Electromagnetic Surveys

The Electromagnetic induction survey as the name implies, uses the principle of induction to measure the electrical conductivity of the subsurface by using the generation of an electromagnetic pulse artificial (primary magnetic field) that causes the induction of a secondary magnetic field within the ground. The measures can be implemented in the time or frequency domain. In the first case the duration of the primary field is very short and you measure the induced field in the ground at certain intervals of time following discontinuation of the primary field.

In the second case (frequency domain) a sensor is used for the generation of the primary magnetic field and, simultaneously, in another sensor, are making the measurements of the field induced in the ground to a specific or multi-frequency surveys. Measurements are performed in both the in-phase component with respect to the primary field, and in the phase quadrature. Data processing allows to trace the conductivity of the ground, and hence defines its nature, and identifying bodies buried with conductivity different from the land encompassing. Electromagnetic surveys are mainly used in archaeological research, for the detection of buried metal objects, such as pipes and drums, cleaning up by mines and explosive remnants of war.