Question: What different types of tecniques are there to locate a buried material?

Jamie Pringle answered on 17 Mar 2011:

Hello victoriabush,

An excellent question! It depends what you are looking for.

If you are looking for small, metallic objects in the ground that doesnt have any other metal in it, e.g. not in your back garden!), then a metal detector may do the job, simple and easy to use.

If you are looking for bigger metal things that are buried deeper in the ground, then you may need to use a magnetometer, which measures very accurate, slight variations in the Earth’s magnetic field, hopefully caused by the object that you are looking for!

If an object is not magnetic, i.e. a body or drugs/cash, then you could use ground penetrating radar. This equipment fires an electro-magnetic wave into the ground, receives the signal and hopefully tells you where the object is buried!

The other major kit we use is electrical resistivity methods as we have found during our research that human decompositional fluids are very conductive in contrast to backgrounds soil water and you can therefore detect where a body is by it’s fluids, giving a resistive low anomaly (as conductivity is the inverse of resistivity – how resistive the ground is to a current).

There are loads of less commonly used techniques, gravity (if the object is very dense), seismics (if very big!!), self-potential (if liquid), acoustic (if in water) and more exotic types.

It depends what the target is, what the site conditions are like, likely depth below ground level, age of burial, etc.

Hope that clarifies matters!