Mount Asama


Mount Asama is a complex volcano situated in the main island of Japan. The most active volcano in Honshu stands 2,568 metres above sea level. Built up from non-alkali mafic and pyroclastic volcanic rocks, it is one of the 100 popular Japanese mountains.

Location: Central Honshu, Japan
Coordinates: 36.406450, 138.522344
Volcano Type: Complex volcano


Mount Asama’s Location


Mount Asama’s Latest Status

2024: Alert Level 1 – Not Active. In 2023, Minor inflation was recorded on Asama’s western flank.


Mount Asama’s Eruptive History

1783 May – Plinian eruption. One of Japan’s largest eruptions in recorded history. This eruption built a new cone, rained pumice and caused massive pyroclastic flows. Activity ended post an enormous explosion that could be heard 300km away. 1400 people died as a direct result of the eruption, however a further 20,000 from famine
1949-59 Ongoing eruptive phase. Smoke observed rising from the crater on multiple occasions
1961 Eruption in Nov – eruption column observed
1973 A number of tremors were recorded before a powerful eruption occurred with lava bombs falling around the crater.
1982-83 Large explosion producing an ash plume to 5000m. A small pyroclastic flow was produced
1995 Series of earthquakes were recorded. No eruption occurred.
2004 After a long period of minor activity, a vulcanian eruption occurred creating a plume to 5000m. Ballistic blocks were ejected.
2008 Small series of eruptions producing minor ash plumes
2009 Following high gas levels, an eruption occurred with the accompanying plume reaching 2000m. Light ash fell on the city of Tokyo.
2019 An (unexpected) eruption occurred in August producing an ash plume to 2000m
2020 The volcano continues to produce steam plumes. Seismicity fluctuates.
2023 JMA has reported inflation is occurring on the western flank. Seismicity and emissions remain high.


Mount Asama Monitoring

For monitoring of Japan’s Volcanoes, please refer to JMA.


Mount Asama Images