scholarly journals Geophysical Investigation Using 3-Dimensional Grid-Formation for Subsurface Lithology Characterization (A Case Study of Ovia North East, Edo State, South South Nigeria)

2021 ◽  
pp. 182-194
Author(s):  
O. J. Airen ◽  
P. S. Iyere
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Geophysical Investigation ◽  
Clayey Sand ◽  
Resistivity Data ◽  
North East ◽  
Lateral Distance ◽  
Lateral Plane ◽  
Resistivity Model ◽  
Edo State

Geophysical investigations using three-dimensional (3D) grid formation was carried out in Ovia North East Local Government Area of Edo State, Nigeria for subsurface lithology characterisation so as to generate a comprehensive basemap of the study area. Twelve (12) traverses in form of a rectangular grid were occupied for the 2D Electrical Resistivity Imaging (ERI) using the Wenner array. The 2D were all collated to form the 3D grid. The 2D Electrical Resistivity data was processed by the inversion of the 2D apparent resistivity data using the DIPRO software to generate the 2D inverted resistivity section while the 3D inverted resistivity model was done by inverting all the twelve traverses using 3DEarthimager software to model the 3D cube. The results of the 2D ERI revealed three (03) to five (05) resistivity structures across the twelve traverses indicating clay/clayey sand, sand and sandstone on a 200 and 300 m lateral distance and corresponding depth of 39.6 and 57.3 m across each traverses. Resistivity values generally varies from 16.8 – 45302 Ωm across Traverse 1 – 12. The layer horizontal depth slices of the 3D inverted resistivity distribution are in six layers, which are; 0 - 5 m, 5 – 10.8 m, 10.8 – 17.4 m, 17.4 – 25 m, 25 – 33.7 m and 33.7 – 43.8 m. The 3D inverted resistivity model within the study area covered lateral plane (the roll axis), 300 m, in the x plane (the pitch axis), 200 m lateral distance was covered and in the depth plane (the yaw axis), a maximum depth of 66 m is imaged. The inverted 3D Resistivity values generally vary from 189 - 6149 Ωm across the study area. The resistivity structures delineated from the 3D model are clayey sand and sand.

Hydrogeophysical Survey of Groundwater Development at Okada Community Ovia North – East L.G.A. Edo State

2018 ◽  
Vol 2 (1) ◽  
pp. 39-45
Author(s):  
M. O. Ehigiator
Keyword(s):  
Global Navigation Satellite Systems ◽  
Geophysical Investigation ◽  
Satellite Systems ◽  
North East ◽  
Long Time ◽  
Electrical Sounding ◽  
Edo State ◽  
Global Navigation Satellite ◽  
Water Problems ◽  
Aquifer Unit

Geophysical investigation was conducted at Okada community in ovia North Local Govertment area of Edo state to determine the prospect of aquifer zone. The Petrozenith PZ-02 Terrameter, one of the Electrical Resistivity Equipment was used to conduct a Vertical Electrical Sounding (VES) in the study area. The Garmin Etrex 10 Global Navigation satellite systems (GNSS) was used to acquire Geodetic coordinates of point where VES observations were made. This research was carried out as a pre-drilling Hydro-geophysical survey conducted for the purpose of surveying and studying the proposed water borehole site at Okada Community that has suffered acute water problems for a very long time. There have been series of boreholes drilled in the studied area but all are dry wells. This survey was conducted to investigate the subsurface complexity of the sites in respect of lithology and to recommend the total drill depth based on the prospective aquifer unit so identified. Result of interpretation suggests that the area is underlain with substantive aquiferous formation but at a depth not exceeding 121.60 m (398.95 ft), which is the lower aquifer unit. The value of elevation at point of observation referenced to mean sea level is 94 m.

scholarly journals Designing Aquifer Model for the Banks of the Serayu River, Sokawera, Somagede, Banyumas, Indonesia by Means of 1D-Electrical Resistivity Data

2021 ◽  
Vol 53 (3) ◽  
pp. 344-357
Author(s):  
Sehah Sehah ◽  
Hartono Hartono ◽  
Zaroh Irayani ◽  
Urip Nurwijayanto Prabowo
Keyword(s):  
Electrical Resistivity ◽  
Model Potential ◽  
Research Area ◽  
Shallow Aquifer ◽  
Shallow Aquifers ◽  
Clayey Sand ◽  
Deep Aquifer ◽  
Resistivity Data ◽  
Deep Aquifers ◽  
Groundwater Aquifer

