Why It Matters: Earthquakes

Interpret types, causes, effects, and scientific measurements of earthquakes and seismic waves


Have you ever wondered why California or Japan has so many earthquakes? Have you ever been in an earthquake and felt the solid ground shake beneath your feet?

Imagine you are going about your normal routine for the day and it is time for you to wrap up your day to head home. As you start gathering your things to take home and work your way out to your car, the following happens (note that this video and the next contain no significant audio):

This earthquake measured a 9.0 on the Richter scale and was the most powerful earthquake to hit Japan and the fourth most powerful recorded by humans. Aftershocks numbered over 1,000, with some over a 6.0 on the Richter scale. Almost 16,000 people died, over 6,000 were injured, and 2,500 were missing. The earthquake also damaged a nuclear facility causing major radioactive leaks. The World Bank estimated the economic cost of damage at $235 billion!

Once the shaking subsided, the following happened:

Learning Outcomes

  • Investigate the causes and common locations of earthquakes
  • Compare and contrast properties and mechanics of different types of waves
  • Define and compare magnitude versus intensity.
  • Understand the hazards of earthquakes and recognize our limited ability to predict seismic activity.


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