Evaluation of Inhomogeneities in Underground Structures Using Non-Invasive Muon Scanning

Mining galleries, transportation tunnels, underground structures in urban areas, or geologically active regions require monitoring to ensure that they do not present risks to the population or the environment. However, devising and implementing safety measures relies on knowledge of the volume in question, which is sometimes difficult to achieve. We review the possibility of detecting underground inhomogeneities using muography, a non-invasive and new technique. Muography - as an alternative to established geophysical methods - relies on the cosmic muon flux as a source. We present in detail the physical properties of muons, why and how they can be used for scanning, and all aspects that need to be taken into account to use muography detectors for volume scanning.