scholarly journals Interpretation of Data from Electrical Resistivity Geophysical Surveys

Nature ◽  
1948 ◽  
Vol 162 (4109) ◽  
pp. 187-187
Author(s):  
J. M. HOUGH
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Surveys

Investigating the Effective Resistivity of Reinforced Concrete Waste Storage Tanks at the Hanford Site

Geophysics ◽  
2021 ◽  
pp. 1-50
Author(s):  
Allan Haas ◽  
Dale F. Rucker ◽  
Marc T. Levitt
Keyword(s):  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Geophysical Methods ◽  
Underground Storage ◽  
Storage Tanks ◽  
Hanford Site ◽  
Underground Storage Tanks ◽  
Effective Resistivity ◽  
Geophysical Surveys ◽  
Wide Range

Industrialized sites pose challenges for conducting electrical resistivity geophysical surveys, as the sites typically contain metallic infrastructure that can mask electrolytic-based soil and groundwater contamination. The Hanford site in eastern Washington State, USA, is an industrialized site with underground storage tanks, piping networks, steel fencing, and other potentially interfering infrastructure that could inhibit the effectiveness of electrical resistivity tomography (ERT) to map historical and monitor current waste releases. The underground storage tanks are the largest contributor by volume to subsurface infrastructure and can be classified as reinforced concrete structures with an internal steel liner. Directly measuring the effective value for the electrical resistivity of the tank, i.e., the combination of individual components that comprise the tank’s shell, is not reasonably possible because they are buried and dangerously radioactive. Therefore, we indirectly assess the general resistivity of the tanks and surrounding infrastructure by developing synthetic ERT models with a parametric forward modeling study using a wide range of resistivity values from 1×10−6 to 1×104 ohm-m, which are equivalent to steel and dry rock, respectively. The synthetic models used the long-electrode ERT method (LE-ERT), whereby steel cased metallic wells surrounding the tanks are used as electrodes. The patterns and values of the synthetic tomographic models were then compared to LE-ERT field data from the AX tank farm at the Hanford site. This indirect method of assessing the effective resistivity revealed that the reinforced concrete tanks are electrically resistive and the accompanying piping infrastructure has little influence on the overall resistivity distribution when using electrically based geophysical methods for characterizing or monitoring waste releases. Our findings are consistent with nondestructive testing literature that also shows reinforced concrete to be generally resistive.

scholarly journals Data for the potential gold mineralization mapping with the applications of Electrical Resistivity Imaging and Induced Polarization geophysical surveys

Data in Brief ◽  
2019 ◽  
Vol 22 ◽  
pp. 830-835 ◽  
Author(s):  
Mohd Hariri Arifin ◽  
John Stephen Kayode ◽  
Muhammad Khairel Izwan ◽  
Hussein Ahmed Hasan Zaid ◽  
Hamzah Hussin
Keyword(s):  
Electrical Resistivity ◽  
Gold Mineralization ◽  
Induced Polarization ◽  
Electrical Resistivity Imaging ◽  
Resistivity Imaging ◽  
Geophysical Surveys

scholarly journals Large-scale electrical resistivity tomography in the Cheb Basin (Eger Rift) at an International Continental Drilling Program (ICDP) monitoring site to image fluid-related structures

Solid Earth ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 1951-1969 ◽  
Author(s):  
Tobias Nickschick ◽  
Christina Flechsig ◽  
Jan Mrlina ◽  
Frank Oppermann ◽  
Felix Löbig ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Fault Zone ◽  
Large Scale ◽  
Monitoring Site ◽  
Earthquake Activity ◽  
Resistivity Tomography ◽  
Scientific Drilling ◽  
Eger Rift ◽  
Geophysical Surveys ◽  
Cheb Basin

