BackgroundMount Washington is an eroded Pleistocene basaltic-andesite shield volcano capped by a steep-sided central plug that is the most prominent landmark between North Sister and Three Fingered Jack volcanoes. The Cache Mountain cinder cones lie to the NE, and the Hayrick Butte tuya and the Recent cinder cone Hoodoo Butte to the NW. A series of aligned spatter cones on the NE flank along a regional fissure that extends to about 4 km from the summit erupted about 1300 years ago, but ejecta from this chain is petrographically similar to Blue Lake Crater ejecta and is considered to have erupted at the same time (Sherrod et al., 2004).
Source: Smithsonian / GVP volcano information
Mount Washington Photos
See also: Sentinel hub | Landsat 8