What are seismic waves? what is their relationship to earthquakes?

Earthquakes generate three types of seismic waves: P (primary) waves, S (secondary) waves and surface waves, which arrive at seismic recording stations one after another. Both P and S waves penetrate theinterior of the Earth while surface waves do not.

When energy is released in the form seismic waves. the waves create movement forming an earthquake.

The answer is D it helped reveal changes in the position and apperance of celestial object