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Report on Aira (Japan) — 18 September-24 September 2024


Aira

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 18 September-24 September 2024
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2024. Report on Aira (Japan) (Sennert, S, ed.). Weekly Volcanic Activity Report, 18 September-24 September 2024. Smithsonian Institution and US Geological Survey.

Weekly Report (18 September-24 September 2024)

Aira

Japan

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

All times are local (unless otherwise noted)


Japan Meteorological Agency (JMA) reported ongoing eruptive activity at Minamidake Crater (Aira Caldera’s Sakurajima volcano) during 16-23 September. Crater incandescence was visible in webcam images during dark hours, and there were occasional very small eruptive events. An explosion at 1332 on 16 September generated an ash plume that rose 1.5 km above the crater rim and drifted NW. During a field visit on 18 September sulfur dioxide emissions were high, averaging 2,200 tons per day. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 1 km away from both 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)