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Report on Aira (Japan) — March 1984


Scientific Event Alert Network Bulletin, vol. 9, no. 3 (March 1984)
Managing Editor: Lindsay McClelland.

Aira (Japan) Tephra causes minor damage

Please cite this report as:

Global Volcanism Program, 1984. Report on Aira (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 9:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198403-282080



31.5772°N, 130.6589°E; summit elev. 1117 m

All times are local (unless otherwise noted)

An explosion at Sakura-jima on 12 April at about 0940, the 95th in 1984, produced an eruption cloud that rose to 2.3 km (table 6). According to press reports, ejecta fell over half the volcano and broke windows at the foot.

Table 6. Damage caused by Sakura-jima eruptive activity in 1984.

Date Time Result
04 Jan 1984 1928 Lapilli broke car windshield at S foot of the volcano.
10 Jan 1984 1457 Air shock cracked a window at E foot.
11 Jan 1984 2140 Air shock cracked three windows.
08 Mar 1984 0724 Lapilli cracked car windshield.
19 Mar 1984 -- Debris flows reached E foot; no damage reported.
30 Mar 1984 1853 Large quantity of lapilli; forest fires started.
12 Apr 1984 0941 Strong air shock cracked three windows at the E and S foot, two windows in Kagoshima.
19 Apr 1984 -- Debris flows occurred.
29 Apr 1984 1800 Large quantities of incandescent ejecta started forest fires in more than 10 places; strong air shock broke a window in Kamoike. (Damage in Kagoshima is rare.)
04 May 1984 -- A windowpane was broken in Yasui.
08 May 1984 -- Air shock broke a hospital window at the SW foot.
23 Jun 1984 -- Heavy ashfall caused a traffic jam and interrupted electric service in Kagoshima.
03 Jul 1984 -- Strong air shock broke windowpanes at a junior high school and a house in Koike at the W foot. A Sakura-jima Volcano Observatory employee was injured by broken glass in Yokoyama at the W foot.
07 Jul 1984 -- A large amount of lapilli broke 11 car windshields and a house windowpane at the NE foot.
21 Jul 1984 -- A large amount of ejecta including pieces up to a few meters in diameter fell at the S foot. Incandescent fragments broke the roofs of 10 houses and a warehouse, burning some slightly. Telephone and electric service was interrupted for a few hours.
10-11 Oct 1984 -- Volcanic gas damaged farm crops at the SW foot.
20 Dec 1984 -- Lapilli broke a few car windshields at the S foot.

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: Kyodo News Service, Tokyo; UPI.