Geoelectrical Resistivity Data Research Articles

A Quantitative interpretation of salt water mixture in the shallow aquifer through the geoelectrical resistivity data

The main problem of groundwater in coastal areas is the intrusion of saltwater into freshwater aquifers. This study aims to predict the amount of saltwater content in aquifers polluted by intro-sea saltwater. In this study, an attempt is made to provide a direct correlation approach for resistivity measurements with the physical characteristics of groundwater. A 2D resistivity survey with the Wenner configuration have been carried out in the coastal area. The geoelectrical resistivity survey is about 3 km from the shoreline. The chemical measurement was done on freshwater, seawater and fresh-seawater mixture, which the mixture was consisted of 25%, 50% and 75% of seawater content. The results showed that the resistivity below 5 ohm.m indicated the presence of seawater with a concentration of more than 50% mixed with fresh water. In general, it can be seen that the decrease in resistivity appears to decrease exponentially with increasing seawater content in the aquifer.

A preliminary groundwater investigation using geoelectrical resistivity survey in the Bengkalis Island, Indonesia

Groundwater resources are one of the natural resources that need to be preserved. The main problem of groundwater in coastal areas is the intrusion of seawater into the groundwater aquifer. The problem will be even more complex when the land is covered by peat soil. The purpose of this study was to investigate the potential of groundwater in the western part of Bengkalis Island. Geoelectrical resistivity data was taken with the Schumberger configuration with the increase in the electrode distance being varied to obtain accurate measurements. Groundwater samples were measured to obtain the physical character of the groundwater. The results show that groundwater close to the shoreline has been contaminated by the presence of seawater intrusion. However, in areas that are a bit far from the shoreline, the shallow aquifer groundwater conditions are still not contaminated by seawater. It can be concluded that the presence of seawater in the aquifer is caused by the trapping of seawater in the aquifer during sediment deposition in the past.

A valuable approach in a quantitative seawater intrusion interpretation from the geoelectrical resistivity data for groundwater investigation in Dumai area, Indonesia

An improvement of geoelectrical resistivity interpretation has been done through this research. Up to now, the geoelectrical resistivity data was interpreted qualitatively especially in the case of the aquifer intruded by seawater, and the percentage of seawater mixture content in the aquifer cannot be predicted. In this research, a valuable approach was used in the prediction of percentage seawater mixture in the shallow aquifer that is intruded by seawater. The study was conducted in the coastal area which is mainly covered by peat soil. The research employed the direct soil resistivity measurement and the ground surface resistivity survey. Geoelectrical resistivity with the Wenner configuration was used for both measurements. The soil character and the fluid content in the soil were measured to obtain their correlation to the direct soil resistivity value. The results show that resistivity value is about 2-5 ohm.m for 50% seawater content mixture in aquifer and it increase to be 5-10 ohm.m for 25% seawater mix to freshwater in the aquifer. The increasing seawater content in the pore soil caused the decreases in resistivity value drastically. The percentage of seawater mixture in the fluid pore soil has been successfully predicted through the geoelectrical resistivity measurement on the surface.

Nonlinear inversion of electrical resistivity sounding data for multi-layered 1-D earth model using global particle swarm optimization (GPSO)

Interpreting geophysical data requires solving nonlinear optimization problem(s) in inversion. Analytical methods such as least-square have some intrinsic limitations, which include slow convergence and dimensionality, making heuristic-based swarm intelligence a better alternative. Large-scale nonlinear optimization problems in inversion can be solved effectively using a technique within the swarm intelligence family called Particle Swarm Optimization (PSO). This study evaluates the inversion of geoelectrical resistivity data with global particle swarm optimization (GPSO). We attempted to invert field vertical electrical sounding data for a multi-layered 1-D earth model using the developed particle swarm optimization algorithm. The result of the PSO-interpreted VES data was compared with that of the least square inversion result from Winresist 1.0. According to the PSO-interpreted VES results, satisfactory solutions may be attained with a swarm of 200 or fewer particles, and convergence can be reached in fewer than 100 iterations. The GPSO inversion approach has a maximum capacity of 100 iterations, more than the least square inversion algorithm of the Winresist, which has a maximum capacity of 30 iterations. The misfit error of GPSO inversion is 6.14×10−7, much lower than that of the least square inversion of 4.0. The GPSO inversion model has lower and upper limit values of the geoelectric layer parameters model to fit the true model better. The limitations of the developed PSO inversion scheme include a slower execution time of the inversion procedures than the least-square inversion. There is a need for a priori knowledge of the number of layers from borehole reports in the study area. The PSO inversion scheme, however, estimates inverted models closer to the true solutions with greater accuracy than the least-square inversion scheme.

