Global Volcanism Program | Image GVP-10704
The Big Obsidian Flow lava flow, covering 20 sq km of the floor of Newberry caldera, was emplaced about 1300 years ago during the last eruption of the volcano. The eruption began from a vent at the base of the south caldera wall. A large pumice fall was followed by an ashflow into Paulina Lake, and finally with emplacement of the obsidian flow. East Lake lies in the background in this view from the south caldera rim.
Photo by Lee Siebert, 2002 (Smithsonian Institution).