Answer:
Primary and secondary waves both are body waves of seismic waves. Primary waves or pressure waves are compression waves and secondary waves are shear waves. These waves are represented by P and S waves respectively.
Differences:
P waves are smaller in size but travel faster, however, cause less damage whereas S waves are greater in size cause more damage, and travel slower.
P waves move in a push-pull pattern and travel through different mediums like solids, liquids, and gases, whereas S waves move in an up-and-down pattern and travel only through one medium that is a solid medium.