Application of Geoelectric Technique in Groundwater Protection of Quaternary Aquifer in Wadi El Natrun, Egypt

Qualitative and quantitative interpretations of the accessible geoelectrical resistivity data were conducted in the area located to the west of Nile Delta on both sides of the Cairo-Alexandria desert road, between latitudes 30.190816° and 30.745892° N and longitudes 29.797607° and 30.702070° E, in the northern Western Desert of Egypt. The study area is covered by thick sedimentary exposures ranging from the Miocene to the Quaternary period. Geological factors such as lithology and geological structures significantly influence the groundwater in the study area. The Quaternary, Pliocene, and Miocene eras make up the majority of strata in the study region that require water.
 The study conducted twenty-three vertical electrical resistivity soundings using the Schlumberger array to define the shallow subsurface geological inferences and investigate the possibilities of finding underground water accumulations and its contamination with clay lenses. The examination of the obtained electric resistivity values revealed the segmentation of the examined section into five geoelectrical units with lateral variations in thicknesses, lithologies, and features. The five geoelectrical units had different compositions, with the first surface unit consisting of silt clay and relatively high resistivity sands and gravels that have been altered laterally. After the surface unit, resistivity ranges from relatively modest to high. Intercalation of sand and clay occurs in the second unit, followed by lenses of relatively medium-resistance coarse sand and clay in the third and fourth units, possibly forming an aquifer, and finally relatively low-resistance sand and clay in the fifth unit.
 Due to the haphazard drilling of hundreds of water wells, significant hydrogeological and environmental issues, such as soil salinization, water head decline, and groundwater salinity deterioration, have occurred. These issues have attracted significant expenditures in the field of land reclamation, both on small and large-scale projects. The study area is divided into five main geoelectrical layers observed along this cross area, as follows:
 The first surface geoelectrical layer (layer A) is characterized by relatively high resistivity ranging from 8.21 to 595.3 Ohm.m. The thickness of this layer varies from 2.1 to 8.86 m. This layer represents the dry surface cover of the area and consists of gravel, sand, and silt clay.
 The second geoelectrical layer (layer B) represents the dry layer lying above the water-bearing formation. It generally consists of sand and clay intercalation. The resistivity of this layer varies from 3.49 to 91.18 Ohm.m, and the thickness of this layer ranges from 17.13 to 38.3 m.
 The third geoelectrical layer (layer C1) is the water-bearing formation that generally consists of coarse sand and clay. The resistivity of this layer varies from 4.41 to 37.5 Ohm.m, and the thickness ranges from 10.38 to 54 m.
 The fourth geoelectric layer (layer C2) represents the lower part of the water-bearing formation. It consists of clayey sand and clay. The resistivity of this layer varies from 1.83 to 30.1 Ohm.m, and the thickness ranges from 17.78 to 31.35 m.
 The last geoelectric layer (layer D) represents the lower layer of investigation, consisting mainly of clay. The resistivity of this layer is generally low, varying within a narrow range of 26.7-39.8 Ohm.m.
 Finally the current study highlights the necessity of conducting in-depth geomorphological assessment studies before developing new reclamation projects, in addition to soil and water assessment.

