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2010 ECU Nearshore Expedition
Mission info 2007 Nancy Foster Cruise
 

Technology

Scuba Diving

The self-contained underwater breathing apparatus or scuba diving system, as we know it today, is the result of technological developments and innovations that began almost 300 years ago. Scuba diving is the most extensively used system for breathing underwater by recreational divers throughout the world, and in various forms is also widely used to perform underwater work for military, scientific and commercial purposes. Click here to learn more about scuba diving and how divers work underwater.

Side-scan Sonar

Side-scan sonar is different in that it gives information about the character of the sea floor rather than just its depth. Side-scan sonars send out sound to either side of the ship's track, and then listen for the echoes that are reflected back. How much sound is reflected back (the "acoustic reflectivity") depends upon the composition, roughness, and slope of the sea floor. This reflectivity information is usually displayed in a black-and- white map, with black representing areas of high reflectivity and white representing areas of low reflectivity. Lava flows, for example, usually show up as dark lobes in side-scan maps, because they are rough and solid and provide a good surface for reflecting sound. In contrast, sandy areas appear relatively light in side-scan maps because the sediments absorb sound instead of reflecting it. Side-scan data also provides information about sea-floor structures because features like fault scarps reflect a lot of sound if they are facing toward the ship, or they cast acoustic shadows if they are facing away from it. Click here for more information about side scan sonar.

Sonar of Strathairly
Side scan sonar of the Strathairly. (Courtesy of ECU)

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