A geoelectric survey using the 1D-electrical resistivity method was applied to design a groundwater aquifer model for the banks of the Serayu River in Sokawera Village, Somagede District, Banyumas Regency, Indonesia. The aim of this research was to identify the characteristics of aquifers in the research area based on resistivity log data. Acquisition, modeling, and interpretation of resistivity data were carried out and the results were lithological logs at seven sounding points. Correlation between the lithological logs resulted in a hydrostratigraphic model. This model is composed of several hydrological units, i.e. shallow aquifer, aquitard, and deep aquifer. The shallow aquifers are composed of sandy clay (10.81-18.21 Wm) and clayey sand (3.04-7.43 Wm) with a depth of groundwater from the water table to 27.51 m. The deep aquifers are composed of sandstone with variation of porosity (2.24-12.04 Wm) at a depth of more than 54.98 m. Based on this model, potential shallow aquifers were estimated to be at sounding points Sch-5, Sch-6, and Sch-7. This hydrostratigraphic model shows that the two types of aquifers are separated by an aquitard layer, allowing groundwater infiltration from the shallow aquifer to the deep aquifer and vice versa. Moreover, the Serayu riverbanks in this research area are estimated to be a groundwater discharge area.

scholarly journals A Resistivity Survey of Phosphate Nodules in Oshoshun, Southwestern Nigeria

2018 ◽  
Vol 65 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Oluseun Adetola Sanuade ◽  
Abayomi Adesola Olaojo ◽  
Adesoji Olumayowa Akanji ◽  
Michael Adeyinka Oladunjoye ◽  
Gabriel E. Omolaiye
Keyword(s):  
Electrical Resistivity ◽  
Apparent Resistivity ◽  
Inversion Algorithm ◽  
Clayey Sand ◽  
Southwestern Nigeria ◽  
Resistivity Data ◽  
Resistivity Method ◽  
Dahomey Basin ◽  
Geophysical Study ◽  
Electrical Resistivity Method

Abstract This geophysical study was carried out to determine the occurrence of phosphate nodules in the Oshoshun Formation of the Dahomey Basin, Southwestern Nigeria. The electrical resistivity method, comprising 1D vertical electrical sounding (VES; using Schlumberger array) and 2D geoelectrical imaging (using Wenner array), was used to determine the nature and depth of occurrence of the phosphate nodules. Six profile lines were established within the study area, and inverted sections were generated from the apparent resistivity data using DIPRO inversion algorithm. Five VES points were also acquired in the study area, and Win- Resist programme was used to process and interpret the field resistivity data. Four pits were dug along the profiles to verify the interpreted results. The results obtained by both techniques reveal similar geoelectric units: the top soil, clay, clayey sand and clay at different depths. These layers host pockets of phosphate nodules (78-≥651 Ωm) with varying thicknesses. The strong correlation between the lithology profiles obtained from the pits and the interpreted results of the inverted apparent resistivity sections demonstrates the efficacy of the electrical resistivity method in characterising phosphate occurrence within the formation.

2D ELECTRICAL RESISTIVITY TOMOGRAPHY FOR THE ASSESSMENT OF MINERALS’ OCCURRENCES IN UGONEKI, EDO STATE, SOUTH-SOUTH, NIGERIA

2021 ◽  
Vol 5 (2) ◽  
pp. 635-639
Author(s):  
Y. S. Onifade ◽  
V. B. Olaseni ◽  
I. G. Baoku ◽  
C. Eravwodoke
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Geophysical Investigation ◽  
Resistivity Tomography ◽  
Entire Study ◽  
The North ◽  
Resistivity Method ◽  
Lateritic Clay ◽  
Edo State ◽  
Entire Study Area

Geophysical investigation using the 2D Electrical Resistivity Tomography (ERT) was carried out to assess the subsurface of Ugoneki and its environs in order to investigate for minerals. A total of six (6) traverses, 200 m long each, three (3) transverse lines were in the North-South direction and the other three (3) traverses in the West-East direction using the Wenner electrode configuration. 2D Wenner resistivity data were acquired along each traverse. The data were inverted to reveal a spatially continuous resistivity distribution in 2D within the study area. The 2D results reveal a depth of 39.6 m across each traverse. Resistivity values vary from 87.1 – 3423 Ωm in the entire study area. From the standard resistivity table, the following solid and non-metallic type of minerals can be delineated in the study area which is representative of sandy clay, lateritic clay sand, sandstone and limestone with resistivity values that range from 87.1 – 89.9 Ωm, 1201 – 1462 Ωm, 2069 – 3423 Ωm, and 2069 – 3423 Ωm respectively. The implication of this research is to know the type and the particular location where these non-metallic solid minerals are located in the subsurface for future exploration. The results of resistivity values are compared with those in the literature and are found to be in good agreement. In order to quantify these minerals, it is also recommended to use higher dimension (3D) of resistivity method (ERT) in the study area.

