Cross borehole electromagnetic tomography : scoping study and literature review

Cross-borehole electromagnetic tomography is a non-contact geophysical method that can be used to generate images of the electrical properties of the subsurface. It is rather underutilised for site-scale investigation, due to the broad range of frequencies over which it must respond and the complicated nature of the electromagnetic fields in this range. However, such a system would find applications in a wide variety of environments, from fracture characterisation in highly resistive crystalline rock to pollution monitoring in conductive landfills. There is currently a gap in the European market for this type of tomography, despite the fact that it is in use and subject to on-going development in Canada, the U.S. and Australia. This report reviews the literature relevant to a cross-hole electromagnetic tomography imaging system and makes recommendations on its design and implementation.