Electrical Resistivity Geophysical Methods Research Articles

Archaeo-Geophysical Investigation of Ife City Grand Resort Iron Smelting Site at Ile-Ife, Southwest Nigeria

Abstract Ile-Ife in southwestern Nigeria is rich in art and craft traditions, most especially iron smelting. The town hosts hundreds of smelting sites with little or no archaeological record. Archaeo-geophysical prospection of a suspected smelting site in Ile-Ife involved the magnetic and electrical resistivity geophysical methods and archaeological excavation with the aim to identify its buried artefacts/features and date the site. The geophysical investigations located a circular/oval-shaped dipolar magnetic anomaly that coincided with a high resistivity zone, typical of a heat-impacted furnace or a slag trench. Iron slag, tuyere, fired clay furnace fragments, and charcoal were recovered from the pits excavated at the locations of the geophysical anomalies. Smelting activity at the site, from dated charcoal, took place at some point between the 13th-15th centuries AD, a middle to late age in Africa’s history of iron smelting. This study, therefore, validated the examined site as an ancient iron smelting site and situated its place in the archaeological history of iron smelting.

Application of Electrical Geophysical Method in Site Selection for Viable Area for Agricultural Practices: A Case Study of Ukpenu-Ibhiese and Iruekpen Edo State-Nigeria

Electrical geophysical method was applied, to select viable area with essential soil nutrients for plant’s growth. Conventional soil test analysis was carried out for the purpose of confirmation. A case study was done at Ukpenu-Ibhiese and Iruekpen in Ekpoma. The result of the electrical resistivity geophysical method showed that southwest and northwest of the area has resistivity values that ranged between 80?m to 170?m while the remaining part of the area has values higher than 170?m, ranged from 580?m to 950?m. Values of organic matter, Nitrogen, Phosphorus, and Potassium, obtained from the soil test in area with 80?m to 170?m indicated good proportion of essential soil nutrients for plant growth while area with resistivity values that ranged from 580?m to 950?m was deficient in essential soil nutrients for plant growth. The results further proved that soil electrical physical properties thus detected and mapped can be used as a proxy of physical, chemical, and biological features relevant for the appropriate site selection and soils management, based on their resistivity behavior, spatial variability, and time dynamics in the area of study.

Interpretation of geophysical and GIS-based remote sensing data for sustainable groundwater resource management in the basement of north-eastern Osun State, Nigeria

This study describes the interpretation of integrated GIS-based remote sensing and electrical resistivity geophysical methods as part of the need to provide groundwater overview for sustainable management in the basement of north-eastern Osun State, Nigeria. Six groundwater conditioning factors are synthesized based on the analytical hierarchy process and multi-criteria decision analysis to produce groundwater potential index map constrained by existing borehole yields. The results indicate that the estimated groundwater potential index map can serve as a gross predictor of the groundwater distribution in the region. This study may influence town planning and land use decisions for sustainable management of groundwater resource in the area.

Relevance of Electrical Resistivity Geophysical Method in Engineering Site Characterization in A Basement Complex Terrain

Relevance of Electrical Resistivity Geophysical Method in Engineering Site Characterization in A Basement Complex Terrain

Relevance of Electrical Resistivity Geophysical Method in Engineering Site Characterization in A Basement Complex Terrain

In this study, relevance of electrical resistivity geophysical technique in engineering site characterization had been demonstrated. The aim of the study was to establish the capability of the technique to unravel subsurface conditions through quantitative assessment/evaluation of subsurface geoelectric parameters. In order to achieve the objectives of the study, twenty (20) VES were acquired using R-50 Resistivity meter.

A novel approach for providing potable water in rural Sodwana Bay, northern Kwazulu-Natal, South Africa

Many people living in the Sodwana area of South Africa do not have access to potable water. Groundwater is the best source of fresh water for the rural community. Potable water in the Zululand coastal plain, Sodwana, South Africa can be enhanced by: (i) providing detailed information on the aquifer system using geophysics; (ii) providing information on groundwater quality and its efficient use; (iii) providing low-cost/low technology local drillers with light-weight, manoeuvrable rigs with trained teams for drilling of 6-inch diameter boreholes. The electrical resistivity geophysical method was used to study the aquifer system and define viable groundwater zones. The electrical resistivity survey increased the borehole success rate by providing information on the aquifer system suitable for water extraction. A hydrocensus was also conducted for identifying boreholes, quality of drilling and for collecting samples for water quality analysis. The result indicated that the groundwater in the area is of suitable quality. Poor quality drilling and inadequate drilling depth indicated a requirement for improved drilling rigs and suitable training. Providing the rural community with suitable drilling equipment, training and adequate information will help to solve the problem of water scarcity and also create jobs.

Geophysical and Hydrologic Studies of Lake Seepage Variability.

Variations in lake seepage were studied along a 130 m shoreline of Mirror Lake NH. Seepage was downward from the lake to groundwater; rates measured from 28 seepage meters varied from 0 to -282 cm/d. Causes of this variation were investigated using electrical resistivity surveys and lakebed sediment characterization. Two-dimensional (2D) resistivity surveys showed a transition in lakebed sediments from outwash to till that correlated with high- and low-seepage zones, respectively. However, the 2D survey was not able to predict smaller scale variations within these facies. In the outwash, fast seepage was associated with permeability variations in a thin (2 cm) layer of sediments at the top of the lakebed. In the till, where seepage was slower than that in the outwash, a three-dimensional resistivity survey mapped a point of high seepage associated with heterogeneity (lower resistivity and likely higher permeability). Points of focused flow across the sediment-water interface are difficult to detect and can transmit a large percentage of total exchange. Using a series of electrical resistivity geophysical methods in combination with hydrologic data to locate heterogeneities that affect seepage rates can help guide seepage meter placement. Improving our understanding of the causes and types of heterogeneity in lake seepage will provide better data for lake budgets and prediction of mass transfer of solutes or contaminants between lakes and groundwater.

