Part 2—Launch My World and Investigate Tsunami Patterns

Step 1 - Launch My World, Open the Tsunami Run-up Project File, and Practice Turning Layers On and Off

1. Launch My World GIS by double-clicking its icon on your desktop or by clicking its icon in the dock (Mac) or Launch Bar (PC).
2. Choose File > Open Project and navigate to the file, Tsunami Runup.m3vz. Select it and then click Open.
   
   Show me how
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   1. Launch My World GIS. A blank map appears.
      
      
   2. Choose File > Open Project.
      
      
   3. Navigate to the file, Tsunami Runup.m3vz.
      
      
   4. Select the file, Tsunami Runup.m3vz. Then click Open.
      
      
   
   
   
   When the project opens, a world map displays. It shows Elevation and Bathymetry with outlines of U.S. States overlaid on top. Layers not visible on the map include: Plate Boundary Types, Continents, Seaside Schools, Oregon Populated Places, Oregon Place Names, Oregon Highways, Tsunami Inundation Area, Seaside Topo, Seaside Aerial, U.S. Rivers, Countries, Lines of Latitude & Longitude, and the Oregon Border.
   
   
   
   
   
   
   
3. Practice turning layers on and off, and exploring active layers.

• To turn a layer on, check in the checkbox next to the layer's name in the Layer List. Layers that are on have an Eye in the checkbox, symbolizing that they are visible. The layers that are visible on the map above include: Elevation & Bathymetry and U.S. States.
• Turn on the Continents and Countries layers. Note that the Countries layer is hidden.
• Turn off the Elevation & Bathymetry layer; it is now possible to see the Countries layer.
• Notice that if you click in the area around a layer's name it turns white, with a yellow border. This indicates that the layer is active. When a layer is active it is the one that the software is engaged with when conducting more in-depth processes. In the map pictured in the example below, the U.S. States layer is both active and visible.
  Show me an example
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  In the map displayed below, the Elevation & Bathymetry layer has been turned off. The U.S. States layer is both active and visible. Click on the image for a larger view.
  

  

  
  
  

Step 2 - Import Tsunami Run-up and Source Events and Look for Patterns

1. Choose File > Import Layer from File and locate the tsunami_runup_event.txt file that you downloaded in Part 1. Single click to select the file, tsunami_runup_event.txt, and then click Open.
2. The Import Text Data window checks that the Latitude and Longitude fields are correct, which they are, so click OK.
3. A new window opens asking where you want to save the file. Navigate to the location where you are saving your GIS data, or leave the default location as the My World data folder, and click Save.
My World GIS imports the .txt file, places it on the map, and saves a copy in the My World "data" folder on your computer.
4. The new data layer should now be visible on the map and in the Layer List. Make it the Active layer and click the Zoom to Active Layer button in the toolbar.
Show me how to add a layer
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1. Choose File > Import Layer from File...
   
2. Locate the .txt file that you downloaded in Part 1. Single click to select the file, tsunami_runup_event.txt, and then click Open.
   
   
3. The Import Text Data window checks that the Latitude and Longitude fields are correct, which they are, so click OK.
   
   
4. A new window opens asking where you want to save the file. Navigate to the location where you are saving your GIS data, or leave the default location, the My World data folder, and click Save.
   


The map now displays the tsunami_runup_events data as blue dots. (Note: your color may be different as My World randomly assigns a color when it imports data.)



5. Repeat this importing and saving process with the tsunami source events.txt file.
6. When you are done importing the layers, edit their appearance. Change the shape of the tsunami source event dots to red stars, and re-label the layer: Tsunami Source Events. Change the tsunami run-up events to blue circles, and re-label the layer: Tsunami Run-up Events.
   Show me the how to edit the appearance of a layer
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   1. Double click on the layer name in the Layer List. An Edit Appearance of Layer window will open.
   2. Change the Layer Name to "Tsunami Source Events", then change the dots to a red star. Click Apply and Close when you are done editing.
      
When you are done you will have two new layers displayed on your map.



