These "hot spots" occur at plate boundaries or at places where the crust is thin enough to let the heat through. The Yellowstone hot spot occurs because of the Earth's thin crust. Geologists have identified about 40-50 such hotspots around the world, with Hawaii, Réunion, Yellowstone, and Iceland overlying the most currently active hot spots.

Move Mouse Over to see where many prominent hot spots are located.

Comparison of Hawaii and Yellowstone        [Back to Top]    
    While scientists were trying to unravel the mystery of the Hawaiian Islands they also discovered a lot about hot spots like the one situated below Yellowstone.
    The great majority of the world's earthquakes and active volcanoes occur near the boundaries of the Earth's shifting plates. Then why are places like the Hawaiian volcanoes and Yellowstone National Park located near the middle of tectonic plates? In 1963, J. Tuzo Wilson, a Canadian geophysicist, provided a brilliant explanation within the theory of plate tectonics by suggesting the "Hot Spot" hypothesis. Wilson's hypothesis has come to be widely accepted today. 
    According to Wilson, the distinctive linear shape of the Hawaiian-Emperor Chain (and the Yellowstone caldera chain) reflects the forward movement of the plates over a deep immobile hot spot. This hot spot partly melts the region just below the above plates, producing small, isolated plumes of magma. Less dense than the surrounding solid rock, the magma rises through thin crust zones where the plate is thinner.  
    
Move Mouse Over to see the Yellowstone caldera chain
From the COTF Education Website
Move Mouse Over to see the Hawaiian Island chain
From the Lokahi Canoe Club Website

Earthquakes         [Back to Top]    
    From 1,000 to 3,000 earthquakes typically occur each year within Yellowstone National Park and its immediate surroundings. Although most are too small to be felt, these quakes reflect the active nature of the Yellowstone region, one of the most seismically active areas in the United States. Some of these quakes are caused by rising magma and hot-ground-water movement, but many of the larger quakes start from regional faults related to crustal stretching and mountain building. The many earthquakes and the movement of magma break up the rock covering, allow ground water to circulate. As the water rises to the surface, natural hot springs and geysers occur.

Move Mouse Over to see the Seismicity map from the past year
Move Mouse Over to see the Seismicity map showing 1983 - 1995
From the University of Utah Seismograph Stations Website