Seismic waves or Earthquake waves are basically of two types. They are body waves and surface waves.
Body waves: They are generated due to the release of energy at the focus and move in all directions travelling through the body of the earth. There are two types of body waves. They are called P and S-waves. P-waves move faster and are the first to arrive at the surface. These are also called primary waves. The P-waves are similar to sound waves. They travel through gaseous, liquid and solid materials. S-waves arrive at the surface with some time lag. These are called secondary waves. They can travel only through solid materials.
surface waves: The body waves interact with the surface rocks and generate a new set of waves called surface waves.