Prospecção geofísica em ocorrência de cobre localizada na bacia sedimentar do Camaquã (RS)

Estudos de pesquisa mineral são fundamentais para o reconhecimento e a incorporação de novas reservas. Esse trabalho apresenta os resultados de aplicação do método geofísico da eletrorresistividade numa ocorrência mineralizada em carbonatos de cobre, por meio da técnica de caminhamento elétrico em arranjo azimutal. A área de estudos está inserida na bacia sedimentar do Camaquã, formada por um conjunto de unidades estratigráficas sedimentares e vulcanogênicas, onde são descritas diversas ocorrências cupríferas. A presença de azurita e malaquita em fraturas e zonas de maior porosidade em arenito encaixante define a geologia local. Os modelos de inversão revelam anomalias circulares de resistividade moderada para até 25m abaixo da ocorrência aflorante e anomalias de baixa resistividade em profundidades abaixo de 25m, além de áreas adjacentes com alta resistividade. Indicadores de mineralização descritos para ocorrências de cobre estudadas, no âmbito da bacia sedimentar do Camaquã, ocorrem na área de estudos e permitem caracterização em termos de resistividade elétrica. Áreas com silicificação apresentam alta resistividade, enquanto que valores intermediários são atribuídos a zonas com carbonatação e, finalmente, áreas de baixa resistividade, provavelmente, indicam concentrações de sulfetos disseminados.

Método da eletrorresistividade aplicado no monitoramento temporal da pluma de contaminação em área de disposição de resíduos sólidos urbanos

Este trabalho apresenta os resultados do monitoramento temporal da pluma de contaminação do aterro controlado de Rio Claro, São Paulo, por meio do método da eletrorresistividade, que consistiu na comparação dos resultados de várias seções de imageamento elétrico, executados nos mesmo locais, nos anos de 1999 e 2008. Zonas de baixa resistividade, com valores menores ou iguais a 50 Ω.m, foram associadas à contaminação por chorume. Desse modo, foi possível identificar dois sentidos do fluxo da pluma: (1) em direção ao sul, e (2) em direção ao oeste. Nas seções de 2008, a pluma de contaminação apresentou-se mais extensa e profunda do que em 1999. De forma complementar, as sondagens elétricas verticais aferiram a profundidade do nível freático e o sentido do fluxo d'água, subsidiando a interpretação dos imageamentos.

Qualidade da água de abastecimento público de Ribeirão Preto em área de abrangência do Aquífero Guarani: determinação de metais e nitrato

This paper presents the results of the Electrical Resistivity geophysical method applied to determine the area of leaching migration originated from solids waste decomposition, disposed in ditch type landfill. When the monitoring of wells or other direct techniques of the environmental investigation is not possible, the geological characterization, supported by geophysics techniques is an alternative for the assessment and monitoring leached materials. The absence of values below 100 ?.m in the reference line at 4 m of depth and the occurrence of these values in the residues ditches and its surroundings indicate the presence of leachate. This relation is a result of the high content of total dissolved solids that characterize the studied contaminant that reduces the electric resistivity.

The use of magnetometry and pole-dipole resistivity for locating Nabataean Hawar archeological site in the SW-Jordan

This paper is focused on the joint use of magnetometry and pole-dipole electrical resistivity geophysical methods for assessing their capability in the detection of a prehistoric site in the southwestern Jordan. The survey area, Auara, was built in the first century BC during the Nabataean time and is located in a very arid environment framed on the east and north by white sandstone hills. In order to test this site, a number of magnetic stations and two pole-dipole resistivity traverses were carried out in the investigated area. Magnetic data were taken with one sensor at height of 0.8 m along survey lines spaced 1 m apart. Resistivity measurements were carried out utilizing the pole-dipole array along two profiles. A total of 32 geoelectrical stations spaced 2 m were made along the two profiles. Magnetic method found structure with contrasting physical properties to those of the surrounding material. The archeological interpretation of such structure is in terms of rectangular cistern (pool) with dimensions 26 × 16 m. A probable location of two buried walls spaced 16 m are indicated by low resistivity values.

Caracterização geoelétrica de contaminantes provenientes da decomposição de resíduos sólidos domiciliares

This paper presents the results of the Electrical Resistivity geophysical method applied to determine the area of leaching migration originated from solids waste decomposition, disposed in ditch type landfill. When the monitoring of wells or other direct techniques of the environmental investigation is not possible, the geological characterization, supported by geophysics techniques is an alternative for the assessment and monitoring leached materials. The absence of values below 100 Ω.m in the reference line at 4 m of depth and the occurrence of these values in the residues ditches and its surroundings indicate the presence of leachate. This relation is a result of the high content of total dissolved solids that characterize the studied contaminant that reduces the electric resistivity.

Geophysics Efficient in Exploring the Subsurface

Data on use of refraction seismic and electrical resistivity geophysical methods, throughout United States, are given; examples of application of these methods to variety of subsurface problems pertinent to highway design and maintenance; studies of landslide conditions and tests made over water-covered areas.