Seismologists, who are experts in the study of earthquakes, have identified that the type of wave that causes most of the shaking felt from an earthquake are Rayleigh waves. These waves, also referred to as ground roll, propagate across the surface of the Earth, causing the ground surface to move up and down. This vertical movement is responsible for the majority of the shaking that we experience during an earthquake. In contrast, Love waves are faster and they move the ground laterally, from side to side, but they are not the primary cause of the shaking felt at the surface. read more >>

Rayleigh waves, also called ground roll, travel like ocean waves over the surface of the Earth, moving the ground surface up and down. They cause most of the shaking at the ground surface during an earthquake. Love waves are fast and move the ground from side to side.read more >>