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Report on Suwanosejima (Japan) — 10 January-16 January 2024


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 10 January-16 January 2024
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2024. Report on Suwanosejima (Japan) (Sennert, S, ed.). Weekly Volcanic Activity Report, 10 January-16 January 2024. Smithsonian Institution and US Geological Survey.

Weekly Report (10 January-16 January 2024)



29.638°N, 129.714°E; summit elev. 796 m

All times are local (unless otherwise noted)

JMA reported that the eruption at Suwanosejima's Ontake Crater continued during 8-15 January. Eruptive events on 11 January produced ash plumes that rose as high as 1.1 km above the crater rim and drifted SE. An explosion at 0548 on 13 January produced an ash plume that rose 800 m and drifted SE. At 0022 on 14 January an explosion ejected large blocks 1.1 km to the N and 1 km to the S of the vent and produced an ash plume that rose 500 m above the crater rim. The Alert Level was raised to 3 (on a 5-level scale) and the public was warned to stay 2 km away from the crater. Another eruptive event at 2313 on 15 January generated an ash plume that rose more than 1 km above the crater rim and drifted S.

Geological Summary. The 8-km-long island of Suwanosejima in the northern Ryukyu Islands consists of an andesitic stratovolcano with two active summit craters. The summit is truncated by a large breached crater extending to the sea on the E flank that was formed by edifice collapse. One of Japan's most frequently active volcanoes, it was in a state of intermittent Strombolian activity from Otake, the NE summit crater, between 1949 and 1996, after which periods of inactivity lengthened. The largest recorded eruption took place in 1813-14, when thick scoria deposits covered residential areas, and the SW crater produced two lava flows that reached the western coast. At the end of the eruption the summit of Otake collapsed, forming a large debris avalanche and creating an open collapse scarp extending to the eastern coast. The island remained uninhabited for about 70 years after the 1813-1814 eruption. Lava flows reached the eastern coast of the island in 1884. Only about 50 people live on the island.

Source: Japan Meteorological Agency (JMA)