Book 12, Question 27
Why Does the Ground Wave in a Quake?
An earthquake sends out waves, just like a pebble makes ripples in a pond. Different waves move the ground in different ways. The waves travel through the ground, but the ground itself stays in place.
More fun facts
- Earthquakes send out seismic waves that shake the ground as they travel.
- Waves that travel through the inside of Earth are called body waves.
- P waves are the fastest and shake the ground first.
- S waves travel about 60 percent as fast as P waves and always arrive after them.
- Some waves move the ground side to side, at right angles to the direction they travel.
Sources: U.S. Geological Survey, U.S. Geological Survey, Exploratorium
Questions kids ask
Why does a quake feel like a jolt and then rolling?
Fast P waves arrive first, then slower S waves and other waves follow.