These waves shake the ground as they pass by. A vibrational disturbance in the Earth that travels at speeds of several kilometers per second. Seismic waves are produced by earthquakes. Also called compressional or longitudinal waves , P waves are the fastest seismic waves produced by an earthquake. They oscillate the ground back and forth along the direction of wave travel, in much the same way as sound waves, which are also compressional, move the air back and forth as the waves travel from the sound source to a sound receiver.
S waves oscillate the ground perpendicular to the direction of wave travel.
They travel about 1.7 times slower than P waves . Because liquids will not sustain shear stresses, S waves will not travel through liquids like water, molten rock, or the Earth's outer core. Two principal types of surface waves , Love and Rayleigh waves , are generated during an earthquakes. Rayleigh waves cause both vertical and horizontal ground motion, and Love waves cause horizontal motion only. They both produce ground shaking at the Earth's surface but very little motion deep in the Earth.