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 |
|---|---|---|---|
| 28 May 1993 | 31 August 1993 | 2 | Near Pyre Peak · Observations: Reported |
| 27 December 1992 | 30 December 1992 | 2 | Pyre Peak (1.5 km south of summit) · Observations: Reported |
| 6 March 1977 | 8 March 1977 | 1 | Pyre Peak (2.5 km SE of summit) · Observations: Reported |
| 2 July 1902 | — | 3 | Observations: Reported |
| 15 April 1892 | — | 3 | Observations: Reported |
| 16 December 1891 | — | 2 | Observations: Reported |
| 1786 | 1790 | ? | Observations: Reported |
| 250 ± 500 years | — | ? | West of Wilcox volcano · Isotopic: Uranium-series |
| 4,050 BCE ± 4,000 years | — | 0 | W flank of cone in eastern caldera · Isotopic: Uranium-series |
| 5,100 BCE ± 2,000 years | — | 0 | W flank of cone in eastern caldera · Isotopic: Uranium-series |
| 7,300 BCE ± 2,250 years | — | 5 | Wilcox volcano · Isotopic: Ar/Ar |
Data: Global Volcanism Program, Smithsonian Institution (#311180)