scholarly journals Identification of zeolite using electrical resistivity tomography in Campang Tiga, South Lampung Regency

2021 ◽  
Vol 882 (1) ◽  
pp. 012046
Author(s):  
Alhada Farduwin ◽  
Pangeran G. Lumbatoruan ◽  
Karyanto ◽  
Dian Triyanto

Abstract Currently, zeolites are widely used in various fields including horticultural, agricultural, household, industrial, water and wastewater management. Due to the increasing use of zeolites, it is estimated that the demand for zeolites will increase in the future. Therefore, it is necessary to conduct a survey to determine the potential of zeolites in an area. Campang Tiga is an area with quite a lot of potential zeolite and is exposed on the surface along with tuffs from the Lampung Formation. To estimate the potential zeolite in this area, it was carried out the Electrical Resistivity (ERT) measurements to determine the distribution and depth of the tuff layer associated with the zeolite. Measurements were made in 3 lines with an electrode spacing of 6 m using a dipole-dipole configuration. The result performs that the zeolites in the area are located at a depth of up to ∼ 10 m and are getting thicker towards the east until they reach a depth of ∼ 20 m. The results of this interpretation have been combined with the results of laboratory measurements of the resistivity value of zeolites in the area. Laboratory test results present that the zeolite resistivity value ranges from 20-300 Ωm.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Carlos Mauricio Paglis

Roots play an important role in plants and are responsible for several functions; among them are anchorage and nutrient and water absorption. Several methodologies are being tested and used to study plant root systems in order to avoid destructive root sampling. Electrical resistivity tomography is among these methodologies. The aim of this preliminary study was to use electrical resistivity for detecting root biomass in coffee trees. Measurements were performed in a soil transect with an ABM AL 48-b resistivimeter with a pole-dipole configuration. The tomograms indicated variability in soil resistivity values ranging from 120 to 1400 Ω·m−1. At the first 0.30 cm soil layer, these values were between 267 and 952 Ω·m−1. Oriented by this result, root samples were taken at 0.10, 0.20, and 0.30 m depths within 0.50 m intervals along the soil transect to compare soil resistivity with root mass density (RMD). RMD data, up to this depth, varied from 0.000019 to 0.009469 Mg·m−3, showing high spatial variability and significant relationship to the observed values of soil resistivity. These preliminary results showed that the electrical resistivity tomography can contribute to root biomass studies in coffee plants; however, more experiments are necessary to confirm the found results in Brazil coffee plantations.


Author(s):  
O. F. Ogunlana ◽  
O. M. Alile ◽  
O. J. Airen

The Electrical Resistivity Tomography (ERT) data was acquired within the area suspected to have high potential for bitumen occurrence using the Wenner-Schlumberger configuration in Agbabu, southwestern Nigeria. PASI 16GL-N Earth resistivity meter instrument was used to acquire data along five (5) traverses with 5m electrode spacing and traverses length of 150m. The apparent resistivity values obtained was processed using RES2DINV software which helped to automatically obtain the 2D inversion model of the subsurface. This study has shown the occurrence of bitumen between the depth of 13.4m and 9.93m for Traverses 1, 2, 3 and Traverses 4, 5 respectively in a 2-Dimensional electrical resistivity images for boreholes with a depth of about 18m. The results indicate that the bitumen is characterized by good lateral continuity and is sufficiently thick for commercial exploitation.


2020 ◽  
Author(s):  
Laurent Gourdol ◽  
Rémi Clément ◽  
Jérôme Juilleret ◽  
Laurent Pfister ◽  
Christophe Hissler

Abstract. Within the Critical Zone, regolith plays a key role in the fundamental hydrological functions of water collection, storage, mixing and release. Electrical Resistivity Tomography (ERT) is recognized as a remarkable tool for characterizing the geometry and properties of the regolith, overcoming limitations inherent to conventional borehole-based investigations. For exploring shallow layers, a small electrode spacing (ES) will provide a denser set of apparent resistivity measurements of the subsurface. As this option is cumbersome and time-consuming, smaller ES – albeit offering poorer shallow apparent resistivity data – are often preferred for large horizontal ERT surveys. To investigate the negative trade-off between larger ES and reduced accuracy of the inverted ERT images for shallow layers, we use a set of synthetic conductive/resistive/conductive three-layered soil–saprock/saprolite–bedrock models in combination with a reference field dataset. Our results suggest that an increase in ES causes a deterioration of the accuracy of the inverted ERT images in terms of both resistivity distribution and interface delineation and, most importantly, that this degradation increases sharply when the ES exceeds the thickness of the top subsurface layer. This finding, which is obvious for the characterization of shallow layers, is also relevant even when solely aiming for the characterization of deeper layers. We show that an oversized ES leads to overestimations of depth to bedrock and that this overestimation is even more important for subsurface structures with high resistivity contrast. To overcome this limitation, we propose adding interpolated levels of surficial apparent resistivity relying on a limited number of ERT profiles with a smaller ES. We demonstrate that our protocol significantly improves the accuracy of ERT profiles when using large ES, provided that the top layer has a rather constant thickness and resistivity. For the specific case of large-scale ERT surveys the proposed upgrading procedure is cost-effective in comparison to protocols based on small ES.


