe natural radiation environment is the main long term source of radiation exposure to man. It consist of cosmic rays, terrestrial radiation and radiation of other radionuclides occurring in the environment and causing external and internal exposure. In addition to natural radiation, different sources of man made radiation exist as well.
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The Application of Shallow Geophysical Methods to Golf Course Management
Authors J. C. Tapias and A. CasasIn the last years proliferation of golf courses in arid and semi-grid zones, where water supply for other more important uses is not sufficienly satisfied, normaly originates vehement opposition by neighbouring people and also environmental associations.
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Using the Geophysical Methods in Frame of the Environmental Projects in City Agglomerations of Slovakia
Authors J. Hricko, P. Bobovnicky and I. TunyiDuring last 5 years, more or less standard geophysical techniques have been used in frame of the huge environmental projects in Bratislava capital and Kosice city. They are: observations of the intensity and changes of the natural and anthropogenic magnetic activity; measurements of the electromagnetic smog level, caused namely by very high frequency radio-transmitters; radioactive pollution and radon risk assessment.
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Protection of Environment from Radioactive Contaminations Caused by Use of Radioactive Isotops in Bore Holes
More LessIn order to control some processes accomplished in drilling wells and in those of production as well as to settle certain geological problems, in Albania are widly used methods of radioactive isotops injection.
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Resistivity Variations in an Earth Embankment Dam in Sweden
Authors T. Dahlin and S. JohanssonRepeated resistivity measurements were started in two embankment dams as part of a research project. The aim of the project is to monitor the seasonal variation of the resistivity and to develop evaluation methods, monitoring systems and installations for embankment dams.
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High Resolution Geophysical Sensing and Imaging
Authors R. J. Sporry, J. Roy, W. A. Hugens and N. SibhatThe need and usefulness of high resolution geophysical sensing and imaging has been illustrated by the results of several recent projects using geophysical techniques in environmental, civil engineering, groundwater, mining, archeological and soil surveys applications.
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Multifold GPR Investigation of the Aquileia Archaeological Park
Authors I. Finetti, M. Pipan and G. CandottiAn Ultra High Resolution geophysical exploration programme was designed and completed in the area of the Aquileia archaeological park (north eastern Italy) as part of a cooperation between the Institute of Geodesy and Geophysics of the University of Trieste and the Superintendency of the Cultural Heritages of the Friuli Venetia Giulia.
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Electromagnetic Auscuftation on Brick Masonry
Authors X. Dérobert, P. Cote and N. Lecocq-LeventSeveral types of auscultation techniques have been tested on brick masonry monuments during the first part of a research program from the CEE "Environment program" (contract EV5V CT 92 - 0106: NDT and system identification to evaluate diagnostics methods and reinforcement techniques applied to historical buildings). We have selected two main sites in Italy: a wall of a Scuola in Venice and a part of rampart in Montagnana.
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The Use of Seismic Prospecting for Prediction of Ground Vibrations
Authors D. Jongmans and C. HorrentIn the last few years, concern about vibrations generated by civil engineering work has dramatically increased. The main seismic wave sources are pile and tie-back driving, quarry blasts, drilling operations and road or train traffic. In inhabited areas such vibrations may have an important impact on people and buildings and may constitute a major problem for the environment.
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Earthquakes 5 pm Daily ?? A Seismic Study to Identify Underground Acoustic Noise Sources
More LessRegular love frequency noises, very similar to distant earthquakes, were reported to the Eotvos Lorand Geophysical Institute in Veszprem, west Hungary, in 1995. Reports came from a small, densely populated urban area, describing the phenomena as frequent, frightening booms, sometimes accompanied by slight ground vibrations.
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Predicting Distribution of Intensity of Ground Vibrations Produced by Blasting
Authors S. Lasocki, J. Matuszyk and M. SzybinskiExplosives are extensively used in underground and open-cast mining, in civil engineering and hydrotechnics, and also in geophysical (seismic) prospecting. Detonation of explosives is a source of ground vibrations which can be hazardous for surrounding buildings and structures.
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A New Procedure to Perform Differential Gravity Measurements
Authors L. Sambuelli and G. RanieriIn a previous work the authors studied the possibility of performing differential underground gravity measurements to detect voids or altered or mineralized rock volumes near tunnels using a new procedure (Ranieri G., Sambuelli L. 1991).
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Advances in ERT Interpretation Methods
Authors D. J. Labrecque and G. MorelliThe objective of electrical resistance tomography (ERT) is to provide images of the subsurface electrical resistivity distribution. Electrical resistivity is a function of the pore water saturation, pore water salinity and soil/rock clay content.
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Improved Near-Surface Geoelectrical Mapping and Interpretation
Authors I. Moller and K. I. SorensenThe electrical profiling method and vertical sounding method are powerful techniques for mapping the near surface geology, e.g. in groundwater investigations, in prospecting for raw materials and in geotechnical investigations.
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Occam's Inversíon of 3D ERT Field Data
Authors G. Morelli and D. J. LabrecqueThe ERT method seeks to image the electrical resistivity of the subsurface by making measurements using numerous combinations of electrodes placed on or below the surface of the earth. It is the nature of the ERT method that the data obtained can only be interpreted using multi-dimensional inverse modeling.
