Report on Asosan (Japan) — May 1996

Bulletin of the Global Volcanism Network, vol. 21, no. 5 (May 1996)
Managing Editor: Richard Wunderman.

Asosan (Japan) Crater glow

Please cite this report as:

Global Volcanism Program, 1996. Report on Asosan (Japan). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 21:5. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199605-282110.

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Asosan

Japan

32.884°N, 131.104°E; summit elev. 1592 m

All times are local (unless otherwise noted)


Red glow has been observed over part of the S wall of Naka-dake Crater 1 since 27 April. The floor of this crater was still covered with water in May. Aso, a 24-km wide caldera, produced pyroclastic-flow deposits during the Pleistocene that cover much of Kyushu. Naka-dake, one of the 15 intra-caldera cones of Aso's caldera, has erupted more than 165 times since 553 AD.

Geologic Background. The 24-km-wide Asosan caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Nakadake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Nakadake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 CE. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Nakadake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations.

Information Contacts: Japan Meteorological Agency (JMA), Volcanological Division, Seismological and Volcanological Department, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.