Report on Aira (Japan) — December 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 12 (December 1992)
Managing Editor: Lindsay McClelland.
Aira (Japan) Continued explosions; no damage
Please cite this report as:
Global Volcanism Program, 1992. Report on Aira (Japan) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 17:12. Smithsonian Institution.
31.593°N, 130.657°E; summit elev. 1117 m
All times are local (unless otherwise noted)
Twelve explosions and three quiet ash eruptions occurred . . . in December . . . . No damage was caused by the eruptions. The highest ash plume rose 2 km on 22 December. Seismicity remained relatively low, with one swarm of 29 earthquakes on 29 December between 0700 and 1900.
A total of 165 explosions was recorded in 1992, down from 295 last year. Yearly ash accumulation [at KLMO] was 2,945 g/m2, up from 1,852 g/m2 in 1991.
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.