Why the Ground Shakes: teacher key

Earthquakes, grade 4 edition, written for 4th grade. An earthquake is the ground shaking fast, and it starts with rock that breaks. Learn about plates, faults, tsunamis and the safe moves to know.

Read the book. Print this page for the key.

Questions and answers

1. What is a fault?
   • A crack in the rocks where one side can move past the other (answer)
   • A kind of rubber band
   • A giant ocean wave
2. What is the epicenter?
   • The place where plates stick
   • The spot on the ground straight above where an earthquake starts (answer)
   • The last aftershock
3. Why do plates stick at their edges?
   • Because of a rubber band
   • Because of tsunamis
   • Because of friction (answer)
4. Why should you go to higher ground after strong shaking near the ocean?
   • A tsunami may follow (answer)
   • The rock needs room
   • Aftershocks only happen up high
5. What does the rock do when the stress gets bigger than the friction?
   • It slips and sends out waves (answer)
   • It turns into a plate
   • It stops the shaking

Words

• epicenter: spot above start
• friction: rubbing that sticks
• plates: big crust pieces
• tsunami: giant ocean wave