What is the relationship between P- and S-waves?
they are both body wave types of seismic waves
seismic waves are of two kinds, Body and surface waves. Body waves are those which travel trough a rock body or the body of layer of earth. Surface waves are those which travel in between the interface of two layers of earth. P and S waves are types of body waves. they differ from each other in speed. P-waves are the fastest waves that travel inside earth and can travel in all mediums. S- waves cannot travel in fluids as they dont have shear force.