Authors :
Vinit J Ganvir; Anil Kumar Chaurasiya; Amaresh Singh
Volume/Issue :
Volume 7 - 2022, Issue 9 - September
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3g9oojz
DOI :
https://doi.org/10.5281/zenodo.7204534
Abstract :
Geophysical methods employ indirect, nonintrusive observations to characterize and map
variations in the physical properties of what lies
concealed beneath the ground surface. The apparent
resistivity (ρa) of the ground can be calculated using
Electrical resistivity method. Using electrical properties
of ground subsurface to characterize and map the
granite gneiss hard rock formation of study area. The
apparent resistivity (ρa) of the ground can be calculated,
and since low porosity bedrock usually exhibits an
electrical resistivity higher than overlying sediment, the
buried topography can be interpreted. Electrical
resistivity can map lateral and vertical variations in
apparent resistivity of geologic material. Resolution is a
function of electrode spacing and resistivity contrast
between lithologically different earth materials. The
resolution of electrical resistivity tomography (ERT)
profile defines the accuracy of interpretation of
subsurface conditions. Because of variability in
resistivities of earth materials, interpretation of
electrical resistivity tomography (ERT) data must be
handled with caution. During ERT survey, when current
is induced to flow through deeper layers, the distance
between current and potential electrodes is gradually
increased. This affects the sensitivity of the ERT method.
Gradually increasing the distance between electrodes
lowers the intensity of current flow, and accordingly the
sensitivity of ERT survey. Thus, interpretation of
smaller scale objects at greater depths becomes
increasingly difficult. Factors such as temperature,
porosity, conductivity, salinity, clay content, saturation
and lithology generally affect the resistivity of earth
materials and can affect the ability of different materials
to conduct electrical current. For instance, dry soil
usually has much higher resistivity than saturated soil.
The same situation appears with weathered and unweathered rock. Weathered rock is usually more porous
and fractured, and it becomes more saturated with
groundwater; as a result, weathered rock has lower
resistivity than intact rock. Total 15 ERT profile carried
out in different geomorphological formation of study
area. It is observed that the apparent resistivity value of
weathered zone occurs less than 100 Ω-m in the northwest region of study area and the apparent resistivity
value of water saturated weathered zone is varies from
100 Ω-m to 200 Ω-m. The resistivity value of fractured
zone is greater than 200 Ω-m with varying depth from
80 m to 100 m. In north-west region of study area occurs
in good water potential zone with high yield and southeast region of study area having low groundwater
potential zone with low yield. The most part of study
area occurs in poor to moderate groundwater potential
zone. The methods provided a more precise hydrogeomorphologic model for the study area. Results from
this study area useful for technical groundwater
managements and they clearly identified suitable
borehole for long term groundwater prospecting. 2D
electrical resistivity imaging method provides promising
input to Groundwater evaluation in complex geology
weathered environment.
Keywords :
Electrical Resistivity Tomography, Induced Polarization, (Schlumberger, Gradient and Dipole-Dipole array Imaging Profile), Inverse resistivity model, Remote Sensing & GIS, Borewell data, Dug well water level, Jhansi district resource map of GSI
Geophysical methods employ indirect, nonintrusive observations to characterize and map
variations in the physical properties of what lies
concealed beneath the ground surface. The apparent
resistivity (ρa) of the ground can be calculated using
Electrical resistivity method. Using electrical properties
of ground subsurface to characterize and map the
granite gneiss hard rock formation of study area. The
apparent resistivity (ρa) of the ground can be calculated,
and since low porosity bedrock usually exhibits an
electrical resistivity higher than overlying sediment, the
buried topography can be interpreted. Electrical
resistivity can map lateral and vertical variations in
apparent resistivity of geologic material. Resolution is a
function of electrode spacing and resistivity contrast
between lithologically different earth materials. The
resolution of electrical resistivity tomography (ERT)
profile defines the accuracy of interpretation of
subsurface conditions. Because of variability in
resistivities of earth materials, interpretation of
electrical resistivity tomography (ERT) data must be
handled with caution. During ERT survey, when current
is induced to flow through deeper layers, the distance
between current and potential electrodes is gradually
increased. This affects the sensitivity of the ERT method.
Gradually increasing the distance between electrodes
lowers the intensity of current flow, and accordingly the
sensitivity of ERT survey. Thus, interpretation of
smaller scale objects at greater depths becomes
increasingly difficult. Factors such as temperature,
porosity, conductivity, salinity, clay content, saturation
and lithology generally affect the resistivity of earth
materials and can affect the ability of different materials
to conduct electrical current. For instance, dry soil
usually has much higher resistivity than saturated soil.
The same situation appears with weathered and unweathered rock. Weathered rock is usually more porous
and fractured, and it becomes more saturated with
groundwater; as a result, weathered rock has lower
resistivity than intact rock. Total 15 ERT profile carried
out in different geomorphological formation of study
area. It is observed that the apparent resistivity value of
weathered zone occurs less than 100 Ω-m in the northwest region of study area and the apparent resistivity
value of water saturated weathered zone is varies from
100 Ω-m to 200 Ω-m. The resistivity value of fractured
zone is greater than 200 Ω-m with varying depth from
80 m to 100 m. In north-west region of study area occurs
in good water potential zone with high yield and southeast region of study area having low groundwater
potential zone with low yield. The most part of study
area occurs in poor to moderate groundwater potential
zone. The methods provided a more precise hydrogeomorphologic model for the study area. Results from
this study area useful for technical groundwater
managements and they clearly identified suitable
borehole for long term groundwater prospecting. 2D
electrical resistivity imaging method provides promising
input to Groundwater evaluation in complex geology
weathered environment.
Keywords :
Electrical Resistivity Tomography, Induced Polarization, (Schlumberger, Gradient and Dipole-Dipole array Imaging Profile), Inverse resistivity model, Remote Sensing & GIS, Borewell data, Dug well water level, Jhansi district resource map of GSI
