Report on Hokkaido-Komagatake (Japan) — 8 November-14 November 2000
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 8 November-14 November 2000
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2000. Report on Hokkaido-Komagatake (Japan). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 8 November-14 November 2000. Smithsonian Institution and US Geological Survey.
42.063°N, 140.677°E; summit elev. 1131 m
All times are local (unless otherwise noted)
According to an Associated Press article, the JMA stated that at 0739 on 8 November an eruption occurred at Komaga-take, which is 710 km NE of Tokyo on Japan's northernmost island of Hokkaido. The eruption produced an ash cloud and coincided with 10 minutes of volcanic tremor. Ashfall was reported in the nearby town of Shikabe, but due to cloudy conditions the height of the ash plume was not observed. The volcano had previously erupted on 4 and 28 September, and 28 October 2000.
Geologic Background. Much of the truncated Hokkaido-Komagatake andesitic volcano on the Oshima Peninsula of southern Hokkaido is Pleistocene in age. The sharp-topped summit lies at the western side of a large breached crater that formed as a result of edifice collapse in 1640 CE. Hummocky debris avalanche material occurs at the base of the volcano on three sides. Two late-Pleistocene and two Holocene Plinian eruptions occurred prior to the first historical eruption in 1640, which began a period of more frequent explosive activity. The 1640 eruption, one of the largest in Japan during historical time, deposited ash as far away as central Honshu and produced a debris avalanche that reached the sea. The resulting tsunami caused 700 fatalities. Three Plinian eruptions have occurred since 1640; in 1694, 1856, and 1929.