Equipment for seabed mapping

SGU (Swedish Geological Survey) utilizes various marine geological measurement systems, samplers, and laboratory equipment in its work of mapping the seabed.

Positioning System

Ocean Surveyor is equipped with advanced systems to accurately store the position of collected survey data. The systems employ satellite-based positioning with two GNSS (Global Navigation Satellite Systems) antennas capable of receiving position data from GPS, Glonass, and Galileo, along with two additional standalone GPS receivers. The system also includes a motion sensor (MRU) that measures the ship's lateral displacement and rotation in all three dimensions. Real-time corrections (RTK) for satellite positions are obtained via mobile data. In summary, the positioning system can determine the position of every part of the ship and its equipment.

SGU's Hydroacoustic System System

Sound waves propagate easily through compact materials such as water, sediment, and bedrock, making them highly suitable for investigating the seabed.

Hydroacoustic Systems

SGU's Marine Sampling Equipment

This includes various sediment samplers, as well as an underwater camera.

Marine Sampling Equipment

SGU's Marine Laboratory Equipment Gamma Detector

SGU has a detector aboard the S/V Ocean Surveyor that is used to measure gamma radiation from the radioactive isotope cesium-137 (Cs-137). Cs-137 is a radioactive isotope that is released from nuclear weapons detonations or accidents at nuclear power plants. The nuclear accident at Chernobyl in 1986 dispersed radioactive substances over large parts of the Baltic Sea and surrounding countries, including Sweden. Sediments deposited on the seabed immediately after 1986 often exhibit a distinct peak in radioactivity, which gradually decreases in younger sediment layers. By measuring the gamma radiation from Cs-137 at different depths at a sampling site, it is possible to determine the amount of sediment deposited after 1986. The average sedimentation rate can then be calculated.

Sediment X-ray Onboard the S/V Ocean Surveyor

Sweden's first operational sediment core X-ray is available onboard the Ocean Surveyor. Samples from the Gemini sampler are X-rayed in very thin layers. This data is presented in image format, allowing structures that are not visible to the naked eye to be clearly discerned. This information can, for example, be used to assess whether the sediment is undisturbed or if it has been eroded or reworked at any point.

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Last reviewed 2023-06-12