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Processing methods for single beam echo sounders: plough marks and sediment characterisation in the North Sea
Janmaat, J.; van Walree, P.; Ainslie, M.A.; Simons, D.G.; Harrison, C.H. (2006). Processing methods for single beam echo sounders: plough marks and sediment characterisation in the North Sea, in: Evolutions in hydrography, 6th - 9th November 2006, Provincial House Antwerp, Belgium: Proceedings of the 15th International Congress of the International Federation of Hydrographic Societies. Special Publication (Hydrographic Society), 55: pp. 10-13
In: (2006). Evolutions in hydrography, 6th - 9th November 2006, Provincial House Antwerp, Belgium: Proceedings of the 15th International Congress of the International Federation of Hydrographic Societies. Special Publication of the Hydrographic Society, 55. International Federation of Hydrographic Society: London. 234 + cd-rom pp., more
In: Special Publication (Hydrographic Society). Hydrographic Society: London. ISSN 0309-8303, more

Available in  Authors 
Document type: Conference paper

Keywords
    Echosounders; Hydrography; Ploughmarks; Sediment texture; Sound measurement; ANE, North Sea [Marine Regions]; Marine

Authors  Top 
  • Janmaat, J.
  • van Walree, P.
  • Ainslie, M.A.
  • Simons, D.G.
  • Harrison, C.H.

Abstract
    Acoustical measurements by single beam echo sounders in the Cleaver Bank area of the North Sea are described. The water depth in the region of interest is about 35 m and the echo sounder frequencies are between 12 and 200 kHz. The data are processed in a number of different ways, each highlighting different features of the seabed. Regions of different morphology can be distinguished when the difference in travel time between two different echo sounder frequencies is plotted versus geographical position. This travel time difference is correlated with grain size, as determined by grain size analysis of available grab samples, which provides a useful clue for automated sediment classification algorithms. Maps of reflected energy or of echo duration show distinctive tracks of width up to 40 m and length up to 5 km. The tracks are not visible in bathymetry maps of the same lateral resolution. We hypothesise that the tracks are regions where the sediment is upset by some anthropogenic activity - such as beam trawler fishing. If this hypothesis is confirmed it may be possible to use similar maps to monitor the activities of the vessels involved in the activity.

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