The number of recorded explosions from the summit crater of Minami-dake was 24 in May. After mid-May, most explosions ejected incandescent tephra, but no damage was reported. In late May activity gradually changed to continuous ash ejection without recorded explosions. Wind carried ash toward the W, causing heavy ashfall in and around the city of Kagoshima, on 25-26 May. The explosion on 19 May, at 0727, produced an eruption column higher that 2,500 m and was associated with 30 seconds of rumbling. Incandescent columns were observed on several occasions: 400 m high for 8 seconds on 4 May; 200 m high for 3 seconds on 5 May and for 5 seconds on 24 May.

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, Tokyo.