Vertical Electrical Sounding Survey Research Articles

Evaluation of groundwater potential in part of Ahmadu Bello University, Zaria, Northwest Nigeria

The need to address the acute water shortage problem within the Ahmadu Bello University Zaria Campus in Samaru necessitated this groundwater exploration project. 2D geoelectric imaging and vertical electrical sounding (VES) surveys were carried out to investigate the groundwater potential of the study area. The 2D geoelectric models and sounding curves obtained were correlated with existing borehole logs obtained from the area, hence validating the results from the 2D resistivity survey. Results from the surveys showed three-layer lithologies with varying thicknesses and resistivity values. The topsoil showed resistivity values of between 4 and 170 Ωm, characteristic of clayey sand and sandy materials. The second layer is characterized by resistivity values ranging between < 4 and 90.6 Ωm, coinciding with zones of the weathered basement. The third layer which has resistivity values ranging between 90 and 550 Ωm constitutes the basement rocks. The thicknesses of the weathered regoliths favourable for groundwater exploration vary from 13.4 m around the Amina Hall, 16.7 m northeast-southwest of Akenzua Hall, 21.2 m northwest-southeast of Akenzua Hall, 24.3 m around Alex Hall and 25.3 m around the Suleiman Hall. These very important parameters reveal the groundwater potential of the study area and therefore suggest that groundwater can be developed and harnessed for use by the University but with a greater yield around the Alex and Suleiman Halls. VES survey was integrated with the 2D resistivity survey to provide information that compliment results from the 2D resistivity survey. The sounding curves were A-Type and H-type curves exhibiting low resistivity values (5–24 Ωm) within the second layer.

Detection of shallow Aquifers Using Vertical Electrical Sounding in Abua Town, Rivers State, Nigeria

Eight Vertical Electrical Sounding surveys were carried out in Abua town in Rivers State, Nigeria to determine the depth to shallow aquifers suitable for borehole drilling for groundwater use in the town. The Schlumberger array method was employed with current electrode spread of 200 m to 600 m and the corresponding electric current and voltage measured. The apparent resistivity was obtained and plotted against half the current electrode spread with the aid of an IPWIN 12 software to obtain the field curves which were interpreted in terms of resistivity, thickness and depth of occurrence. The results revealed two to four geoelectric sections with resistivity values of 8.29 Ω to 777 Ω. The maximum depth penetrated was 56.5 m with the maximum current electrode spread used. A shallow aquifer close to the surface at Omelema waterside was observed with a thickness of 49 m. The abnormal resistivity value of this zone indicates that it was probably contaminated by saline water intrusion. At Abua LGA site, a shallow aquifer was also observed at a depth of 7.86 m. At the dump site, the shallow aquifer was contaminated by leachates while at Omelema primary school site the result revealed unconsolidated sediments. The results for Abua Amp site and Rghom site also revealed shallow aquifers at depths of 4 m and 6 m respectively.

Characterization of Quaternary Deposits in the Bou Ahmed Coastal Plain (Chefchaouen, Morocco): Contribution of Electrical Prospecting

The Bou Ahmed plain, which is part of the internal area of the Rif, is located along the Mediterranean coast, 30 kilometers of Oued Laou town. This basin is made up by a quaternary filling mainly formed by detrital fluvial facies, channeled conglomerates surmounted by fluvial sand interlayered with pebbles; these facies can be new potential aquifers formations areas. Therefore, the main goal of this study is to build a lithostratigraphic three dimensional model to identify the hydrogeological units and the reservoir geometry of the Bou Ahmed plain. In order to achieve this goal, we have created a database made up by Vertical Electrical Sounding surveys and drilling data integrated into a Geographic Information System. This database allowed us to establish a three-dimensional model of the bottom, geoelectric cross-sections, isopach and isoresistivity maps of new potential aquifers units. This approach allowed us to explain the modalities of deposition for the quaternary deposits of the Bou Ahmed plain and to identify potential hydrogeological reservoirs. These results will also be used to develop a hydrodynamic model based on MODFLOW code in the Bou Ahmed aquifer.

