Vertical Electrical Sounding Measurements Research Articles

Assessment of Potential Potable Water Reserves in Islamabad, Pakistan Using Vertical Electrical Sounding Technique

This study aimed to investigate the potential reserves of potable water in Islamabad, Pakistan, considering the alarming depletion of water resources. A detailed vertical electrical sounding (VES) survey was conducted in two main localities: Bara Kahu (Area 1) and Aabpara to G-13 (Area 2), based on accessibility, time, and budget constraints. A total of 23 VES measurements were performed, with 13 in Area 1 and 10 in Area 2, reaching a maximum depth of 500 m. Geologs and pseudosections were generated to assess lithological variations, aquifer conditions, and resistivity trends with depth. Statistical distribution of resistivity (SDR), hydraulic parameters, true resistivity, macroanisotropy, aquifer depth and thickness, and linear regression (R2) curves were calculated for both areas, providing insights into the aquifer conditions. The results revealed that the study areas predominantly consisted of sandy lithology as the aquifer horizon, encompassing sandstone, sandy clay, and clayey sand formations. Area 2 exhibited a higher presence of clayey horizons, and aquifers were generally deeper compared to Area 1. The aquifer thickness ranged from 10 m to 200 m, with shallow depths ranging from 10 m to 60 m and deeper aquifers exceeding 200 m. Aquifers in Area 1 were mostly semi-confined, while those in Area 2 were predominantly unconfined and susceptible to recharge and potential contamination. The northwest–southeast side of Area 1 exhibited the highest probability for ground resource estimation, while in Area 2, the northeast–southwest side displayed a dominant probability. The study identified a probable shear zone in Area 2, indicating lithological differences between the northeast and southwest sides with a reverse sequence. Based on the findings, it is recommended that the shallow aquifers in Area 1 be considered the best potential reservoir for water supply. In contrast, deeper drilling is advised in Area 2 to ensure a long-lasting, high-quality water supply. These results provide valuable information for water resource management and facilitate sustainable water supply planning and decision making in Islamabad, Pakistan.

Estimasi Kedalaman Batuan Dasar di Kampung Yabaso Kabupaten Jayapura Menggunakan Metode Vertical Electrical Sounding Konfigurasi Schlumberger dan Metode HVSR

Research on the estimation of bedrock depth in Yabaso village, Jayapura district using the Schlumberger configuration Vertical Electrical Sounding (VES) method and the HVSR method has been carried out. The total observation points are three points where VES is one point and VHSR are two observation points. VES measurements used a set of resistivity meter model AK HV 500 with a maximum spread length of the current electrode is 100 m. HVSR measurements use a portable seismograph set and the measurement time for ambient seismic waves is 60 minutes. VES and HVSR data processing respectively using IPI2Win and Geopsy software. The model parameters resulting from the inversion of the VES data show that there are nine layers with a resistivity range between 18 – 25,260 Ωm. Layer 1 is a heap of sandy gravel with a resistivity value of 92 Ωm. Layers 2 to 7 are part of alluvium formations and coastal deposits (Qa) with resistivity values of 18 – 264 Ωm. While layers 8 and 9 are fragments of weathered ultramafic rock (um) and compact and dry ultramafic rock respectively. The source rock (bedrock) is layer 9 which is at a depth of 42 m. The results of HVSR data processing show that the natural frequencies at the two observation points are very small (<2.5 Hz), namely 0.85 Hz and 0.83 Hz. According to Kanai's classification, this frequency value is type I, class IV, namely alluvial rock. The depths of source rock based on the HVSR method at measurement points 1 and 2 are 43 m and 44 m, respectively. There is agreement in the estimation of the depth of the source rock obtained from the VES and HVSR methods even though the two methods utilize two different physical parameters.
 Keywords: HVSR; VES configuration Schlumberger; Resistivity; Jayapura

APPLICATION OF GEOELECTRICAL METHOD TO STUDY GROUNDWATER POTENTIAL IN ISARA, REMO NORTH MUNICIPAL AREA OF OGUN STATE, NIGERIA.

