Global Volcanism Program | Image GVP-06547
The easternmost of the two East Lake obsidian flows forms the sparsely vegetated area in the center of the photo near the SE shore of East Lake. This rholitic flow, another one to the west, and associated pumice deposits were erupted from fissures parallel to the inner caldera wall about 3500 years ago. These were the second youngest eruptions of obsidian lava flows in Newberry caldera.
Photo by Lee Siebert, 1997 (Smithsonian Institution).