Report on Aira (Japan) — February 1998
Bulletin of the Global Volcanism Network, vol. 23, no. 2 (February 1998)
Managing Editor: Richard Wunderman.
Aira (Japan) Several explosions during January-February
Please cite this report as:
Global Volcanism Program, 1998. Report on Aira (Japan). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 23:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199802-282080.
31.593°N, 130.657°E; summit elev. 1117 m
All times are local (unless otherwise noted)
Sakura-jima produced frequent explosions in December 1997-January 1998 (BGVN 23:01). A 20 January volcanic ash advisory reported an eruption at 1227. An 8 February advisory reported an eruption at 0420; the volcanic ash cloud reached ~2.1 km altitude and drifted SE. A notice later in the day reported another eruption at 0508 with an ash cloud at ~2.1 km altitude extending SE. A 16 February advisory reported an eruption on 15 February that sent a plume to the E at ~18 km altitude. Observers in Kagoshima Airport saw a volcanic ash cloud to the SE and S at 0600 on 16 February. Satellite images did not show a plume due to the presence of low weather clouds. A 24 February ash advisory noted an eruption at 0705; volcanic ash extended E at ~18 km altitude.
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: Sakurajima Volcanological Observatory (SVO), Disaster Prevention Research Institute (DPRI), Kyoto University, Sakurajima, Kagoshima, 891-14, Japan; Volcanological Division, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.