The Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 17-24 November with 25 eruptive events and eight explosions. Nightly crater incandescence was visible in webcam images. Sulfur dioxide emissions were characterized as extremely high, averaging 3,500 tons per day on 17 November. Explosions were recorded at 0554 on 17 November, at 0717, at 0732, and at 2305 on November 18, at 1814 on 19 November, at 0027 and 1929 on 21 November, and at 2120 on 24 November. Ash plumes from most of the explosions rose 400-2,400 m above the crater rim and drifted SE and E; no emissions from the 24 November explosion were visible, possibly due to weather conditions. Most of the explosions ejected somewhat large or large blocks as far as 1 km from the vent. Eruptive events during 17-19 and 21 November produced ash plumes that rose as high as 2.1 km above the crater rim and drifted E and SE. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to be cautious within 2 km of both the Minimadake and Showa craters.

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.

Source: Japan Meteorological Agency (JMA)