Why are p waves called push up waves

P waves are called push-pull waves because they move along a horizontal path. As they do this, they expand and contract material.

The P wave can move through solid rock and fluids, like water or the liquid layers of the earth. It pushes and pulls the rock it moves through just like sound waves push and pull the air ... P waves are also known as compressional waves, because of the pushing and pulling they do.