Satellite image of Fukutoku-Okanoa volcano (11 Feb 2010, NASA Earth Observatory)
Fukutoku-Okanoba is a submarine volcano 5 km NE of the small pyramidal island Minami-iwo-jima in the Japanese Volcano Island chain. Eruptions and submarine hydrothermal activity often cause water discoloration in the area, and during eruptions, the volcano has built several temporary new islands. The first observation of a new island was in 1904-05 when it formed Shin-Iwo-jima ("New Sulfur Island"). Small new islands were also formed during the eruptions in 1914 and 1986.
Fukutoku-Okanoba is part of an elongated submarine volcano with 2 major peaks aligned NNW-SSE, and trachyandesitic in composition, similar to neighboring Iwo-jima volcano.