3D Modelling of Geoelectrical Resistivity Data to Determine the Direction of Landslides in Kastoba Lake, Bawean Island, Indonesia

Landslides are one of the factors caused by subsurface structures that are not compact, and have low density or resistivity values due to changes in groundwater. Rainwater that infiltrates into the ground will reach to an impermeable layer which is identified as a slip plane. This research was conducted in the Kastoba Lake area, Bawean Island, Indonesia. The purpose of this study is to determine the slip plane and the direction of the landslide in the studied area. Data acquisition was carried out based on a preliminary study of residual anomaly contour analysis from gravity data, then geoelectric data acquisition was carried out in the studied area. The results of lithological analysis on 3D geoelectric resistivity modeling in this study obtained three layers of subsurface structures, namely topsoil, clay, and lavas. The slip plane of the study area is above the clay layer (7.25 meters depth). The results of the 3D interpretation indicated that the direction of the landslide was towards the north, as evidenced by the existence of public information that the area studied had landslides with the avalanche direction towards the north. For further analysis, a factor of safety analysis is needed based on the analysis of the bore hole drilling method in the studied area

Numerical modeling of 2-D and 3-D geoelectrical resistivity data for engineering site investigation and groundwater flow direction study in a sedimentary terrain

Numerical modeling of 2-D and 3-D geoelectrical resistivity data for engineering site investigation and groundwater flow direction study in a sedimentary terrain

Application of GSTAR(1,1) model for layer peat soil predicted based on resistivity log data

In this study, GSTAR modeling was carried out with the inverse of distance weight matrix obtained from Geoelectrical Resistivity data at several peatland locations around the Universitas Tanjungpura, Pontianak. This data can identify the subsurface layer of the soil through the electric current that binds into the soil. However, due to the limitation of the tool to measure the resistivity value, it can only measure 1/5 of the depth of the observation length. To overcome this problem, predictions are made at the next depth using the GSTAR model. The study began by measuring the resistivity value of the land using the geoelectric method and mapping it. Through this GSTAR modeling, predictions are made for the unobserved subsurface to determine the type of soil layer. Knowing the type of deeper soil layer can help contractors build plant concrete stakes to keep buildings safe on peatland. The results of the GSTAR(1.1) model are not accurate enough to estimate the resistivity value data. This is possible because the correlation between rock ages is not the same, so further analysis is required.

Integrated Very Low Frequency and Geoelectrical Resistivity Methods to Study Possibility Shallow Groundwater Pathway in Bedrock Area

Exploration of groundwater movement has a specific challenge in thick forest area and cover with the shallow hard rock. The use of active and passive geophysical method is needed for groundwater exploration. This study aims to explore the prospect of groundwater zone especially for the groundwater pathway in the area around the hot spring zone. Geoelectrical resistivity and very low frequency (VLF) methods were used with electrode spacing of 2 meter and reading stations of about 5 meter, respectively. The geoelectrical resistivity was carried out using the Wenner configuration in the sites around the hot spring. The results show that the VLF model indicates occurrence of the conductive zones at the depth of about 10 m. The geoelectrical resistivity data show the same pattern with the VLF image. These conductive zones which is appeared in the VLF model are indicating as the zone of groundwater water pathway from the source to the hot spring zones. The geoelectrical resistivity data also showed the same possibility of groundwater pathway.

Sea Water Intrusion Monitoring on the Sendangbiru of the Southern Malang Coastal Area based on Geoelectrical Resistivity Data

The study was conducted with the objective to distinguish the presence of seawater intrusion layer or salt-water aquifer distribution along the data acquisition line at the locations. Data acquisition was conducted by using the Wenner-Schumberger configuration of geoelectrical resistivity. From this research, 4 lines and 4 points of vertical electrical sounding (VES) data for every line were obtained with the distance between electrode a as 10m. Based on the data processing, obtained depth up to 120m with the smallest resistivity value is 0.02Ωm and the largest is 6764.52Ωm. To make the distribution of resistivity values along the path line of the study, cross sections were made until a depth of 120m. Based on the cross-section, the low resistivity value (less than 1.5 Ωm) that interpreted as a seawater intrusion layer or salt water aquifer distribution is located at varying depths. There are intrusions for the SB1 cross section, there is an intrusion at a depth of 6m-7m as far as 10m, at a depth of 6m-8m as far as 10m for the SB2 cross section and at a depth of 22m - 26m as far as 25m for the SB3 cross section.

