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 |
|---|---|---|---|
| 21 September 1865 | 16 January 1866 | 2 | Observations: Reported |
| 15 August 1859 | 17 August 1859 | 2 | Observations: Reported |
| 15 October 1781 | 2 July 1801 | ? | Crater Rock · Sidereal: Dendrochronology |
| 480 ± 37 years | — | ? | Crater Rock · Isotopic: 14C (calibrated) |
| 4,940 BCE ± 150 years | — | 2 | Lower NE flank (SSW of Parkdale) · Isotopic: 14C (uncalibrated) |
Data: Global Volcanism Program, Smithsonian Institution (#322010)