Secondary Wave

Real World Example

Imagine standing in a line at a concert where the crowd is so eager that they start to push and pull, causing you to sway up and down with their movements. This is similar to how secondary waves, or S-waves, in an earthquake move the ground up and down as they travel through it. Just like how the crowd's energy causes you to move without you having direct control, S-waves transfer energy through the Earth, causing the ground to oscillate vertically, much like your body does in that concert line.