Ground-Penetrating Radar (GPR)
Definition
A geophysical method that transmits electromagnetic pulses into soil and records reflections from subsurface discontinuities. In forensic burial detection, it identifies the stratigraphic disruption of a grave cut rather than the remains directly. Depth penetration is soil-dependent (best in dry sand, worst in wet clay).
- Method
- Electromagnetic pulses reflected off subsurface discontinuities
- Target
- Detects grave-cut stratigraphic disruption, not remains directly
- Best medium
- Dry sand
- Worst medium
- Wet clay
- Use case
- Forensic burial and clandestine grave detection
Common questions
Why does GPR detect the grave cut instead of the body itself?+
Digging and refilling a grave disturbs the natural soil layering, and it is this disrupted stratigraphy, along with the different compaction and moisture retention of backfilled soil, that reflects radar pulses differently from undisturbed ground. The body itself often produces a weak or absent signal, especially once skeletonised.
Why does GPR performance vary so much by site?+
Radar penetration depends on the soil's electrical conductivity. Wet clay and saline soils absorb and scatter the signal heavily, limiting depth and resolution, while dry, sandy or loamy soils allow much deeper, clearer penetration. A site survey is normally needed before relying on GPR results.
Related terms
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