Goal: In this lesson you will examine the locations of earthquakes and volcanoes in relationship to faults, and the impact on the countries in Africa to gain a better understanding of the human dimension of natural hazards in Africa.
GIS Skills Involved: Map symbolization and creating map layouts
Materials:To complete this lesson you will need ArcView software and the Africa Lesson data (Download the Data for Activities 4-7).
Step 1. Let's make a map in ArcView showing the locations of large earthquakes, recently active and historic volcanoes, earthquake faults, and population densities in Africa. Open ArcView and click "OK" in the pop up window (this will create a new project with a new view). The next screen will ask if you would like to add data to the view. Click "Yes" and add the following shapefiles (navigate to the folder where you saved the Africa Lesson data and hold down the shift key to add more than one shapefile at a time): country.shp, popden.shp, faults.shp, afr_eq.shp, volrecen.shp and volafr.shp. Put a check mark next to each one to make them visible.
Step 2. Choose "Properties" from the View pulldown menu and rename the view to "Faults, Earthquakes, and Volcanoes in Africa". Click OK.
Step 3. Now let’s rename the themes. Make the theme active by clicking on its name (i.e., its name appears raised). From the Theme pulldown menu choose "Properties" and change the name. Do this for all themes:
Step 4. Arrange the themes so they are in the following order – Recent Volcanoes, Historic Volcanoes, Earthquakes, Africa Faults, County, and Population Density.
Step 5. There are two types of faults in our Africa Fault theme: normal faults (referred to here as rift faults) and thrust faults. Let’s display them both as Unique Values. Double-click on the Africa Faults theme to bring up the Legend Editor. In the Legend Editor window select "Unique Value" as the Legend Type and "Type" for the Values Field. Double-click on the line symbol next to the value "rift" to bring up the Pen Palette. In the Pen Palette window change the size to 2. Click on the paintbrush icon to bring up the Color Palette and choose a bright green. Next, double-click on the line symbol next to the value "thrust-fault" and change the size to 2. Click on the paintbrush icon to bring up the Color Palette and choose a light blue. Click Apply in the Legend Editor to apply your changes to the view.
Step 6. Now let's display the Population Density Theme as a Graduated Color. Double-click on the Population Density theme to bring up the Legend Editor. In the Legend Editor window select "Graduated Color" as the Legend Type and "Density" for the Classification Field. Select "Yellow Monochromatic" for the Color Range (see image below). Click "Apply" in the Legend Editor to apply your changes to the view.
A) What areas in Africa have high population densities (6-9), and also have some risk from earthquakes and volcanoes?
Step 7.Change the colors, sizes, and symbols of the remaining themes:
B) Where (country) and when (year) did the last volcano erupt? Hint: Sort one of the fields in the Volcanoes Theme Table in descending order (it might also help to turn the other themes off so you see just the volcanoes).
C) Which country in Africa has the most historic volcanoes (to see country names make sure the Country theme is selected and use the Identify tool to find the country name)?
D) Which country in Africa has the most recent volcanoes and is most at risk from volcanoes that may erupt in the future?
Step 8.Create and print a few different map layouts. Select a few different theme combinations and print the layouts. For example, you can make a map showing recent and historic volcanoes and countries (turn the country labels on by going to Theme —> Auto-Label), or a map showing Earthquakes and Faults.
Save your project and exit ArcView.
*** End of Africa Activity 5 for ArcView ***
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