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Report on Aira (Japan) — December 1985


Scientific Event Alert Network Bulletin, vol. 10, no. 12 (December 1985)
Managing Editor: Lindsay McClelland.

Aira (Japan) Eruption plumes on 24th and 31st

Please cite this report as:

Global Volcanism Program, 1985. Report on Aira (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 10:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198512-282080



31.5772°N, 130.6589°E; summit elev. 1117 m

All times are local (unless otherwise noted)

Weather satellite images on 24 and 31 December show eruption plumes from Sakura-jima. On the 24th an approximately 200-km plume extended SW, then turned E for about 60 km. The ash cloud was fairly dense and milky gray in color. On the 31st there was a 120-km V-shaped plume ESE of the volcano. The end of the plume was about 40 km wide and very diffuse.

Further Reference. Eto, T., Kamada, M., and Kobayashi, T., 1987, The 1983-1986 Activities of Sakura-jima Volcano in XIX IUGG General Assembly, 1987, Report on Volcanic Activities and Volcanological Studies in Japan for the Period from 1983 to 1986, p. 18-27.

Geological Summary. The Aira caldera in the northern half of Kagoshima Bay contains the post-caldera Sakurajima volcano, one of Japan's most active. Eruption of the voluminous Ito pyroclastic flow accompanied formation of the 17 x 23 km caldera about 22,000 years ago. The smaller Wakamiko caldera was formed during the early Holocene in the NE corner of the caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim and built an island that was joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4,850 years ago, after which eruptions took place at Minamidake. Frequent eruptions since the 8th century have deposited ash on the city of Kagoshima, located across Kagoshima Bay only 8 km from the summit. The largest recorded eruption took place during 1471-76.

Information Contacts: M. Matson, NOAA/NESDIS; JMA, Tokyo.