Abstract. The Cheb Basin, a region of ongoing swarm earthquake activity in the western Czech Republic, is characterized by intense carbon dioxide degassing along two known fault zones – the N–S-striking Počatky–Plesná fault zone (PPZ) and the NW–SE-striking Mariánské Lázně fault zone (MLF). The fluid pathways for the ascending CO2 of mantle origin are one of the subjects of the International Continental Scientific Drilling Program (ICDP) project “Drilling the Eger Rift” in which several geophysical surveys are currently being carried out in this area to image the topmost hundreds of meters to assess the structural situation, as existing boreholes are not sufficiently deep to characterize it. As electrical resistivity is a sensitive parameter to the presence of conductive rock fractions as liquid fluids, clay minerals, and also metallic components, a large-scale dipole–dipole experiment using a special type of electric resistivity tomography (ERT) was carried out in June 2017 in order to image fluid-relevant structures. We used permanently placed data loggers for voltage measurements in conjunction with moving high-power current sources to generate sufficiently strong signals that could be detected all along the 6.5 km long profile with 100 and 150 m dipole spacings. After extensive processing of time series for voltage and current using a selective stacking approach, the pseudo-section is inverted, which results in a resistivity model that allows for reliable interpretations depths of up than 1000 m. The subsurface resistivity image reveals the deposition and transition of the overlying Neogene Vildštejn and Cypris formations, but it also shows a very conductive basement of phyllites and granites that can be attributed to high salinity or rock alteration by these fluids in the tectonically stressed basement. Distinct, narrow pathways for CO2 ascent are not observed with this kind of setup, which hints at wide degassing structures over several kilometers within the crust instead. We also observed gravity and GPS data along this profile in order to constrain ERT results. A gravity anomaly of ca. −9 mGal marks the deepest part of the Cheb Basin where the ERT profile indicates a large accumulation of conductive rocks, indicating a very deep weathering or alteration of the phyllitic basement due to the ascent of magmatic fluids such as CO2. We propose a conceptual model in which certain lithologic layers act as caps for the ascending fluids based on stratigraphic records and our results from this experiment, providing a basis for future drillings in the area aimed at studying and monitoring fluids.

SOME RESULTS OF GEOPHYSICAL PROSPECTING CONDUCTED FOR THE GEOLOGICAL SURVEY OF INDIA FROM 1945–1948

Geophysics ◽  
1950 ◽  
Vol 15 (4) ◽  
pp. 704-731
Author(s):  
G. Dessau
Keyword(s):  
Electrical Resistivity ◽  
Spontaneous Polarization ◽  
Geological Survey ◽  
Foundation Engineering ◽  
Geophysical Prospecting ◽  
Geophysical Surveys ◽  
Engineering Problems ◽  
Geophysical Investigations ◽  
The Many ◽  
Geological Background

The methods used and some results obtained from geophysical investigations conducted by the Geophysical Section of the Geological Survey of India from 1945–1948 are presented. The many difficulties encountered in obtaining the proper instruments necessitated the widespread use of equipment made by the Section. This is one of the reasons why electrical resistivity and spontaneous polarization methods were employed in preference to others. The majority of the geophysical surveys during this three year period were concentrated in the search for minerals, water supplies, and in the solution of foundation engineering problems. The emphasis on these phases of geophysical prospecting rather than on oil surveys was necessary because, of the types of equipment available, as well as the priority assigned to these projects. Two spontaneous polarization, two magnetic, and two resistivity surveys are described, in addition to one carried out jointly by electrical and seismic methods. The geological background of these investigations are also briefly mentioned together with some details of the equipment used.

scholarly journals Geophysical characterization and hydraulic properties of unconsolidated floodplain aquifer system in Wamako area, Sokoto State, north-western Nigeria

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
O. A. Akinbiyi ◽  
M. A. Oladunjoye ◽  
O. A. Sanuade ◽  
O. Oyedeji
Keyword(s):  
Electrical Resistivity ◽  
Grain Size Analysis ◽  
Appreciable Amount ◽  
Size Analysis ◽  
Computer Assisted ◽  
Aquifer System ◽  
Geophysical Surveys ◽  
Sandy Material ◽  
2D Resistivity ◽  
North Western

