Several sonar technologies are used to map and locate objects on the seafloor. Multibeam sonars create high resolution images by using multiple, simultaneous sonar beams (sound waves) at once in a fan-like pattern or “swath.” This tool is also useful because it can measure the depth of the seafloor which helps create two- or three-dimensional bathymetric maps. Side-scan sonars are also used to generate imagery the seafloor based on the intensity of the acoustic reflections, but does not measure depth. This tool is useful in collecting information about the physical makeup of the seafloor, as well as identifying obstructions and debris on the seafloor. Synthetic Aperture Sonars (SAS) use an artificial array to generate higher resolution imagery than traditional side scan sonars, though its use is often limited by availability and expense. Magnetometers can detect changes in the magnetic field on the seafloor which helps researchers locate ferrous (containing iron) objects, like a shipwreck.
Once an object is located, imaging techniques like photogrammetry help document the details of the wreck. This technique works by stitching together several photos to create three-dimensional models.