Lobby > Exhibits > Why Geysers Erupt > Underlying Geology > Exploring the Hotspot

The Yellowstone Volcano is a hotspot—an area on the Earth’s surface that shows signs of long-lasting volcanic activity. Hotspots are not fully understood. One theory suggests that the Yellowstone hotspot is caused by the North American plate slowly drifting over a stationary heat source. In this theory, a plume of magma rises from the core-mantle boundary of the Earth to trigger a chain of volcanic eruptions at the surface.

Another theory proposes that the continental plate is slowly pulling apart here, allowing the hot, plastic rock to melt in areas weakened by stretching and thinning.

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