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Report on Aira (Japan) — December 1990

Bulletin of the Global Volcanism Network, vol. 15, no. 12 (December 1990)
Managing Editor: Lindsay McClelland.

Aira (Japan) Strong explosions; 4,000-m ash cloud

Please cite this report as:

Global Volcanism Program, 1990. Report on Aira (Japan). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 15:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199012-282080.

Volcano Profile |  Complete Bulletin


Aira

Japan

31.593°N, 130.657°E; summit elev. 1117 m

All times are local (unless otherwise noted)


Minami-dake cone exploded four times in December, bringing the year's total of explosions to 119, up from 44 in 1989. An explosion at 0452 on 4 December ejected incandescent material that formed a column 500 m high, the highest since November 1988. Lightning was observed in the ash cloud for 26 minutes following the explosion. Another explosion, at 1019 on 25 December, ejected a 4,000-m-high ash cloud, and blocks that broke a car windshield 5 km E of the summit crater. It was the fifth event to cause damage during 1990 (table 10). The month's other two explosions occurred on 26 and 28 December. Only 4 g/m2 of ash was deposited 10 km W of the crater during December, a substantial decline from previous months.

Figure (see Caption) Figure 16. Monthly number of recorded explosions at Sakura-jima, 1955-1990. Courtesy of JMA.

Table 10. Damage from explosions at Sakura-jima, 1988-1990. Car windshields were broken by block or lapilli-fall, whereas windowpanes were mainly broken by air shocks. Ashfall damage is not included. Courtesy of JMSA.

Date Damage
30 Jan 1988 35 house windowpanes.
03 Feb 1988 Two car windowshields and four windowpanes.
09 Feb 1988 One car windshield.
27 Mar 1988 Two car windshields.
28 Jan 1989 Eight car windshields.
01 May 1990 21 house windowpanes.
28 Aug 1990 Two car windshields.
30 Nov 1990 Thirteen car windshields and four windowpanes.
30 Nov 1990 Nine car windshields and five windowpanes.
25 Dec 1990 One car windshield.

Further References. Eto, T., 1988, An estimation of the amount and dispersal of volcanic ash-falls ejected by summit eruptions at Sakura-jima volcano: Proceedings, Kagoshima International Conference on Volcanoes, p. 448-451.

Kamo, K., 1988, A dialogue with Sakura-jima volcano: Proceedings, Kagoshima International Conference on Volcanoes, p. 3-13.

Sakura-jima Volcanological Observatory, 1988, Volcano monitoring at the Sakura-jima Volcanological Observatory: Proceedings, Kagoshima International Conference on Volcanoes, p. 230-233.

Uhira, K., and Ueda, Y., 1988, Volcano monitoring at Kagoshima Local Meteorological Observatory of the JMA: Proceedings, Kagoshima International Conference on Volcanoes, p. 227-229.

Geologic Background. 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 Aira caldera, along with several post-caldera cones. The construction of Sakurajima began about 13,000 years ago on the southern rim of Aira caldera and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kitadake summit cone ended about 4850 years ago, after which eruptions took place at Minamidake. Frequent historical eruptions, recorded since the 8th century, have deposited ash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.

Information Contacts: JMA.