Mount Asama (浅間山, Asama-yama) is an active complex volcano in central Honshū, the main island of Japan.

[4] The mountain is built up from non-alkali mafic and pyroclastic volcanic rocks dating from the Late Pleistocene to the Holocene.

[10] The geologic features of this active volcano are closely monitored with seismographs and strategically positioned video cameras.

[14] A Swiss research team found Mount Asama's volcanic eruption could have contributed to extreme weather that caused severe famine, torrential rain and consecutive cold summers in Europe.

In the late Heian Period (794–1185) the diary of the court noble Fujiwara no Munetada reported that Mount Asama erupted on 29 August 1108.

He wrote that a local report described rice paddies and fields could not be farmed due to being covered by a thick layer of ash.

The climactic eruption began on 4 August and lasted for 15 hours,[17] and contained pumice falls and pyroclastic flows.

Mount Asama continued to have small eruptions, tremors and earthquakes in February and remained on level-3 alert, with a danger zone within 4 km (2.5 mi) of the crater.

Onioshidashi (Japanese: 鬼押出し) "expelling demons" is the name of a lava flow on the northern slope of Mount Asama.

Visitor numbers peaked at 265,000 in 1994; however, seismic activity at nearby Mount Asama was one reason for frequent closures.

In the anime Neon Genesis Evangelion, the Eighth Angel, Sandalphon, was located inside Mount Asama.