Bandai Volcano | John Seach


Honshu, Japan

37.60 N, 140.08 E
summit elevation 1819 m

Bandai volcano is an andesitic stratovolcano located in the southern part of the NE Honshu arc, Japan. During the past 5000 years, four major phreatic explosions have occurred at the volcano.

Bandai-type (Bandaian) eruptions is the name given to major slope failures caused by phreatic eruptions. Bezymianny-type eruptions (1956) include a magmatic component. Slope failure without eruption has occurred at Unzen volcano in 1792.

2000 Earthquakes
On 15th August, 416 earthquakes, and two periods of volcanic tremor were recorded at Bandai volcano. Climbers were banned from the mountain from 18th August.

1987 Earthquake swarm
An earthquake swarm was recorded at Bandai volcano on 16th June with 155 events measured.

1888 Eruption and Avalanche
A large phreatic eruption at Bandai volcano on 15th July 1888 produced a major debris avalanche, and pyroclastic flows. The eruption was caused by an outburst of self-sealed hydrothermal fluids within the volcano. There was little warning of the eruption, and the eruption finished in a short period of time. Precursory seismic activity consisted of small earthquakes felt at the northern base of the volcano on 8-10 July, and moderate earthquakes on 13-14 July. No other changes were observed in the volcanic activity before the eruption.

The eruption began on 15th July with two strong earthquakes. The second earthquake lasted for a minute, and the eruption began while the earthquake was occurring. Twenty explosions occurred successively in 1 min, with a huge thundering noise. Within 10 min of the explosions, a major debris avalanche descended to the northern flank of the volcano, and pyroclastic flows traveled 6 km.

The main explosive eruption lasted for a few minutes, but thundering sounds continued for about 2 hours. An eruption plume reached 5 km above the volcano. A
secondary debris avalanche flowed down through Biwazawa Valley, and buried approximately half of the houses in the village of Mine. The avalanche was caused by Failure of the northern sector of the volcano, including Kobandai cone. The estimated volume was 1.5 cubic km, and covered an area of 34 sq km. Eyewitnesses reported the avalanche traveled at 80 km/hr.

Further Reading
Reid, M.E., 2004. Massive collapse of volcano edifices triggered by hydrothermal pressurization. Geology, 32(5), pp.373-376.

Yamamoto, T., Nakamura, Y. and Glicken, H., 1999. Pyroclastic density current from the 1888 phreatic eruption of Bandai volcano, NE Japan. Journal of volcanology and geothermal research, 90(3-4), pp.191-207.

Moriya, I., 1988. Geomorphological development of Bandai volcano. Journal of Geography (Chigaku Zasshi), 97(4), pp.293-300.

Bandai Volcano Eruptions

1888, 1808?, 1787, 1767?, 1719, 1611?, 806.