Impedance Tomography Research Articles

Two-Dimensional Resistivity Modeling of Seawater Intrusion Along the West Flood Canal, Semarang

The northern coastal area of Semarang City has significant problems with a decrease in groundwater quality due to seawater intrusion. Increasing groundwater extraction and subsidence due to the city growth worsen the condition. It is necessary to collect information on the contaminated location to develop a strategy to decrease the spreading of seawater intrusion. This study aims to identify the presence of seawater intrusion zones in groundwater and estimate the spread distance of seawater intrusion to the land. We applied the electrical resistivity tomography method to obtain the image of the subsurface. A geo-electric survey with a dipole-dipole multi-electrode configuration was completed along the West Flood Canal. The subsurface model result indicated that the identified seawater intrusion zone is associated with a low resistivity value of less than 3 Ohm.m. The zone is about 0 - 70 meters deep near the coast and is thinning to about 2600 meters to the south. The result confirms that seawater has penetrated long distances to the land.

Time-Lapse Geophysical Measurements for Monitoring Coastal Groundwater Dynamics in an Unconfined Aquifer.

The coastal zone, which is the interface between land and sea, is hydrodynamically very active due to the complex interactions of various hydrological controls and variable-density fluids. These forces vary over time, resulting in a state of dynamic equilibrium in the system. The major hydrological processes in coastal aquifer systems are salt water intrusion and submarine groundwater discharge, which are interdependent. Monitoring these complex processes is crucial for sustainable coastal zone management but poses a significant research challenge. In this study, we demonstrate the effectiveness of non-invasive geophysical techniques, specifically the time-lapse electrical resistivity imaging method, in conjunction with groundwater monitoring, for monitoring coastal groundwater dynamics in an unconfined aquifer at varying time scales and hydrogeological settings present at formerly glaciated sites worldwide. We generated two-dimensional baseline salt water intrusion maps for the test site, located on the coast of Rhode Island, USA. The time-lapse electrical resistivity survey method enables the rapid estimation of fresh groundwater discharge. Our approach offers insight into the mechanisms and seasonably variable salt water-freshwater interactions in unconfined heterogeneous aquifers. Although the results are site-specific, their implications are broad and may stimulate other studies related to sea to land pollution (sea water intrusion) and land to sea pollution (groundwater discharge) in heterogeneous coastal aquifer settings.

Detecting soil water redistribution in subsurface drip irrigated processing tomatoes using electrical resistivity tomography, proximal sensing and hydrological modelling

In this study, multiple soil-plant-atmosphere continuum (SPAC) monitoring methodologies, including electrical resistivity tomography (ERT), proximal thermal sensing techniques, and micrometeorological data, were combined with two-dimensional (2-D) soil hydrological modelling using HYDRUS 2-D to explore the soil water redistribution, and infer the relative crop water status in a subsurface drip irrigated (SDI) processing tomato field located in California (Yolo County, USA). Specifically, time-lapse ERT surveys were performed at two transects distributed parallel and perpendicular, respectively, to the SDI line, during an irrigation event. The ERT results were compared to HYDRUS 2-D outputs and the relative differences were explained in the form of local heterogeneities in electrical resistivity (ER) changes, as a proxy for soil water content (SWC) variations. Concurrent simultaneous soil wetting and root water uptake during the last irrigation event of the season caused negligible changes in ER in the active root zone. Slight differences in ER were observed in the top 20 cm along the dripline, confirming that the emitter spacing is small enough to create a wetted strip along the processing tomato bed. These changes were also compared to SWC values measured with time domain reflectometry soil moisture sensors. A comparison between HYDRUS 2-D and ERT confirmed negligible changes in ER during irrigation due to simultaneous wetting and root water uptake processes. In addition, a good correlation was observed between the proximal sensed and the ERT results. Finally, the findings of this study underscore the necessity of using multiple methods for improving our knowledge of the SPAC system under real field conditions.