Fifteen (15) Vertical Electrical Sounding (VES) and three (3) Constant Separation Traversing (CST) data were acquired within the study area using Pasi Terrameter (model 16GL). The Schlumberger electrode array was deployed for the VES while Wenner array was used for the 2-D CST. Both qualitative and quantitative approach were used for the VES measurements. The raw data were Curve-matched and inversion of the data using WinResist (1.0) to create a model of perfect fit indicating layer thickness and resistivity values for individual layers while the 2D resistivity data were processed using Res2Dinv software. The 2D resistivity structures revealed the lateral and the vertical variations of the subsurface information having resistivity values ranging from 81.8 to 5250 Ωm. The geoelectric sections revealed five to six geoelectric layers, which correspond to the topsoil, clayey sand, lateritic clayey sand and sand. The topsoil is characterized by resistivity values ranging from 29.8 to 358.5 Ωm and layer thickness of 0.6 to 0.8 m. The clayey sand had resistivity and layer thickness values ranging from 81.4 to 278.0 Ωm and 2.4 to 7.1 m respectively. The lateritic clayey sand had resistivity values ranging from 782.0 to 2414.1 Ωm. and layer thickness of 5.4 to 61.2 m. The sand in the third layer in VES 1 to 7, 9 and 10 has resistivity values ranging from 398.6 to 600.7 Ωm and layer thickness of 2.3 to 25 3 m is characterized as seasonal aquifer. The result of this study has further highlighted the capabilities of the electrical resistivity techniques in groundwater investigation

Hydraulic characterization of the Adamawa-Cameroon aquifer using inverse slope method

AbstractFifty vertical electrical soundings were carried out in the Adamawa region of Cameroon. The interpretation was done using inverse slope method (ISM) and curve matching methods. The aim was to employ the applicability and suitability of the ISM in deciphering the vertical electrical sounding (VES) data for groundwater and hydrogeophysical purposes in the Pan-African aquifers. The ISM can be used to interpret VES data collected with any electrodes array. The results obtained by the ISM geo-electrical interpretation correlate/agree well with the available lithological logs used in constraining the interpretation. The resistivity values obtained through this method are in the range of 20–900 Ω m with a mean of 241 Ω m and a standard deviation of 228 Ω m. The aquifer thickness is in the range of 2–90 m, with an average of 33 m and a standard deviation of 21 m. Resistivity, thickness and depth of the Pan-African aquifer in the Adamawa region, Central Africa have been determined and characterized using both the ISM and an integrated protocol of interpolation technique. The ISM can therefore be recommended for the interpretation of VES measurements in the similar Pan-African context worldwide.

Exploring hydrogeological parameters by integration of geophysical and hydrogeological methods in northern Khartoum state, Sudan

The recent study aims to detect the spatial distribution of the hydraulic parameters and evaluate the protective capacity of the groundwater aquifers in northern Khartoum state using geophysical and hydrogeological methods. The study area is located in the transition zone between the sedimentary basin and the area dominated by crystalline basement rocks. Vertical electrical sounding (VES) measurements, using Schlumberger configuration, were taken along three profiles to delineate the thicknesses of the sediments and groundwater aquifers. The VES measurements were combined with the lithology logs to reduce the uncertainty of the resulting models. VES findings denoted that the study area comprises two hydraulically connected aquifers. The upper aquifer is composed of fine sandstone with an average thickness of 50 m, and the lower aquifer has a thickness of up to 150 m. These two aquifers are confined to semi-confined, separated by relatively thick aquitards. To evaluate the aquifer quantitively, pumping test analysis using Cooper-Jacob method was applied to estimate the aquifer's hydraulic parameters, including transmissivity and hydraulic conductivity. The pumping test approach is costly and time-consuming, and extrapolation of the results is restricted to homogeneous boundary conditions. Since groundwater aquifers are mostly heterogeneous, a geophysical-based method called Dar Zarrouk parameters was applied to give a continuous estimate for the hydraulic parameters. Dar Zarrouk parameters include longitudinal conductance and transverse resistance, combining the true resistivity and thickness obtained from the inverted VES data to determine the hydraulic parameters. The calculated hydraulic parameters from the pumping test and Dar Zarrouk parameters showed high compatibility. Furthermore, longitudinal conductance was used to predict the protective capacity of the aquifers. Generally, it ranged from good to very good protective capacity suggesting potable water quality. The findings of this research indicated that the groundwater aquifer in the study area is ideal for groundwater exploitation. However, this study recommends applying a detailed geophysical survey to reduce the uncertainty of the resulting geological and hydrogeological models.

