In the foreground is a hummock of a debris avalanche deposit produced by collapse of the Augustine summit about 450 years ago. The avalanche swept into Kamishak Bay and traveled a distance of 11 km from the summit, forming the 2 x 3 km wide West Island. The fine-grained component of this avalanche hummock has been removed by the powerful Cook Inlet tides. The eruption was accompanied by a small lateral blast.

Photo by Lee Siebert, 1987 (Smithsonian Institution).

This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Galleries: Debris Avalanches / Landslides | Stratovolcanoes | Lava Domes

Keywords: debris avalanche deposit | deposit | stratovolcano | lava dome | emissions | gas | gas plume | hummock

Augustine