NEPTUNE Canada

Quakes and Rocks (Grade 9)

Author: Betsy Hedberg

Learning Objective(s)

Students will gain knowledge of how and why earthquakes occur, what we can gain from studying previous earthquakes and how we can reduce the loss and damage from future earthquakes.

Introduction

Have a brief class discussion about the effects of earthquakes (tsunamis, landslides, construction damage, and loss of life). Do they remember any occurring recently/in the recent past? Ask for ideas as to how we can prepare ourselves for future earthquakes. Include – monitoring, earthquake proof buildings and preparation in the home.

Materials

• computer and Internet
• geological processes table
• vocabulary books

Activity

1. Have students research earthquakes using resources from the TheTech, PBS and USGS.
2. Ask students to write the following words in their vocabulary books and search the web to discover the meanings:
   1. aftershock
   2. amplitude
   3. asthenosphere
   4. convergent
   5. core
   6. crust
   7. divergent and transform plate boundaries
   8. epicentre
   9. fault
   10. lithology
   11. mantle
   12. Mercalli scale
   13. mid ocean ridge
   14. Pangaea
   15. seismic waves
   16. seismology
   17. subduction zone
   18. trenches
   19. tsunami
   20. Have students use the internet to help them fill in the following table to review the geological processes that are associated with earthquakes:

   Questions	Answers
   Why do earthquakes occur?
   Where do earthquakes usually occur?
   What happens underground during an earthquake?
   What happens on the ground during an earthquake?
   What are the three different types of plate boundaries?
   What is the difference between the magnitude and intensity of earthquakes?
   How is magnitude and intensity measured?

   Extension

   • Test students on the meanings of the new words. Ask all the students to hand in their vocabulary books.
   • Ask the students to stand up and when they are asked a word they must either describe the correct meaning of the word or repeat the correct spelling before they can sit down.
   • Have students pretend they are government officials – what is their city doing to protect the people against earthquakes, tsunamis, landslides and building damage?

   Assessment

   • Do the students fill in the table fully and correctly using the new vocabulary?
   • Do the students fully understand how earthquakes occur, do they use the new vocabulary?

   Answers to the questions

   Questions	Answers
   Why do earthquakes occur?	Pressure builds up in the crust as plates are being pushed and pulled between each other. The plate will bend to a certain extent and then when the stress exceeds the strength of the rock it will break generating a seismic wave (an earthquake).
   Where do earthquakes usually occur?	Earthquakes usually occur at plate boundaries.
   What happens underground during an earthquake?	Plates suddenly shift due to the build up of pressure at the boundary of the two plates.
   What happens on the ground during an earthquake?	Shock/seismic waves travel through the land, moving ground, creating cracks and destabilising land as well as the structure which are on top of it.
   What are the three different types of plate boundaries?	Convergent – involves subduction and plates moving towards each other. Divergent – involves seafloor spreading and plates moving away from each other. Transform – involves plates slipping past each other.
   What is the difference between the magnitude and intensity of earthquakes?	Magnitude is the amount the ground moves during an earthquake. Intensity is based on the earthquakes effects on man-made structures.
   How is magnitude and intensity measured?	Magnitude is measured on the Richter scale and Intensity is measured on the Mercalli scale.

   Related Website

   Adapted from Discovery Education lesson plan on earthquakes.

   Tags

   earthquake, earthquakes, plate movement, plate tectonics, plate boundaries, seismicity, seismology, seismometer, seismograph, subduction, tsunami, tsunami warning system, tsunami detection, tsunamis