New Semi Quantitative Approach for Interpreting Vertical Electrical Sounding (VES) Measurements by Using Fractal Modeling Technique, Case Study from Khanasser Valley, Northern Syria

Fractal modeling technique, with adapting the concentration-number (C-N) model and the threshold break points concept is newly proposed to interpret vertical electrical sounding (VES) measurements distributed along a given profile. New semi quantitative approach is consequently proposed to rapidly differentiate between different apparent resistivity populations, where 2D semi quantitative interpretation and a primary geological analysis could be constructed. The new technique is practiced and tested on a case study taken from Khanasser Valley, Northern Syria, where different selected profiles (LP1, LP2, LP3, and TP5) are interpreted. The availability and the feasibility of the proposed approached are confirmed and approved through the different comparisons between the multi fractal established cross sections and the traditional 1D VES interpretation models. It is recommended to routinely use this new proposed fractal approach in the geoelectrical researches for interpreting VES measurements distributed along a given profile.

The Evolution and Development of Solution Dolines with Horizontal Growth and the Processes of Their Floors: A Case Study on the Plate-Shaped Dolines of the Bükk Mountains, Aggtelek Karst and Pádis Plateau

This study investigated the evolution and development of plate-shaped dolines (depressions with a large diameter, small depth and plain floor) within the framework of a case study. For the determination of their morphological characteristics, the morphological parameters of 16 dolines were measured and calculated (their average values were compared to the parameter average values of the dolines of other doline types). Based on the data from the vertical electrical sounding measurements, the superficial deposit and the morphology of the bedrock of six dolines were studied. It can be stated that the plate-shaped dolines increased in size by widening. They were formed at sites where the water drainage and material transport capacities of the epikarst of the bedrock ceased on doline floors, while the drainage and material transport took place at the margin of the dolines. Their genetic varieties were plate-shaped dolines with a karren, plate-shaped dolines with a drawdown doline, plate-shaped dolines with a subsidence doline, plate-shaped dolines without a drawdown doline and plate-shaped dolines with a partial doline.

Estimation of hydraulic parameters by using VES sounding and neural network techniques in the semi-arid Khanasser valley region, Syria

This paper discusses the in near–real time processing of Global Navigation Satellite An alternative approach based on using Vertical Electrical Sounding (VES) measurements and Artificial Neural Network (ANN) technique is newly proposed for computing the hydraulic conductivity K and the transmissivity T of an aquifer. VES measurements in the locations, where available water samples exist are required in such an approach, in order to train a neural network with fitting capability to evaluate both the hydraulic conductivity and transmissivity. The hydraulic conductivity and transmissivity are thereafter extrapolated by the use of trained neural network, even in the VES points where no water samples exist. This approach is practiced and tested in the Khanasser valley, Northern Syria, where the hydraulic conductivity and the transmissivity of the Quaternary aquifer is computed. We find an acceptable agreement between the hydraulic conductivity values obtained by the new approach and those obtained by the pumping test, which range between 0.864 and 8.64 m/day.

