scholarly journals GROUNDWATER PROSPECTION IN THE MUNICIPALITY OF PIÇARRA-PA USING VERY LOW FREQUENCY AND RESISTIVITY

2012 ◽  
Vol 30 (3) ◽  
Author(s):  
Gilvana Bezerra de Sousa ◽  
José Gouvêa Luiz
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Integrated Analysis ◽  
Groundwater Extraction ◽  
Fracture Zones ◽  
Southeastern Part ◽  
Very Low Frequency ◽  
Electrical Sounding ◽  
Sediment Layers ◽  
The City

This study was conducted in the municipality of Pic¸arra, located in the southeastern part of the state of Par´a. The aim of the study was to use geophysical methods to map the lineaments associated with bedrock fractures and the nature of the subsoil using the Very Low Frequency (VLF) electromagnetic method and the electrical resistivity in vertical electrical sounding (VES) technique. The integrated analysis of the geophysical data delineated two hydrogeological domains, namely, fracture zones and sediment layers on the bedrock, that could be potential locations of wells for groundwater extraction. The study was designed to identify the most promising units for groundwater extraction and the best locations for the construction of wells to supply groundwater to the city.

scholarly journals Fracture zones detection for groundwater exploration integrating Resistivity Profiling and Very Low Frequency electromagnetic methods (Errachidia basin, Morocco)

2019 ◽  
Vol 49 (2) ◽  
pp. 181-194
Author(s):  
Youssef Ait Bahammou ◽  
Ahmed Benamara ◽  
Abdellah Ammar ◽  
Ibrahim Dakir
Keyword(s):  
Low Frequency ◽  
Groundwater Exploration ◽  
Depth Range ◽  
Fracture Zones ◽  
Real Component ◽  
Very Low Frequency ◽  
Resistivity Measurements ◽  
Electromagnetic Methods ◽  
Groundwater Supply ◽  
Resistivity Profiling

Abstract Resistivity Profiling and Very Low Frequency (VLF) electromagnetic methods were introduced to study fracture zones detection in Zaouia Jdida locality, within the Errachidia basin. The Horizontal Profiling was conducted in Wenner-α array, with AB = 300 m and profile lines oriented NW–SE and NE–SW. The resistivity measurements were taken using MAE advanced geophysics instruments. The VLF profiles were implanted with the length reaches 1000 m and profile lines oriented in NE–SW direction. The VLF measurements were collected using T-VLF iris instrument and the data filtering was done using KHFFILT software. Two filters, Karous-Hjelt and Fraser, were applied to the real component of the secondary electromagnetic field. The qualitative interpretation of resistivity results, showed the presence of subsurface targets; fracture zones were detected at 70m, 240m and 450m positions along the profile P1, at 180m, 340m and 450m positions from the profile P2. The semi-quantitative interpretation of VLF results revealed the presence of two principal fracture zones at L3 and L5 locations, oriented NW–SE, at a depth range of 30 m to 60 m. The VLF anomaly observed at L3 location is confirmed by the resistivity measurements from the profile P1 (at 70m station). The identified fractures represent the potential zones for groundwater supply and then will have an implication on storage and movement of groundwater in the prospect area.

Geophysical Surveys in Engineering Geology Investigations With Field Examples

2018 ◽  
pp. 257-280
Author(s):  
Ali Aydin ◽  
Erdal Akyol ◽  
Mahmud Gungor ◽  
Ali Kaya ◽  
Suat Tasdelen
Keyword(s):  
Geophysical Methods ◽  
Soil Layer ◽  
Low Frequency ◽  
Groundwater Exploration ◽  
Sufficient Information ◽  
Surface Mapping ◽  
Geophysical Field ◽  
Survey Techniques ◽  
Geophysical Study ◽  
Electrical Sounding

