Acoustic Remote Sensing

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The primary aim of INFOMAR as a marine mapping project is to describe the physical features of the seabed. This includes the measurement of water depth (bathymetry), definition of seabed structures and identifying sediment type and distribution, both on and below the seabed. This is achieved using a range of hydrographic and geophysical instruments.

Acoustic devices emit sound energy, in a series of continuous pulses, into the water column and detect the returning echoes. This is called sonar.  Different echo strengths indicate different seabed features (or morphology) and the different physical characteristics of the seafloor.  By knowing the speed at which sound travels through water (approx. 1500 m per second), depth can be calculated from the echo return time.  This method produces extremely accurate measurements, which when coupled with accurate positioning systems and motion sensors can be used to produce very accurate seafloor maps.  Similarly by knowing the speed of sound through different rock and sediment layers under the seabed, our acoustic systems can measure the thickness of these layers to map the sub-surface structure of the seabed. The primary acoustic devices used by the INFOMAR programme are:

  • Multibeam sonar echosounder
  • Singlebeam echosounder 
  • Shallow Seismic Pinger/Sub Bottom Profiler
  • Seismic Sparker
  • Side Scan sonar

Download more information on each technique using the blue buttons provided.