Abstract The subsurface internal geometry of Rima River floodplain located in north-western area of Nigeria was investigated using 2D resistivity imaging, vertical electrical sounding (VES) and laboratory analyses. Four profiles were acquired using Wenner array. The apparent resistivity computed was used to produce 2D electrical resistivity pseudosections using RES2DINV software. A total of nine VESs were acquired along the four profiles in the study area with AB/2 of 1 to 100 m. Quantitative interpretation of VES curves was done by partial curve matching and computer-assisted 1D forward modelling with the WinResist version 1.0 software. Five pits were dug along the profiles to confirm the interpreted results from the geophysical surveys. Soil samples were collected from the pits at various depths, and hydraulic conductivity (K) was estimated in the laboratory using the constant head permeability test following standard procedure. Interpretations of electrical resistivity technique show three to four subsurface layers including topsoil, sandy material and clay/saturated clayey materials. The sandy material is believed to be saturated with water with appreciable amount of porosity and permeability. This layer was further confirmed by pitting around the study area. From the laboratory and empirical estimation of K, it was discovered that the K value ranges from 10−2 to 10−6 m/s, which shows that the sample is clean sand which is moderately to highly permeable. The grain size analysis revealed from the cumulative plot that the sample falls predominantly within medium-sized sand, which makes the study area a good aquifer system.

scholarly journals Geophysical site assessment of an active urban development site, southeastern suburb of Cairo, Egypt

2020 ◽  
Vol 54 (1) ◽  
pp. qjegh2018-151
Author(s):  
N. I. Medhat ◽  
M. Atya ◽  
E. A. Ragab ◽  
A. A. El-Kenawy ◽  
M. Abdel Zaher ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Structural Damage ◽  
Residential Buildings ◽  
Seismic Refraction ◽  
Urban Site ◽  
Site Assessment ◽  
Near Surface ◽  
Geophysical Surveys ◽  
Quarry Blasting ◽  
Ground Stability

There has been significant structural damage of newly built residential buildings in Quarter-27 District in the SE of Cairo, Egypt. A nearby active limestone quarry may also be affecting ground stability. This paper shows how a near-surface geophysical survey could characterize the site, unusually after the initial housing construction had already been undertaken. Geophysical surveys included seismic refraction (acquired between phases of quarry blasting), electrical resistivity and ground penetrating radar (GPR) 1D and 2D datasets. Geophysical results produced maps of a 3D ground model that also included water table depth, known major faults and a saturated layer that may have caused the building damage. Of the geophysical techniques trialled electrical resistivity tomography and GPR data were deemed optimal. This study shows that it is possible to undertake geophysical surveys to characterize a restricted urban site development.

Preliminary use of ground-penetrating radar and electrical resistivity tomography to study tree roots in pine forests and poplar plantations

2008 ◽  
Vol 35 (10) ◽  
pp. 1047 ◽  
Author(s):  
Terenzio Zenone ◽  
Gianfranco Morelli ◽  
Maurizio Teobaldelli ◽  
Federico Fischanger ◽  
Marco Matteucci ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ground Penetrating Radar ◽  
Electrical Resistivity Tomography ◽  
Water Saturation ◽  
Three Dimensional ◽  
Tree Roots ◽  
Resistivity Tomography ◽  
Shape Distribution ◽  
Geophysical Surveys ◽  
Ground Penetrating

