The final phase of this episode built the summit cone of Mount Bachelor.
Follow this track and subsequent path, which has recently been re-laid to limit erosion, all the way to the summit cone of West Lomond.
It formed only within the past 40,000 years, and the pre-1980 summit cone began rising about 2,200 years ago.
The pre-1980 summit cone started to form during the Castle Creek period.
Named for its location on the side of the main summit cone of Mount Erebus.
The volcano's peak contains an array of steep summit cones, which are frequently active.
This is Seatallan's principal satellite, a broad ridge falling from the east of the summit cone.
Active fulmaroles are found in the eastern crater and in the saddle between the two summit cones.
The current summit cone was developed within the earlier caldera.
It is within this summit cone that the active lava lake continuously degasses.