Report on Fukutoku-Oka-no-Ba (Japan) — December 1995
Bulletin of the Global Volcanism Network, vol. 20, no. 11 (December 1995)
Managing Editor: Richard Wunderman.
Fukutoku-Oka-no-Ba (Japan) Discolored seawater
Please cite this report as:
Global Volcanism Program, 1995. Report on Fukutoku-Oka-no-Ba (Japan) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 20:11. Smithsonian Institution.
24.285°N, 141.481°E; summit elev. -29 m
All times are local (unless otherwise noted)
An aviator flying over the waters of the southern Volcano Islands for Japan's Maritime Safety Agency reported seeing light-green seawater on 25, 27, and 28 November. Discolored seawater was last seen at this location in September 1993.
Geologic Background. Fukutoku-Oka-no-ba is a submarine volcano located 5 km NE of the pyramidal island of Minami-Ioto. Water discoloration is frequently observed from the volcano, 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.
Information Contacts: Volcanological Division, Seismological and Volcanological Department, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan.