JMA reported that an explosion at Minamidake crater (at Aira Caldera’s Sakurajima volcano) was recorded at 0043 on 14 November, producing a large ash cloud that rose over 4 km above the crater rim. Incandescent material was ejected more than 1 km from the crater. The report noted that this was the first occurrence of an ash plume rising above 4 km since 16 July 2018. Two events occurred during 16-19 November with the larger plume rising 1.6 km into the clouds. The Alert Level remained at 3 (on a 5-level scale).

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 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.

Source: Japan Meteorological Agency (JMA)