The broad Medicine Lake shield volcano, seen here on the horizon from Soldier Mountain to its south, is truncated by a 7 x 11 km caldera. Medicine Lake volcano has erupted lavas of widely varying composition ranging from basalt to rhyolite. The largest eruption of Medicine Lake during the past 11,000 years produced a massive basaltic lava flow from Giant Crater about 10,600 years ago. The flow traveled a distance of 45 km down the broad valley in the center of the photo from its vent on the SSW flank.

Photo by Lee Siebert, 1998 (Smithsonian Institution).

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

Medicine Lake