Report on Aira (Japan) — November 1977
Natural Science Event Bulletin, vol. 2, no. 11 (November 1977)
Managing Editor: David Squires.
Aira (Japan) Explosion on 28 November breaks 60 windows in buildings on the S flank
Please cite this report as:
Global Volcanism Program, 1977. Report on Aira (Japan). In: Squires, D. (ed.), Natural Science Event Bulletin, 2:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.NSEB197711-282080.
31.593°N, 130.657°E; summit elev. 1117 m
All times are local (unless otherwise noted)
Maximum ash cloud height during October was 2,500 m above the crater. Some incandescent material was ejected and reflected glow was occasionally observed. The air shock from an explosion at 0347 on 30 November broke [102 windowpanes] in villages about 3 km S of the summit. Tephra started grass fires, but these were quickly extinguished. No [injuries] resulted from the explosion, the 21st to occur in November.
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, Tokyo; Japanese Press.