Assessing the effects of 1D assumption violation in vertical electrical sounding (VES) data processing and interpretation

This research aimed to discover the possible effects of 1D assumption violations on VES data interpretations. In order to do so, 1D inversion results of logarithmically spaced and linearly spaced VES measurements are compared with their relevant 2D inverted models. Some real case studies are also examined by 1D and 2D inversions to test the results. It is found that linearly spaced VES measurements are not really suitable for 1D inversion in the case of 1D assumption violations and logarithmically spaced VES can better handle these problematic features. In the case of semi-infinite horizontal layers and also small surface resistivity inhomogeneities, logarithmically spaced VES datasets mostly provide a reliable 1.5D model while linearly spaced VES datasets suffer from remarkable artifacts. In the case of vertical structures, both linearly spaced and logarithmically spaced VES techniques fail. In this case (i.e., a vertical dike), artifacts in the form of “extra layer” appear in those VES stations that are adjacent to the dike. However, for VES stations on the dike structure, no extra layer appears in the 1D inversion result. It must be emphasized that 1D violating features are not improbable in many geological situations so they must be considered in mind when processing and interpreting the geophysical VES data.

Electrical imaging of the geoenvironment around water infrastructures in Istanbul city

Subsurface structures from two different districts of Istanbul, hosting waste and freshwater transmission lines, were imaged by geoelectrical method. The environmental impact on Kagithane-Terkos freshwater transmission line is one of the issues. That waterline underwent a substantial landslide damage. The previous site selection of Kagithane-Terkos line was only based on surface geological observations. Even though the pipeline was positioned away from the surface scarps of landslides, the pipes were damaged. To find out the reason, we made some vertical electrical sounding measurements using Schlumberger array in the region. We inverted the electrical sounding data using 2D inversion technique. The final geoelectrical images show main landslide failures, at about 10–30 m depth, which are overlain by debris with a resistivity value of with <6 Ω m. The geoelectrical findings reveal that a buried major failure surrounds the surface landslides behind. Consequently, the water infrastructure remains under the influence of landslide. Our second application site was the area of the Sazlidere tunnel, which will transfer wastewater, polluting Sazlidere dam, to the treatment plant. The geoelectrical images along Sazlidere tunnel route show resistive (<100 Ω m) and moderately conductive (≤50 Ω m) structures along the tunnel axis, representing unaltered to highly weathered rocks, respectively. Furthermore, consecutive hidden fault zones which severely affect the construction process of the tunnel are detected and located.

Geoelectric Characterization of Thermal Water Aquifers Using 2.5D Inversion of VES Measurements

This paper presents a short theoretical summary of the series expansion-based 2.5D combined geoelectric weighted inversion (CGWI) method and highlights the advantageous way with which the number of unknowns can be decreased due to the simultaneous characteristic of this inversion. 2.5D CGWI is an approximate inversion method for the determination of 3D structures, which uses the joint 2D forward modeling of dip and strike direction data. In the inversion procedure, the Steiner’s most frequent value method is applied to the automatic separation of dip and strike direction data and outliers. The workflow of inversion and its practical application are presented in the study. For conventional vertical electrical sounding (VES) measurements, this method can determine the parameters of complex structures more accurately than the single inversion method. Field data show that the 2.5D CGWI which was developed can determine the optimal location for drilling an exploratory thermal water prospecting well. The novelty of this research is that the measured VES data in dip and strike direction are jointly inverted by the 2.5D CGWI method.

Gana’da bazı topluluklarında elektromanyetik ve elektrik rezistivite yöntemlerle kullunılarak yeraltı su kaynakları araştırması

The electromagnetic profiling and Vertical Electrical Sounding (VES) data were acquired from some communities in the Twifo – Hemang Lower Denkyira District of the Central region of Ghana, in order to determine zones of high groundwater potentials and to recommend suitable sites to drill boreholes for community water supply. The research reported here covered three communities namely; Esukese Ekyire, Kwanyarko. First the electromagnetic measurements were carried out, qualitative interpretations of the data were carried out and weathered rock zones were identified. Then the VES measurements using Schlumberger array were conducted at points on the electromagnetic traverse that displayed weathered zones. ZONDIP1D software was used in creating 1D sounding curve models of geological subsurface structures beneath the sounding points. Results of the modelling suggest that the communities are underlain by three to four geological layers. Interpretations of the 1D inversion of the VES data provide the resistivities and thicknesses of subsurface layers. On the basis of resistivity values and thicknesses of the layers in the 1D models, sites were recommended to drill boreholes for community water supply.

