These islands and peninsulas on the north coast of Augustine formed in 1883 when collapse of the summit produced a large debris avalanche. Deposits from the highly mobile avalanche extended the island up to 2 km beyond the pre-1883 shoreline. Pyroclastic flows from that eruption also reached the new coastline and emplaced the light-colored deposits to the lower left.

Photo by Lee Siebert (Smithsonian Institution).

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

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Augustine