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Report on Fukutoku-Oka-no-Ba (Japan) — 29 December-4 January 2022


Fukutoku-Oka-no-Ba

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 December-4 January 2022
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2021. Report on Fukutoku-Oka-no-Ba (Japan). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 December-4 January 2022. Smithsonian Institution and US Geological Survey.

Weekly Report (29 December-4 January 2022)

Fukutoku-Oka-no-Ba

Japan

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

All times are local (unless otherwise noted)


The Japan Coast Guard reported that during a 27 December overflight of Fukutoku-Oka-no-Ba, observers noted that the island formed in mid-August had become smaller since 14 December, and had almost eroded below the ocean surface. No eruptive activity was observed, though brownish water spouted from the E end of the island. Yellowish-green water and a string of floating pumice, 400 m long, was circulating 5 km E. Discolored water was visible around almost the entire coast of Minami-Ioto (5 km SSW).

Geological Summary. 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.

Source: Japan Coast Guard