Pavlof Sister (United States)

Status Normal Eruption Unknown 2142m
Stratovolcano (Subduction zone / Continental crust (> 25 km))

Located at the end of a chain of volcanoes trending NE from Emmons Lake caldera, the symmetrical Pavlof Sister stratovolcano is somewhat more eroded than its twin volcano to the SW, Pavlof. Pavlof Sister, along with Pavlof and Little Pavlof is a stratovolcano that formed outside of the Emmons Lake caldera; these and other volcanoes inside Emmons Lake caldera are not glaciated and thus would have formed since the area was last glaciated about 15-20,000 years ago. The 2142-m-high volcano is almost 400 m lower than Pavlof and has a sharper-peaked summit. Some sources attributed a period of intermittent eruptive activity from 1762 to 1786 CE to Pavlof Sister, but other sources consider this event to have been from Pavlof volcano. The two symmetrical volcanoes form a dramatic backdrop to Pavlof Bay and Volcano Bay near the western end of the Alaska Peninsula.

The summits of the twin volcanoes of Pavlof Sister (left) and Pavlof (right) rise to 2142 m and 2519 m, respectively, above a low, roughly 1100-m-high saddle. They are viewed here in 1975 from lowlands to the NW. The somewhat less eroded Pavlof volcano, its slopes darkened by recent ashfalls, has been the source of frequent eruptions in historical time. Little Pavlof, a small satellitic volcano on the right flank of Pavlof, was also constructed along a line of vents trending NE from Emmons Lake caldera.

Photo by Tom Miller, 1975 (U.S. Geological Survey, Alaska Volcano Observatory).

Last updated 2019-08-04 00:28:03