A gravity-based structure (GBS) is a support structure held in place by gravity. The most notable application for a GBS is an offshore oil platform. These structures are often constructed in fjords since their protected area and sufficient depth are essential for construction. A GBS intended for use as an offshore oil platform is constructed of steel reinforced concrete, with tanks or cells, some of which are used to control the buoyancy of the GBS. When completed, a GBS is towed to its intended location and sunk. Prior to deployment, a study of the seabed has to be done in order to ensure it can withstand the vertical load exerted on it by that structure.