There are three main types of seismic waves according to its characteristic speed and manner of travel:
Primary waves or P waves #rarr# travel the fastest #rarr# travel through solids, liquids, and gases #rarr# push-pull waves #rarr# causes rock to move back and forth.
Secondary waves or S waves#rarr#travel slower than p waves #rarr# travel only through solids#rarr# causes rock to move side to side.
Surface waves or L waves#rarr# slowest seismic waves #rarr# travel from the focus directly upward to the epicenter#rarr# move along the earth's surface up and down #rarr# cause the most of the damage during earthquake because they bend and twist the earth's surface.