Compared to P waves how is the speed of S waves generally?

Correct answer: Slower

The direct answer is A: S waves are slower than P waves. Earthquakes produce different seismic waves. P means primary because these waves usually reach a recording station first, while S means secondary because they usually arrive later. The main reason is speed: P waves are compressional waves and can travel through solids, liquids and gases; S waves are shear waves and travel only through solids. Therefore, when both move through the same suitable material, P waves generally have a greater speed than S waves. Option A is correct because slower means that S waves take more time to cover the same distance. Option B is wrong because S waves do not normally move faster than P waves. Option C is wrong because their speeds are not equal; the difference in arrival time is useful to scientists. Option D is wrong because S-wave speed is not zero in solid rocks, although S waves cannot pass through liquid layers. The accurate memory cue is: P comes before S, so P is faster and S is slower.