Very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) investigation for groundwater potential evaluation in a complex geological terrain around the Ijebu-Ode transition zone, southwestern Nigeria

2012 ◽  
Vol 9 (4) ◽  
pp. 374-396 ◽  
Author(s):  
Olawale O Osinowo ◽  
A Idowu Olayinka
Keyword(s):  
Electrical Resistivity ◽  
Transition Zone ◽  
Low Frequency ◽  
Groundwater Potential ◽  
Southwestern Nigeria ◽  
Very Low Frequency ◽  
Potential Evaluation

scholarly journals Electromagnetic profiling of Owena Dam, Southwestern Nigeria, using very-low-frequency radio fields

2016 ◽  
Vol 63 (4) ◽  
pp. 237-250 ◽  
Author(s):  
Cyril Okpoli ◽  
Raphael Tijani
Keyword(s):  
Low Frequency ◽  
Soil Mass ◽  
Internal Erosion ◽  
Dam Failure ◽  
Real Component ◽  
Southwestern Nigeria ◽  
Very Low Frequency ◽  
Embankment Dams ◽  
Fractured Zones ◽  
Basement Structures

AbstractVery low frequency (VLF) was used to assess variations in overburden composition, bedrock lithology and the concealed basement structures within the bedrock of Owena Dam in Igbara-Oke of the Precambrian Basement Complex of Southwestern Nigeria. Five VLF-electromagnetic (EM) traverses were occupied at 5 m intervals. The VLF normal and filtered real component anomalies identify major geological interfaces suspected to be faults/fractured zones. The points of crossover between the real and imaginary components delineate the fractured zones, which were identified as areas of possible seepage (piping and sloughing). The internal erosion (permeability) of soil mass eventually leads to the formation of an open conduit in the soil, which may lead to failure of the embankment/dam. The fractured zones are suspected to be present at all traverses. In total, 21 fractured zones were identified along the dam embankment, with the deepest occurrence at Traverse 5. These seepage zones cause heterogeneity in the subsurface composition, which could lead to dam failure. The result of the study suggests that VLF is an adequate method of monitoring seepages in embankment dams.

scholarly journals Hydrogeophysical investigation of groundwater potential and aquifer vulnerability prediction in basement complex terrain – A case study from Akure, Southwestern Nigeria

2016 ◽  
Vol 63 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Opeyemi J. Akinrinade ◽  
Rasheed B. Adesina
Keyword(s):  
Low Frequency ◽  
Groundwater Potential ◽  
Aquifer Vulnerability ◽  
Hydraulic Gradient ◽  
Protective Capacity ◽  
Real Component ◽  
Southwestern Nigeria ◽  
Reconnaissance Survey ◽  
Transverse Resistance ◽  
Optimum Position

AbstractThis study provides a model for the prediction of groundwater potential and vulnerability of basement aquifers in parts of Akure, Southwestern Nigeria. Hydrogeophysical surveys involving very-low-frequency electromagnetic (VLF-EM) profiling and electrical resistivity (ER) sounding, as well as evaluation of hydraulic gradient using three-point method, were carried out. Ten VLF-EM reconnaissance survey traverses, with lengths ranging from 55 m to 75 m, at 10 m station separation, and 12 vertical electrical sounding (VES) stations were occupied. Two-dimensional map of the filtered real component reveals areas of high conductivity, indicative of linear features that can serve as a reservoir or conduit for fluid flow. Interpretation of the VES results delineates three to four geoelectric units. Two aquifer zones were identified, with resistivity values in the ranges of 20 Ωm to 310 Ωm and 100 Ωm to 3,000 Ω m, respectively. Transverse resistance, longitudinal conductance, coefficient of anisotropy and hydraulic gradient have values ranging from 318.2 Ωm2 to 1,041.8 Ωm2, 0.11 mhos to 0.39 mhos, 1.04 to 1.74 and 0.017 to 0.05, respectively. The results of this study identified two prospective borehole locations and the optimum position to site the proposed septic system, based on the aquifer’s protective capacity and groundwater flow properties.

Integrated very low-frequency EM, electrical resistivity, and geological studies on the Lanta Khola landslide, North Sikkim, India

Landslides ◽  
2009 ◽  
Vol 7 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Shashi Prakash Sharma ◽  
K. Anbarasu ◽  
Saibal Gupta ◽  
A. Sengupta
Keyword(s):  
Electrical Resistivity ◽  
Low Frequency ◽  
Very Low Frequency

scholarly journals Investigation of groundwater potential using integrated geophysical methods in Moloko-Asipa, Ogun State, Nigeria

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
A. A. Alabi ◽  
S. A. Ganiyu ◽  
O. A. Idowu ◽  
A. F. Ogabi ◽  
O. I. Popoola
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Sampling Interval ◽  
Groundwater Potential ◽  
Groundwater Exploration ◽  
Protective Capacity ◽  
Southwestern Nigeria ◽  
Industrial Growth ◽  
Geoelectric Section ◽  
Weathered Layer

AbstractWater is essential for livelihood, development, and industrial growth. Its exploration in sufficient quantity is required where it does not freely occur on the surface. This research was aimed to delineate aquifer regions and provide information on the subsurface lithology of Moloko-Asipa Southwestern Nigeria. A combination of eight traverses investigated with very low frequency electromagnetic (VLF-EM) method at 5 m constant sampling interval and ten vertical electrical sounding (VES) were carried out in the survey. Measurements from the VLF-EM survey were processed with Karous and Hjelt filtering to give the resistivity contrast across the selected profiles. The VES data processing involved an automatic approximation of the initial resistivity and thickness of the geoelectric layers with IPI2Win and further filtering by WinResist iteration. Estimation of Dar-Zarrouk parameters was also employed to investigate the aquifer protective capacity of the area. The processed VLF-EM results showed the geology of the area to an average depth of 25 m. The geoelectric section of the VES data revealed minimum of 3 layers from sandy top soil to weathered layer and fresh basement with an average resistivity values of 1,816, 926 and 17,503 Ωm, respectively. The integration of VLF-EM and VES in the investigation revealed that the potential for groundwater exploration in the study area is poor due to the thin nature of the weathered layer and its shallow depth to basement. The aquifer protective capacity of the area was likewise inferred to be poor.

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