In this activity you will look at patterns of earthquakes below earth’s surface and relate them to plate movement. You will create cross-sections.

How does the direction of plate movement relate to the patterns of earthquakes observed around the world?

Download Seismic Eruption from http://www.geol.binghamton.edu/faculty/jones/

Scroll halfway down the page and look for the following link: SeismicEruptionSetup.exe. Click on that link and the software will download to your desktop.

NOTE: Seismic Eruption software runs on PC’s only.

This activity addresses NSES standards for earth and space science and inquiry at grades 5-8 for structure of the earth system
(http://books.nap.edu/readingroom/books/nses/6d.html#es).

1. Click the Seismic Eruption icon on your desktop.
2. Click the Start button in the middle of the page. A new window will come up. Click the Go at the bottom of the page. A second window will open.
3. Click the World button in the center of the screen to watch all earthquakes that have occurred in the world from January 1, 1960, until the present time.
4. Set the program to display six months per second by clicking the up arrows on the speed control below the map.
   
5. Go to the Control Menu, select Time to Pause at end… A dialog box will appear. Type as many 9s in the box as you can.
   
6. Observe the earthquakes as they are plotted around the world.

The three different types of plate boundaries are identified according to the plate motions at the point of contact. Draw a sketch of the different types of boundaries (convergent, divergent and transform).

1. Go to the Control Menu and select “Set-up Cross-Section View.”
   
2. Click anywhere on the map. This will cause an icon like the one below to appear. (Move the icon to any location by clicking and dragging it.)
   
3. Now change the length and width of the box. Increase the number in the length window to 1500 and width to 500 by using the arrows or typing in numbers.
4. Click the Redraw button and watch what happens to the icon.
5. Change the azimuth. (It will change how the red line is drawn in comparison to the bottom of the screen.) Change the azimuth numbers to 20, 0 and -20 and click Redraw each time.
6. Place the cross-section tool anywhere along a plate boundary. Be sure to place the azimuth so that it is perpendicular to the plate boundary and crosses over the plate boundary. You want the boundary to be in the center of icon. Then click the OK button.
   
7. View the cross section by going to the Control Menu, selecting “Map View/3-D/Cross-section” and clicking the “Cross-Section View.”
8. Open a blank Word Document. Save it to your desktop or wherever your teacher tells you with your name, your class period, and the Title: PlatePictures_YourName_ClassPeriod.doc (for example, PlatePictures_Amy6.doc).
9. Use the world map and the cross-section tools to collect screenshots of cross-sections from two convergent, two divergent and two transform plate boundaries. To collect images: To do this you will need to take screenshots. On a PC, click the “Print screen” (PrtScn) button on your keyboard, which saves the image to your clipboard. Paste or insert the image in the Word document.
10. Type a caption below each screenshot describing where in the world the image was taken and what type of plate boundary is represented; also describe the frequency of earthquakes, the magnitude, depth and location of earthquakes (do earthquakes fall on the boundary, near the boundary?).
11. Print your “Plate Pictures” document.
12. On each cross-section picture use a pen that draws on black paper to draw the plates in relationship to the earthquakes. (If you don’t have a pen that draws on black paper, draw a picture next to the image.)

1. Describe how the movement of plates along a divergent boundary accounts for the patterns of earthquakes you have been describing?
2. Describe how the movement of plates along a convergent boundary accounts for the patterns of earthquakes you have been describing?
3. Describe how the movement of plates along a transform boundary accounts for the patterns of earthquakes you have been describing?

Geologists like to analyze problems (such as the geologic history of an area, the layers and patterns of rocks below the earth’s surface, or the movements of plates on earth) by constructing cross-sectional views.

1. Why is using the cross-section tool so important for geologists?
2. What did you find out using the tool that you thought was harder to figure out without the tool?

There are three different kinds of convergent boundaries. Compare the earthquake patterns. For example, are the earthquake patterns for oceanic-continental convergent boundaries the same as those for oceanic-oceanic convergent boundaries or for continental-continental convergent boundaries? Use the Seismic Eruption software to investigate this question.