Strain, Slip and Chance: teacher key

Earthquakes, grade 6 edition, written for 6th grade. Scientists cannot say when the next quake will come, but they can measure strain and size. See how rock slips, how quakes are measured and what the odds mean.

Read the book. Print this page for the key.

Questions and answers

1. What does magnitude measure?
   • How far you are from the epicenter
   • The size of the earthquake itself (answer)
   • How tall a tsunami grows
2. What can scientists figure out about future earthquakes?
   • The chance of them (answer)
   • The exact day
   • The exact hour
3. At what speed do the Pacific and North American plates slide past each other in California?
   • Ten feet a day
   • About two inches a year (answer)
   • Not at all
4. Why does magnitude stay the same from town to town?
   • Because it measures how hard each town shook
   • Because every town has a seismograph
   • Because it measures the earthquake itself, not the place (answer)
5. In the book, what does 'strain' act like?
   • A rubber band pulled too tight (answer)
   • A wave in deep ocean
   • A phone alert

Words

• strain: stretch that builds
• fault: crack in rock
• magnitude: quake size
• epicenter: spot above start
• seismograph: shaking recorder