Beyond the outer core lies the mantle, a 1,800-mile-thick layer of viscous molten rock on which Earth's outermost layer, the crust, rests. On land, the continental crust is an average of 19 miles ...

Stable parts of the Earth's crust may not be as immovable as previously thought. While much of the crust is affected by plate tectonic activity, certain more stable portions have remained ...