The Japan Coast Guard reported that during a 26 August overflight of Fukutoku-Oka-no-Ba, observers noted that the W island was unchanged while the E side had mostly eroded, leaving two small islands. While no eruptions were visible, gray material from the central vent was intermittently ejected to the sea surface and brown, discolored water was widely distributed, especially to the W.

Geological Summary. Fukutoku-Oka-no-ba is a submarine volcano located 5 km NE of the island of Minami-Ioto. Water discoloration is frequently observed, and several ephemeral islands have formed in the 20th century. The first of these formed Shin-Ioto ("New Sulfur Island") in 1904, and the most recent island was formed in 1986. The volcano is part of an elongated edifice with two major topographic highs trending NNW-SSE, and is a trachyandesitic volcano geochemically similar to Ioto.

Source: Japan Coast Guard