Blue Lake Crater

Blue Lake Crater is a series of at least three overlapping explosion craters along a NE trend slightly east of the crest of the Cascade Range in the state of Oregon. Explosions through pre-existing bedrock about 1,300 years ago deposited basaltic bombs and cinders, and spread tephra to the E and SE during perhaps the youngest eruption in the Santiam and McKenzie Passes region. The eruption created an elongated, steep-walled crater with a low rim that rises about 50 m above adjacent topography.

The crater is now filled by the 300 x 800 m Blue Lake, immediately west of the glacial moraine dammed Suttle Lake. A chain of spatter cones, 6 km to the SSW and about 4 km NE of Mount Washington, is aligned with Blue Lake Crater and has ejecta that are petrographically similar and may have been erupted at the same time.