| Blue Lake Crater | |
|---|---|
 Blue Lake Crater (prior to the B&B Complex fires in summer 2003) | |
| Floor elevation | 3,461 ft (1,055 m)[1] |
| Geology | |
| Type | Maar |
| Age | Holocene[2] |
| Geography | |
| Location | Jefferson County, Oregon, USA |
| Coordinates | 44°24′45″N 121°46′11″W / 44.4126174°N 121.7697778°W [1] |
| Topo map | USGS Three Fingered Jack[1] |
Blue Lake Crater (also known as Blue Lake Maar)[3] is a maar, or a broad, low-relief volcanic crater, in the U.S. state of Oregon. Located in Jefferson County, it consists of three overlapping craters, which hold Blue Lake. The drainage basin for Blue Lake has very steep, forested slopes and is mostly part of the explosion crater left by the volcano's eruption. The volcano lies within the Metolius River basin, which supports a wide array of plant life, large and small mammals, and more than 80 bird species. A 2009 Oregon law designated the Metolius River basin as an area of critical concern, preventing large-scale development and protecting wildlife.
Despite having erupted at some point within the past 4,000 years, Blue Lake Crater is considered one of the least-known Holocene volcanoes in the Cascade volcanic arc. It forms a modest volcanic cone, its lake surrounded by a crescent-shaped, agglutinate ridge consisting of volcanic bombs. The northern side of Blue Lake Crater's rim collapsed during eruptive activity, while the southern wall remains intact. The overall composition is mafic (rich in magnesium and iron), chiefly basalt and picrite basalt (picrobasalt). Other associated volcanic features include a chain of spatter cones about 3.7 miles (6.0 km) to the south, which erupted material that shares petrographic qualities with erupted material from Blue Lake Crater. Geologists disagree on the exact date of Blue Lake Crater's most recent activity; W. E. Scott and E. M. Taylor place the eruption at 3,440 ± 250 years ago, while more recent publications estimate that date as the maximum age and suggest it is more likely the eruption occurred about 1,330 ± 140 years ago. The United States Geological Survey has assessed the threat potential from Blue Lake Crater as "Low/Very Low."
Part of the Elliott Corbett Memorial State Recreation Site, Blue Lake Crater supports an arts center named Caldera, as well as a resort. There is a campground on nearby Suttle Lake, and Blue Lake is used for fishing. The surroundings support hiking and horseback riding. The discontinuity of publicly accessible land has made the Blue Lake area little-known as a recreation destination, though a round-trip on the public trails runs for more than 2 miles (3.2 km), beginning with a scramble.
- ^ a b c "Blue Lake". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved March 23, 2019.
- ^ Jensen 2009, p. 77.
- ^ Ruscitto et al. 2010, pp. 154–156.