Khazanah ◽  
2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Jefri nainggolan ◽  
◽  
Muhammad Fajar ◽  

Research has been carried out to determine subsurface conditions. The research objective was to determine the physical properties of the soil in order to evaluate and provide recommendations for solving foundation problems. The methods are the resistivity geoelectric and IP geoelectric method (induced polarization) with ERT (Electrical Resistivity Tomography), SPT (Standard Penetration Test) and laboratory test results. The results of the resistivity values obtained varied in the range from 17.0 - 172.0 ohm m with a depth of 0 m - 2.87 m, most of which were interpreted as alluvium soil, namely sandy loam. This is reinforced by the results of the IP method where the low chargebility value is around 0.130 - 4.70 msec. In addition, it was found that from the SPT test, it was obtained that the variation of blows from 14 to 21 N at a depth of 0 - 5.50 meters and >60 N from a depth of 5.50 - 20 m which stated that most of them consisted of clay and sandstones. Then based on laboratory tests, it was found that at a depth of 3 - 3.5 meters it consisted of 86.47% clay with a plastic limit of 37.07% and the water content was 39.41%, while at a depth of 9 -9.5 meters it consisted of sandstones which the characteristic is non- plastic with a water content of up to 72.04%. It is concluded that the surface soil is conductive, it is necessary to hold special treatment for this type of soil in order to avoid erosion when it is saturated with water and it is hoped that the stability of the soil will be better. One of two ways is by mixing high density soil and making a "chicken claw" foundation to strengthen the foundation with a depth of more than 5.0 meters. Keywords: Geoelectric, Standard Penetration Test, Resistivity, Chargebility, Foundation.


2021 ◽  
Vol 11 (10) ◽  
pp. 4455
Author(s):  
Alfonso Gutiérrez-Martín ◽  
José I. Yenes ◽  
Marta Fernández-Hernández ◽  
Ricardo Castedo

The paper proposes a novel methodology for the stabilization of shallow foundations, with a simplified model combined with 3D electrical resistivity tomography (ERT-3D and consolidation injections. To determine its usefulness, the method has been applied in a case located in Estepona (southern Spain). The chosen tomography model is the dipole–dipole configuration, with an optimized distance between electrodes of 0.80 m for a better visualization of the foundation subsoil; with this parameterization, a total of 72 electrodes were installed in the analyzed case. In this work, the depth of the anomaly in the building’s supporting subsoil was detected ranging from 2.00 m to 3.90 m deep. The study also delineates areas of high resistivity variations (50–1000 Ω m) in the middle and eastern end of the field. These data have been validated and corroborated with a field campaign. The results of the ERT-3D monitoring are presented, once the investment data has been processed with the RES3DINV software, from the beginning to the end of the stabilization intervention. The novelty occurs with the interaction between the tomography and the foundation consolidation injections, until the final stabilization. This is a very useful methodology in case of emergency consolidation, where there is a need to minimize damage to the building. Thus, people using this combined system will be able to practically solve the initial anomalies of the subsoil that caused the damages, in a non-invasive way, considerably lowering the value of the resistivities.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 69
Author(s):  
Azadeh Hojat ◽  
Maddalena Ferrario ◽  
Diego Arosio ◽  
Marco Brunero ◽  
Vladislav Ivov Ivanov ◽  
...  

We present the results of laboratory experiments on a down-scaled river levee constructed with clayey material collected from a river embankment where a permanent resistivity instrument has operated since 2015. To create potential seepages through the levee, two zones (5 × 4 cm and 10 × 2 cm) were filled with sand during the levee construction. Electrical resistivity tomography (ERT) technique and Fiber Bragg Grating (FBG) technology were used to study time-lapse variations due to seepage. The ERT profile was spread on the levee crest and the Wenner array with unit electrode spacing a = 3 cm was used. Six organic modified ceramics (ORMOCER) coated 250 μm-diameter fibers were deployed in different parts of the levee. Time-lapse measurements were performed for both techniques from the beginning of each experiment when water was added to the river side until the water was continuously exiting from the seepage zones. The results showed that ERT images could detect seepages from the early stages. Although with a short delay compared to ERT, fiber optic sensors also showed their ability to detect water infiltrations by measuring temperature changes. Both technologies being successful, a discussion about respective peculiarities and pros and cons is proposed to suggest some criteria in choosing the proper technique according to the specific needs.


