Precise seafloor bathymetric surveys began with the appearance of the multi-beam echo sounder. It was able to observe the seafloor topography in detail using multi-beam sounding technology. To this day, the multi-beam sounding technology is revealing many significant seafloor features.
In recent years, multi-beam technology for shallow and deep waters has significantly advanced. Also, the processing and application technology for multi-beam bathymetric data has significantly advanced, corresponding to the progress of peripheral technologies, such as dynamic motion sensors and GPS. The synthetic aperture technique has been successfully applied to the multi-beam echo sounder, SeaBeam 2000, and has shown features of the seafloor in considerable detail. Furthermore, the three-dimensional acoustic-image animation technique has been developed using SeaBeam 2000 swath bathymetry and IZANAGI side-scanning sonar data. The animation around the earthquake focus sea area provides us with a lot of seafloor topographical information efficiently and accurately.