National Teachers Enhancement Network: Lesson Plan

Mountains in Chile caused by convergent plate motion

Lesson Plan: Earthquake Depth
Subject: Earth and Space / Geology / Plate Tectonics
Classtime: 3-5 50-minute class periods
Grade Level: 9-12

Materials/Technology:

computer with internet access
MSExcel (or other spreadsheet)
colored pencils
folder in which to place project

Safety, Handling, Disposal:
Close supervision is strongly recommended when students are conducting searches on the Internet. Inappropriate sites are easy to access either by mistake or on purpose.

Learner Outcomes:
Students should be able to:

Use a search engine to find resources on the Internet.
Interpret a map and record information accurately on it.
Transfer latitude and longitude lines to a map.
Use an Internet map viewer as a tool of learning.
Use computer technology to gather information.
Locate and place earthquake epicenters on a map using latitude and longitude.
Determine if the depth of an earthquake has any relationship to the distance from a plate boundary.

Problem/Purpose:
Does the depth of an earthquake have any relationship to the distance from a plate boundary?

Background/Inquiry:
All around the Earth the surface is in motion. We can not see it move because the motion is so slow. Over time, however, the surface is moving hundreds and thousands of miles. The surface is not all moving in one direction, but is broken into many sections called 'plates' that move in different directions. The plates move toward each other at an extremely slow rate, and over time forces exerted will cause something to shift or break - what we call an earthquake.

Fig. 1 Map of the Earth's surface and the major plates

Vocabulary List: Here.

Hypothesis: Example - 'Deeper earthquakes will be closer to the plate edge.'

Procedure:
Geologists say that as an oceanic plate collides with a continental plate, the oceanic plate will be pushed under the continental one. Study the diagram below to learn more. (It is suggested to go through procedure steps 1-7 together with the class to demonstrate the techniques of this exercise. After this, the students will be prepared to analyze a plate boundary on their own.)

Fig. 2 Convergent plate boundary

Use the computer and Internet, your textbook, or this map to find an area where an oceanic plate is moving toward a continental plate. One such place is along the west coast of South America from 20 degrees South to 30 degrees South.
Look at the direction of plate movement and write the longitude and latitude of a 10 degrees N-S by 20 degrees E-W rectangle from the boundary in the direction of movement.
Use the ArcExplorer Web to draw a map that includes the area you want. Begin by loading an appropriate map service into the right-hand window. On the toolbar, click the "Add Services" button (the fifth from the right, with a "plus" sign on it. A pop-up window appears. From the "Look In" drop-down list, select ESRI. Click OK. An Add Services pop-up window appears. Scroll down the list and select "ESRI_Land". Click Add. Click Close. A map loads into the right window. Students will have to click and zoom in on the area that they want to look at. Students may have to "click and zoom" several times times in order to get a map that is a 10-degree N-S by 20-degree E-W rectangle. If ArcExplorer is not working, try this one.
Print a copy of the map. Use an atlas or Chile map to label the lines of longitude and latitude on your map.
Students find information about the earthquakes in their area of study by looking at NEIC Earthquake Search (*Note: A bit of study and experimentation on this page is required to learn how to use it. Be sure to scroll to the top!). When they have found data for at least 50 quakes, save the information to their folder as "quakeinfo." (Note: students could keep a computer folder for their work or a paper folder or both.)
Students print a copy of their "quakeinfo."
Students plot the locations of the earthquakes on their maps using a green pencil for the shallow quakes, yellow pencil for the medium quakes, and red pencil for the deep quakes. (Use 0-50Km as shallow, 51-100Km as medium and >100Km as deep)

Results/Analysis:
The following tasks should be completed in order in the student's hardcopy folder or packet.

Print a copy of the map obtained from Xerox PARC Viewer.
Label the lines of latitude and longitude on map.
List at least 50 earthquakes from NEIC Earthquake Search for your map.
Plot the location of all 50 earthquakes on your map with colored pencils.

Conclusions:
Does there seem to be any relationship between the distance from a plate boundary and the depth of earthquakes? Explain using data from your maps.

Does your map look like this one? (only if your location was South America!)

Assessments: None

Integration: None

Reflections:
Share your thoughts on this lesson with the NTEN team.

Please send an e-mail to Patti Harrison.

Extensions:
(1) Are there any volcanoes in the area you studied? If so, name them. Are they active today? (Check here to find out.)

(2) Use MSExcel to plot the depth vs. distance from the plate boundary. Hint: use a wizard to help if you're unfamiliar with the great graphing capability of the program.

References/Resources:
URLs used:

ArcExplorer Web
NEIC Earthquake Search: http://wwwneic.cr.usgs.gov/neis/epic/epic_rect.html#NEIC Earthquake Search
Volcano search: http://volcano.und.nodak.edu/vw.html

Credits
Contributing Teacher: David Fish
NTEN Course: K-12 Earth Science
Instructor: Jerry Nelson
Teaching Assistant: Bill Ochs
Developing Team:
T.L. Buck Buchanan, Cathy Hensel, Patti Harrison, John Usher, Don Wilson
HTML Programmers: Christy Cousineau, John Usher, Ching-Kwong Chia

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