1. Double-click the ArcMap icon on your computer s desktop. 2. When the ArcMap start-up dialog box appears, click An existing map and click OK.

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1 Module 2, Lesson 1 The earth moves In this activity, you will observe worldwide patterns of seismic activity (earthquakes) and volcanic activity (volcanoes). You will analyze the relationships of those patterns to tectonic plate boundaries and major physical features of the earth s surface. Then you will identify cities at risk. Step 1: Open a map document 1. Double-click the ArcMap icon on your computer s desktop. 2. When the ArcMap start-up dialog box appears, click An existing map and click OK. 1

2 3. Navigate to the module 2 folder (OurWorld2\Mod2) and choose Global2.mxd (or Global2) from the list. 4. Click Open. When the map document opens, you see a map with three layers turned on: Continent Outline, Continents, and Ocean. The check mark next to the layer name tells you the layer is turned on and visible on the map. Step 2: Analyze earthquake locations You will now compare the predictions you made in the Supplement about earthquake and volcano locations to actual data using GIS. 1. Turn on the Earthquakes layer by clicking the box to the left of the name in the table of contents. 2

3 This places a check mark in the box, and earthquake points are drawn on the map. The points show the locations of earthquakes that occurred between January 2004 and April Q1 Q2 Do earthquakes occur in the places you predicted? List the regions you predicted correctly for earthquake locations. What patterns do you see on the map? Answers to questions in this activity should be recorded on the answer sheet. Step 3: Sort and analyze earthquake magnitudes You can take a closer look at the data behind the dots by looking at the attribute table of the Earthquakes layer. An attribute table contains specific information about the features in a layer. In the Earthquakes layer, each point represents an earthquake with a magnitude of 3.5 or greater on the Richter scale. You will focus on the 20 strongest earthquakes. 1. In the table of contents, right-click Earthquakes and click Open Attribute table. You see all the attribute data associated with the yellow earthquake points on the map. (Do not maximize this table it will prevent you from viewing the map at the same time.) 2. Scroll down to see more records. Remember, each record in this table represents one point on the map. 3. Click the field (column heading) labeled MAGNITUDE to select it. This field represents the magnitude of the earthquakes. Now you will put the magnitudes in order from largest to smallest. 3

4 4. Scroll up to the top of the table. Right-click the MAGNITUDE field heading and click Sort Descending. The records are rearranged from largest to smallest. Now you will select the 20 largest earthquakes. 5. Hold down the Ctrl key, click the small gray box to the left of the first record in the table, and drag your mouse until the first 20 records are highlighted in blue. To make sure you have highlighted 20 earthquakes, look at the status bar at the bottom of the table. It should look like the following graphic: If you select too many records, click the Options button at the bottom of the table, click Clear Selection, and try again. You can stretch the bottom of your table to make it easier to select 20 earthquakes. When you select a record in the attribute table, its point on the map will be highlighted also. 6. Move the attribute table out of the way so you can see where the 20 strongest earthquakes are located on the map. Q3 How do the 20 selected locations compare to your Supplement map? List three ways. 7. At the bottom of the attribute table, click the Options button and click Clear Selection. If you don t see the Options button, your table window may be too narrow. Widen your table window until you can see the Options button near the bottom right corner of the table. 8. Close the attribute table. 4

5 Step 4: Analyze volcano data 1. Turn off the Earthquakes layer and turn on the Volcanoes layer. Q4 How do the volcano locations compare with your original predictions? List the regions of volcanic activity you predicted correctly. Q5 What patterns do you see in the volcano locations, and how do they compare with the earthquake patterns? (Turn the Earthquakes layer on and off as needed.) The data includes volcanoes that are not active. You will focus on the active volcanoes. Step 5: Select all active volcanoes 1. In the table of contents, right-click Volcanoes and click Open Attribute Table. The Type field tells you if a volcano is active, potentially active, or solfatara (emits gases but is otherwise inactive). 2. Right-click the Type field heading and click Sort Ascending. Scroll down and you will notice that there are many active volcanoes. It would be difficult to highlight all of these, as you did with the Earthquakes layer. Instead, you will select all of the active volcano records at once. 3. At the bottom of the attribute table, click the Options button and click Select By Attributes. 4. You will complete the Select by Attributes dialog box working from top to bottom. Make sure Method is set to Create a new selection. Double-click Type in the list of fields. Click the equals sign (=). On the right-hand side, click the Get Unique Values button. Three values appear in the list of unique values. Double-click Active in this list. 5

6 The information now appearing in the lower area of the dialog box ( TYPE = Active ) is known as a query expression. 5. Click the Verify button near the bottom of the dialog box. If the expression is successfully verified, click OK. If you receive a syntax error, check that your equation is exactly like the one in the picture above. If it isn t, click the Clear button and try again. 6. At the bottom of the dialog box, click Apply. All the active volcanoes are selected and highlighted blue, both in the table and on the map. 7. Close the Select by Attributes dialog box. Close the attribute table to see the map. Use the Zoom and Pan tools or the middle scroll button on your mouse to explore where the active volcanoes are located. Q6 What pattern do you see? Q7 Formulate a hypothesis as to why volcano eruptions and earthquakes happen where they do. Step 6: Identify active volcanoes on different continents 1. Click the Identify tool. The Identify window displays. Click in the Identify from drop-down menu and select Volcanoes from the list. 2. Move your cursor over the map display. Notice how the cursor has an i next to it. 6

