Augustine is the most active volcano of the eastern Aleutian arc. It consists of several overlapping lava domes that frequently produce explosive eruptions and are notorious for collapsing, producing glowing avalanches (block and ash flows). 
Augustine volcano had a devastating eruption 1883 when large parts of the summit dome complex collapsed. In the following century, several eruptions associated with dome growth have restored the volcano's height again. Historical eruptions after that date were typically explosive, producing pyroclastic pumice flows and block-and-ash flows, followed by regrowth of the lava domes.
The oldest exposed rocks on the flanks of Augustine are little more than 40,000 years old. At least 11 large debris avalanches have reached the sea during the past 1800-2000 years, and five major pumiceous tephras have been erupted during this interval.