Mapping the seafloor

Bathymetry data being collected as we transit across the Pacific. Blue represents areas of greater depth while warmer colors represent areas of shallower depth

Echosounders measure the depth of water by timing how long it takes sound to travel from a pinger on the ship down to the seafloor and back.  Modern echosounders create a fan of sound beams reaching out on both sides of the ship to give a wide band of measurements. By “mowing the lawn” the ship can produce a complete map from several passes.   The maps show volcanoes, geological faults, sediment-filled valleys and long, thin ridges built from small volcanic cones. They are crucial in working out the evolution of the ocean floor.