Eruption history
VEI – Volcanic Explosivity Index: 0 = lava outpouring, 4 = like Eyjafjallajökull 2010, 6 = like Pinatubo 1991, 7 = like Tambora 1815. The scale is logarithmic – each step is about 10 times more material.
| Start | End | VEI | Vent and dating |
|---|---|---|---|
| 31 March 2000 | 15 September 2001 | 2 | Usu N flank (Kompira-yama & W Nishi-yama) · Observations: Reported |
| 7 August 1977 | 16 March 1982 | 3 | Usu-Shinzan · Observations: Reported |
| 23 June 1944 | 19 September 1945 | 2 | Usu East flank (Showa-Shinzan) · Observations: Reported |
| 25 July 1910 | 16 November 1910 | 2 | Usu North flank (Meiji-Shinzan) · Observations: Reported |
| 22 April 1853 | 16 September 1853 | 4 | O-Usu · Observations: Reported |
| 12 March 1822 | 16 September 1822 | 4 | Foot of Ko-Usu dome, Ogari-yama · Observations: Reported |
| 23 January 1769 | — | 4 | Ko-Usu · Observations: Reported |
| 1690 ± 10 years | — | ? | Usu · Correlation: Tephrochronology |
| 16 August 1663 | 5 September 1663 | 5 | Usu · Observations: Reported |
| 25 July 1638 | — | ? | Usu · Observations: Reported |
| 19 May 1626 | July 1626 | ? | Usu · Observations: Reported |
| 4,600 BCE ± 200 years | — | ? | Usu · Isotopic: 14C (calibrated) |
| 6,550 BCE ± 1,500 years | — | ? | Usu · Isotopic: 14C (calibrated) |
Data: Global Volcanism Program, Smithsonian Institution (#285030)