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Global GIS Lesson:
Exploring North American Earthquakes
By Joseph J. Kerski
Part 1: What's Shakin?
In this part, you will examine earthquakes across North America, noting their distribution, magnitude, and depth, and also examining certain regions on the continent.
After accessing the Global GIS interface, you will be viewing the "G" part of GIS with the map on the right side and a set of tools across the left and the top.
Turn off (uncheck) all themes except for the following:
Access the Movies, 3D menu at the top and run nam_eq_anima.avi. Use the slider bar to position the movie at specific years you wish to investigate further.
Close the movie and return to your GIS. Now you can further analyze the earthquake theme and draw some conclusions.
Make volcanoes visible by checking the box to the left of the theme name.
Single click on the earthquakes theme so that it becomes raised up, or “active.”
Each row in the table represents one earthquake in the dataset.
Click on the "magnitude" field and sort it in descending order .
Navigate to the top of the table and click on the row containing the earthquake with the highest magnitude to select it. You may have to select the black selection arrow to select a row . The row will appear in yellow.
Close the table. In the Global GIS Tools box, on the right side of Viewing Tools, go to “More Tools.” Select the "Zoom to Selected" tool in the Global GIS Tools box:
Use the "zoom into center" button a number of times to zoom into your selected earthquake .
Turn on the themes political boundaries, and political boundary labels.
Access the earthquakes table again and clear your selection .
Select the field "km" in the table. This represents the depth of the earthquakes in kilometers underneath the surface.
Click on the "km" field and sort it in descending order . Navigate to the top of the table and click on the row containing the earthquake with the greatest depth to select it. The row will appear in yellow.
Close the table and select the "Zoom to Selected" tool in the Global GIS Tools box . Use the "zoom into center" button a number of times to zoom to your selected earthquake.
Pan to the United States.
Pan to the western side of the United States to the area of California. You could turn on the US Counties theme to see California counties all in the same color.
Turn on major cities and turn off earthquakes. You might have to zoom in to see the labels.
Zoom to the center of the Pacific Coast of the United States, central California and Nevada.
Use the "Create Profile" tool and draw a line from Carson City, Nevada, southwest to San Francisco, California. Choose to profile the data set “elevation.”
Turn earthquakes back on.
Zoom out to California, turn off earthquakes, and note the location and names of the 6 major cities. Turn earthquakes back on.
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