scholarly journals Subsurface Investigation of Basement Structures Using Electrical Resistivity Methods at Zainawa Village Kano, Nigeria

Author(s):  
Ahmed Lawal ◽  
Adamu Abubakar

Electrical Resistivity Methods involving Schlumberger Vertical Electrical Sounding (VES) and Wenner Electrical Profiling (EP) were carried out to map the Geological features of the earth subsurface in Zainawa Area of Kano State, Nigeria. Five profiles were established; consist of six (6) VES points at each profile. GEOPULSE resistivity meter (SAS 300) was used for the data acquisition. The field data obtained have been analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity. A maximum of three geoelectric subsurface layers were delineated from the VES master curves. The geoelectric section beneath the study area was composed of top soil (clayey-sandy and sandy-lateritic), weathered layer, partly weathered (fractured basement) and fresh basement. The resistivity value for the topsoil layer varies from 20 Ωm to 600 Ωm with thickness ranging from 0.5 to 7.2 m. The weathered basement has resistivity values ranging from 15 Ωm to 593 Ωm and thickness of between 2.75 to 33.04 m. The fractured basement has resistivity values ranging from 201 Ωm to 835 Ωm and thickness of between 11 to 20.4 m. The fresh basement (bedrock) has resistivity values ranging from 1161 Ωm to 3115 Ωm with infinite depth. The depth to basement map was produced to give a good picture of the basement topography within the study area. The depth to basement ranges from 11 m around VES 01 to 85 m around VES 25 m. The map also reveals linear structures (VES 05, 21, 22 and VES 23) which trends in the NE-SW direction. These structures suggest a basement depression at these points. However, the depth from the topsoil to the bedrock surface varies between 2.5 to 37.75 m.

2021 ◽  
Vol 6 (1) ◽  
pp. 14-26
Author(s):  
Ibrahim Mohammed ◽  
◽  
Suleiman Taofiq ◽  

Vertical Electrical Soundings (VES) afford fast and economical measurements used in geophysical exploration. VES was used for groundwater exploration at the permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi. Eighteen (18) Vertical Electrical Sounding (Schlumberger array, maximum AB/2 distance 100 m) were performed, data were acquired using ABEM terrameter (SAS 300c), to determine the geoelectric units in the subsurface stratigraphy as well as to delineate groundwater potential in the area via electrical resistivity soundings. Field data collected was analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity in ohm-meter. Data was interpreted in terms of the resistivity and thickness of subsurface layers. Results indicates that three to five (3-5) distinct layers in the study area namely; top soil which is mainly sand, clayey sand/loose sand, sandy clay/fine sand and clay unit were delineated. The result also revealed that water bearing formation exists in the third layer in some identified VES locations i.e VES 3, VES5, VES13 and VES14 with very good aquifers, with thickness and corresponding resistivity values of 40.5, 37.5, 45.8, 60 m and 173, 148, 222 and 432 Ωm respectively. The electrical resistivity data, therefore gives reasonable accurate results that can be used to understand stratigraphy and sedimentary configuration in ground water exploration.


2019 ◽  
Vol 66 (2) ◽  
pp. 121-128
Author(s):  
Adedibu Sunny Akingboye ◽  
Isaac Babatunde Osazuwa ◽  
Muraina Zaid Mohammed

AbstractElectrical resistivity tomography (ERT) was used for delineating significant subsurface hydrogeological features for sustainable groundwater development in Etioro-Akoko area, Southwestern Nigeria. This study was necessitated by challenges posed on groundwater supplies from wells and boreholes in Etioro-Akoko and the neighbouring fast growing towns and villages. Field data were acquired over the area with ABEM Lund Resistivity Imaging System and were subsequently processed and inverted through RES2DINVx64 software. Results showed four distinct subsurface layers: topsoil, weathered layer, fractured bedrock and fresh bedrock (basal unit). Localised bedrock depressions occasioned by fracturing and deep weathering of less stable bedrock minerals were delineated with resistivity and thickness values ranging from 50 to 650 Ωm and 12 to ---gt--- 25 m, respectively. The localised depressions mirrored uneven bedrock topography and served as the preferential groundwater storage and hydrogeological zones in the area. The two hydrogeological zones significant for groundwater development included overburden-dependent aquifers and fractured dependent bedrock aquifers. It was, therefore, concluded that groundwater storage potential was depended on hydrogeological zones particularly at major localised bedrock depressions where fractures and groundwater recharges/discharges were evident. Wells and boreholes were proposed at bedrock depressions with thickness value not less than 12 and ---gt--- 25 m, respectively, for enhanced groundwater sustainability and quality assurance in the area.


