Alaska Volcano Observatory

View of the southwest side of Bogoslof, July 14, 2019. Castle Rock is the prominent outcrop near the coast (erupted between 1796-1804). The high point on the island is a lava dome partially buried by pyroclastic debris. The sloping feature on the right side of the photograph are pyroclastic deposits from the 1926-27 eruption mantled by 1-2 m of material from the 2016-2017 eruption. At the base of the 1926-27 deposits are a few hydrothermally altered zones related to the 2016-2017 activity. Some of these areas are still warm. The vapor plume extending off to the right (south) is a persistent feature derived from ongoing degassing from numerous fumaroles in the center part of the island.