Report on Aira (Japan) — November 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 11 (November 1980)
Managing Editor: David Squires.
Aira (Japan) Lapilli and air shocks break windows
Please cite this report as:
Global Volcanism Program, 1980. Report on Aira (Japan) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 5:11. Smithsonian Institution.
31.593°N, 130.657°E; summit elev. 1117 m
All times are local (unless otherwise noted)
The number of recorded explosions declined from 21 in September to four in October, then increased to 21 in November. The highest October ash cloud reached 2.0 km, on the 1st. None of the October activity caused any damage. Lapilli from the largest November tephra cloud, which rose 2.5 km on the 8th, broke five car windshields. The air shock from the 28 November explosion broke two [windowpanes] in a hotel at the base of the volcano. No injuries were reported.
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 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, Tokyo.