Daikoku is a sumbarine volcano with a conical summit in the Japanese Volcano Islands chain. It sits on an elongated E-W-trending ridge SE of Eifuku submarine volcano and rises to within 323 m of the sea surface. It has a crater with a black pool of liquid sulfur discovered in 2006.
Daikoku submarine volcano is one of about a dozen submarine volcanoes displaying hydrothermal activity in the southern part of the Izu-Marianas chain.
A steep-walled, 50-m-wide cylindrical crater on the north flank, about 75 m below the summit, is at least 135 m deep and was observed to emit cloudy hydrothermal fluid. During a NOAA expedition in 2006, scientists observed a convecting, black pool of liquid sulfur with a partly solidified, undulating sulfur crust at a depth of 420 m below the summit of Daikoku. Gases, particulate with the appearance of smoke, and liquid sulfur were bubbling up from the back edge of the sulfur pool.
