Abstract / Description of output
Voids in archaeology tend to be found under hard surfaces (concrete, stone slabs) in buildings, e.g. churches, and under roads, e .g. roman drains. This makes them difficult to survey with more established techniques like resistivity and magnetometry, as probe insertion is impossible - special transducers would have to be used - and there is generally too much metal in an urban environment to carry out a successful magnetometry survey [Rodwell, 1989].