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

My World Icon
  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.

    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 eye check 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.
  • When you are done exploring how the layers work, turn off all the layers except Elevation & Bathymetry and U.S. States.
  • 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.
    4. 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.
    5. 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 zoom to active layer button in the toolbar.
    6. 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.) tsunami run up events now on map

    7. Repeat this importing and saving process with the tsunami source events.txt file.
    8. 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.
    9. When you are done you will have two new layers displayed on your map. both layers on map

    10. 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?
      • Are there locations that do not have tsunamis? Why do you think this is the case?
    11. 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

    Now that you have investigated tsunami sources and run-up locations, look more closely at the types of plate boundaries that generate earthquakes that can cause tsunamis.
    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 pan tool 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?
      • Are there areas where there are convergent plate boundaries that do not have many tsunami source events?
    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?
      • How many tsunamis run-ups have taken place along Eastern U.S. coastlines vs. Western coastlines?
      • Do you observe any other patterns on the map?
    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.
    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.
    4. This map shows the new layer that was generated.
    5. 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 Open table icon 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.
      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".
  • The selected tsunami events are now on the map and highlighted in yellow. Note the distribution of these larger tsunami events. Are they concentrated in certain locations?
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  • To prepare for Part 3, turn off all layers other than U.S. States and Oregon Border. Oregon is centered in the map view, and only these two layers should showing on the map.
  • Step 5 – Save the My World Project File with a New Name

    1. Now that you have added new data and changed the zoom level of the map, you will want to save your project a second time. Choose File > Save Project As... and name your project Tsunami Runup_Part2, or some other unique name. Then click the Save button.
    2. If this is the end of your session, quit My World GIS.
    If you have trouble downloading data or saving the project file, then use this completed (and saved) project file.
    Tsunami_Runup_Part2.m3vz ( PRIVATE FILE 12.3MB Nov8 10)
    Right-click (PC) or control-click (Mac) the link above to download the file.

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