Advanced Potential Field Analysis Applied to Mise‐à‐la‐Masse Surveys for Leakage Detection

Abstract

AbstractTraditionally interpretation of Mise‐à‐la‐masse (MALM) is limited to the visualization of equipotential contours in order to infer qualitatively the extent of the anomaly. MALM inversion algorithms rely on having a good knowledge of the electrical resistivity distribution in the subsoil. Conversely, potential imaging methods have shown their strength for several applications to quickly estimate the depth of sources even in highly heterogeneous media. In the case of the MALM method, the physics may be described by Poisson's equation. As the conductivity term is modulating the flux of current, MALM is generally referred to as a pseudo‐potential method. In this work, we have tested, for the first time, the application of the potential field theory to MALM in order to identify the current source depth. Synthetic modeling shows that the proposed algorithm is effective and efficient, using surface voltage measurements for different resistivity contrasts, anomaly depths and noise levels. We then applied the method to the real field case of a landfill leakage and showed how very different source depth estimates result from an intact or a damaged landfill liner.