Groundwater potential estimation using vertical electrical sounding measurements in the semi-arid Khanasser Valley region, Syria

Traditional and polar vertical electrical sounding (VES) techniques were used for computing and characterizing the transmissivity of the Quaternary and Palaeogene aquifers in the Khanasser Valley, northern Syria. The VES technique with its different applied approaches is inexpensive, easy and gives rapid results with high spatial resolution. The Dar-Zarrouk parameters were determined to estimate the groundwater potential of the aquifers. The results show the mean transmissivity of the Quaternary aquifer to be 49 m2/d (minimum: 10 m2/d; maximum: 131 m2/d; standard deviation: 32 m2/d), and that of the Palaeogene aquifer is 0.94 m2/d (minimum: 0.31 m2/d; maximum: 1.54 m2/d; standard deviation: 0.33 m2/d). Editor D. Koutsoyiannis Citation Asfahani, J., 2013. Groundwater potential estimation using vertical electrical sounding measurements in the semi-arid Khanasser Valley region, Syria. Hydrological Sciences Journal, 58 (2), 468--482.

ANN based inversion of DC resistivity data for groundwater exploration in hard rock terrain of western Maharashtra (India)

Inversion of vertical electrical sounding (VES) data, especially from the crystalline hard rock area, assumes a special significance for groundwater exploration. Here we used a newly developed algorithm based on the Bayesian neural network (BNN) theory combined with Hybrid Monte Carlo (HMC)/Markov Chain Monte Carlo (MCMC) simulation scheme to invert the Direct Current (DC) VES measurements obtained from 30-locations around Tenduli-Vengurla, Sindhudurg district, Maharashtra, India. The inversion results suggest that the top layer is mostly comprised of laterites followed by mixture of clay/clayey sand and garnulites/granite as basement rocks. The source of groundwater appears to be accessible in weathered/semi-weathered layer of laterite/clayey sand that exists within the depth of 10–15 m from the surface. The NW–SE trending major lineaments and its criss-crosses are also identified from the apparent and true resistivity surface map. The pseudo-section at different depths in the western part of the area, near Nivti, shows extensive influence of saltwater intrusion and its impact reaching up to the depth of 30 m from the surface along the coastal area. Our results also show that intrusion of saline water decreases from the western part to the eastern part of the region. Two dimensional modeling of four resistivity profiles from the study region identified two potential groundwater reservoirs; one lying between Path-Tenduli and another in between Mat and Zaraph. The deduced true electrical resistivity section against depth correlates well with available borehole lithology in the area. The results presented here would be useful for interpreting the geological signatures like fractures, major joints and lineaments, which in turn will be helpful for identifying groundwater reservoirs and drainage pattern in the crystalline hard rock area. The newly developed HMC-based BNN method is robust and would provide insights for constraining the geophysical models and criteria for modeling resistivity data.

Delineation of shallow resistivity structure around Malvan, Konkan region, Maharashtra by neural network inversion using vertical electrical sounding measurements

