Layers of the Earth and Earthquake lesson

Hi everyone!  I teach a multi level Adult Ed class in Western PA.  I recently did an Earth and Space lesson on the layers of the Earth.  Instead of a humdrum lesson, we began by talking about the recent earthquake activity in California and the projections that there will be a catastrophic earthquake on the west coast at some point.  One student Googled the largest earthquake in recorded history and read a bit about the 9.5 magnitude Chilean earthquake in 1960. We talked about why earthquakes happen, which allowed us to talk about the layers of the Earth in a way that tied the information to something everyone seemed interested in. 

We talked about the science of measuring earthquake strength which led to a brief math lesson on the Richter Scale and the more modern Moment Magnitude Scale which are both logarithm scales used to measure earthquakes.  I introduced logarithm scales, which helped everyone understand that a magnitude 8 earthquake is actually 10 times the power of a magnitude 7 (10 to the power of 7, versus 10 to the power of 8).   

We discussed tectonic plates and I gave everyone a map of the earth showing the tectonic plates superimposed on the continents.  We discussed the Ring of Fire in light of the California earthquakes, tsunamis caused by earthquakes, and why the location of the Fukashima nuclear power plant might not have been a good idea in light of the map.

I will return to this part of the discussion when we cover radiation in our physical science section, since the leak at Fukashima exposed a lot of people to radiation including US military members with cancer who assisted during the crisis and are now suing plant operators for lying about the radiation level.

We also discussed the fact that there are earthquakes in our part of the country, such as the recent ones in Ohio which some students felt.  We discussed the fact that the waves of an earthquake travel farther in the Northeast, since the rock here is older and more stable which allows these waves to travel further as opposed to the younger rocks on the West Coast which absorb the energy of the quakes and don't allow it to travel as much.  I can see that this lesson was endless, but we did have to stop at some point. That night, there was an earthquake in Chile with the Tsunami warnings which followed and students brought this information up at the next class. 

It would be great if all science lessons could tie in with something in the news, so it peaks students' interest. Thanks for reading!





Hi Mary:

Thank you for posting your lesson, Mary.  It is so true -- once started, the science connection carries everyone on and on.  You and your students used several of the "Eight Scientific Practices" but I want to highlight your use of mathematics and computational thinking via the logarithmic scale to measure earthquakes.  Khan Academy has an interesting video describing why the logarithmic scale is so helpful for measuring some phenomena, like earthquakes.

And, if you want to see where earthquakes are happening right now, visit the USGS Earthquake Map at  It looks like Perry (Oklahoma), Challis (Idaho), Soledad (California), and Ferndale (California) had earthquakes in the last day.



Hi Cynthia,

Thanks so much for your response. I really like the USGS website and will bookmark it for future class discussions. This is a good site not only for earthquakes, but graphic interpretation in general. It took me a few minutes to decide what I was looking at and how to change the data expressed. This site would bring up lots of questions about what we are seeing when we change the map layers. Other points to discuss could be latitude, longitude, map scale, plate boundaries, etc.  Khan Academy has a great way to explain things in understandable language. I enjoy reading other people explain things since we all need help in that department.

Thanks for all of your help!
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