This chapter focusses on geophysical survey techniques, employed in engineering geological investigations and it includes case studies. Goal of a geophysical study in an engineering geological research is to display discontinuities in the rock masses, physico-mechanical properties of soils and rocks, groundwater exploration, faults, landslides, etc. It is also helpful to learn type and thickness of soil, layer inclination. These techniques include engineering geological surface mapping, geotechnical drilling and in situ testing.Then the obtained geophysical field data are analyzed and interpreted in conjunction with the results of geological information.The most common geophysical methods namely seismic, magnetometric, vertical electrical sounding (VES), Very Low Frequency (VLF) Electromagnetics methods, ground penetration radar (GPR) provide sufficient information about the subsurface although they have their limitations, setting up the minimum tests requirements in relation to the type of the geological formations.

Modeling and inversion of magnetic and VLF-EM data with an application to basement fractures: A case study from Raigarh, India

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. B133-B140 ◽  
Author(s):  
V. Ramesh Babu ◽  
Subhash Ram ◽  
N. Sundararajan
Keyword(s):  
Spatial Distribution ◽  
Low Frequency ◽  
Analytical Signal ◽  
Magnetic Data ◽  
Fracture Zones ◽  
Very Low Frequency ◽  
Subsurface Resistivity ◽  
Spatial Locations ◽  
And Inversion

We present modeling of magnetic and very low frequency electromagnetic (VLF-EM) data to map the spatial distribution of basement fractures where uranium is reported in Sambalpur granitoids in the Raigarh district, Chhattisgarh, India. Radioactivity in the basement fractures is attributed to brannerite, [Formula: see text] complex, and uranium adsorbed on ferruginous matter. The amplitude of the 3D analytical signal of the observed magnetic data indicates the trend of fracture zones. Further, the application of Euler 3D deconvolution to magnetic data provides the spatial locations and depth of the source. Fraser-filtered VLF-EM data and current density pseudosections indicate the presence of shallow and deep conductive zones along the fractures. Modeling of VLF-EM data yields the subsurface resistivity distribution of the order of less than 100 ohm-m of the fractures. The interpreted results of both magnetic and VLF-EM data agree well with the geologic section obtained from drilling.

scholarly journals Geophysical and Geotechnical Investigation for Post Foundation Studies, Faculty of Social Sciences and Humanities, Federal University Oye Ekiti

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Akindeji Fajana ◽  
Olayiwola Olaseeni ◽  
Odunayo Bamidele ◽  
Oladunjoye Olabode
Keyword(s):  
Geophysical Methods ◽  
Low Frequency ◽  
Clay Content ◽  
High Concentration ◽  
Very Low Frequency ◽  
Social Sciences And Humanities ◽  
Building Foundation ◽  
Geological Features ◽  
Geotechnical Investigations ◽  
Clay Formation

A combined geophysical methods involving very low frequency-electromagnetic, electrical resistivity, magnetics prospecting method and geotechnical investigations were used in delineating the causes of cracks on the buildings of Faculty of Social Science and Humanities, Federal University Oye- Ekiti. Five (5) Very Low Frequency-Electromagnetic traverses, Twenty-one (21) Vertical Electrical Soundings and three (3) magnetic profiles were occupied and investigated around the distress building. Two (2) locations were also occupied for geotechnical investigations. Three major layers were delineated in the study area which includes the topsoil, weathered/fractured layer and fresh basement. The VES curve types obtained were A, H, K and Q curves. The buildings were found to be situated within the area of a fairly high concentration of fractures that can aid subsidence in the area and relatively low resistivity zones typical of incompetent clay formation. The geotechnical results also show that the soil has relatively high clay content. Based on the consistency limits. The soils within the area is classified as medium plasticity, hence, the soils are expected to exhibit medium swelling potential. It can however be concluded that the subsoils on or within which buildings are founded within the study area are not competent. From the result, the building failure observe as cracks and foundation subsidence may have been caused by the foundation soils that made up of incompetent materials (clay) which could compress on imposing loads by differential settlement. It is noteworthy that geological features such as fractures/faults delineated within the bedrock is also inimical to the building foundation.

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