Nature Inspired Bargain Optimization Algorithm for Effective Interpretation of Geoelectrical Data

Geoelectrical resistivity data collected from the ground contain lot of noises and errors. It requires efficient algorithm to reduce the errors to make an actual inversion models. Though different algorithm can be applied, nature inspired algorithm is more potential in inverting geoelectrical data in an elegant and comprehensive way. Bargain Optimization (BO) algorithm is framed on the concept of bargaining things to purchase for needs. In general, effective bargaining results in more profit and leads to loss when it fails. In this research work, Bargain Optimization algorithm is applied to invert geoelectrical data and the effective bargaining will take time to process and to obtain the required model. The input data is AB/2, apparent resistivity data and the inverted model through BO algorithm is successfully matched with the available litholog section of the study area. The output graphs have profit/loss bar graph, which reveals the status of bargaining during a particular number of epochs.

Groundwater exploration in hard rock terrains of East Godavari district, Andhra Pradesh, India using AHP and WIO analyses together with geoelectrical surveys

<abstract> The need for groundwater exploration in India has been increasing enormously, due to the non-judicial use of available water resources. The present study area is located between longitudes from 81°52′20.293′′ to 82°29′32.058′′ E and latitudes from 17°01′6.71′′ to 17°38′ 12.906′′ N in the Eastern Ghats mobile belt region of East Godavari district. The study area is characterized by a wide range of geological settings and high and irregular topographic features. The area is identified by Government as highly backward and Tribal people dwell here. For exploring good aquifer in the study area, the information of ten parameters together with geoelectrical resistivity data has been collected. Analytical Hierarchy Process (AHP) is used as the decision-making technique which uses the weights of different thematic layers (parameters) favorable for groundwater recharge, storage and location. Various thematic layers (parameters) of geology, geomorphology, soil, slope, lineament density, drainage density, groundwater level, Land use/Land cover, rainfall and coefficient of electrical anisotropy were considered in this analysis. A comprehensive groundwater prospect map has been prepared and validated with aquifer thickness map derived from the analysis of geoelectrical data. The entire study area has been classified into different potential zones of good, moderate and poor for groundwater exploration. The good groundwater potential zone is covering an area of 750.91 sqkm (28.4%) with aquifer thickness varying in the range 40–140 m, moderate potential zone encompasses 46.1% of the study area with an areal extent of 1220.33 sqkm and aquifer thickness is about 20–40 m. The remaining area of 24.5% is poor aquifer zone with thickness less than 20 m. </abstract>

Application of geoelectrical resistivity method for the assessment of shallow aquifer quality in landfill areas.

In this article, a valuable approach utilizing the relationship between select physical water and soil characteristics and geoelectrical resistivity data was used to recognize and trace groundwater contamination by using the geoelectrical resistivity data of a landfill area. It can reduce uncertainty in geoelectrical resistivity interpretation. By interpreting and calibrating the resistivity model with the lithology and physical characters of water samples, it was possible to identify the unique paths of landfill leachate that occurred throughout a shallow aquifer. The water physical property analysis showed that the landfill area was contaminated by a relatively high amount of total of dissolved solids (TDSs). A scatter plot of TDS values and directly measured resistivity showed that resistivity decreased with increasing TDSs. The movement direction of the landfill leachate in the aquifer system was clearly observed in a depth slice of the resistivity distribution. The aquifer is considered to be contaminated starting from the landfill zone and extending to the northeastern part of the study area.

Slope Stability Analysis for Landslides Natural Disaster Mitigation by Means of Geoelectrical Resistivity Data in Gedangan of South Malang, East Java, Indonesia