7 3. Click an active volcano on the map. The Identify window shows you the name of the volcano, its elevation, type, and country. For example: 4. Move the Identify window so you can see your map. Using the scroll button on your mouse, zoom in to the continent of your choice. Remember, you can zoom in and out by scrolling your mouse scroll button, and you can pan your map by holding down the scroll button and moving your mouse. Q8 Use the Identify tool to find the names, elevations, and countries of three active volcanoes. 5. Close the Identify window. 6. Click the Clear Selected Features button to unselect all of the active volcanoes. 7. Click the Full Extent button to see the entire world on the map. Step 7: Add the plate boundaries layer The earth is always changing. The crust of the earth is composed of several tectonic plates that are always on the move. The effects of movement are most noticeable at the boundaries between the plates. Q9 Based on the locations of earthquakes and volcanoes, where do you think the plate boundaries are? Draw them on the Supplement map. You will now investigate the locations of plate boundaries and their effects on adjacent physical features. The four basic types of plate boundaries are: Divergent boundary. One or two plates are splitting apart. New crust is being formed from the center of the earth, causing the plate to spread. Rift valleys are one example of this type of plate movement. 7

8 Convergent boundary. Two plates are colliding, forcing one plate to dip down underneath another one. The plate that is folding under has old crust that is being destroyed, while the plate on top has mountains and volcanoes being formed. In the ocean, these appear as trenches. Transform boundary. Plates are sliding against each other, causing large fault lines and mountains to form. Here, the crust is neither created nor destroyed. Plate boundary zones (zigzagged). Plate boundaries appear erratic (zigzagged). Scientists believe there are microplates in these areas, but it is unclear what effect they have on the physical environment. 1. Turn off the Volcanoes layer. 2. Click the Add Data button. 3. Navigate to the module 2 Data folder (OurWorld2\Mod2\Data). Double-click World2.gdb to open it. Click plates. 4. Click Add. The plates layer is added to your table of contents. 5. In the table of contents, click the symbol beneath plates. The Symbol Selector opens. 6. On the right side, click the Fill Color drop-down arrow and click No Color. This will create an outline of the plate boundaries. 7. Click the Outline Color drop-down arrow. Pause your cursor over a color to see its name. Click the Electron Gold color. 8

9 8. Increase the Outline Width to Click OK. The gold outline symbol appears in the table of contents and on the map. Q10 Compare the actual plate boundaries to the ones you drew on the Supplement map. Record all similarities and differences. Step 8: Add a layer file and an image In order to get a closer look at physical features and plate boundaries, you will add two more layers: Major Physical Features.lyr: a layer showing major landforms and ocean floor features of the planet Earth_wsi.sid: a color-shaded relief map of the earth made from a satellite image 1. Click the Add Data button and then click the Up One Level button to navigate to the Data folder. Double-click the LayerFiles folder to open it. 2. Double-click Major Physical Features.lyr to add it to your map. 3. Click the Add Data button and then click the Up One Level button to navigate to the Data folder. Double-click the Images folder to open it. 4. Click earth_wsi.sid once and click Add (a file with a.sid extension is a compressed image file). 9

10 5. In the table of contents, click earth_wsi.sid and drag it above the Continents layer. Q11 Are there any areas where physical features, plate boundaries, and seismic and volcanic activities overlap? 6. Identify physical features at plate boundaries (move the mouse pointer over a physical feature to see the Map Tip). Q12 Write the names of physical features in the first column of the table on the answer sheet and label them on the Supplement map. The first entry in the table is already completed for you as an example. 7. In the table of contents, right-click plates and click Label Features. You will make the text white and bold so the labels are easier to read. 8. Right-click plates and click Properties. Click the Labels tab. In the Text Symbol area, click the black color box and choose white. Click the Bold button. Click OK. Q13 In the second column of the table on the answer sheet, write how you think each physical feature was created. Refer to the descriptions of the types of plate boundaries on pages 7 and 8. 10

11 Step 9: Identify major cities at high or low risk for seismic or volcanic activity 1. Turn off earth_wsi.sid. Move the Major_cities layer to the top of the table of contents and turn it on. 2. Use the Zoom, Pan, and Identify tools to identify cities that have a high risk or low risk for an earthquake or a volcanic eruption. Q14 List five high-risk cities and five low-risk cities. Remember to turn layers on and off and move them around as needed. 3. Ask your teacher where to save this map document and how to rename it. If you are not going to save the document, choose Exit from the File menu. Click No when you are asked if you want to save changes. In this lesson, you used different layers to find the locations of earthquakes and volcanoes around the world. You were then able to identify cities at high or low risk for seismic or volcanic events. 11