Electrical resistivity tomography

Electrical resistivity tomography is a geophysical imaging method that estimates subsurface electrical resistivity from currents injected through electrodes and resulting voltage measurements.

Electrical resistivity: Electrical resistivity measures how strongly a material opposes electric current. It is the underground property that the method seeks to estimate.
Groundwater: Water located beneath Earth's surface in saturated soil and rock. Its distribution and salinity can produce resistivity contrasts useful for mapping aquifers.
Ohm's law: The relation between voltage, current, and resistance in an electrical circuit. It underlies the link between injected current and measured voltage.
Induced polarization: A geophysical method that measures delayed voltage responses after injected current is switched off. It uses related electrode surveys but targets chargeability as well as resistivity.
Four-electrode method: A measurement technique that injects current through two electrodes and measures voltage between two others. Separating current and voltage electrodes reduces contact-resistance effects in field measurements.
Contaminant hydrogeology: The study of how pollutants move and transform in groundwater systems. Conductive contaminant plumes can create anomalies that resistivity surveys help delineate.
Electrical conductivity: A measure of how readily a material conducts electric current, reciprocal to resistivity. Images may be expressed as conductivity instead, the reciprocal property.
Electrical impedance tomography: An imaging method that estimates internal electrical impedance from boundary current and voltage measurements. It is the closely related medical and laboratory imaging framework for electrical measurements.
Wenner array: An electrode configuration with four equally spaced electrodes arranged along a line. Its geometry provides one common pattern for collecting resistivity data.
Landslide: The movement of rock, soil, or debris down a slope under gravity. Imaging water-rich zones and buried boundaries can help characterize unstable slopes.

Linked from 11 pages