When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
Blue Lake Crater
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Blue Lake crater and a chain of spatter cones between Blue Lake and Mount Washington may be the youngest volcanic features in Central Oregon's Santiam and McKenzie Passes region.
Location: Oregon, Jefferson County
Latitude: 44.411° N
Longitude: 121.774° W
Elevation: 1,230 (m) 4,035 (f)
Volcano type: Maar
Most recent eruption: 1300 years ago
Nearby towns: Sisters
Threat Potential: Low/Very Low*
*based on the National Volcano Early Warning System
A chain of spatter cones trends north-northeast for 1.5 km in line with Blue Lake crater; none of the spatter vents fed lava flows. The crater, now occupied by Blue Lake, erupted a tephra plume that was deflected by gentle winds blowing to the east-northeast and produced a fall deposit that blanketed the Suttle Lake trough. The deposit is thicker than 2 m (7 ft) along the southwestern shore of Suttle Lake. Blue Lake itself is surrounded by a modest cone of cinder and welded spatter. Radiocarbon dating of forest litter from below products of the chain of spatter cones indicates eruption about 1,300 years ago. Tephra from Blue Lake crater is similar to that from the chain of spatter cones and, taken together with the alignment of the chain and crater, suggests that all the vents were active during a single eruptive episode.