No description available.

No description available.

Twenty-one Schlumberger resistivity soundings were performed on the island of Maui. Analysis consisted of one-dimensional modeling using an automatic ridge-regression inversion algorithm (Anderson, 1979). The inversion results were compared with available well-log information and geologic maps in order to make geologic interpretations. The soundings were conducted primarily to estimate the depth to and the electrical resistivity of, seawater-saturated basalt for different parts of the island. The resistivity of seawater-saturated basalt on Maui ranges between 3.5 and 60 ohm-meters. The lowest values occurred near Ukumehame canyon, on the south rift zone of West Maui. In this area, which is the site of a warm water (33°C) well, the computed resistivity for seawater-saturated basalt is about 4 ohm-m. Using typical Hawaiian basalt porosity values of 15% to 25%, Archie's Law implies temperatures of between 62° and l7loC at depths below 200 meters in the Ukumehame area. Freshwater piezometric heads were estimated from the sounding data. The largest freshwater head (91 m) was obtained in Keanae valley. The inferred large volume of freshwater is perched on Keanae alluvial valley fill and is observed in a well (W100) towards the back of the valley. All other freshwater heads are under 4 m, indicating that the freshwater lens is rather thin near the coast at the areas surveyed. / ill / maps

This study sets out to evaluate the use of geophysical methods for delineating buried stream channels, which can act as zones of preferential flow within a less hydraulically conductive aquifer. This information is important for gaining an understanding of flow dynamics of alluvial systems. The most reliable method of delineating the dimensions of aquifers is by drilling, which is an expensive proposition and is best preceded by a preliminary geophysical study to help define target zones for a drilling program. The study area is located adjacent to the Coerney River in the Sundays River Valley. Geologically it consists of approximately 5 metres of alluvial fines, covering 3 metres of coarse cobbles and boulders, all underlain by alternating siltstone and sandstone beds of indeterminate thickness. Throughout the area the water is very shallow at approximately 2 metres depth and the groundwater tends to be very saline. An air photo study revealed an old oxbow channel that had been covered over by subsequent agricultural land use. The geophysical methods available for the study were portable seismic refraction, electrical resistivity and electromagnetics. Preliminary field tests clearly showed that seismics did not produce valid results. The methods of electrical resistivity and electromagnetics produced good data and were subjected to further assessment. A grid was surveyed over the study area and both geophysical methods were applied at regularly spaced stations. Soil samples were taken over the same survey grid and analyzed for electrical conductivity in a soils laboratory. The results were compared to the geophysical data in an attempt to quantify the relationship between geophysical response and soil salinity. The data from the electromagnetic survey showed areas of low electrical conductivity which was a possible indication of zones of preferential groundwater flow. A transect of boreholes was drilled over selected electrical conductivity lows and successfully intersected the buried stream channel. A comparison of the borehole logs with the layered earth models from the Vertical Electrical Soundings indicated that the electrical resistivity method was not responding to the features of the buried stream channel and the cobblestone layer. This proved the electromagnetic method to be more valuable for this particular study

No description available.

Delaware County, Indiana, is characterized by its glacial sediments and topography. With increasing development, the need for reliable, cost-effective subsurface surveying methods becomes more important. This thesis explores the possibilities of electrical resistivity methodology. Fifty survey sites were established on a one-mile grid over twenty square miles west of Muncie, Indiana. Three electrode arrays were tested, Wenner, Lee Partitioning, and Schlumberger, and the data interpreted by three methods, logarithmic curve matching, Moore's cumulative method, and Barnes' layer method.No one method proved to be completely accurate and reliable. Used in conjunction, however, data from the three are consistent and the techniques are viable measures for the analysis of heterogeneous glacial sediments. Additionally, apparent resistivity values which characterize the particular sediments in the study area were established and several pervasive stratigraphic units were defined.Ball State UniversityMuncie, IN 57406

