The Little Glass Mountain obsidian flow is seen here from Pumice Stone Mountain, named for the mantle of white pumice (foreground) from Little Glass Mountain. The 0.4 km³ obsidian flow was erupted from a currently buried vent below the Little Mt. Hoffman cone seen here behind the flow. The Little Glass Mountain pumice eruption and obsidian flow occurred about 950 years ago during one of the more recent eruptions from Medicine Lake.

Photo by Lee Siebert, 1998 (Smithsonian Institution).

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

Keywords: lava flow | obsidian | caldera

Medicine Lake