-
1989 BCE
Hydrothermal Eruptions
During this period, there was a series of ash producing hydrothermal explosions. -
275 BCE
Ape Canyon Stage
During this period, lava domes formed in two stages. -
28 BCE
Cougar Stage
The cougar stage was the most active stage before the spirit lake stage. -
18 BCE
Swift Creek Stage
This short period was mostly the construction of the dacite domes. -
3 BCE
Smith Creek Stage
Smith Creek was a highly active time the volcano. Some of the eruptions were 4 times bigger than the one in 1980. -
3 BCE
Pine Creek Eruptive Period
During this period the volcano Ejected compacted ash. -
2 BCE
Castle Creek Eruptive Period
This period produced compacted ash, lava flows, and many lava domes. -
Goat Rocks Eruptive Period
This period included the last lava flow and eruptions until 1980. -
Cataclysmic Eruption Of May 1980
This eruption was the biggest since 1857. This eruption was followed by a debris avalanche. -
Secondary Succession
After the eruption of 1980 secondary succession begins.