Assessing the dam's stability of the pond at the ‘El Bosque’ renaissance garden (Béjar, Spain)

AbstractThe renaissance botanical garden of ‘El Bosque’ in Béjar (Salamanca, Spain) presents a pond bounded by a dam in its western part. The latter is formed by two masonry walls interconnected by buttresses. Cubic spaces in between are filled with a variable grain‐size material (silty sand) that allows limited water flow. In recent years, the southern part of the dam has experienced localized and random subsidence that jeopardizes the entrance to part of the garden. To regain access, a proper and reliable diagnosis of the origin, magnitude and relevance of the subsidence must be made. In this regard, we have undertaken a microgravity survey in the dam area to identify places with an anomalous distribution of the filling material in order to foresee further sinking or potential collapsing areas. The precise positioning (2 mm resolution) and accurate terrain correction needed in this kind of high‐resolution gravity surveys (points every 1.5 m) were achieved by creating a detailed digital terrain model (cm resolution) with a remotely piloted aircraft. In addition, we performed three electric resistivity tomography (ERT) profiles at different levels of the garden: (i) on the dam itself; (ii) right on the foot of the dam and parallel to it (5 m below and ∼17 m to the W); and (iii) a bit farther, but also parallel to the dam (8 m below and ∼27 m to the W). The ERT profiles identified high conductivity in water‐saturated areas and determined the paths that rainfall and pond's seepage water follow in the dam and its underground, formed by granites. The geophysical studies were paired with geotechnical analyses of the sunk materials. The study concluded that the thinnest fraction of the dam's filling material (i.e., silts) is being washed away, leaving behind sand with less density and stability, susceptible to collapse. Thus, the observed sinking is related to soil piping, that is to soil internal erosion and compaction issues that force the soil material to re‐adjust geometrically and volumetrically.

Rapid warming and degradation of mountain permafrost in Norway and Iceland

Abstract. With the EU-funded PACE (Permafrost and Climate in Europe) project at the turn of this century, several deep boreholes (100 m+) were drilled in European mountain sites, including in mainland Norway, Svalbard and Sweden. During other projects from 2004 and the International Polar Year (IPY) period in 2006–2007, several additional boreholes were drilled in different sites in both Norway and Iceland, measuring temperatures along both altitudinal and latitudinal gradients. At most sites, multi-temporal geophysical soundings are available using electrical resistivity tomography (ERT). Here, we study the development of permafrost and ground temperatures in mainland Norway and Iceland based on these data sets. We document that permafrost in Norway and Iceland is warming at a high rate, including the development of taliks in both Norway and Iceland in response to global climate change during the last 20 years. At most sites, ground surface temperature (GST) is apparently increasing more strongly than surface air temperature (SAT). Changing snow conditions appear to be the most important factor for the higher GST rates. Modelling exercises also indicate that the talik development can be explained by both higher air temperatures and increasing snow depth.

Emancipating from (Colonial) Genealogies of the Techno-social Networks or Reversing Power Relations by Turning the Predator into Prey in Jordan Peele’s Nope

The article aims to map the contemporary techno-social networks, together with delineation of the algorithmic governmentality, computational unconscious, the epistemic structure of the Eurocentric matrix of power haunted by its own repetition of the constant abyss of horrors, only to search for gestures of resistance. Gestures of resistance, contrary to the false conviction of capitalist realism, can be found everywhere, including in Jordan Peele's Nope (2022). Through a variety of motifs, themes, and cultural and cinematic references, Peele creates a resistance image, i.e., an image that resists the historical trajectory of the violence of the digital colonial matrix of knowledge. In particular with Nope, in which the history of racial violence is disentangled by evoking the relation between the entanglement of capital and epistemic violence embodied in an all-devouring predator UFO. But Nope is also about visualizing silenced histories. Indeed, to strive to capture UFO with the camera is to break away from modernity as a totalizing onto-epistemology and in this register generating a false universal subject of a Man.

Assessing Shallow Soft Deposits through Near-Surface Geophysics and UAV-SfM: Application in Pocket Beaches Environments

This study employs a multimethod approach to investigate the sediment distribution in two pocket beaches, Ramla Beach and Mellieha S Beach, in Malta. Both study sites were digitally reconstructed using unmanned aerial vehicle (UAV) photogrammetry. For each case, an ERT and a dense network of ambient seismic noise measurements processed through a horizontal-to-vertical spectral ratio (HVSR) technique were acquired. Electrical resistivity tomography (ERT) analysis enables the estimation of sediment thickness in each beach. HVSR analysis revealed peaks related to beach sediments overlying limestone rocks in both sites and also indicated a deeper stratigraphic contact in Mellieha S Beach. Based on ERT measurements, sediment thickness is calculated for each HVSR measurement. Interpolation of results allows for bedrock surface modelling in each case study, and when combined with digital terrain models (DTMs) derived from photogrammetric models, sediment volumes are estimated for each site. The geometry of this surface is analyzed from a geological perspective, showing structural control of sediment distribution due to a normal fault in Mellieha S Beach and stratigraphic control facilitated by a highly erodible surface in Ramla Beach. The results emphasize the importance of adopting a three-dimensional perspective in coastal studies for precise sediment volume characterization and a deeper understanding of pocket beach dynamics. This practical multimethod approach presented here offers valuable tools for future coastal research and effective coastal management, facilitating informed decision making amidst the growing vulnerability of coastal zones to climate change impacts.

