A seismic station recorded the P-wave, but no S-waves, from an earthquake because S-waves were what?

P-waves are the primary seismic waves generated during an earthquake. They are the fastest and they are the first waves that arrive at the seismic station. S-waves are the secondary waves. They travel through solids but not through liquids or gases. This is evidence that the outer core does not behave like a solid substance.