A study entitled slope stability analysis for landslides natural disaster mitigation by means of geoelectrical resistivity data in Gedangan of South Malang, East Java, Indonesia has been conducted. This study aims to obtain the physical parameters that cause landslides that occur in Gedangan village, Gedangan sub-district, Malang district. The research was conducted using geoelectrical resistivity method by applying a vertical electrical sounding (VES) model and Wenner-Schlumberger configuration. From the data as a result of field data acquisition, processing and interpretation are carried out to obtain landslide parameters. By merging each vertical electrical sounding (VES) point, physical parameters will be obtained as the basis for local landslide analysis. The results of the cross-sectional line A (GED4-GED1-GED2) indicate the presence of an average slope surface or topography that is relatively parallel with the average slope sliding plane which is about 7° whereas line B (GED1-GED3-GED5) is around 15°. The average thickness of the overlying layer in the slip plane both on line A and line B is around 65m. The slope condition of the slip plane (angle and thickness of the layer) indicates an unstable condition. For stable conditions F> = 1.2, the maximum thickness of the cover layer at line A is 54 m while in line B is 8.2 m. For stable conditions F> = 1.5, the maximum thickness of the cover layer for line A is 25.5 m while in line B is 5.85 m. To overcome the landslide, the proposed solution was by doing a reduction/dredging of the cover layer or installation of the bored piles.

Determination of bed rock depth using joint geoelectric and HVSR methods

To obtain hard rock (bed rock) as the pedestal of the toll road, it had been measured of the thickness of layers of soft or weathered rock that covers the bed rock. Direct measurements carried out by drilling will require a long time and great cost. Therefore, indirect measurements were made by geophysical estimation using resistivity method and were cross-checked with the HVSR method. To get the resistivity data in the research area, in this survey was conducted geoelectric sounding acquisition as much as 16 points whereas data acquisition by using microtremor measurements performed at nine measurement points. The result of the analysis of geoelectric data with HVSR data gives slightly different layer thickness value. The survey area consists of two layers of soil with soft rock layers one were suspected to be sandy silt, and silty sand whereas the soft layer 2 was sandy gravel silt, each with varying thickness. The bed rock in this area is breccia that applies as half space with the thickness is not detected by the measurement. The apparent resistivity curves were obtained from geo-electrical resistivity data have similar curves with the HVSR ones. From the inversion, the result of the bedrock depth from geo-electric resistivity compared to HVSR ones give difference slightly.

Implementation of least-square constrain inversion method of geoelectrical resistivity data Wenner-Schlumberger for investigation the characteristic of landslide

Parameters that used to find out how landslides occur and how much the risk of disasters due to landslides is the characteristics of the slide surface. There are many studies conducted using the Geoelectric method which uses single configuration electrodes to assess landslides. Conversely, The results of previous studies have not been generally accepted. This condition is caused by each study area having unique and very complex conditions. In addition, the results of interpretation with inversion methods are not unique and bivalent. Nevertheless, inversion methods are used to interpret the Geoelectric data. In this research, we implementation of Least-Square constrain Geoelectrical resistivity that the data are measured through Wenner-Schlumberger configurations. The characteristic of landslide depends on, such as the type of rock, the slide surface, the depth and the slope angle of the landslide. Accordingly, we implementation of Least-Square Inversion Constrain Geoelectrical resistivity data Wenner-Schlumberger configurations to determine the characteristic of landslide. Data obtained through Geoelectrical exploration using with an automatic resistivity meter. The result, the rock structure in Malalak of Agam consists of clay, sandstone, Andesite, and Limestone and Dolomite. The depth and the slope angle of the slide surface of the active landslide are 43 degrees and 23 meters. Implementation this research can be used to develop mitigation of landslide deserter.

Review on the role of geoelectrical surveys in characterizing and deriving the constraints and hydrogeological conditions in semi arid Khanasser Valley region in Syria