Detecting the Effect of Soil Compaction Processes on the Distribution of Subsurface Resistivity Using 2D Resistivity Imaging

Detecting the Effect of Soil Compaction Processes on the Distribution of Subsurface Resistivity Using 2D Resistivity Imaging

Combining Electrical Resistivity, Induced Polarization, and Self-Potential for a Better Detection of Ore Bodies

Electrical resistivity (ER), induced polarization (IP), and self-potential (SP) are three geophysical methods that have been broadly used in the realm of mineral exploration. These geophysical methods provide complementary information, each exhibiting a distinct sensitivity to various types of mineral deposits. Considering the relationship among these three methods, we propose an integrated approach that merges their respective information to offer an improved localization technique for ore bodies. First, we invert the electrical conductivity distribution through electrical resistance tomography (ERT). Then, we use the inverted conductivity distribution to invert the IP and SP data in terms of chargeability and source current density distributions. Then, we normalize the inverted chargeability and source current density distributions and we combine them to obtain an ore body index (ORI) χ used to delineate the potential locations of ore deposits. We design this index to be sensitive to the presence of ore bodies, which are reflected by either strong and localized source current density (SP) and/or strong chargeability values (IP). The proposed method is first validated using a synthetic model with two distinct anomalies characterized by different properties. The results show the limitation of individual inversion, as each method exclusively detects one of these anomalies. The combined approach allows a better characterization of the target. Then, the approach is applied to a sandbox experiment in which two metallic bodies are buried in water-saturated sand used as the background. Again, the proposed methodology is successfully applied to the detection of the metallic targets, improving their localization compared with individual methods.

Delineation of LNAPL plumes in a clay-rich site in Gyeongsangnam-do Province, South Korea: integration of geophysical survey data with borehole data and soil sampling information.

To effectively delineate the spatial distribution of oil contaminant plumes, geophysical methods indirectly measure the physical properties of the subsurface and can provide spatial information and images on a large scale, as opposed to traditional direct methods such as borehole drilling, sampling, and chemical analysis, which are time-consuming and costly. However, interpreting geophysical responses over non-aqueous phase liquid (NAPL)-contaminated sites is not straightforward due to inconsistent responses from biodegraded oil contaminants. In this study, we performed multi-geophysical surveys including seismic refraction, ground-penetrating radar, electrical resistivity tomography (ERT), and induced polarization (IP) surveys, to locate NAPL-contaminated zones in a clay-rich site. To reduce ambiguity in discriminating between oil contaminants and clay layers, we first figure out the geological structure of the site by interpreting geophysical data incorporating with borehole data. The ERT data highlighted the heavily contaminated regions in the unsaturated zone but were less distinctive below groundwater levels. Conversely, IP responses revealed potential hotspots within the clay layers, extending beneath the groundwater. Considering the 3D geological model, NAPL-contaminated zones are properly delineated through interpretation of ERT and IP data together with borehole data, and the contaminant source zone was properly estimated within the site.

Unveiling a hidden fortification system at “Faraglioni” Middle Bronze Age Village of Ustica Island (Palermo, Italy) through ERT and GPR prospections

We carried out a geophysical research project in the Middle Bronze Age village of Ustica (Palermo, Sicily, Italy), named “Faraglioni Village” after the stack formations which detach from the coast north of the archaeological site. The investigation, which comprised Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) techniques, allowed us to discover the buried foundations of an outwork fortification system never evidenced by previous archaeological studies, only hypothesised from the observation of aerial photography and partially outcropping boulders, which align roughly parallel to the main defensive wall of the Village.Our geophysical prospection involved the entire 250 m-long arc of the outward village defensive wall, with the acquisition of eleven ERT profiles and 27 GPR scans. The techniques were selected based on both favourable logistics and methods applicability: ERT sections allowed us to trace a series of high-resistivity anomalies arranged to form an arc-shaped structure along the perimeter of the defensive wall. GPR investigation was localised in the most accommodating patch of terrain of the site, with the effort of intercepting clear enough sections of the target, to determine more accurately its shape, depth, and overall dimensions. Our discovery paves the way for new investigations, mainly aimed at defining the timing of construction of the fortification system, as well as the function of the remains of other architectural structures identified close to the wall, which could represent the target of further geophysical investigations.

