Earthquakes
There are three different types of seismic waves:
Recent earthquake example: http://en.mercopress.com/2016/11/04/earthquake-hits-central-chile-but-no-tsunami-alert
- Primary waves (P-waves): moves out of the focus, fastest out of all the three, move back/forth, push/pull, and has longitudinal waves (like a slinky).
- Secondary waves (S-waves): slower than P-waves, can only move through solid rock, move out from the focus, side/side, up/down, right angle to P-waves, and has transverse waves (like a snake).
- Surface waves (L-waves): formed when P and S waves reach the Earth's surface, causes ground to shake, and side to side plus roll like an ocean wave.
Recent earthquake example: http://en.mercopress.com/2016/11/04/earthquake-hits-central-chile-but-no-tsunami-alert