This is the NE margin of the Big Obsidian Flow, which erupted from a vent near the Newberry southern caldera wall about 1,300 years ago into this crater, whose forested rim is seen in the background.

Photo by Lee Siebert, 1981 (Smithsonian Institution).

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

Keywords: lava flow | obsidian

Newberry