Modeling resistivity profiles, especially from hard rock areas, is of specific relevance for groundwater exploration. A method based on Bayesian neural network (BNN) theory using a Hybrid Monte Carlo (HMC) simulation scheme is applied to model and interpret direct current vertical electrical sounding measurements from 28 locations around the Malvan region, in the Sindhudurg district, southwest India. The modeling procedure revolves around optimizing the objective function using the HMC based sampling technique which is followed by updating each trajectory by integrating the Hamiltonian differential equations via a second order leapfrog discretization scheme. The inversion results suggest a high resistivity structure in the north-western part of the area, which correlates well with the presence of laterites. In the south-western part, a very high conductive zone is observed near the coast indicating an extensive influence of saltwater intrusion. Our results also show that the effect of intrusion of saline water diminishes from the south-western part to the north-eastern part of the region. Two dimensional modeling of four resistivity profiles shows that the groundwater flow is partly controlled by existing lineaments, fractures, and major joints. Groundwater occurs at a weathered/semi-weathered layer of laterite/clayey sand and the interface of overburden and crystalline basement. The presence of conduits is identified at a depth between 10 and 15 m along the Dhamapur–Kudal and Parule–Oros profiles, which seems to be potential zone for groundwater exploration. The NW–SE trending major lineaments and its criss-cross sections are indentified from the apparent and true resistivity surface map. The pseudo-section at different depths in the western part of the area, near Parule, shows extensive influence of saltwater intrusion and its impact reaching up to a depth of 50 m from the surface along the coastal area. Further, the deduced true electrical resistivity section against depth correlates well with available borehole lithology in the area. Present analyses suggest that HMC-based BNN method is robust for modeling resistivity data especially in hard rock terrains. These results are useful for interpreting fractures, major joints, and lineaments and crystalline basement rock and also for constraining the higher dimensional models.

Quaternary aquifer transmissivity derived from vertical electrical sounding measurements in the semi-arid Khanasser Valley Region, Syria

Vertical electrical sounding technique (VES) is used as an alternative approach to pumping test for computing the Quaternary aquifer transmissivity in the Khanasser Valley, Northern Syria. The method is inexpensive, easy and gives faster results with higher special resolution than the traditional pumping technique. The hydraulic conductivity values obtained using VES agree with the pumping test results, which in the Khanasser Valley vary between the order of 0.864 and 8.64 m/day (10−5 and 10−4 m/s). The probable location of the Quaternary aquifer in the Khanasser Valley is obtained through the transmissivity map derived from VES. The knowledge of transmissivity is fundamental for modeling and management processes in the Khanasser Valley. Other similar semiarid regions can benefit from the approach successfully applied in the study area.

2D interpretation of vertical electrical soundings: application to the Sarantaporon basin (Thessaly, Greece)

A large-scale vertical electrical sounding (VES) survey was applied at the basin of Sarantaporon, Elassona in order to study the tectonic and hydrogeological setting of the area. A large number of VES was obtained on a near-regular grid and data were initially processed with 1D inversion algorithm. Since some of the dense measured soundings were collinear, it was possible to combine 1D sounding data and produce 2D data sets which were interpreted using a fully 2D inversion algorithm. 2D geoelectrical models were in very good agreement with the existing drilling information of the area. 2D interpretation results were combined to produce pseudo-3D geoelectrical images of the subsurface. Resulting geoelectrical interpretations are in very good agreement with the existing geological information and reveal a relatively detailed picture of the basin's lithology. Further, the results allowed us to obtain new, and verify existing, structural information regarding the studied area. Overall, it is concluded that 2D interpretation of 1D VES measurements can produce improved subsurface geophysical images and presents a potential useful tool for larger scale geological investigations especially in the case of reprocessing existing VES data sets.

Using geophysical methods to define the attitude and extension of water-bearing strata in the Miocene sediments of the Pannonian Basin

