Strong eruption of Sakurajima sends ash plume 4.5 km into the air, Japan

Following a week of relatively low activity, Japanese Sakurajima volcano (Showa crater/Aira caldera) has become more active again during the past days.

A particularly strong vulcanian explosion occurred this morning (October 24) and produced an ash plume that rose up to 4 500 m (15 000 ft) altitude.

JMA reported that three explosions from Showa crater ejected tephra as far as 1 300 m during October 14 – 17. The Alert Level remained at 3 (on a scale of 1 – 5).

The Tokyo VAAC reported that on October 16, 18 and 21 ash plumes rose to altitudes of 1.8 – 3 km (6 000 – 10 000 ft) a.s.l. and drifted S, SE, and NE.

Video credit VolcanoDiscovery

Geologic 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. (GVP)