Characterization of seepage in an earthfill dam by the integration of geophysical surveys and geotechnical data

Seepage is a common phenomenon in earthfill dams, and one that typically warrants episodic assessment and monitoring by regulatory agencies. Geophysical surveys provide a convenient, cost-effective, and convenient means for assessing seepage, but only if they are applied in effective combinations and if the data are analyzed properly. In the present study, a self-potential survey of streaming potential and a 2D electrical resistivity tomography survey were notably successful in detecting seepage under the embankment of the nearly 90-year-old Standing Rock Dam No. 1 in South Dakota, USA. Self-potential (SP) measurements show a localized negative anomaly of up to 27 mV on the upstream side of the dam, which we interpret to be the inlet or recharge zone for seepage, and a positive anomaly of up to 20 mV on the downstream side, which we interpret to be the outlet or discharge zone. The spatial correlation between our resistivity models, SP data, and topography was excellent. Water-saturated, conductive deposits in the dam's embankment match a negative SP amplitude in the inlet or recharge area. Similarly, water-saturated electrically conductive sediments are characterized by a positive SP amplitude in the discharge area where surface seepage occurs in a topographic low. Six years of water-level measurements in the existing piezometers interpreted relative to the properties and spatial distribution of coarser-grained alluvium (sand and gravel) underneath the dam's embankment fill, suggest that most seepage occurs under the dam. Our approach to assessing seepage in this project should be widely applicable to earthfill dams worldwide, and our modeled results constitute a valuable case study.

Electrical Resistivity - Tomography Studies In Determining Shallow Aquifer Potential Zones a Case Study in Different Terrains

The study documents the effectiveness of 2 D (Two Dimensional Electrical Resistivity Survey (Tomography) to map shallow subsurface geological formations namely recent Alluvium, Gondwana deposits and hard rock deposits. 2 dimensional Electrical Resistivity Survey (or tomography) was conducted at 2 locations at Valarpuram and one location Madurantakam areas. Gondwana deposits mask Valarpuram Thandalam, villages (at Kancheepuram District, Tamilnadu). To the east of Valarpuram alluvium thickness increases at shallow depths. Weathered and hard granitic gneiss and hard charnockite rocks overlie topsoil in Madurantakam areas (Chengalpettu District, Tamilandu). The survey was conducted to 12 m depth to decipher shallow permeable zones. Gondwana formations consisting of clays, siltstones are predominant in Valarpuram Thandalam and surrounding areas. Hard rock formations are found in Madurantakam areas. 2 Dimensional Resistivity Survey results indicate 2-D sections with very low resistivity values in the range of 2 to 4 ohm-m in Valarpuram Thandalam areas indicating predominant clay deposits with poor ground water potential. To the east of Valarpuram Thandalam resistivity data is of moderately higher value indicating sand deposits at shallow depths. These are ideal locations for dug wells. Low to moderate values at shallow depths indicating weathered thickness up to 12 m are observed at Madurantakam location. From 12m depth steep rise in resistivity values are observed in hard indicating presence of massive rock from 12m depth and below areas. Thus, 2 D Resistivity Imaging Technique are helpful in delineating shallow aquifer potential and this in turn helps in deciding the depth of open wells with high precision.

New MT surveys and 3D resistivity imaging beneath the Ngozi-Rungwe volcanoes at the triple rift junction of the East African Rift System in SW Tanzania: Support for integrated interpretations of geothermal conceptual models

The geothermal system related to the Ngozi and Rungwe volcanoes, SW Tanzania, lies at the intersection of the west and east branches of the East African Rift System and has been investigated by many geoscientists for decades. Here we present a 3D electrical resistivity model based on 190 magnetotelluric resistivity soundings that have been integrated with geochemical and geological results to support the development of the geothermal resource conceptual model presented here. The model includes two separate reservoirs, a larger system located beneath the Rungwe volcano and a smaller chloride water reservoir located under the Ngozi caldera, which contains a neutral chloride hot spring with geothermometry >230°C. An extensive conductive clay cap with variable thickness extends along the 30 km long NW-SE trending Ngozi-Rungwe Fault Zone from the Kiejo area SE of the Rungwe volcano to the Ngozi caldera. The absence of geothermal surface manifestations directly over the inferred Rungwe upflow zone is consistent with effective sealing of the proposed underlying geothermal reservoir by the clay cap. The scarcity of thermal manifestations on the up-dip margins of the low-resistivity clay cap can be explained by coincidence of the base of the clay cap with impermeable Precambrian formations and by structural boundaries. This interpretation implies that the area with the highest geothermal resource potential is the Rungwe volcano where proposed drilling sites might intersect the proposed high-temperature reservoir.

