What is 2D electrical resistivity imaging?
2D Resistivity Imaging uses an array of electrodes (typically 64) connected by multicore cable to provide a linear depth profile, or pseudosection, of the variation in resistivity both along the survey line and with depth.
How do you do electrical resistivity imaging?
The method of measuring subsurface resistivity involves placing four electrodes in the ground in a line at equal spacing, applying a measured AC current to the outer two electrodes, and measuring the AC voltage between the inner two electrodes.
What is the purpose of electrical resistivity imaging?
Electrical resistivity imaging (ERI) is a non-destructive method for subsurface investigations. Although it’s not as popular as ground penetrating radar (GPR), it has its advantages and can be very useful in some situations. ERI involves the measurement of the apparent electrical resistivity of subsurface materials.
What is 2D geophysical survey?
In two-dimensional (2D) reflection seismic surveying both the sound source and the sound detectors (numbering up to a hundred or more per shot) are moved along a straight line. The resultant product can be thought of as a vertical sonic cross-section of the subsurface beneath the survey line.
What is Schlumberger array?
The Schlumberger array is an array where four electrodes are placed in line around a common midpoint. The two outer electrodes, A and B, are current electrodes, and the two inner electrodes, M and N, are potential electrodes placed close together.
How does an ERT work?
Replacement enzymes for ERT are derived from human, animal, and plant cells that are then genetically modified and processed before being given to the patient. By receiving these enzyme replacements, the body is able to successfully perform the functions inhibited by the deficiency.
What is resistivity method?
Electric resistivity methods are a form of geophysical surveying that aids in imaging the subsurface. These methods utilize differences in electric potential to identify subsurface material.
What is electrical resistivity profiling?
Electrical resistivity profiling is simply a two-dimensional resistivity method, where an image representing a slice of the earth is created and electrical property contrasts are used to interpret differing geological or hydrogeological conditions. We use color contouring to visually identify these conditions.
What is the difference between Schlumberger and Wenner array?
Schlumberger is the best method used for vertical electrical sounding for practical reasons. It is less labor-intensive than the Wenner array (see below) because you only need to move the two transmitting electrodes for each new reading, whereas the Wenner requires moving all four electrodes for each new measurement.
What is Schlumberger method?
The Schlumberger method was developed to increase the voltage signal for the earlier, less sensitive instruments, by placing the potential probes closer to the current probes. The soil resistivity measurements will be affected by existing nearby grounded electrodes.
What is ERT analysis based on?
ERT provides an image with the distribution of subsurface resistivity. Based on resistivities of different subsurface materials/rocks, the resistivity image can be converted into the subsurface image having different lithologies/rocks18. The interpretation of resistivity results is called as pseudosection50.