During an earthquake two main types of body waves—primary (P) waves and secondary (S) waves—are generated and detected by seismographs.
(i) Define P-wave and S-wave.
(ii) For each, state whether it is a transverse or a longitudinal mechanical wave.
(iii) Explain, with reference to particle motion and the nature of the Earth’s outer core, why S-waves cannot travel through the liquid outer core whereas P-waves can.