Airborne and Land-based Controlled-source Electromagnetic Surveying in Challenging Electromagnetic Environments

Exploring for underground resources using land-based electromagnetic methods can be very challenging due to the presence of strong human-generated and “geological” noise. In such context, some passive EM techniques like the Magneto-Telluric method may not be applicable at all and a dedicated toolbox of EM techniques capable of dealing with these issues is required. We focus here on the challenges encountered while exploring for geothermal resources in volcanic islands, namely a highly heterogeneous near-surface creating strong static-shifts, the presence of a sea/land transition zone and a high degree of urbanization over the area of interest. We will show that a combined airborne and land-based controlled-source EM approach provide a robust approach and illustrate these aspects with an EM dataset acquired over the Martinique Island, in the French Lesser Antilles. We believe this work sets the foundations for more robust geophysical exploration workflows in such challenging EM environments.