Space missions . Solar System . Volcanoes 101 . Site map . Seismic waves transmit the energy to the surface.
Earthquakes generate three types of seismic waves.
Primary, or P Waves, are the first to reach the surface. P Waves compress and expand the rock and liquid ahead of them. A third type, surface waves, are created by the interaction of other waves hitting the surface and can travel great distances. Many of the most damaging seismic waves are generated at subduction zones. Earth's crust is made up of a dozen or so major tectonic plates, each moving about four inches a year.