GEOLOGY

Detailed explanation-1: -They can move at rates of up to four inches (10 centimeters) per year, but most move much slower than that. Different parts of a plate move at different speeds. The plates move in different directions, colliding, moving away from, and sliding past one another.

Detailed explanation-2: -Earth’s land masses move toward and away from each other at an average rate of about 1.5 centimeters (0.6 inches) a year. That’s about the rate that human toenails grow!

Detailed explanation-3: -The movement of the plates creates three types of tectonic boundaries: convergent, where plates move into one another; divergent, where plates move apart; and transform, where plates move sideways in relation to each other. They move at a rate of one to two inches (three to five centimeters) per year.

Detailed explanation-4: -The average rate of plate movement is approximately 5 cm/yr (about as fast as fingernails grow). This rate is perceptible but only over a long time.

Detailed explanation-5: -This axis cuts the surface at the ‘pole of rotation’. The plates move relative to one another over the asthenosphere (q.v.) at speeds of the order of 10–100 mm per year.