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Report on Fukutoku-Oka-no-Ba (Japan) — May 1996

Bulletin of the Global Volcanism Network, vol. 21, no. 5 (May 1996)
Managing Editor: Richard Wunderman.

Fukutoku-Oka-no-Ba (Japan) Discolored seawater

Please cite this report as:

Global Volcanism Program, 1996. Report on Fukutoku-Oka-no-Ba (Japan). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 21:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199605-284130.

Volcano Profile |  Complete Bulletin


Fukutoku-Oka-no-Ba

Japan

24.285°N, 141.481°E; summit elev. -29 m

All times are local (unless otherwise noted)


During the first half of May, aviators of the Maritime Safety Agency and the Maritime Self-Defense Force reported discoloration of seawater at Fukutoku-Okanoba. Similar discoloration has been observed since November 1995 (BGVN 20:11/12, 21:01, 21:03, and 21:04). An overflight on 23 May indicated no discolored seawater.

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: Japan Meteorological Agency (JMA), Volcanological Division, Seismological and Volcanological Department, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.