In 2008, the Japanese government designated the sea-floor hydrothermal ore deposit as one of the important seabed resources together with oil, natural gas, and methane hydrate. Since then, a large amount of research expenses were spent on the development of technology to locate sea-floor hydrothermal ore deposit, and the technology is advancing.
Akira Asada of Tokyo University developed a sensor that analyzes the shape of the seabed using sound waves. The transmitters installed on the probe discharged from the ship transmit sound waves toward the seabed, and 48 underwater microphones receive returned sound waves. The round-trip time and intensity of the sound waves are figured out for each transmitter, and the data are used to draw 3D seabed maps in real time. It is possible to draw a seabed map with the radius of 300 m if sound waves are transmitted more than 100 m above the seabed. The 3D map has a difference of only about 5 cm. Akira Saito of Waseda University focused on that electrical properties vary with the kind of rock and mineral, and developed a technology to study the distribution of such metals as gold, copper in a sea-floor hydrothermal ore deposit.
Japan is said to have the world largest amount of sea-floor hydrothermal ore deposits. At present, it has15 sea-floor hydrothermal ore deposits.