Here's why:

* Earthquakes are the primary source of seismic waves. When an earthquake occurs, it releases energy that travels through the Earth as waves.

* There are different types of seismic waves:

* P-waves (primary waves) are compressional waves that travel fastest and can move through solids, liquids, and gases.

* S-waves (secondary waves) are shear waves that are slower than P-waves and can only travel through solids.

* Surface waves travel along the Earth's surface and are slower than P- and S-waves. They are responsible for the most damage during earthquakes.

Since the energy released by an earthquake radiates outward in all directions, the seismic waves travel in all directions as well.