which seismic waves compress and expand rocks in the direction the waves travel
Different types of seismic waves include: Surface waves: Seismic waves that travel along the Earthâs surface. Body waves: Seismic waves that travel through the Earthâs interior. There are two types: Primary waves (P waves): Body waves that compress and expand rock in the direction the waves travel (like a slinky). Secondary waves (S waves): Body waves that shake material at right angles to the direction the waves travel (like shaking a rope). Solid rock transmits S waves, but gases and liquids do not.