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Report on Akan (Japan) — February 2006


Bulletin of the Global Volcanism Network, vol. 31, no. 2 (February 2006)
Managing Editor: Richard Wunderman.

Akan (Japan) Eruption on 21 March 2006 results in small ash fall

Please cite this report as:

Global Volcanism Program, 2006. Report on Akan (Japan) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 31:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200602-285070



43.384°N, 144.013°E; summit elev. 1499 m

All times are local (unless otherwise noted)

Yukio Hayakawa of Gunma University notified the Bulletin staff that a very small eruption occurred on the morning of 21 March 2006 at Me-Akan. Tremor first started at 0628, followed by the eruption 0637. The Japan Meteorological Agency (JMA) issued a second-level alert at 0643. Ash was found on the snow at 10 km SE of the volcano. No towns or villages were threatened as the volcano is in a remote location, although there are some hot-spring hotels in the area. Me-Akan erupted in 1996 and 1998 from within the summit crater, but the March 2006 eruption was from the NE flank.

According to a news report by Reuters, a JMA official stated that "gray ash was discovered on the snow around the summit, but no movement of lava was detected, and we do not think a large eruption is likely."

Geological Summary. Akan is a 13 x 24 km caldera located immediately SW of Kussharo caldera. The elongated, irregular outline of the caldera rim reflects its incremental formation during major explosive eruptions from the early to mid-Pleistocene. Growth of four post-caldera stratovolcanoes, three at the SW end of the caldera and the other at the NE side, has restricted the size of the caldera lake. Conical Oakandake was frequently active during the Holocene. The 1-km-wide Nakamachineshiri crater of Meakandake was formed during a major pumice-and-scoria eruption about 13,500 years ago. Within the Akan volcanic complex, only the Meakandake group, east of Lake Akan, has been historically active, producing mild phreatic eruptions since the beginning of the 19th century. Meakandake is composed of nine overlapping cones. The main cone of Meakandake proper has a triple crater at its summit. Historical eruptions at Meakandake have consisted of minor phreatic explosions, but four major magmatic eruptions including pyroclastic flows have occurred during the Holocene.

Information Contacts: Yukio Hayakawa, Gunma University, 4-2 Aramaki-machi, Maebashi City, Gunma, 371-8510, Japan (URL: http://www.hayakawayukio.jp/English.html/); Japan Meteorological Agency, Kishocho-881, 3-4 Ote-machi, Chiyoda-ku, Tokyo 100-0004, Japan; Reuters Foundation Alert Net (URL: http://www.alertnet.org/).