Hydrogeophysical assessment and protective capacity of groundwater resources in parts of Ezza and Ikwo areas, southeastern Nigeria

Geoelectrical investigations were carried to determine the aquifer potentials and protective capacity of Ezza and Ikwo areas, Ebonyi State, Southeastern Nigeria. A total of thirty-five (35) Vertical Electrical Sounding survey was conducted using the Schlumberger configuration to evaluate the character of the aquifers in the studied locations. Geoelectric sections derived from the modeling of the sounding data reveal 4 to 7 subsurface layers. The Vertical Electrical Sounding curves obtained were QH, QHK, QHKH, QQH, KHK, QHAK, and QQHK. The third and fourth layers constitute the aquiferous zones. The aquifer resistivity ranges from 11.7 to 814 Ωm, while the aquifer thickness and depth range from 99.2 to 3.4 m and 8.7 to 105.8 m respectively. The Dar Zarrouk (longitudinal conductance and transverse resistance) parameters were determined from the results. The longitudinal conductivity ranges from 0.004975 to 2.9573 mhos, whereas the transverse resistance ranges from 70.1 to 17,161.6 Ωm2. Furthermore, the aquifer potentials of the study area were shown to differ with aquifer size, structure and characteristics are influenced by the underlying geology generally. From the study, it was concluded that the western axis of the study area underlying the Ebonyi Formation has a higher aquifer potential compared to the eastern axis underlying the Abakaliki Formation. This is supported by the geology of the area with the Abakaliki Formation dominated by shales that have very low permeability, while the Ebonyi Formation consists of shales with alternations of sandstone which supports good aquifer conditions. The study area has a moderate aquifer protective capacity.

Hydro-geologic, Corrosivity and Geotechnical Implications of Geoelectric Sounding Survey at FUTA Cooperative Housing Estate, Ilaramokin near Akure Southwestern Nigeria

&#x0D; Aim: Groundwater potential evaluation, corrosivity and geotechnical competence investigations of the subsurface layers were carried at FUTA Cooperative Housing Estate, Ilaramokin near Akure Southwestern Nigeria in order to facilitate proper positioning of facilities within the estate.&#x0D; Methodology: A total of 14 vertical electrical sounding (VES) data was acquired across the estate using Schlumberger array.&#x0D; Results: The VES survey results delineated 3 - 5 geoelectric layers across the estate which corresponds to the topsoil, weathered layer, partially weathered basement, partially fractured basement and the presumed fresh bedrock. The groundwater potential map of the estate revealed that the groundwater potential is moderate (GWP of 0.5 - 0.75) to high (GWP of 0.75 - 1.0) in the western and southeastern parts of the estate. The depth slice corrosivity maps (1.0, 2.0 and 3.0 m) of the estate indicated that the corrosivity of the subsurface layers within the estate reduces with depth. The 0.5 m depth slice isoresistivity map of the estate indicates that the central and a segment of the southwestern parts of the estate are characterized with low resistivity (50 - 100 Ωm) indicating incompetence, while the estate flanks (west and east) are considered to be moderately competent (100 - 350 Ωm). Likewise, the 1.0 m depth slice isoresistivity map of the estate reveals that the central and western parts of the estate are characterized with low resistivity (50 - 100 Ωm) suggesting incompetent layer, while the northern, southern and eastern parts of the estate are moderately competent (100 - 350 Ωm).&#x0D; Conclusion: These results suggested that structural failures can be expected on any engineering structures sited at the central, northern, southern and eastern parts of the estate. Groundwater efforts should be concentrated at the western and southeastern parts of the estate.

