Report on Azumayama (Japan) — October 2001
Bulletin of the Global Volcanism Network, vol. 26, no. 10 (October 2001)
Managing Editor: Richard Wunderman.
Azumayama (Japan) Short-term increase in seismic activity during April-May 2001
Please cite this report as:
Global Volcanism Program, 2001. Report on Azumayama (Japan) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 26:10. Smithsonian Institution.
37.735°N, 140.244°E; summit elev. 1949 m
All times are local (unless otherwise noted)
On 29 May 2001 the Fukushima Local Meteorological Observatory reported that seismicity increased slightly beneath Azuma during the month. The seismic network maintained by the Coordinating Committee for the Prediction of Volcanic Eruptions detected 51 small volcanic earthquakes during 21-22 May and 39 events on 21 May (the most recorded in one day since November 1998). During March four low-frequency tremor events were recorded, and 40 were detected in April. The observatory last reported that by 22 May, local residents had felt 33 earthquakes.
Geological Summary. The Azumayama volcanic group consists of a cluster of stratovolcanoes, shield volcanoes, lava domes, and pyroclastic cones. The andesitic and basaltic complex was constructed in two E-W rows above a relatively high basement of Tertiary sedimentary rocks and granodiorites west of Fukushima city. Volcanic activity has migrated to the east, with the Higashi-Azuma volcano group being the youngest. The symmetrical Azuma-Kofuji crater and a nearby fumarolic area on the flank of Issaikyo volcano are popular tourist destinations. The Azumayama complex contains several crater lakes, including Goshikinuma and Okenuma. Historical eruptions, mostly small phreatic explosions, have been restricted to Issaikyo volcano at the northern end of the Higashiyama group.
Information Contacts: Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan; The Japan Times; 5-4, Shibaura 4-chome, Minato-ku, Tokyo 108-0023, Central P.O. Box 144, 352, Tokyo 100-8691 (URL: http://www.japantimes.co.jp/).