In this study, we assess the possibility of using ground penetrating radar (GPR) and electrical resistivity tomography (ERT) as indirect non-destructive techniques for root detection. Two experimental sites were investigated: a poplar plantation [mean height of plants 25.7 m, diameter at breast height (dbh) 33 cm] and a pinewood forest mainly composed of Pinus pinea L. and Pinus pinaster Ait. (mean height 17 m, dbh 29 cm). GPR measures were taken using antennas of 900 and 1500 MHz applied in square and circular grids. ERT was previously tested along 2-D lines, compared with GPR sections and direct observation of the roots, and then using a complete 3-D acquisition technique. Three-dimensional reconstructions using grids of electrodes centred and evenly spaced around the tree were used in all cases (poplar and pine), and repeated in different periods in the pine forest (April, June and September) to investigate the influence of water saturation on the results obtainable. The investigated roots systems were entirely excavated using AIR-SPADE Series 2000. In order to acquire morphological information on the root system, to be compared with the GPR and ERT, poplar and pine roots were scanned using a portable on ground scanning LIDAR. In test sections analysed around the poplar trees, GPR with a high frequency antenna proved to be able to detect roots with very small diameters and different angles, with the geometry of survey lines ruling the intensity of individual reflectors. The comparison between 3-D images of the extracted roots obtained with a laser scan data point cloud and the GPR profile proved the potential of high density 3-D GPR in mapping the entire system in unsaturated soil, with a preference for sandy and silty terrain, with problems arising when clay is predominant. Clutter produced by gravel and pebbles, mixed with the presence of roots, can also be sources of noise for the GPR signals. The work performed on the pine trees shows that the shape, distribution and volume of roots system, can be coupled to the 3-D electrical resistivity variation of the soil model map. Geophysical surveys can be a useful approach to root investigation in describing both the shape and behaviour of the roots in the subsoil.

scholarly journals Multidisciplinary Approach to a Recovery Plan of Historical Buildings

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Luciana Orlando
Keyword(s):  
Electrical Resistivity ◽  
Seismic Data ◽  
Electrical Resistivity Tomography ◽  
Multidisciplinary Approach ◽  
Seismic Refraction ◽  
Lateral Velocity ◽  
Resistivity Tomography ◽  
Multiple Data ◽  
Geophysical Surveys ◽  
Joint Interpretation

The paper emphasizes the advantages of employing multiple data techniques—geology, GPS, surveys of cracking, boreholes, seismic refraction and electrical resistivity tomography—to image the shallow stratigraphy and hypothesize the cause of instability of an urban area. The study is focused on the joint interpretation of the crack pattern, topographic monitoring and the features of the underground, to define the area affected by instability and the direction of ground motion with the objective to advance a hypothesis on the cause of the instability of the area and to depict the main features. Borehole stratigraphies for a univocal interpretation of the lithology of electrical and seismic data and electrical resistivity tomography to constrain the interpretation of the lateral velocity variations and thickness of seismic bedrock were used. The geophysical surveys reveals to be complementary in the depicting of underground features. The study is approached at small and medium scale.

scholarly journals Subsurface Geological Characterization of the Late Neogene–Quaternary Argive Basin, Peloponnese, Greece Using Transient Electromagnetic Data and Vintage Stratigraphic Logs

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 317
Author(s):  
Hector R. Hinojosa-Prieto ◽  
Pantelis Soupios ◽  
Pavel Barsukov
Keyword(s):  
Electrical Resistivity ◽  
Sedimentary Basin ◽  
Aegean Sea ◽  
Tectonic Structures ◽  
Transient Electromagnetic ◽  
Geophysical Surveys ◽  
Late Neogene ◽  
Half Graben ◽  
Joint Interpretation ◽  
Surface Geology

The onshore and offshore clastic deposits of the Argive Basin and the Argolic Gulf, respectively, in Peloponnese, Greece, form a Late Neogene–Quaternary half-graben that connects with the Aegean Sea. The onshore Late Neogene–Quaternary sequence, comprised of chaotically intercalated cohesive and granular clastic deposits, is in angular unconformity with bedrock comprised of Triassic–Upper Cretaceous strongly-weathered, highly-fractured karstic limestones thrusted against Paleogene flysch deposits. While the surface geology of the Argive Basin is well-known, the subsurface geology remains both poorly mapped and understood. We utilized transient electromagnetic (TEM) soundings coupled with 185 vintage stratigraphic logs, current surface geology knowledge, and insights from available geophysical surveys to characterize the subsurface conditions of this sedimentary basin. We estimated the thickness of the young deposits (the depth to bedrock) and detected potential subsurface tectonic structures. The TEM-FAST 48HPC data acquisition system with integrated inversion and visualization software package was used with a single-loop dimension of 50 m × 50 m to collect a total of 329 TEM soundings at 151 stations scattered throughout the basin. The TEM station spacing varied from 200 to 750 m allowing the mapping of 80 km2. The total depth of investigation with the inverted TEM data and the lithology logs was 130 m and 183 m, respectively. The joint interpretation produced several quasi-two-dimensional electrical resistivity profiles that traverse the sedimentary basin in various azimuths and depth slices of average electrical resistivity covering the basin. The depth slices and the vintage stratigraphic logs revealed an uneven bedrock topography overlain by an irregularly thick (over 180 m) Late Neogene–Quaternary heterolithic sediment cover.

