Towards High-Resolution Imaging Of Subsurface Pollution: An Introduction To The Magneto-Electrical Resistivity Imaging Tool (Merit)

In order to obtain unique, high-resolution images of subsurface contaminant movement it is<br>particularly promising to combine data resulting from application of several geophysical<br>monitoring techniques. We propose the Magneto-Electrical Resistivity Imaging Tool (MERIQ as<br>a suitable method that aims to combine traditional electrical resistivity tomography (ERT) and<br>magnetometric resistivity (MMR). MERIT involves simultaneous measurement of both the<br>electric and the magnetic field responses to injection of a low-frequency current into the ground<br>using modern lock-in technology, While the feasibility of ERT imaging of subsurface pollution<br>has been proven beyond doubt, MMR has almost exclusively been used by the mining industry,<br>and suitable data inversion schemes are not readily available. In order to resolve this<br>shortcoming, we present an algorithm that allows reconstruction of the subsurface bulk electrical<br>conductivity distribution from surface magnetic field data. The solution is unique in two<br>dimensions. Forward and inverse modelling experiments involving conceptual and synthetic data<br>are described, proving the usefulness of the proposed framework for the inversion of MMR data.