Complex sentence: Rayleigh waves are generated by the interaction of P-and S-waves at the surface of the earth, and travel with a velocity that is lower than the P -, S -, and Love wave velocities.
Split into simpler sentences: Rayleigh waves are generated by the interaction of P-and S-waves at the surface of the earth. Such Rayleigh waves travel with a velocity that is lower than the P -, S -, and Love wave velocities.