# Global GIS Lesson: Part 4

### Exploring North American Earthquakes

By Joseph J. Kerski

#### Part 4: Investigating Your Community

In this part, the USGS needs you to report on your own community’s vulnerability to earthquakes.

Make the themes you have been working with the active theme by clicking once on it. Use shift-click to select multiple themes. Clear any previous selections using the clear selection tool .

Zoom to the state where you go to school (or your country if you live in Canada, Mexico, or Central America).

Make earthquakes the active theme by single clicking on it.

Label  the magnitudes of the earthquakes.

1. In what country do you live?
2. In what state or region do you live?
3. Describe what you consider to be the major natural hazards faced by your community, and where you consider earthquakes to be in this list of hazards.
4. Describe the pattern and the number of earthquakes in your country, state, region, and community.
5. Use the select feature button to draw a box around the earthquakes that are in your region or state. After selecting the earthquakes, access the table . Look in the box in the upper left that indicates how many earthquakes are selected. How many earthquakes occurred in your selected region? Include a description of how much land you included in your selection box in your answer.
6. How do the pattern and number of earthquakes in your area compare to what you learned earlier about the pattern and number of earthquakes in Alaska and California?

Examine the earthquake map theme legend.

1. What is the range (minimum and maximum) of earthquakes that you are examining?

In the Global GIS Tools box, select the Earthquake Tool.

Click the "Show Magnitudes Between Min and Max" button and set the minimum magnitude to 6 and the maximum to 9. Press "Reset Mag Range" to reset the map, as follows:

1. Where do most of the large (at least magnitude 6) earthquakes occur?
2. Do the large earthquakes have the same pattern of occurrence in North America as those that you examined earlier that included magnitude 4 and 5 earthquakes? Why or why not?

Zoom closer to your own community at a scale of approximately 1:700,000.

1. Now that you know how to move to specific earthquakes, generate a search radius, as follows:

Next, generate a report , generate a report for the earthquake nearest your community. Print the report and make at least five observations for your report for the USGS about the vulnerability of your own area—its population, roads, airfields, dams, and other critical infrastructure.

1. Describe the earthquake nearest your community: Indicate the location of your school and community area, the direction from your school, the date it occurred, the magnitude, the depth, and the time of day it occurred.
2. Does anything surprise you about the earthquake event? Do you remember the earthquake? Did it cause any damage? Ask someone in your community to determine if they remember it; if you can find someone, indicate their response. If not, do some research on the earthquake and report the findings.
3. Congratulations! You have completed the fourth part of the assignment and are contributing much to the understanding of earthquakes in North America. Indicate what you consider to be the most surprising thing you have learned in this part, the most interesting thing, and the most significant thing.