Integrated Analysis of Geophysical Data for Road Networks Sub Base Lithology Integrity Assessment Case Study in Crystalline Basement Complex, Southwestern Nigeria

Magnetics and Electrical resistivity methods were used in the evaluation of the subsurface integrity of a 2500 m segment of Ipinsa road off the Ilesha-Akure expressway adjacent to the Federal University of Technology, Akure, Ondo State, Nigeria in order to provide guidelines for the authority whenever the road is to be constructed. The road was investigated using geophysical prospecting methods involving Magnetics profiling and Vertical Electrical Sounding (VES) technique. The magnetic data were analysed first by taking care of diurnal variation and the results were presented as relative magnetic. The VES results were presented as geoelectric sections. The results from the two methods were stacked for easy correlation. The results from the Magnetics method study shows the presence of near-surface linear geologic structures and of varying length, depth, and altitude at different distances (350, 550, 650, 840, 870, 900, 1080 and 1160 m) and depths (5, 12, 13, 15, 15.5, 16, 17 and 19 m) respectively, which suggest the probable fracture zones that are inimical to the foundation of the road subgrade. The vertical electrical sounding survey were conducted at points of anomaly and non-anomalous zones based on the magnetic survey results. This is done to further delineate the fracture zones and correlate the results to get enough information of the subsurface. The corresponding geoelectric results delineated weathered/fractured bedrock with resistivity range of 222 - 412 Ωm at distances 650, 800 - 900 and 1080 - 1160 m along Traverses A and B. Likewise at distances 1380 - 1600 m, 2040 m, 2240 m, 2260 m and 2540 m along traverses’ C and D. The integrity assessment of the Ipinsa road network sub base lithology was successfully assessed using the geophysical modeled results and possible fractured bedrock and saturated/clayey sub soil material zones that are inimical to road stability were delineated. The research findings are valuable for precise decision in road infrastructural design.

Optimizing groundwater quality exploration for irrigation water wells using geophysical technique in semi-arid irrigated area of Pakistan

Geophysical method using vertical electrical sounding (VES) technique, in combination with borehole lithological data analysis was used to locate the subsurface layers containing good quality water in District Okara, Punjab Pakistan. Ten VES surveys (VES-1-10) were conducted by utilizing the Schlumberger electrode configuration. A calibrated model was developed for the study area by integrating the resistivity and lithological data. The model showed that the study area has three geoelectric layers below the water table with resistivities 50-100 Ω-m, 25-50 Ω-m and <25 Ω-m describing the good, marginal and poor quality water layers respectively. Integrated data analysis show that six sites (i.e., VES-1, VES-2, VES-3, VES-5, VES-7, & VES-10) have layers of good quality water at different depths. Out of these 6 sites, 3 sites (VES-3, VES-7 and VES-10) are suitable for installing the irrigation water wells in terms of water quality and potential while the remaining three sites (VES-1, VES-2 and VES-5) were not suitable due to shallow thickness of good quality aquifer. Three sites VES-3, VES-5 and VES-10 were selected for drilling in order to validate the modeled results, samples were collected from each 1.5–3.0 m depth for the laboratory analysis. The results showed that the resistivity data were in close agreement with the lithological data and VES-10 was most suitable for groundwater extraction. An Irrigation tube-well was installed at VES-10 and its quality was monitored for one year which showed successful supply of groundwater in terms of quality and potential.

Investigation of the Effect of Highway Runoff along Lagos-Badagry Expressway Using Electrical Resistivity Tomography and Physiochemical Methods

Geophysical and physiochemical investigations were carried out along Lagos-Badagry Expressway, Southwest, Nigeria on three locations dominated by highway runoff, with a view to monitoring the effect of highway runoff on nearby groundwater. The locations were: Iyana Isashi, Iyana Era and Agbara. An overview of the subsurface resistivity distribution was achieved employing Vertical Electrical Sounding (VES) using Schlumberger array and Two-dimensional (2D) resistivity imaging (Wenner array). The ABEM Terrameter SAS 1000 was used for both VES and 2D resistivity surveys and the data were analysed using IPI2win and RES2DINV, respectively. The VES results showed up to four geoelectric layers consisting of sand, clayey sand, clay and sandy soils. The resistivity at Agbara was found varying from 3.52 Ωm - 11 Ωm. This low resistivity value showed a high level of infiltration of highway runoff into the subsurface, thereby causing contamination of the groundwater. Iyana Isashi and Iyana Era have a relatively moderate resistivity values ranging from 103 Ωm to 178 Ωm. Physiochemical analysis of groundwater samples collected at the study locations revealed high electrical conductivity, total dissolved solids and pH values. The results of the borehole sample taken at 32 m away from the profile point at Agbara produced higher values of electrical conductivity and total dissolved solids than those of other locations, hence validating the electrical resistivity surveys, indicating that the groundwater sample from the survey point at Agbara is contaminated.