2019 ◽  
Vol 9 (15) ◽  
pp. 2963 ◽  
Author(s):  
Yin-Chun Hung ◽  
Chih-Ping Lin ◽  
Chin-Tan Lee ◽  
Ko-Wei Weng

Electrical resistivity tomography (ERT) is one of the most widely used geophysical methods in geological, hydrogeological, and geo-environmental investigations. Although 3D ERT is now available, 2D ERT remains state-of-the-practice due to its simplicity in fieldwork and lower space requirements. 2D ERT assumes that the ground condition is perpendicular to the survey line and outside the survey line is homogeneous. This assumption can often be violated in conditions such as geologic strikes not perpendicular to the survey line and topographic changes or buried objects near the survey line. Possible errors or artifacts in the 2D resistivity tomogram arising from violating the 2D assumption are often overlooked. This study aimed to numerically investigate the boundary effects on 2D ERT under various simplified conditions. Potential factors including resistivity contrast, depth and size of buried objects, and electrode spacing were considered for the parametric studies. The results revealed that offline geologic features may project onto the 2D tomogram to some extent, depending on the aforementioned factors. The mechanism and implications of boundary effects can be drawn from these parametric studies.


2021 ◽  
Vol 25 (4) ◽  
pp. 1785-1812
Author(s):  
Laurent Gourdol ◽  
Rémi Clément ◽  
Jérôme Juilleret ◽  
Laurent Pfister ◽  
Christophe Hissler

Abstract. Within the critical zone, regolith plays a key role in the fundamental hydrological functions of water collection, storage, mixing and release. Electrical resistivity tomography (ERT) is recognized as a remarkable tool for characterizing the geometry and properties of the regolith, overcoming limitations inherent to conventional borehole-based investigations. For exploring shallow layers, a small electrode spacing (ES) will provide a denser set of apparent resistivity measurements of the subsurface. As this option is cumbersome and time-consuming, larger ES – albeit offering poorer shallow apparent resistivity data – is often preferred for large horizontal ERT surveys. To investigate the negative trade-off between larger ES and reduced accuracy of the inverted ERT images for shallow layers, we use a set of synthetic “conductive–resistive–conductive” three-layered soil–saprock/saprolite–bedrock models in combination with a reference field dataset. Our results suggest that an increase in ES causes a deterioration of the accuracy of the inverted ERT images in terms of both resistivity distribution and interface delineation and, most importantly, that this degradation increases sharply when the ES exceeds the thickness of the top subsurface layer. This finding, which is obvious for the characterization of shallow layers, is also relevant even when solely aiming for the characterization of deeper layers. We show that an oversized ES leads to overestimations of depth to bedrock and that this overestimation is even more important for subsurface structures with high resistivity contrast. To overcome this limitation, we propose adding interpolated levels of surficial apparent resistivity relying on a limited number of ERT profiles with a smaller ES. We demonstrate that our protocol significantly improves the accuracy of ERT profiles when using large ES, provided that the top layer has a rather constant thickness and resistivity. For the specific case of large-scale ERT surveys the proposed upgrading procedure is cost-effective in comparison to protocols based on small ES.


Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1067 ◽  
Author(s):  
Nicolas Greggio ◽  
Beatrice Giambastiani ◽  
Enrico Balugani ◽  
Chiara Amaini ◽  
Marco Antonellini

High-resolution electrical resistivity tomography (ERT) with electrode spacing of 1 m proved to be an effective methodology to characterize ephemeral, sparse, and discontinuous freshwater lenses within the almost completely salinized shallow aquifer of the low coastal zone near Ravenna. ERT profiles with a vertical resolution of 0.25–0.5 m, once calibrated with groundwater data (water table depth and electrical conductivity) collected in multi-level sampler systems at the same spatial resolution, are reliable and provide repeatable measurements in time. The ERT methodology allows for fast data acquisition over large areas and it also permits the study of the evolution in time of freshwater availability in coastal zones, which is important for local ecosystems and soil resources. This makes high-resolution ERT a valid tool to aid local stakeholders and decision makers to effectively manage freshwater lenses, and guarantee their preservation or augmentation by means of managed aquifer recharge.


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