Explanation:
The main characteristics that will determine the wave that will arrive at a seismic station first is the velocity of the wave.
Both S and P - waves are known as body waves as they travel through a body.
P-waves are primary longitudinal waves that uses a series of rarefactions and compressions to propagate parallel to the medium. They have the fastest velocity of all seismic waves. So they arrive at the station first.
S-waves are secondary or shear waves. They are transverses waves. They are the second waves to arrive a seismic station.
