In this activity, you will use software called Seismic Eruption that plots earthquakes around the world to determine if there are any patterns to the depth and magnitudes of earthquakes. An earthquake is a sudden breaking of rock that results from stress building on a rock. However, only cold, brittle rocks are broken; if a rock is heated, it can deform over time instead.

Are there any patterns to the depth and magnitude of earthquakes 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.

1. Click the Plates button in the lower right to view the earth’s plates.
2. Look at the map key on the right-hand side of the map.
   
3. What color are the shallowest earthquakes? What color are the deepest earthquakes?
4. What size circles are the smallest earthquakes? What size are the largest?
5. Increase the EQ Cutoff number (to 6.5) by clicking the up or down arrow. Then click the Repeat button. How does the total number of earthquakes change?

1. Are there any earthquakes near divergent boundaries with depths greater than 150 km? Why do you think this is?
2. Identify three areas with many earthquakes deeper than 150 km.
3. In general, for the there areas listed above, how do the earthquake depths change as you move farther away from the boundaries?
4. Where do you see more large earthquakes (magnitude 7 or greater) near divergent boundaries or convergent boundaries?
5. Compare the locations of large earthquake (magnitude 7 or greater) to the location of deep earthquakes. Do they occur together or are they found in different places? Explain you findings.

What comments can you make about the patterns of earthquake depth along each of the different types of plate boundaries? Explain what might account for these different patterns.

The patterns of earthquakes are characteristic of the processes that occur in the area. How do the following process, one plate subducting under another plate and plates pulling away from each other, account for the patterns of earthquake magnitude and depth you observed?