Figure 4. The side-scan sonar towfish that made the images for the map. The device sends out pulses of acoustic energy to either side as it is towed behind a boat. An on-board computer records the echos returned from the seabed and forms a black and white image, on a special roll of paper, of the seafloor up to 100 m to either side of the boat. The vessel may travel up to ten knots while gathering the data.

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Last updated on October 6, 2005

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