oa An Overview of Airborne Electromagnetics for 3D High-resolution Mapping

Airborne electromagnetics (AEM) is an efficient tool for mapping the subsurface. AEM delivers a very high data coverage compared to the costs, and the direct outputs are high-resolution resistivity images of the subsurface. In particular the time domain methods (TEM) are well suited for mapping of the salt-fresh water boundary in coastal zones, aquifers, paleo-channels, mineralisations and general structural geological mapping. The development of AEM systems and data processing systems has been intensive during the past 10– 15 years because of better electronics and faster and more flexible computers. While most AEM systems in the 1980s were limited to detection of mineralisations, modern system generations measures full spectra, yields absolutely calibrated data and accurate descriptions of the system transfer function. This, in combination with much enhanced inversion and forward algorithms, makes AEM a suitable candidate for mapping targets which so far have not be possible.