The ground beneath your feet is passing through the Earth at a rate of 10 centimeters a year

Though you may not realize it, the ground below you is traveling across the Earth at a rate of about 10 cm/year,or the speed at which your fingernails grow.This is due to plate tectonics,or the large-scale movement of Earth's continents.The motion occurs within the top two layers of the Earth's mantle,the lithosphere and asthenosphere.The lithosphere,which includes the crust and uppermost mantle,comprises the land around you.Beneath the lithosphere is the asthenosphere the highly viscous but solid rock portion of the upper mantle.