NW Eifuku is a small submarine volcano that exhibits vigorous thermal activity. The summit of the basaltic-to-andesitic volcano lies 1,535 m below the ocean surface; the seamount lies at the NW end of a 25-km-long chain of submarine volcanoes that includes Eifuku and Daikoko. Hydrothermal fluid emission includes liquid carbon dioxide bubbles venting from "white smokers," one of only two places where natural liquid carbon dioxide emission has been observed. The hydrothermal field, named Champagne, was discovered during a 2003 NOAA expedition and lies in the steep headwall of a slope-failure scarp that cuts the summit and SW side of the volcano.