7. For the moment, turn off (hide) the Tsunami Source Events layer and look for patterns in the run-up data. While exploring the data, consider the following questions:
   • How are the tsunami run-up events distributed around the world?
     Show me the answer
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     Tsunamis occur on almost all shorelines, including the Great Lakes. They are more frequent on the Pacific Ocean coasts than the Atlantic.
   • Are there locations that do not have tsunamis? Why do you think this is the case?
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     There are very few tsunamis in the Arctic Ocean. The tectonic boundaries there are generally inactive.
8. Turn on (make visible) the Tsunami Source Events layer and look for patterns and relationships between tsunami sources and run-ups.

Step 3 - Turn on Plate Boundary Types and Look for Relationships in the Data

1. To make the map a little simpler to interpret, turn off the Elevation & Bathymetry layer.
2. Turn on the Plate Boundary Types layer.
3. Turn layers on and off, and use the Move Map tool to move around the map to search for relationships between Plate Boundary types, Tsunami Source Events, and Tsunami Run-up Events. While exploring, consider the following questions:
   • Do tsunami source events appear to be located more often along any particular plate boundary type?
     Show me the answer
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     Tsunami source events tend to cluster around convergent plate boundaries, such as in Indonesia.
     
     
   • Are there areas where there are convergent plate boundaries that do not have many tsunami source events?
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     There have not been many tsunami source events in the Arctic Ocean.
4. Turn on the U.S. States layer and use the Zoom In tool to zoom in to the United States. While exploring the map, consider the following questions:
   
   
   • How many earthquakes have taken place along the in Eastern U.S. coastlines vs. Western coastlines?
     Show me the answer
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     More earthquakes have taken place on the Western U.S. coastline.
   • How many tsunamis run-ups have taken place along Eastern U.S. coastlines vs. Western coastlines?
     Show me the answer
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     The Western U.S. has had many more tsunamis due to the fact that, in general, there are more earthquakes in the Pacific Ocean basin.
   • Do you observe any other patterns on the map?
     Show me a possible answer
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     Both tsunamis and earthquakes appear to be rare (non-existent) in Gulf of Mexico.
5. In order to study the area related to the Case Study scenario, you will narrow the focus to the Oregon coast. Use the Zoom In tool to zoom in to the U.S. West coast, and finally to Oregon. Turn off the Plate Boundary Types layer and turn on and make active the Tsunami Run-up Events layer.

Step 4 - Use Analyze Mode to Investigate the Historical Tsunami Records for Oregon

1. Click on the Analyze tab. In Analyze mode, choose Select...By Value.
   In the panel to the right, make the following choices:
   • Select Records from: Tsunami Run-Up Events.
   • Whose: State Is OR (Oregon).
   • Check the box Make Selection a New Layer. Type "Oregon Tsunami Events" in the Result Name field. Click OK.
     Show me the dialog box
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2. A new layer will appear on the top of the Layer List. This new layer is a subset of the original one, it contains only the Oregon Tsunami Run Up Event data. If necessary, use the drop-down menu to change the Legend to the following:
   Color: Uniform and blue.
   
3. Turn off (hide) the original Tsunami Run Up Event layer with all the data.
This map shows the new layer that was generated.


4. Next, find the largest tsunami run-ups in Oregon.
   • Turn on and make the Oregon Tsunami Events layer active. Click the Show Table of the Active Layer button to explore the data in the layer. You will notice there are now 93 records in the layer (this number is in the upper left-hand corner of the table).
   • Open the table of the layer, scroll across the table to find the water height field, Water_HT.
   • Sort the table by Water_HT. When you have the data sorted in descending order, hold down the shift key, and click on the rows to select all the tsunamis that had a Water Height (Water_HT) of 3.0 meters or larger. Then click the Make Selection from Rows button. This will make a selection showing only the larger tsunamis. There are seven records in this new selection.
   In the table of the layer, note the dates and locations of this group of larger tsunamis. Recall that there are many small undetected tsunamis on the coasts; this set of tsunamis was considerably larger than average. Examine the data table and note that all but one are due to the same March 1964, "Good Friday" Earthquake.
   • When you are done exploring the data table, close the Table of Layer window.
   Show me how to make a selection from rows.
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   1. Open the Table of the Layer, then scroll across the table until you locate the Water_HT field. Click on the header of the field to sort the data in the column, ascending or descending.
      
      
   2. Once the data is sorted descending (largest values on top), hold the shift key and select the records that have a water height greater than three meters.
      
      
   3. Click the Make Selection from Rows button and give the selection a new name, "water height > 3 meters".