Author(s):  
N. Kure ◽  
H. I. Daniel ◽  
C. G. Afuwai ◽  
E. J. Adoyi ◽  
I. A. Bello

Geophysical investigation for engineering studies was carried out around Faith Academy, Marmara village, Kaduna within the basement complex of North-Western Nigeria. Six Vertical Electrical Sounding (VES) were established using Schlumberger configuration. The geoelectric section revealed five subsurface layers defined by the topsoil, which comprises humus, clay and laterite; followed by weathered layer which comprises of sandy soil, fractured layer which constitutes of coarse grain sands and gravels and fresh basement which is porphyritic granite. The resistivities and thicknesses of the topsoil range from 47 - 4212 Ωm and 2 - 5 m respectively. The weathered/fractured basement has average thickness of 42 m with resistivity ranging from 350 - 774 Ωm. The Areas found to meet the conditions of high basement resistivity and shallow depth to basement, are found to be at VES A1, A2, A3, A4 and A6. Hence, VES A1 have been found to be the competent zones within the study area, and are good for the construction of high-rise buildings, roads and bridges. VES A3, A4 and A6 are areas that do not meet the conditions for construction of a high-rise buildings. However, VES A3, A4 and A6 appears to be viable for groundwater exploration with aquifer thickness ranges between 18 - 42 m and depth ranges of 6 - 10 m, while the average depth to fresh basement is 43 m.


2021 ◽  
Vol 5 (1) ◽  
pp. 18
Author(s):  
Matthew Tersoo Tsepav ◽  
Aliyu Yahaya Badeggi ◽  
Obaje Nuhu George ◽  
Usman Yusuf Tanko ◽  
Ibrahim Samuel Ibbi

<p>Electrical resistivity method employing the Schlumberger array was used to occupy forty four (44) vertical electrical sounding points in Lapai town with the aim of determining the depth to aquifers, aquifer thicknesses and aquifer protective capacity. The G41 Geotron resistivity meter was used in obtaining the apparent resistivity data which was processed using Interpex 1XD resistivity interpretation software. The results revealed four lithologic sections which include top lateritic soil, sandy clay, fractured basement and fresh basement. Both confined and unconfined aquifers were identified within the area, with four classes of aquifer proactive capacities as high, moderate, weak and poor. While the aquifer at VES 20 was highly protected, twenty other aquifers were moderately protected, eight others had weak protection and fifteen aquifers were poorly protected. The aquifers were generally of good thicknesses and at varying reasonable depths, making them good reservoirs of water in appreciable quantity. The average aquifer thickness was estimated to be 48.36m while the average depth to aquifers was estimated to be 56.68m.</p>


Author(s):  
O. F. Ogunlana ◽  
O. M. Alile ◽  
O. J. Airen

The Electrical Resistivity Tomography (ERT) data was acquired within the area suspected to have high potential for bitumen occurrence using the Wenner-Schlumberger configuration in Agbabu, southwestern Nigeria. PASI 16GL-N Earth resistivity meter instrument was used to acquire data along five (5) traverses with 5m electrode spacing and traverses length of 150m. The apparent resistivity values obtained was processed using RES2DINV software which helped to automatically obtain the 2D inversion model of the subsurface. This study has shown the occurrence of bitumen between the depth of 13.4m and 9.93m for Traverses 1, 2, 3 and Traverses 4, 5 respectively in a 2-Dimensional electrical resistivity images for boreholes with a depth of about 18m. The results indicate that the bitumen is characterized by good lateral continuity and is sufficiently thick for commercial exploitation.


