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 ArcGIS software and the Africa Lesson data (Download the Data for Activities 4-7).
Step 1.Let's make a map in ArcGIS showing the locations of large earthquakes, recently active and historic volcanoes, earthquake faults, and population densities in Africa. Open ArcGIS and start with a new empty map.
Step 2. Use the Add Data tool ; to add the following shapefiles: country.shp, popden.shp, faults.shp, afr_eq.shp, volrecen.shp and volafr.shp
Step 3. Now let’s rename the layers. Right-click on the layer name, select "Properties" and click on the "General" tab to rename the layers. You can enter the new name in the box next to "Layer Name".
Step 4. Arrange the layers 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 layer: 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 layer to access the Layers Properties and click on the "Symbology" tab. Click on "Categories" and select "Unique Values". Under Value Field, select "Type" and click "Add All Values". Click "Apply" and close the Layer Properties dialog box. Click on the line symbol next to the value "rift" to bring up the Symbol Selector. Change the size to 2 and choose a bright green color. Next, click on the line symbol next to "thrust-fault" and change the size to 2 and choose a light blue. Click "OK" in the Layer Properties to apply your changes to the view.
Step 6. Now let’s display the Population Density layer as a Graduated Color. Double-click on the Population Density layer to bring up the Layer Properties and click on the "Symbology" tab. Click "Quantities" and select "Graduated Color". Choose "Density" for the Classification Field, and click "Apply" and close the Layer Properties dialog box.
A). Which countries 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 layers:
B) Where (country) and when (year) did the last volcano erupt? Hint: Sort one of the fields in the Volcanoes Attribute Table in descending order.
C) Which country in Africa has the most historic volcanoes?
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. To create a map layout go to View —> Layout View. Select a few different layer 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 double clicking on the countries layer, click the "Labels" tab, and put a check mark next to "Label Features in this layer"), or a map showing just Earthquakes and Faults.
Save your project and exit ArcGIS.
*** End of Africa Activity 5 for ArcGIS ***
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