Using Vertical Electrical Soundings to characterize seawater intrusions in the southern area of Romanian Black Sea coastline

Seawater intrusions are a major environmental hazard for coastal freshwater aquifers. They are generated mainly by the uncontrolled exploitation of freshwater in pumping stations, if the aquifers are in hydraulic connection with the sea. In Romania, such marine intrusions have occurred in the southern part of Black Sea’s coastline, in Costinești and Vama Veche resorts, contaminating the main aquifers hosted in Sarmatian (late Middle Miocene) limestones, at distances ranging from hundreds of meters to over 2 km inland. For the study of these salinization phenomena, Vertical Electrical Sounding (VES) surveys were performed in the affected areas. These surveys allowed the delineation and spatial–temporal monitoring of the intrusions and offered information related to faults that may have provided pathways for seawater migration toward the exploitation wells. The 1D interpretation of VES apparent resistivity data was performed via a set of novel software applications. The forward modeling component of the applications uses digital linear filtering and allows the simulation of theoretical VES responses for horizontally-layered geological media with virtually unlimited number of layers. The pseudo-inversion component of the applications is based on a random sampling of the parameters space of the geoelectrical models. The interpretation of VES surveys recorded in Vama Veche area by using the elaborated software indicates that the seawater intrusion occurs at more than 40 m depth. This agrees with a well flow test which produced saltwater at 40–60 m depth in that area.

Geoelectrical resistivity investigation for hydrogeology conditions and groundwater potential zone mapping of Kodavanar sub-basin, southern India

The main purpose of this study was to determine the hydrogeological conditions and to identify the groundwater potential zone in Kodavanar sub-basin using vertical electrical sounding (VES). IGIS DDR3 instrument was used in the present study to achieve the target. GIS plays a powerful tool which is used in the current study to detect the favorable groundwater potential zone and suitable sites for artificial recharge. Basically, the subsurface investigation was carried out through the geophysical surveys (Schlumberger method). To achieve the aim, 50 VES survey was carried out in distinctive parts of the study area. The field data were interpreted by IPI2Win software, which is used to determine the resistivity and thickness of the different layers. Finally, the deciphered information was approved with the bore well information at the recommended site. It demonstrates that the outcome found from IPI2Win programming was observed to be 100% right in the field check. The spatial distribution maps for weathered zone resistivity and its thickness were prepared using conventional GIS method. All the themes were integrated into the GIS platform.

Application of vertical electrical sounding for groundwater exploration of Cape Coast municipality in the Central Region of Ghana

