Approximately 1,000 to 3,000 earthquakes occur each year in the Yellowstone area; most are not felt. The 1959 Hebgen Lake earthquake (M7.3) caused significant damage to park roads, show here near Gibbon Falls.
mantle definition. The region of the interior of the Earth between the core (on its inner surface) and the crust (on its outer). Note: The mantle is more than two thousand miles thick and accounts for more than three-quarters of the volume of the Earth.
The asthenosphere is the part of the mantle that flows and moves the plates of the Earth. The Mantle. The mantle is the layer located directly under the sima. It is the largest layer of the Earth, 1800 miles thick.