Report on Bandaisan (Japan) — November 1988
Scientific Event Alert Network Bulletin, vol. 13, no. 11 (November 1988)
Managing Editor: Lindsay McClelland.
Bandaisan (Japan) Increased seismicity
Please cite this report as:
Global Volcanism Program, 1988. Report on Bandaisan (Japan). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 13:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198811-283160.
37.601°N, 140.072°E; summit elev. 1816 m
All times are local (unless otherwise noted)
Seismicity increased toward the end of November. A total of 188 events were recorded by the seismometer 1.8 km NNW of the summit, up sharply from the background level of ~20/month (figure 1).
Geologic Background. One of Japan's most noted volcanoes, Bandaisan rises above the north shore of Lake Inawashiro. This complex is formed of several overlapping andesitic stratovolcanoes, the largest of which is Obandai. Kobandai volcano, which collapsed in 1888, was formed about 50,000 years ago. Obandai volcano was constructed within a horseshoe-shaped caldera that formed about 40,000 years when an older volcano collapsed, forming the Okinajima debris avalanche, which traveled to the SW and was accompanied by a plinian explosive eruption. The last magmatic eruption took place more than 25,000 years ago, but four major phreatic eruptions have occurred during the past 5000 years, two of them in historical time, in 806 and 1888. Seen from the south, Bandaisan presents a conical profile, but much of the north side of the volcano is missing as a result of the collapse of Ko-Bandai volcano during the 1888 eruption, in which a debris avalanche buried several villages and formed several large lakes.
Information Contacts: JMA; AP; UPI.