Early November snowfall at Haku-san accentuates the volcano's name, which means White Mountain. Eruptions at multiple vents along a roughly N-S line give the complex stratovolcano an elongated profile; the volcano is viewed here from the west. Holocene eruptions have consisted of phreatic or phreatomagmatic explosions from several summit craters. Historical eruptions were recorded over almost a thousand-year period until the 17th century.
This outcrop along the Oshira-kawa river east of Haku-san volcano in Japan shows textures that are common at debris-avalanche deposits. Large fractured clasts are carried in a finer matrix that shows variations in color. This results from the transport of small discrete segments of the volcano for long distances without being totally disaggregated and mixed together. This debris avalanche was produced by a volcanic landslide from the summit and eastern flank of Haku-san about 4200 years ago.