The focus of this study is to delineate groundwater-bearing zones for the drilling of boreholes to ensure sustainable water supply in the Cape Coast municipality using the vertical electrical sounding (VES) technique. A total of 25 VES points were conducted of which thirteen (13) were test drilled. The VES survey was conducted using the ABEM SAS 1000 Terrameter with the Schlumberger configuration and a maximum half current electrode spacing (AB/2) of 100 m. The VES data were processed and interpreted using the ZONDIP resistivity inversion software. Both qualitative and quantitative interpretations were used to ascertain the best points for drilling a successful borehole (yield > 13 l per minute). The criteria used in selecting a promising site for test drilling are as follows: the nature of the curve (observing the nature of the VES curves), the overburden thickness and the bedrock resistivity. The study revealed a drilling success rate of 90% with an average borehole yield of 118 l/m. A careful review of the resistivity variation with depth revealed that areas with the increasing trend of resistivity from the overburden to the bedrock are most likely to produce unproductive wells whilst areas with decreasing resistivity trend from the overburden to the bedrock are more likely to produce productive wells. The reflection coefficient (Rc) values generally range between − 0.8274 and 0.1210 and suggest a highly fractured formation with respect to the Sekondian rocks. Within the granite, the Rc showed more competent formation with values ranging from 0.4040 to 0.6136. A comparison between the depth to bedrock as predicted by VES and the borehole logs was in strong agreement with the correlation coefficient value (R2 = 0.9089). On the other hand, the study revealed a relatively week correlation (R2 = 0.4325) between the final drilled depth and the borehole yield. The study also finds four major groundwater-bearing zones in the terrain which range between 12 and 28 m, 31 and 40 m, 43 and 59 m, and 80 and 104 m. The bedrock resistivity values most likely to yield productive boreholes with yields greater than 13 l/m range from 54 to 845 ohm-m with a decreasing resistivity between the overburden and the bedrock. Bedrock resistivities more than 900 Ωm with an increasing resistivity between the overburden and the bedrock are most likely to be unsuccessful. Within the terrain, the average depth for drilling productive wells in the Sekodian rocks is 68 m with the final borehole depth ranging from 35 to 120 m. The study therefore has demonstrated the efficacy of the VES technique as a tool in delineating groundwater potential zones for the drilling of boreholes.

Resistivity and Seismic Refraction Studies on Kısıklı Landslide (Antalya, Turkey)

When natural slope is disturbed by human activity such as road construction and infrastructure, continuous landslide monitoring is important to prevent loss of material and life. Therefore, this study aims to determine the landslide material, the possible sliding surface and the influence of groundwater on the landslide occurrence. Low cost monitoring landslide is performed which is vertical electrical sounding (VES) and seismic refraction methods. Case study in Kisikli district, Antalya Province, Mediterranean Region of Turkey. VES survey was performed using Schlumberger electrode array at six locations. VES results interpretation leads to detect of maximum five geo-electrical layers. First, second and third layers represent saturated and permeable layer, while fourth and fifth layers correspond to an impermeable layer. Seismic refraction measurements were carried out on three profile layers. Low velocity and elastic parameters relatively correspond to the permeable materials in near surface with thickness about 4-5 m higher porosity. The integrated of VES and seismic survey allows mapping the weathered material at depth and providing depth information of the sliding surface which occurs at a depth between approximately 5 m and 20 m.

Discovery of buried historical structures in the Kaveri–Kollidam interfluve, southern India

AbstractThe Srirangam interfluve, formed between the Kaveri and Kollidam Rivers in southern India, has been a religious and cultural human settlement for over 2000 years of recorded history. It contains thousands of ancient, yet in use, man‐made structures. Owing to its geographic location, and episodic catastrophic floods from the Kaveri and Kollidam Rivers, the region has been inundated frequently leading to the burial of many smaller structures. Thematic maps of geomorphology, vegetation index, land use, digital elevation model, slope, etc., have been generated through multi‐temporal remote sensing satellite images. A compilation of historic (stone inscriptions, temple documents) and literature data followed by detailed survey of the region using vertical electrical sounding (VES) and ground‐penetrating radar (GPR) through 200 and 400 MHz shielded antennas has led to the discovery of several buried manmade structures at various depths ranging from 0.54 to 3.55 m below ground level (b.g.l.) that were known only in the literature, hearsay and folklore. The VES, GPR and field surveys delineated four major soil/sediment horizons below the ground surface. Sedimentological characteristics of a massive river sand bed found overlying a weathered zone suggest deposition during a major catastrophic flood. The occurrence of flood deposits burying historic structures especially adjoining the regional tectonic structure indicate episodically active climatic and tectonic processes that played a significant role in the burial of ancient‐historic land surface and manmade structures that were under desolation after invasion and desecration by war‐lords of yore. This study demonstrates the potential of combining traditional knowledge and modern technologies to gain insights to locate historic/archaeological sites and discover buried structures.

