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 mantle layer is the largest of the class. About half of our planetâs mass. The mantle is composed of very hot dense rocks, That move and flow, always on the go, they never lock, Extract from http://www.educationalrap.com/song/layer...