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The Assessment of Hydraulic Properties from Geophysical Data: Groundwater Protective Layers
More LessThe protection of our groundwater resources against pollution from industry, agriculture, or waste dumps is mainly given by layers of low hydraulic conductivity. In Quaternary deposits these layers consist of clay or marl, a sand-clay mixture.
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New Strategies for Surface and Borehole Electromagnetic Methods in Hydrogeophysical Investigations
Authors N. B. Christensen and K. I. SorensenThe widespread problems with the quality of ground water call on the one hand for a much more detailed and on the other hand a regional covering with geophysical data, when performing a hydrogeophysical investigation.
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Use of Conductivity Survey in Defining a Policy of Rehabiltation of a Salt Affected Oasis in Tunisia
Authors J. O. Job, Y. Albouy, G. Bellier, N. Gaaloul, M. Arfaoui, F. Khalifa, M. Gasmi and B. AskriSegdoud is an oasis situated at 70 km south-ouest of Gafsa, south Tunisia (Fig. 1) downwards small colluvial fans produced by quaternary wadis, descending from cretaceous Jebel el Negueb. This material, interbedded with mio-pliocène clays and marls, and ancient terrases of oued Mit is rich in gypsum and magnesium salts.
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Experiences of 2-D Geoelectrical Imaging
Authors P. Chiara, A. Godio, L. V. Socco and A. ZerilliOver the past three years we have carried out several two-dimensional (2-D) electrical imaging in order to verify the reliability of this technology in different environmental and geological conditions. The 2-D resistivity imaging method is in wide use and successfully employed for detecting pollutants diffusion, in groundwater monitoring, in buried bodies and cavities detection problems.
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Contribution of Electrical and Electromagnetic Methods to a Dump Site Reconnaissance near Paris
Authors A. Bouvier and L. FrobertOld quarries of limestones, gypsum, sands or clays have been frequently used as rubbish tips over the years. New rules and environmental recommandations to avert or limit spreading of polluting substances have forced the municipalities to take actions for the treatment of polluted soils and rehabilitation of dump sites.
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Integrated Geophysical Methods for Sensing Buried Wastes in Abandoned Gravel Pits near Barcelona (Spain)
Authors E. Busquet, A. Casas, V. Pinto and L. RiveroThe industrial expansion of Barcelona city and their metropolitan area of influence during the sixthy's and seventy's gived as consequence an important inquiry for building materials. Many gravel-pits were intensively exploted, and when abandoned, converted into uncontrolled landfills refilled with industrial and domestic wastes (fig. 1).
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Integrated Interpretation of RMT Data and Borehole Results on a Waste Site near Cologne
More LessWaste sites are usually characterized by high electrical conductivities compared with surrounding geological structures. The Radiomagnetotelluric (RMT) technique is very efficient in waste disposal exploration. It uses radiotransmitters in the frequency range between 10 kHz and 300 kHz. Two horizontal electric and magnetic field components are measured from radiotransmitters perpendicular to each other. The observed transfer functions (e.g. apparent resistivity and phase data) are interpreted in the same way as it is usually done with magnetotelluric data.
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3D Visualisation of a Waste Deposit near Huttenried (Bavaria) using Radio Magnetotelluric Data
Authors G. Zacher, B. Tezkan, F. M. Neubauer and I. MullerThe application of geophysical methods to waste disposal investigation becomes increasingly popular since their contribution to the pollution risk estimation is being recognized. In particular geophysical methods are faster and more cost-effective than conventional drilling. Waste sites are usually characterized by a high electrical conductivity compared with surrounding geological structures.
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Determination of Physical Parameters of Urban Waste Dumps Via Integrated Geophysical Methods
Authors M. Bernabini, E. Cardarelli and C. TedeschiDuring the last few years Applied Geophysics has further extended its field of action to the study of problems related to environment protestion, in particular to the discharge of urban wastes.
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Integrated Geophysical Survey Across a Waste Disposal Site
Authors E. Lanz, A. Pugin, H. Horstmeyer and A. GreenOver the past decade there has been a significant increase in the demand for engineering geophysical solutions to problems associated witti the unconsolidated sedimentary layers of the shallow subsurface. A whole palette of geophysical techniques is available for studying the upper tens of meters of the underground, with a trend toward higher resolution surveying. In Switzerland, as in most other countries, large quantities of industrial and household waste have been buried in landfill sites. For many of the older sites, there is a lack of credible information concernmg the exact location, dimensions and contents of the site.
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Reflection Profiling Using Engineering Seismic Equipment - a Case History from Slovenia
By A. GosarSeveral seismic reflection surveys were carried out in last years in Slovenia using 24 channel engineering seismograph, single geophone per channel and personal computer based processing software. Their scope was mainly within hydrogeological investigations and for locating faults. A reflection line recorded near the Krsko nuclear power plant (NPP) site, reported here, is used to present the optimization of acquisition parameters.
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