Global Volcanism Program | Image GVP-03231
The massive Medicine Lake volcano in NE California, seen here from the NE, is a 50-km-wide shield volcano that is truncated by a 7 x 11 km wide caldera. During the Holocene, obsidian flows have been erupted from summit and flank vents, and voluminous basaltic lava flows have erupted from vents on the north and south flanks. The latest eruptions of Medicine Lake volcano took place about 1000 years ago.
Photo by Julie Donnely-Nolan, 1982 (U.S. Geological Survey).