Global Volcanism Program | Image GVP-06546
The East Lake obsidian flows and associated pumice deposits erupted from fissures parallel to the inner caldera wall. The westernmost of the two obsidian flows immediately south of East Lake is seen here. It traveled to the north towards East Lake, part of which can be seen beyond the forested area in the center of the photo, below the eastern caldera wall.
Photo by Lee Siebert, 1997 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.