Author(s):  
Olisah Nzemeka

An investigation using electrical resistivity method was conducted around a solid waste dumpsite at Nsukka in Nsukka L.G.A of Enugu State, Nigeria to investigate the level of groundwater contamination. Electrical Sounding (VES) and 2D resistivity imaging were used with a digital read out resistivity meter (ABEM SAS 1000) to acquire data in the area. A total of eight (8) sounding and six (6) 2D resistivity imagings were carried out in the area. A contaminant leachate plume was delineated in 2D resistivity sections as low resistivity zones while the VES shows the depth of aquifer. In 2D pseudosections where bluish colours with low resistivities (less than 20.80Ωm) with the depth ranging from 1.28m to 17.1m in the Line 1 and 2 are seen as contaminated zones. The rest of the lines are not contaminated because of their high resistivities (greater than 20.80Ωm). The result of the electrical resistivity survey also showed 4 - 5 layers geo-electric sections and an AA and AK type sounding curves. The VES result shows that VES 1A, 1B, 2A and 2B which are carried out on line 1 & 2 of the wenner lines showed signs of contamination with low resistivity values less than 20.80Ωm complementing the wenner results. The contamination has not yet got to where the aquifer is located on the lines. Since the depth to the aquifer ranges from 30.26m to 155.43m while maximum depth of contamination is 17.1m. It is believed that the leachate has not percolated down to the aquiferous zones as such aquifers are presumed to be free.


2018 ◽  
Vol 19 (1) ◽  
pp. 24-34
Author(s):  
Budy Santoso

Bungaya Kangin Village, Bebandem District, Karangasem Regency, Bali Province consists of paddy fields and settlements, required therefore a water source / aquifer  that can meet all these needs. One of the Geophysical Methods that can identify the aquifer is the Geoelectric Method. Geoelectric method used in this research is Resistivity Method. Data acquisition using Vertical Electrical Sounding (VES) and Electrical Resistivity Tomography (ERT) Methods. VES method is a method of measurement to determine the variation of resistivity vertically at one point. Electrical Resistivity Tomography (ERT) method is a method of measuring resistivity on soil surface / rock by using many electrode (51 electrode), to obtain sub-surface resistivity variation  lateraly and verticaly, to obtain sub-surface image. The equipment used for geoelectric measurements is  Resistivity Meter of Naniura NRD 300 Hf which has been equipped with a switchbox to adjust the displacement of 51 electrodes. Based on the resistivity modeling results, the aquifers in the study area were found in rough sandstones with resistivity values : (49 - 100) Ohm.m.  


2021 ◽  
Vol 20 (1) ◽  
pp. 125-140
Author(s):  
J.O. Coker ◽  
A.O. Atilade ◽  
A.A. Alabi ◽  
D.S. Ebeniro ◽  
G.O. Layade

Water is an essential commodity for life survival on Earth. Groundwater exists below the surface in the soil pores, fractures within rocks, fissures, and other weak geological features or zones. The aim of this research was to delineate groundwater potential within the Forest Research Institute of Nigeria (FRIN) and hence determining the possible areas suitable for siting borehole for sustainable potable water supply. Four electromagnetic traverses were carried out and ten vertical electrical sounding (VES) points were identified for detailed probing using the Schlumberger configuration. Wenner array survey was also carried out along two traverses. The VES data collected was processed using curve matching and Computer software called Winresist while Wenner array was processed using RES2DINV. The results from the interpretation of the four (4) EM profiles revealed low conductivity zone with a value ranging from 4.6 to 19.7 mS m.-1 The results of VES give a maximum of four subsurface geoelectrical layers with five curve types, which are K, Q, AK, HK, and KH. The weathered basement has a resistivity value ranging from143.8 to 450 Ωm and depth to basement ranging between 13.9 m and 39.4 m. The interpretation of the ten VES points obtained suggested that three VES points (VES 2, 5, and 7) are suitable for borehole drilling. The results of the 2D resistivity value ranges from 17.5 to 747 Ωm with a varying depth between 3.25 and 15.9 m. The results of the integrated geophysical survey techniques have proven to be an effective method for groundwater delineation in the study area. Keywords: Aquifer, Borehole, Electromagnetic, Geoelectric, and Groundwater


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