Geospatial technique for delineation of groundwater potential zones in mine and dense forest area using weighted index overlay technique

In the present study, groundwater potential zones for the assessment of groundwater availability in Samij sub-basin, which lies in Tensa valley of Sunderghar district, Odisha were established with the integration of remote sensing and geographical information system support. Delineation of potential groundwater zones in the study area was done using the IRS-LISS III, Cartosat-I satellite data of 30m resolution and Survey of India toposheets. Various thematic layers viz., geomorphology, slope, land-use, lineament density, drainage density, and soil map generated in this study were transformed to raster data using the feature to raster converter tool in ArcGIS 9.3. The integration of all the thematic maps results into five groundwater potential zones: poor, moderate, good, very good, and excellent. Further, the weighted range for various groundwater potential zones was categorized as excellent (7.10–8.00), very good (6.1–7.0), good (5.1–6.0), moderate (4.1–5.0), and poor (0.0–4.0). The results were compared with the vertical electrical sounding survey data for ground truth cross-verification. The results showed that the study area falls within the range of ‘moderate to good’ groundwater potential zones, which accounts for about 75% of the total study area.

Geophysical evaluation of groundwater potential in part of southwestern Basement Complex terrain of Nigeria

The geophysical assessment of groundwater in Awa-Ilaporu, near Ago Iwoye southwestern Nigeria was carried out with the aim of delineating probable areas of high groundwater potential. The area falls within the Crystalline Basement Complex of southwestern Nigeria which is predominantly underlain by banded gneiss, granite gneiss and pegmatite. The geophysical investigation involves the very low frequency electromagnetic (VLF-EM) and Vertical Electrical Sounding (VES) methods. The VLF-EM survey was at 10 m interval along eight traverses ranging between 290 and 700 m in length using ABEM WADI VLF-EM unit. The VLF-EM survey was used to delineate areas with conductive/fractured zones. Twenty-three VES surveys were carried out with the use of Campus Ohmega resistivity meter at different location and at locations areas delineated as high conductive areas by VLF-EM survey. The result of VLF-EM survey along its traverse was used in delineating high conductive/fractured zones, it is, however, in agreement with the delineation of the VES survey. The VES results showed 3–4 geoelectric layers inferred as sandy topsoil, sandy clay, clayey and fractured/fresh basement. The combination of these two methods, therefore, helped in resolving the prospecting location for the groundwater yield in the study area.

Vertical electrical sounding to delineate the potential aquifer zones for drinking water in Niamey city, Niger, Africa

Niger is a landlocked African country and the only source of surface water is the Niger River which flows in the western part of Niger and only few villages near to the river gets benefited from it, leaving most of the areas dependent on groundwater solely. The groundwater resources in Niger are mainly used for drinking, livestock and domestic needs. It can be observed that the water exploitation is minimal there due to several factors like undeveloped areas, less population, limited wells, rain-fed irrigation, etc. The delineation of potential aquifer zones is an important aspect for groundwater prospecting. Hence, the direct current (DC) resistivity soundings method also known as vertical electrical sounding (VES) is one of the most applied geophysical techniques for groundwater prospecting that was used in the capital city, Niamey of Niger. Twelve VES surveys, each of AB spacing 400 m were carried out in lateritic and granitic rock formations with a view to study the layer response and to delineate the potential zones. Potential aquifer zones were at shallow depth ranging from 10 to 25 m for the drilled borehole depth of 80–85 m in every village. Analysis of the result showed a good correlation between the acquired data and the lithologs.