Geoelectrical Characterization of the Al-Kawamil New Settlement, Sohag, Egypt

2019 ◽  
Vol 24 (2) ◽  
pp. 327-332
Author(s):  
Mohammed A. Mohammed ◽  
Abdelbaset M. Abudeif
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Site Investigation ◽  
University Campus ◽  
Clayey Sand ◽  
Near Surface ◽  
Drilling Site ◽  
The University

Electrical resistivity tomography (ERT) is one of the most effective geophysical methods used to acquire detailed pictures of subsurface conditions without drilling. Site investigation using two- and three-dimensional electrical resistivity imaging is now a fundamental step before the design and construction of campus buildings at the University of Sohag in Egypt. In this study, an ERT survey was implemented at two pre-defined sites with the aim of selecting the most favorable location for construction of a new educational building on the university campus. The resistivity results were confirmed with boreholes drilled at both sites. RES2DINV and RES3DINV software were used for data processing and interpretation. The results show that the near surface sedimentary succession beneath both sites consists of four geoelectrical and lithological units. From the surface to a depth of 20 m, these layers are: unit 1) unconsolidated boulders and gravels intercalated with percentages of sand and reddish clay; unit 2) fine crushed calcareous gravels and sands with clays intercalations; unit 3) dry sand and clayey sand; and unit 4) shale, at the base. According to an evaluation of the presence and abundance of shale and sand contents cracks, fissures and faults, the second site is identified as more suitable for construction.

scholarly journals Magma reservoir beneath Azumayama Volcano, NE Japan, as inferred from a three-dimensional electrical resistivity model explored by means of magnetotelluric method

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Masahiro Ichiki ◽  
Toshiki Kaida ◽  
Takashi Nakayama ◽  
Satoshi Miura ◽  
Mare Yamamoto ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Confidence Interval ◽  
Hydrothermal Fluid ◽  
Volume Fraction ◽  
Source Region ◽  
Three Dimensional ◽  
Magma Reservoir ◽  
Resistivity Model ◽  
Magnetotelluric Method ◽  
Ne Japan

AbstractAn electrical resistivity model beneath Azumayama Volcano, NE Japan, is explored using magnetotelluric method to probe the magma/hydrothermal fluid distribution. Azumayama is one of the most concerning active volcanoes capable of producing a potential eruption triggered by the 2011 Tohoku-Oki Earthquake. The three-dimensional resistivity model reveals a conductive magma reservoir (< 3 Ωm) at depths of 3–15 km below sea level (bsl). The 67% and 90% confidence intervals of resistivity are 0.2–5 Ωm and 0.02–70 Ωm, respectively, for the magma reservoir. We assumed dacitic melt + rock at a shallow depth of 4 km bsl and andesitic melt + rock at a greater depth of 9 km bsl. The confidence interval of resistivity cannot be explained by using dacitic melt + rock condition at a depth of 4 km bsl. This suggests that very conductive hydrothermal fluids coexist with dacitic melt and rock in the shallow part of the magma reservoir. For the depth of 9 km bsl, the 67% confidence interval of resistivity is interpreted as water-saturated (8.0 weight %) andesitic melt–mafic rock complex with melt volume fractions greater than 4 volume %, while the shear wave velocity requires the fluid and/or melt volume fraction of 6–7 volume % at that depth. Considering the fluid and/or melt volume fraction of 6–7 volume %, the conductive hydrous phase is likewise required to explain the wide range of the 67% confidence interval of resistivity. The Mogi inflation source determined from geodetic data lies on the resistive side near the top boundary of the conductive magma reservoir at a depth of 2.7 or 3.7 km bsl. Assuming that the resistivity of the inflation source region is above the upper bound of the confidence interval of resistivity for the conductive magma reservoir and that the source region is composed of hydrothermal fluid + rock, the resistivity of the source region is explained by a hydrothermal fluid volume fraction below 5 volume %, which is the percolation threshold porosity in an effusive eruption. This indicates that the percolation threshold characterizes the inflation source region.

scholarly journals Deep Electrical Resistivity Tomography for a 3D picture of the most active sector of Campi Flegrei caldera

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. Troiano ◽  
R. Isaia ◽  
M. G. Di Giuseppe ◽  
F. D. A. Tramparulo ◽  
S. Vitale
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Three Dimensional ◽  
Campi Flegrei ◽  
Gaseous Emissions ◽  
Resistivity Tomography ◽  
Tectonic Reconstruction ◽  
Resistivity Model ◽  
Fumarole Field ◽  
First Time

Abstract The central sector of the Campi Flegrei volcano, including the Solfatara maar and Pisciarelli fumarole field, is currently the most active area of the caldera as regards seismicity and gaseous emissions and it plays a significant role in the ongoing unrest. However, a general volcano-tectonic reconstruction of the entire sector is still missing. This work aims to depict, for the first time, the architecture of the area through the application of deep Electrical Resistivity Tomography. We reconstructed a three-dimensional resistivity model for the entire sector. Results provide useful elements to understand the present state of the system and the possible evolution of the volcanic activity and shed solid bases for any attempt to develop physical-mathematical models investigating the ongoing phenomena.

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