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
Black Butte Crater Lava Field
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The Black Butte Crater lava field (formerly known as the Shoshone lava field), located about 30 miles north of Twin Falls, Idaho, is the westernmost of the young basaltic lava fields of the Snake River Plain.
Location: Idaho, Snake River Plain
Latitude: 43.18° N
Longitude: 114.35° W
Elevation: 1,478 (m) 4,849 (f)
Volcano type: Shield volcano
Threat Potential: Low/Very Low*
*based on the National Volcano Early Warning System
Based on a single radiocarbon age, the Black Butte Crater eruption occurred about 12,000 calendar years ago as a relatively quiet effusion of basalt that produced an L-shaped lava flow 2-to-5 km (1.2-to-3 mi) in width that extends 60 km (37 mi) south and west of the vent area. The orientation of the lava field was determined by the Big Wood River valley, which was filled during the eruption, forcing the river to the western and northern margins of the lava field. The voluminous flow diverted the Big Wood and Little Wood River channels so that they now join 40 km (25 mi) west of their former confluence.
The vent at Black Butte Crater caps a lava shield that lies at the northeast end of the lava field. The vent area contains a complex lava lake that forms a 6-part, flower-petal-like depression with steep-sided walls, up to 30 m (98 ft) high; the lava lake covers an area of 2 km2 (0.8 mi2). The steepest part of the lava field hosts a lava tube and channel system, which extends 5 km (3 mi) southeast of Black Butte Crater and displays both roofed and collapsed portions. The roadside attraction of the Shoshone Ice Caves is located on this lava tube.
There is no threatening hazard from the Black Butte Crater Lava Field as it was a one-time (monogenetic) basaltic shield eruption, which will not recur. The probability of a future eruption in this region is very low. Unlike areas to the east, such as Craters of the Moon, it is not part of a well-defined, volcanic-rift-zone system in the eastern Snake River Plain.