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Report on Akan (Japan) — March 1988


Akan

Scientific Event Alert Network Bulletin, vol. 13, no. 3 (March 1988)
Managing Editor: Lindsay McClelland.

Akan (Japan) Continuous steam emission

Please cite this report as:

Global Volcanism Program, 1988. Report on Akan (Japan) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 13:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198803-285070



Akan

Japan

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

All times are local (unless otherwise noted)


After small ash eruptions in January and February activity declined in March. However, steam emission was continuous, with the highest plume rising 500 m above the crater on 9 March.

Geological Summary. Akan is a 13 x 24 km caldera located immediately SW of Kussharo caldera in eastern Hokkaido. The elongated, irregular outline of the caldera rim reflects its incremental formation during major explosive eruptions from the early to mid-Pleistocene. There are four post-caldera stratovolcanoes, three at the SW end of the caldera and the other on the NE side. 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. The Meakandake group, composed of nine overlapping cones E of Lake Akan, has produced mild phreatic eruptions since the beginning of the 19th century. The main cone of Meakandake proper has a triple crater at its summit. Although recorded eruptions at Meakandake have consisted of minor phreatic explosions, four major magmatic eruptions with pyroclastic flows have also occurred during the Holocene.

Information Contacts: JMA.