Multi-Method Survey
Definition
The deployment of two or more independent geophysical methods over the same search area. Anomalies confirmed by multiple methods carry higher confidence because they are unlikely to share the same false-positive sources.
- Definition
- Two or more independent geophysical methods over one search area
- Benefit
- Cross-confirmed anomalies carry higher confidence
- Field
- Forensic geophysics, clandestine grave search
- Common pairing
- Ground-penetrating radar with magnetometry or resistivity
Common questions
Why is a single geophysical method usually not enough for a search?+
Each method has its own false-positive sources, for example ground-penetrating radar can flag tree roots or utility lines, so relying on one method risks digging at anomalies that a second, independently-sourced method would have ruled out.
What does it mean when the methods disagree on a target location?+
Disagreement lowers confidence in that anomaly rather than confirming it, and the search team typically treats agreement across methods, not any single strong reading, as the trigger for excavation.
Related terms
- Dielectric Permittivity
- A soil's capacity to store and transmit electric field energy. Higher water content raises permittivity and slows the radar wave. The contrast...
- Electrical Resistivity
- The resistance of a volume of soil to electrical current flow. Wet, clay-rich, or decomposing organic material has low resistivity. Dry sand...
- Magnetic Susceptibility
- A measure of how strongly a material is magnetised by an external field. Topsoil heated by fire or biological activity has elevated...
- Physical Contrast
- The difference in a measurable soil property (density, susceptibility, resistivity, permittivity) between a target and its surrounding host material. No contrast means...
- Signal-to-Noise Ratio (SNR)
- The ratio of anomaly amplitude to background variation. Pipes, cables, rocks, roots, and instrument drift all add noise. A target is detectable...