Airborne electromagnetics in Europe: recent activities and future goals

Abstract

Annika Steuer and Uwe Meyer of the Federal Institute for Geosciences and Natural Resources, report on a recent gathering of organizations in Europe using airborne electromagnetics. In numbers, European systems are dominated by frequency domain instruments. The Geological Surveys of Norway, Germany, and Austria, as well as the AWI, use helicopter electromagnetic (HEM) systems, which differ in the number of frequencies and configuration of the coil systems. NGU and GBA use the Geotech Hummingbird, NGU with three horizontal coplanar and two horizontal coaxial coils whereas GBA uses four horizontal coplanar coils. BGR operates a DIGHEM bird from Fugro with five horizontal coplanar coils. AWI developed a dual-frequency HEM system, specially designed for the sounding of seaice thicknesses in Polar Regions. The Geological surveys of the United Kingdom (BGS) and Finland (GTK) established a 'Joint Airborne-geoscience Capability' (JAC) based on a system originally developed by GTK. They operate a fixed wing aircraft carrying a four-frequency system using vertical coplanar coils. The Swedish Geological Survey and the University of Uppsala also use a fixed-wing. Both developed a new VLF instrument working in the wide frequency band of 1-350 kHz. At present, the only time-domain system in Europe is operated by the University of Aarhus. The Aarhus Sky TEM system is a transient electromagnetic technique in a 'central loop'-like configuration, towed by a helicopter.