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 |
|---|---|---|---|
| 10 April 2010 | 21 July 2010 | 1 | Summit crater · Observations: Reported |
| 1 April 2009 | 1 April 2009 | 1 | Observations: Reported |
| 8 May 2008 | 8 May 2008 | 1 | Observations: Reported |
| 7 January 2008 | 7 January 2008 | 1 | Observations: Reported |
| 23 August 2006 | 23 August 2006 | 1 | Observations: Reported |
| 17 February 2006 | 17 February 2006 | 1 | Observations: Reported |
| 12 April 2005 | 18 May 2005 | 1 | Observations: Reported |
| 30 November 2004 | 9 December 2004 | 1 | Observations: Reported |
| 11 January 2001 | 24 November 2002 | 2 | Observations: Reported |
| 27 June 2000 | 28 September 2000 | 3 | Summit and submarine western flank · Observations: Reported |
| 3 October 1983 | 4 October 1983 | 3 | SW flank (4.5 km long NE-SW fissure) · Observations: Reported |
| 24 August 1962 | 27 August 1962 | 2 | NE flank · Observations: Reported |
| 12 July 1940 | 5 August 1940 | 3 | Oyama, NE flank · Observations: Reported |
| 3 July 1874 | 17 July 1874 | 3 | NNE flank (560 m) · Observations: Reported |
| 11 November 1835 | — | 2 | West flank (east and SE of Ako) · Observations: Reported |
| 27 January 1811 | 28 January 1811 | 2 | Summit and NE flank? · Observations: Reported |
| 17 August 1763 | 1769 | 4 | Oyama, SSW flank (Shinmio maar) · Observations: Reported |
| 4 February 1712 | 1714 | 3 | SW flank (Kuwanoki-daira) · Observations: Reported |
| 31 March 1643 | April 1643 | 3 | SW flank (SE of Ako, Kuwanoki-daira?) · Observations: Reported |
| 22 November 1595 | — | 2 | SE flank · Observations: Reported |
| March 1535 | — | 2 | SE flank · Observations: Reported |
| 24 December 1469 | — | 3 | Oyama · Observations: Reported |
| November 1154 | — | 3 | NE flank? · Observations: Reported |
| 1085 | — | 2 | Observations: Reported |
| c. 850 | — | 4 | Oyama and East flank (Mi-ike maar) · Observations: Reported |
| 23 June 832 | — | 3 | Observations: Reported |
| 750 ± 50 years | — | 3 | NE flank · Isotopic: 14C (calibrated) |
| 500 ± 50 years | — | 3 | Daihannya-yama · Isotopic: 14C (calibrated) |
| 320 ± 500 years | — | 3 | Sabigahama · Correlation: Tephrochronology |
| 260 ± 500 years | — | 4 | Correlation: Tephrochronology |
| 50 BCE ± 50 years | — | 3 | Taira-yama · Isotopic: 14C (calibrated) |
| 600 BCE ± 500 years | — | 3 | Correlation: Tephrochronology |
| 950 BCE ± 200 years | — | 4 | Hatchodaira caldera, S flank (Furumio maar) · Correlation: Tephrochronology |
| c. 1,250 BCE | — | 3 | Correlation: Tephrochronology |
| 1,450 BCE ± 500 years | — | ? | NW flank (NGS scoria layer) · Correlation: Tephrochronology |
| 1,800 BCE ± 50 years | — | 3 | South flank (Mizutamari maar) · Correlation: Tephrochronology |
| 2,000 BCE ± 100 years | — | 3 | Isotopic: 14C (calibrated) |
| 2,900 BCE ± 500 years | — | 4 | Correlation: Tephrochronology |
| 6,450 BCE ± 500 years | — | 4 | NW flank · Correlation: Tephrochronology |
Data: Global Volcanism Program, Smithsonian Institution (#284040)