The Snake River Plain and the Yellowstone Hot Spot

The geysers, hot springs, and bubbling mud pots of Yellowstone National Park indicate there is extra heat beneath this corner of Wyoming. Geologists and volcanologists think the heat is from a hot spot beneath Yellowstone. A long line of features that extends to the west from Yellowstone are interpreted to be the track left in the continent from the hotspot. Most of these features are part of the Snake River Plain.



The Snake River Plain extends 400 miles (650 km) westward from northwest Wyoming to the Idaho-Oregon border. The Snake River Plain is a broad, flat arcuate depression which is concave to the north and covers one quarter of the state of Idaho. Elevations on the Snake River Plain decrease from the east (4,400-5,000 feet; 1,350-1,525 m) to the west (2,950-3,900 feet; 900-1,200 m). Some features within the Snake River Plain become younger to the east. For example, calderas become progressively younger from west to east. The Yellowstone calderas are they youngest and mark the approximate location of the hotspot.


Yellowstone has had three very large eruptions in the last 2 million years. During each event, a large volume of rhyolite magma was erupted from a shallow level in the crust and a large caldera formed. These eruptions occurred 2.0, 1.3, and 0.6 million years ago. The volume of lava erupted makes the 1980 eruption of Mount St. Helens look very small.


Seismologists, scientists that study earthquakes, think they have detected the path the magma follows from the hot spot to shallow levels beneath Yellowstone. They used earthquake waves. The waves travel fastest in cold, dense rock. In warmer, less dense rocks, the waves slow down. A zone of warmer rocks has been mapped beneath Yellowstone.

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Sources of Information

Christiansen, 1984, Yellowstone magmatic evolution: its bearing on understanding large-volume explosive volcanism, in Boyd, F.R., ed., Explosive volcanism: Inception, evolution, and hazards: National Research Council Studies in Geophysics, Washington, D.C., National Academy Press, p. 96-109.

Newhall, C.G., and Dzurisin, D., 1988, Historical unrest at large calderas of the world: U.S. Geological Survey Bulletin 1855, v. 2, p. 755-772.

Smith, R. B., and L. W. Braile, 1994, The Yellowstone Hotspot, in J. Volcanology and Geotherm. Resesarch, eds. D.P. Hill, P. Gasparini, S. McNutt and H. Rymer, H., 61:121-188.

Smith, R.B., and Braile, L.W., 1983, Crustal structure and evolution of an explosive silicic volcanic system at Yellowstone National Park, in Boyd, F.R., ed., Explosive volcanism: Inception, evolution, and hazards: National Research Council Studies in Geophysics, Washington, D.C., National Academy Press, p. 96-109. 


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