Magnetometers

Marine magnetometers serve to detect magnetic anomalies caused by ferromagnetic objects on or in the ocean floor, sediment changes or sudden modifications to the topography of the ocean floor.

Unexploded Ordnance (UXO)

Marine magnetometers are not only used for geophysical investigations, but are also especially deployed for UXO detection surveys. These investigations are used to detect "ammunition" on and in the ocean floor that were dropped and dumped into the North and Baltic Sea territories during the world wars. Investigations such as these are predominantly conducted in areas where offshore wind farms and their grid connections are planned. Planar recording of these areas calls for the measuring sensors to be specially arranged. The measuring sensors are determined according to the topography of the local ocean floor and the desired resolution of the investigation. The following arrangements are offered at the present time:

  • 3 Geometrics G-882 caesium vapour magnetometers with a permanently horizontal arrangement
  • 2 Geometrics G-882 caesium vapour magnetometers in a gradiometer arrangement
  • 7 vertical fluxgate gradiometers (FGM650) in a permanently horizontal arrangement

Specially designed wings or basic slides are used as device carriers for these arrangements. The following example shows a planar evaluation of magnetometer data (left) and the associated "sound image" generated by the side scan sonar (right). The anomalies detected indicate a lost drill pipe, which is visible between the footprints of a platform according to the side scan sonar's data.


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