A resistivity survey is based on the principle that the distribution of electrical potential in the ground around a current-carrying electrode depends on the electrical resistivities and distribution of the surrounding soils and rocks. The field procedure is to apply an electrical direct current (DC) between two electrodes implanted in the ground and to measure the difference of potential between two additional electrodes that do not carry current.
Usually, the potential electrodes are in line between the current electrodes, but in principle, they can be located anywhere. The current used is either direct current, commutated direct current. All analysis and interpretation are done on the basis of direct currents. The distribution of potential can be related theoretically to ground resistivities and their distribution for some simple cases, notably, the case of a horizontally stratified ground and the case of homogeneous masses separated by vertical planes.
Resistivity unit and applications
We have an ABEM Terrameter SAS1000 capable of probing down to 500m. Main application is for:
- Groundwater exploration
- Corrosion protection and electrical grounding studies
- Geological profiling (2D)
- Landfill site and leachate contamination
- Residential Subdivsion
- Industrial plants
- Corrosion studies