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Report on Fukutoku-Oka-no-Ba (Japan) — October 1981


Scientific Event Alert Network Bulletin, vol. 6, no. 10 (October 1981)
Managing Editor: Lindsay McClelland.

Fukutoku-Oka-no-Ba (Japan) Frequent water discoloration observed during January-October 1981

Please cite this report as:

Global Volcanism Program, 1981. Report on Fukutoku-Oka-no-Ba (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 6:10. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198110-284130



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

All times are local (unless otherwise noted)

The Japan Maritime Safety Agency (JMSA) continues frequent monitoring flights over several known submarine volcanoes. [Discolored water at Fukutoku-Okanoba was specifically noted, in an included table of observations, on 9 and 29 January, 12 and 20 February, 12, 13, and 16 March, 20 April, 16, 17, and 22 July, 17 August, and 17 September 1981 (see table 1 below).]

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.

Information Contacts: JMSA, Tokyo; JMA, Tokyo.