Report on Aira (Japan) — May 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 5 (May 1987)
Managing Editor: Lindsay McClelland.
Aira (Japan) Minor ash eruptions but no recorded explosions
Please cite this report as:
Global Volcanism Program, 1987. Report on Aira (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198705-282080
Aira
Japan
31.5772°N, 130.6589°E; summit elev. 1117 m
All times are local (unless otherwise noted)
No explosions were recorded during April although ash clouds were often present. The maximum ash cloud height was 1,500 m above the summit crater (Minami-dake) on 3, 4, and 8 April. 43 g/m2 of ash accumulated at [KLMO]. Only one explosion has been recorded since 24 January. This is the lowest level of activity since May-August 1979.
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: JMA.
