Electrical Resistivity Tomography (ERT)
Definition
A method using multiple electrodes on a line or grid to inject current and measure voltage, computing a two-dimensional or three-dimensional resistivity section of the subsurface. Lower resistivity zones indicate moisture, clay, or decomposing organic material.
- Method type
- Multi-electrode current injection survey
- Output
- 2D or 3D resistivity section
- Low resistivity indicates
- Moisture, clay, decomposing organics
- Setup
- Electrodes on a line or grid
Common questions
How does ERT differ from a simple single-reading resistivity survey?+
A simple survey takes point measurements across a grid to flag anomalies at one depth, while ERT uses many electrodes and multiple current-injection geometries to build a full depth profile, letting an investigator see how an anomaly changes with depth, which helps distinguish a grave from a shallow surface feature.
What practical limitation affects ERT use at a crime scene?+
Electrodes need direct soil contact and a survey line takes time to set up and run, so ERT is generally slower and more labour-intensive than magnetometry or ground-penetrating radar, making it better suited to confirming a specific target area than to rapidly scanning a large search zone.
Related terms
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- Wenner Array
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