Improving soil thickness estimations and its spatial pattern on hillslopes in karst forests along latitudinal gradients

Soils provide storage space for nutrients and water, which governs many hydrological processes and functions in the natural ecosystems. Due to the complex soil-rock structures and localized climate, soil thickness and stock vary distinctly in different karst areas in southwest China. The difficulties of soil detection and the non-transparent underground soil-rock structures limit a deeper understanding of the spatial distribution of soils and their ecological functions. In this study, we employed electrical resistivity tomography (ERT) combined with soil probes to detect the spatial distribution of soils on hillslopes in karst forests in southwest China. The ERT surveys were conducted at six sites with 19 plots (20 × 30 m2) along latitudinal gradients. The results show that the ERT method performs well in visualizing the complex soil–bedrock interfaces and patchy distribution of soils in karst hillslopes, with remarkable consistency with the observed soil thickness and rock outcrops. Soil probes often hit rocks in soils (which we call a “rock barrier effect”), resulting in an underestimation of the mean soil thickness within the one-meter exploration depth by ∼0.18 m. This indicates that soil stock estimates derived from soil probes may be obviously underestimated in karst areas where the rock barrier effects are widespread. Meanwhile, the concept of equivalent soil thickness is proposed to remove the impact of scattered bedrock on soil stock estimation. For the six selected sites, the ERT-inferred mean soil thickness, equivalent soil thickness, and stock are 0.86 m, 0.60 m, and 0.10 m3/m3 respectively, with a trend of decreasing from high to low latitudes. Moreover, the rock outcrop coverage rate explains 52 % (60 %) of the variation in soil thickness (stock), followed by the annual mean temperature. This study emphasizes the importance of considering bedrock topography and its distribution in improving the detection of soil distribution, and the implications of the findings in this study are perhaps most profound for soil thickness-related soil erosion, soil water storage, and carbon storage in karst critical zones.

Geophysics for underground engineering

The growth of underground engineering brought a need for the use of geophysical methods for research of underground constructions rather different in approach compared to that of civil engineering. These changes relate to surface measurement on the one hand and the development of new specialised methods used for underground work on the other. The results of a complete documentation of mining work, the application of the resistivity methods used underground and also the use of 3D electrical resistivity tomography, are all presented here.

A deep-learning framework for borehole formation properties prediction using heterogeneous well-logging data: A case study of a carbonate reservoir in the Gaoshiti-Moxi area, Sichuan Basin, China

The properties of borehole formations, such as porosity, permeability, and water saturation, play a crucial role in characterizing and evaluating subsurface reservoirs. Although core sample experiments offer precise measurements, they are time consuming and cost intensive. An alternative method is to use the logging data to construct an empirical model that predicts formation properties, which is widely studied due to its speed and affordability. Nevertheless, because the response of a logging point reflects its surrounding formation, conventional logging methods relying on point-to-point (P2P) mapping perform poorly in complex reservoirs. Furthermore, the resolution of conventional logging is lower compared with imaging logging. To address these limitations, this study presents a novel approach to predict formation properties based on a deep-learning framework using heterogeneous well-logging data. Our neural network framework takes short sequences of conventional logging data and windowed imaging logging data as inputs. The neural network applies 1D convolution to extract features from the conventional logging sequences and 2D convolution to extract features from the resistivity imaging data. Then, these two feature vectors are fused and fed into a multilayer fully connected neural network to predict formation properties. A case study of a carbonate reservoir demonstrates that our method delivers more accurate predictions of formation porosity, permeability, and water saturation than the P2P, sequence-to-point, and image-to-point prediction methods. Moreover, it is expected that our paradigm will serve as a source of inspiration for forthcoming research endeavors aimed at enhancing the accuracy of predicting borehole formation properties in complex reservoirs.