Abstract This paper is a general review which basically focuses on the role of geoelectrical surveys in characterizing and deriving the constraints and hydrogeological conditions in semi arid Khanasser valley region and its surroundings in Northern Syria. Schlumberger configuration has been used to carry out ninety six vertical electrical soundings VES, distributed on nine transverse and three longitudinal profiles. Their quantitative 1D interpretations with different techniques yield to develop several alternative approaches, that enable us to derive and determine the hydrological parameters of the structures controlled by the groundwater distributions. Two different northern and southern geological structures separated by Hobs-Serdah water divided line were electrically characterized. Both of them are of very conductive zones of a resistivity less than 4 Ωm, and related to the intrusion of salty water in Quaternary and Paleogene aquifers. The qualitative interpretation of the iso-apparent resistivity maps for different AB/2 spacings has allowed the delineation of those two structures. Those two identified structures have their evident influences on the distributions of thicknesses, resistivity, salinity, hydraulic conductivity, and transmissivity of both Quaternary and Paleogene aquifers. The high resistivity exceeding 300 Ωm on the measured VES is a very good signal of the presence of basalt formation of upper Miocene age in Jebel Al Hass in the west and Jebel Shbith in the east. The geometry and the electrical characteristics of Quaternary and Paleogene aquifers and the top of Maestrichtian have been well recognized. Quaternary paleosabkhas, fractured zones and tectonic features of the subsurface of Khanasser valley have been delineated through analyzing VES distributions along the executed longitudinal and transverse profiles. Different empirical relationships have been already established through coupling geoelectrical resistivity and hydrochemical data, which allows to derive and establish different salinity maps for different AB/2 spacings, and to outline the boundaries between fresh, brackish and saline waters. Two different alternative approaches have been also developed for geophysically computing and estimating the hydraulic conductivity and the transmissivity of the aquifers in the study region. The different hydrogeophysical approaches developed in this integrated geophysical research project for water resource management have been successfully applied in Khanasser valley, and can be recommended to be practiced in similar worldwide areas.

English

English

GROUNDWATER INVESTIGATION USING RESISTIVITY METHOD AND DRILLING FOR DROUGHT MITIGATION IN TULUNGAGUNG, INDONESIA

Research of the groundwater in Pakel, Bandung and BesukiSubdistricts, Tulungagung District has been implemented. The research area is located in the rice field area, previously an area of annual flooding inundation during the rainy season. This situation troubles the community and local government of Tulungagung District. During the dry season, the mud cracks, making it difficult as agricultural land. The research was done using Geoelectrical Resistivity Schlumberger configuration method. The measurement point is located in the three Subdistricts with a total of 19 measurement points. The study location is at 111.75988880EL; -8.2264166670 SL to111.84541670 EL; 8.1309166660 SL or covers an area of 101km2. The length of the track used is a maximum of 600 meters. Based on the results of the geoelectrical resistivity data, it was found two types of aquifers, which are open aquifers in depth ranging from 6 m to 21 m and a confined aquifer in depth ranging from 90 to 115 m. In addition to the geoelectrical information data, drilling was done at an accessible point by heavy equipment in the Gempolan Village, PakelSubdistrict. At the drilling point, artesian wells were obtained at a depth of 108 meters and can rise to 2 meters above the soil surface. The discovery of artesian wells is then used by residents to meet the needs of clean water considering that in this area most wells are smell and iron contain.

Response of Gravity, Magnetic, and Geoelectrical Resistivity Methods on Ngeni Southern Blitar Mineralization Zone

The research with entitle response of gravity, magnetic, and geoelectrical resistivity methods on Ngeni Southern Blitar mineralization zone has been done. This study aims to find the response of several geophysical methods of gravity, magnetic, and geoelectrical resistivity in an integrated manner. Gravity data acquisition was acquired 224 data which covers the whole region of Blitar district by using Gravity Meter La Coste & Romberg Model “G”, and magnetic data acquisition were acquired 195 data which covers the southern Blitar district only by using Proton Precession Magnetometer G-856. Meanwhile geoelectrical resistivity data only done in Ngeni village which is the location of phyropilite mining with the composition content of Fe, Si, Ca, S, Cu, and Mn by using ABEM Terrameter SAS 300C. Gravity data processing was performed to obtain the Bouguer anomaly value, which included unit conversion, tidal correction, drift correction, correction of tie point, base station correction, free air correction, and Bouguer correction. Magnetic data processing has been done by some corrections i.e daily, drift, and IGRF(International Geomagnetic Refference Field) to obtain the total magnetic anomaly. From gravity data processing has been obtained the simple Bouguer anomaly value in range from -10mGal until 115mGal. From this data processing has been obtained the total magnetic anomaly value in range from -650nT until 800nT. Meanwhile from geoelectrical resistivity 3.03Ωm until 11249.91 Ωm. There is a correlation between gravity anomaly, magnetic anomaly, and geoelectrical resistivity anomaly that are associated with deep anomaly, middle anomaly, and shallow anomaly.