Comparison of Near-surface Sensitivity Functions of Airborne and Ground-based EM Systems
L.M. Madsen, K.V. Lassen, E. Auken and A.V. Christiansen
Event name: Second European Airborne Electromagnetics Conference
Session: Forward Modelling and Inversion I
Publication date: 03 September 2017
Info: Extended abstract, PDF ( 732.79Kb )
Price: € 20
Knowledge of the sensitivity function of an electromagnetic (EM) system helps to assess the advantages and shortcomings of the system set-up. We have computed 3D sensitivity functions of three different EM systems – one airborne (SkyTEM) and two ground-based systems (tTEM and GCM) – in order to compare the sensitivity distribution of the different transmitter-receiver set-ups. The results show that the GCM has the highest sensitivity to near-surface structures, but also has a very limited footprint depth. The SkyTEM and tTEM systems have comparable sensitivities vertically in the ground with a 90% footprint depth around 5 m for early time measurements. However, the sensitivity of the SkyTEM system is distributed must wider horizontally than the tTEM.