PyMERRY: A Python solution for an improved interpretation of electrical resistivity tomography images

Electrical resistivity tomography (ERT) is a widely used geophysical method for studying geologic hazards, civil engineering, and environmental remediation. It provides information about the subsurface’s resistivity distribution by analyzing electrical data collected at the surface or in boreholes. However, interpreting ERT images can be complex due to ambiguities in their resolution. To address this issue, we develop a postprocessing method called Python iMprovement of Electrical Resistivity tomography ReliabilitY (PyMERRY) to improve the reliability of ERT images. The PyMERRY code can be applied to any 2D resistivity model obtained from ERT inversion software. It computes a coverage mask that defines the domain well constrained by the data and the inversion process. It also evaluates the resistivity uncertainties in the ERT models. In addition to the sensitivity approaches, PyMERRY provides low- and high-resistivity values for all covered cells. Synthetic tests indicate that the approach is efficient and highlight the importance of resistivity contrasts, mesh selection, electrode spacing, and profile length in the reliability of ERT images. Compared with previous studies, using PyMERRY in south-central Bhutan allows a more accurate interpretation of ERT images. It confirms a high-resistivity contrast across the topographic frontal thrust and reveals the existence of small-scale variations.

High-resolution geophysical investigations in the central Apennines seismic belt (Italy): Results from the Campo Felice tectonic basin

The Campo Felice basin, in the central Apennines seismic belt (Italy), developed in the hangingwall of a 30 km-long system of NW-trending normal faults with Holocene paleoseismic activity and potential sources of M 6–7 earthquakes. We provide the first subsurface images of a key portion of the basin bounded by the Mt. Cefalone fault along two intersecting profiles trending NNE-SSW (CF-Dip, 1195 m-long) and WNW-ESE (CF-Strike, 1315-m long). We combined high-resolution depth-migrated reflection sections with P-wave velocity and electrical resistivity tomography models. CF-Dip profile displays a wedge-like syn-tectonic sedimentary sequence of alluvial and glacial deposits with Vp ∼ 2500–3000 m/s and resistivity > 500 Ωm in the hangingwall of Mt. Cefalone fault, overlying a high-Vp (>4000 m/s) limestone bedrock ∼ 300 m deep. The whole sequence displays reflectors truncated by the Mt. Cefalone fault zone and subsidiary antithetic faults. CF-Strike profile, tied to three 80–110 m-deep boreholes, shows a thick fluvio-lacustrine sequence with low-Vp (<2000 m/s) and low resistivity (<100 Ωm), and a bedrock that deepens to the southeast (>450 m). Single-station ambient noise measurements display Horizontal to Vertical Spectral Ratios with peaks at ∼1 Hz, decreasing to ∼0.8 Hz to the southeast in agreement with the bedrock deepening indicated by seismic profiling. According to our results, the Campo Felice basin is a deep asymmetric half-graben controlled by faulting whose activity likely started before the Middle Pleistocene. Our minimum displacement estimate accrued in the past 0.5 Ma by the Mt. Cefalone fault is in the range of ∼100–250 m.

The Geophysical Investigation of Leachate Formation in Mgbuka Obosi, Idemili North Local Government Area of Anambra State, Nigeria

The contamination of leachates (a polluted liquid made up of various toxic substances) from landfills is a significant environmental concern, especially in developing countries.This contaminated fluid is formed when rainwater interacts with refuse and travels through the pore spaces in soil. Constant migration of this fluid poses a significant threat to the quality of both surface and groundwater in and close to the landfill area. To determine the extent of leachate formation, the study used both Very Low-Frequency Electromagnetic (VLF-EM) and Electric Resistivity Tomography (ERT) to locate and define the spatial distribution of the leachate plume migration pathway at Mkpuka Obosi Dumpsite in Idemili North LGA of Anambra, Nigeria. Seven profiles were surveyed for both the VLF-EM and ERT. The VLF-EM survey, with a profile length of 100 to 200m and a 10m interstation spacing, revealed the presence of a conductive pollutant (leachate plume) in the subsurface. The results from the 2D ERT survey that employed a Wenner array with a profile length of 100 to 200m and an electrode spacing of 5m, divided the subsurface into six zones with an unusually low resistivity ranging from 0-250\(\Omega\)m. The leachate plumes were interpreted as the zone with the lowest resistivity of 0 to 25\(\Omega\)m, having an average thickness of approximately 10m and extending beyond the probed depth of 50m. Additionally, the percentage of leachate was found to be concentrated primarily at the center of the landfill and gradually decreasing proportionally from the center. Thus, emphasizing the importance of addressing the issues in landfill management.