scholarly journals GEOELECTRICAL SIGNATURES AND THEIR RELATIONSHIPS WITH THE LATERITIC HORIZONS: A CASE STUDY OF THE N4EN MINE’S IRON CAVE, CARAJÁS COMPLEX, BRAZIL

2019 ◽  
Vol 37 (4) ◽  
pp. 235
Author(s):  
GUILHERME A. S. PROSDOCIMI ◽  
MARCO A. DA S. BRAGA ◽  
MARCELO R. BARBOSA ◽  
IURI VIANA BRANDI
Keyword(s):  
Electrical Resistivity ◽  
Well Logging ◽  
Near Surface ◽  
Applied Geophysics ◽  
Geophysical Surveys ◽  
Iron Mine ◽  
Northern Brazil ◽  
Iron Formations ◽  
Lateritic Profile

ABSTRACT The Brazilian speleological heritage is protected by laws, and every region where caves are present requires scientific studies to assist in environmental licensing. In the context of mining in iron formations, the near-surface geophysical studies using electroresistivity survey were performed in the cave N4E-0022, located at the N4EN iron mine, Carajás Complex, northern Brazil. The near-surface geophysical surveys generated continuous images that enhanced the lithostructural mapping of the lateritic profile, especially in places to which access by conventional methods was difficult. The electrical resistivity profiles were acquired with the dipole-dipole arrangement in the upper portion of the cave. Three sections were performed in SW-NE direction and two in SE-NW direction, totaling 435 meters of acquisition. The geoelectrical signatures were correlated with the lithologic logs of drillholes, the geophysical well logging and with the typical lateritic profile in the cave N4E-0022 surroundings. The results showed a satisfactory interpretation for the near-surface geoelectrical profiles and evolved to a comparison with the lateritic profile (lateritic crust, transition horizon, and saprolite horizon), providing inherent resistivity signatures for each modeled material.Keywords: applied geophysics, iron cave, Carajás.RESUMO O patrimônio espeleológico brasileiro é protegido por leis, e qualquer região com a presença de cavidades precisa de estudos científicos para auxiliar o licenciamento de empreendimentos. No contexto da mineração em terrenos ferríferos, estudos geofísicos rasos utilizando eletrorresistividade foram executados na cavidade N4E-0022, localizada no extremo norte da Mina de N4EN, Complexo Carajás. A geofísica rasa gerou imagens contínuas que potencializaram o mapeamento lito-estrutural do substrato rochoso, principalmente em locais de difícil acesso aos métodos convencionais. Os perfis de eletrorresistividade foram adquiridos com arranjo dipolo-dipolo na porção superior da cavidade. de modo paralelo entre si na porção superior da cavidade. Três seções foram executadas na direção SW-NE e duas na direção SE-NW, totalizando 435 metros de aquisição. As assinaturas geoelétricas das seções foram correlacionadas com as descrições litológicas de furos de sondagem, perfilagens geofísicas de furos de sonda e o mapeamento de detalhe do perfil laterítico no entorno da cavidade N4E-0022, evidenciando um resultado satisfatório para as interpretações realizadas. Os resultados evoluíram para uma comparação com o perfil de alteração típico de rochas ferruginosas (crosta laterítica, horizonte de transição e saprolito), e forneceram assinaturas de resistividades inerentes à cada material modelado. Palavras-chave: geofísica aplicada, caverna ferrífera, Carajás.

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