Sediment Thickness / Subottom Profiler
When you need informations on the sediment thickness in order to bury cable or for dredging,
Subottom profiler is used. It can be fixed to the boat or used like a towfish (need a winch), it
measures the sediment thickness at the vertical of the instrument. It is speacilallly used in
order to detect the transition between bedrock and sediment cover until several meters (up to
The reflectivity of the seafloor provide informations of the nature the seafloor (hard or soft,
smooth or rough) combined with sampling, you can draw a chart of type of sediment that
cover the seafloor. The equipment used is a side scan sonar. The SSS offers a view black and white of the
seafloor, like a photography, where you can distinguish the shadows of the objects, which is
useful when you need to map any contact point or obstacle for your project.
In order to carry out sediment sampling, we use these two types of equipment: a Van Veen grab (on the right) for surface samples, and a “free fall” corer (on the left) to make stratigraphic log of the first sedimentary layers . The granulometry is performed in the laboratory by sieving.