Abstract In the area near the village of Jazak (southern part of Fruska Gora mountain, Serbia), hydrogeological investigations were carried out for the purpose of finding a water supply source to provide an adequate volume of water for a mineral water bottling plant. The first exploratory borehole (IBJf-1) penetrated a water-bearing layer of Miocene organogenic limestones. This aquifer has a thickness of about 30 m and a yield of only 2.2 l/s, which falls short of the required water volume (5 l/s). The objective of further exploration was to define the attitude and extension of the aquifer and thus select a more favourable site for a new exploratory borehole that would secure the required volume of water. For this purpose, geophysical exploration was carried out in 2003 through vertical electrical sounding (VES) and high-resolution 3D reflection seismic methods. The VES measurements enabled determination of aquifer depth and indicated that the water-bearing strata extend over the entire area studied. However, because of the equivalence problem, it was not possible to determine the thickness of the water-bearing stratum based solely on the VES data. Thus, the 3D seismic method was used in the second stage of investigation. A low-cost 3D seismic survey was carried out with fixed receiver lines, using a vibrator as the source of the seismic waves. From the 3D seismic data it was possible to determine the aquifer thickness. The depth of the aquifer determined by interpretation of the 3D seismic data was in accordance with the depth determined by the VES method. Based on the assumption that the hydraulic conductivity of this formation is identical or similar over the entire area, as well as the fact that the first well showed the presence of a subartesian aquifer, we proposed drilling another borehole (IBJf-2) in the zone where the data indicated that the water-bearing stratum was much thicker. The data obtained by drilling and coring were in agreement with the predicted aquifer thickness. Pumping tests showed that the water discharge in borehole IBJf-2 was 6 l/s. The results show that the objective of delineating the groundwater body by combined application of two geophysical methods (VES and 3D seismic) was successfully performed.

Delineation of shallow resistivity structure in the city of Burdur, SW Turkey by vertical electrical sounding measurements

The city of Burdur, which is built on an alluvium aquifer, is located in one of the most seismically active zones in southwestern Turkey. The soil properties in the study site are characterized by unconsolidated and water-saturated sediments including silty, clayey and sandy units, and shallow groundwater level is the other characteristic of the site. Thus, the city is under soil liquefaction risk during a large earthquake. A resistivity survey including 189 vertical electrical sounding (VES) measurements was carried out in 2000 as part of a multi-disciplinary project aiming to investigate settlement properties in Burdur city and its vicinity. In the present study, the VES data acquired by using a Schlumberger array were re-processed with 1D and 2D inversion techniques to determine liquefaction potential in the study site. The results of some 1D interpretations were compared to the data from several wells drilled during the project. Also, the groundwater level map that was previously obtained by hydrological studies was extended toward north by using the resistivity data. 2D least-squares inversions were performed along nine VES profiles. This provided very useful information on vertical and horizontal extends of geologic units and water content in the subsurface. The study area is characterized by low resistivity distribution (<150 Ωm) originating from high fluid content in the subsurface. Lower resistivity (3–30 Ωm) is associated with the Quaternary and the Tertiary lacustrine sediments while relatively high resistivity (40–150 Ωm) is related to the Quaternary alluvial cone deposits. This study has also shown that the resistivity measurements are useful in the estimation of liquefaction risk in a site by providing information on the groundwater level and the fluid content in the subsurface. Based on this, we obtained a liquefaction hazard map for the study area. The liquefaction potential was classified by considering the resistivity distributions from 2D inversion of the VES profiles, the types of the sediments and the extended groundwater level map. According to this map, the study area was characterized by high liquefaction hazard risk.

Resistivity measurements for groundwater investigation in the Umm Al-Aish area of northern Kuwait

With a view to testing the possibilities and limitations of geoelectrical methods in exploration and evaluation of groundwater resources in Kuwait, vertical electrical sounding measurements (VES), utilizing the Schlumberger array, were conducted in the Umm Al-Aish area. Here, localized fresh water zones occur in the upper portions of Pleistocene sand and gravel aquifers. Iterative automatic inversion of VES data, coupled with borehole information, resolved with some confidence the dry/saturated and fresh/saline water interfaces and revealed some correspondence between lithostratigraphical units and resistivity values. Maps of resistivity and transverse resistance values agree reasonably with the general hydrogeological condition in the area. The results confirm the hypothesis that potable groundwater is associated with low relief, mainly along the central axial trend of the basin, where seasonal recharge is likely. Correlations have been established between aquifer resistivity and water salinity and to a lesser extent between aquifer transverse resistance and potential area(s) for fresh groundwater production. These correlations could be used to assist in exploration and evaluation of groundwater resources in new target areas in Kuwait where lithostratigraphical and hydrogeological information is very limited.