6. Magnetism (for the record)

Magnetism is rarely used for reconnaissance in civil engineering. The method is based on the detection of anomalies in the earth's magnetic field. The only application found in civil engineering is the search for buried objects containing a lot of iron. For example, we may want to check that there are no wrecks of metal barges at the bottom of a river, or look for unexploded bombs buried in the sediments before the construction of a harbour structure.

For the study of ancient discharges, electromagnetic methods of the dipole-dipole type 7.3