When the Earth does quake and shake, how does it move?

well according to my geology teacher, he explained that an earthquake occurs when two tectonic plates collide, or rub with each other which causes a tremendous amount of force being released that spreads in a wave manner just how you would throw a rock in a pond and the ripples spreading out in all directions. underneath the earths crust, there is pressure from all the energy and magma contained that its trying to find a way out through an open fissure or ridge and that pressure being released cause movement of the tectonic plates, and therefore the earth moves with shakes and quakes.