Le stockage est la méthode de traitement des déchets non dangereux la plus communément utilisée dans le monde entier car elle est un moyen simple et économique pour leur élimination. Malgré une volonté nationale et européenne pour réduire le stockage de déchets biodégradables, une quantité non négligeable est encore enfouie entrainant la mise en place de modes de gestion spécifique. Autrefois exploitées comme de simples fosses de remplissage, les installations de stockage de déchets non dangereux (ISDND) sont aujourd’hui des ouvrages complexes dont l’objectif est de réduire l’impact environnemental et de valoriser énergétiquement le biogaz produit par la biodégradation de la matière organique. Afin d’accélérer les processus de biodégradation un casier de déchets peut être exploité en mode bioréacteur en réinjectant des lixiviats pour augmenter la teneur en eau des déchets. Le défi des années 2000 était de dimensionner et valider les systèmes de réinjection de lixiviat pour garantir une distribution optimale de la teneur en eau dans les massifs de déchets. Aujourd’hui, la question est de de suivre l’évolution de la biodégradation en tous points d’un massif pour notamment comprendre l’effet de ce mode de gestion. Les méthodes géophysiques en plus d’être non-destructives et spatialisantes sont utilisées depuis des années sur les ISDND et pourraient être sensibles à l’évolution de la biodégradation d’un massif de déchets, comme cela a été démontré pour la biodégradation d’autres milieux. Ainsi la problématique de cette thèse est d’évaluer la capacité de certaines méthodes géophysiques pour suivre l’évolution des paramètres bio-physico-chimiques d’un massif de déchets au cours de sa biodégradation. Un premier travail bibliographique a permis d’identifier quatre méthodes électriques parmi les méthodes géophysiques disponibles pour répondre à cette question :• La résistivité électrique• Le potentiel spontané• La polarisation provoquée• La polarisation provoquée spectraleAprès cet état de l’art, le travail de thèse a été séparé en trois parties. La première a été consacrée à la mise en place du suivi de ces quatre méthodes à l’échelle du laboratoire dans des conditions contrôlées, la seconde à analyser le suivi géophysique long terme sur le site industriel de la SAS Les Champs Jouault et la dernière a évaluée les observations à ces deux échelles. Enfin, la conclusion présente le potentiel de la méthode de mesure du potentiel provoquée comme la plus pertinente pour suivre l’évolution de la biodégradation d’un déchet non dangereux au cours du temps et aborde son utilisation dans un cadre industriel. / Storage is the most commonly used waste treatment method in the world because it is a simple and economical way to dispose of solid waste. Despite a national and European desire to reduce the storage of biodegradable waste, a significant amount is still buried, leading to the implementation of specific management methods. Formerly exploited as mere filling pits, MSWL are today complex structures whose objective is to reduce the environmental impact and energetically valorize the biogas produced by the biodegradation of organic matter. In order to accelerate biodegradation processes, a waste cell can be operated in bioreactor mode by reinjecting leachates to increase the water content of the waste. The challenge of the 2000s was to size and validate leachate re-injection systems to ensure optimal distribution of water content in the waste mass. Today, the question is to monitor evolution of the biodegradation in all points of a waste mass in particular to understand the effect of this management mode. Geophysical methods in addition to being non-destructive and spatializing have been used for years on MSWLs and could be sensitive to the evolution of a waste mass biodegradation, as has been demonstrated for the biodegradation of others environments. Thus the problematic of this thesis is to evaluate the capacity of certain geophysical methods to monitor the evolution of the bio-physicochemical parameters of a waste mass during its biodegradation. A first bibliographic work identified four electrical methods among the geophysical methods available to answer this question:• Electrical resistivity• Self potential• Time domain induced polarization• Spectral induced polarizationAfter this state of the art, the thesis work was separated into three parts. The first one was devoted to the implementation of the monitoring of these four methods at the laboratory scale under controlled conditions, the second to analyze the long-term geophysical monitoring at the industrial site of SAS Les Champs Jouault and the last one to evaluate the observations at these two scales. Finally, the conclusion presents the potential of time domain induced polarization method as the most relevant to monitor the evolution of a waste mass biodegradation over time and discusses its use in an industrial setting.