Electrical and electromagnetic surveys to locate possible causes of water seepage to ground surface at a quarry open pit near Helwan city, Egypt

Water seepage to ground surface at a limestone quarry located at Wadi Garawy about 20 km south-east of Helwan city in Egypt posed a real threat to the mining activity at the quarry. The quarry area is known to be very dry for decades and away from water utilities and infrastructures that may cause water leaks to the quarry. Geophysical investigation including 1D Vertical Electrical Sounding (VES), 2D Electrical Resistivity Tomography (ERT) and 1D Transient Electromagnetic (TEM) surveys were conducted to characterize the rock sequence and locate what could be a possible source of water seepage to the quarry. The resistivity profiles generated from the VES and TEM surveys mapped the rock units in the area down to depths exceeded 100 m. The ERT profiles acquired from the quarrying zone close to the water seepage spot have imaged the top of groundwater level at few meters below the ground surface at the quarry open pit. The spot of groundwater seepage seemed to occur at an area of limestone dissolution that were filled by finer sediments. The finer sediments acted as a hydrological conduit that allowed an upward seepage of groundwater to ground surface under the capillary action effect.

Using Vertical Electrical Soundings for Characterizing Hydrogeological and Tectonic Settings in Deir El-Adas Area, Yarmouk Basin, Syria

The present study is aimed at characterizing the subsurface geological and tectonic structure in Deir El-Adas area, by using Vertical Electrical Sounding survey (VES) and hydrogeological investigations, in order to determine the causes of the failure for the majority of the wells drilled in the area. The survey data was treated in three different approaches including direct VES inversion, pseudo-2D method and horizontal profiling, in order to maximize the reliability of the data interpretation. The results revealed the presence of a local faulted anticline structure at the top of the Paleogene formation, underneath the basaltic outcrops where Deir El-Adas village is situated. The appearance of this subsurface anticline structure has complicated the local hydro-geological situation, and most likely led to limitation of the groundwater recharge in the area. Moreover, the performed piezometric and discharge maps indicated the presence of a notable groundwater watershed, in addition to feeble water productivity of the wells drilled adjacent to Deir El-Adas, mostly related to the subsurface geological and tectonic settings in the area.

Geophysical Investigation of the Precambrian Marble Occurrence in Itobe Area, Central Nigeria

Aim: The aim of the study is to delineate the outline of the Itobe marble using geophysical electrical survey method. Study Design: Eight (8) vertical electrical sounding surveys were carried out along a profile parallel to the trend of the marble outcrop. Place and Duration of Study: The study area is Itobe and its environs in Kogi state, central Nigeria. Field geophysical resistivity survey of the study area was carried out between January and April 2012. Methodology: The field resistivity sounding surveys were carried out with an ABEM SAS (1000) Terrameter using the Schlumberger electrode array. Interpretation of the resistivity sounding data was carried out first by curve matching technique and followed by computer iterative interpretation technique using the Winresist software (version 1.0). Results: The results of the study revealed the occurrence of an additional marble unit (Mass III) at an elevation of 105m besides two marble units identified from outcrop studies. The thickness of the marble in mass I is 0.6m and that of mass II is 6m. Conclusion: The outcrop geological survey revealed the occurrence of two marble units Short Research Article British Journal of Applied Science & Technology, 4(13): 1891-1904, 2014 1892 (described as mass I and mass II).The geophysical survey revealed an additional marble unit (described as mass III) in the study area.

Karstic water exploration using the Schlumberger VES and dipole-dipole resistivity profiling surveys in the Tepal area, west of Shahrood, Iran

To have sustainable development in a country, the need for clean groundwater resources is undoubted. Due to the importance and high quality of karstic waters in supplying water in Iran, especially in Shahrood city, this study aim to recognize and explore Karstic waters in southwest of Tepal area, Shahrood. For this purpose, the study used the integration of the results obtained from the methods of vertical electrical sounding (VES) and resistivity profiling. The VES surveys were performed in 10 sounding points using the Schlumberger array with electrode separations of a maximum 500 meters. The resistivity profiling surveys were carried out along four lines with a length of more than four kilometers using dipole-dipole electrode array with 75m electrode spacing and dipole steps 1 to 8 in the study area. Then, one-dimensional (1-D) modeling and interpretation of the sounding results, using master curves and IX1D software, and twodimensional (2-D) modeling and interpretation of the profiling results using Res2DINV were made. As a result of the interpretation and integration of the results, karstic water zones in the study area were recognized, and based on that, suitable locations for drilling to access and extract karstic groundwater were introduced.