Week 7: Investigating Earthquake Activity

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Getting to Know Spatial Querying in AEJEE

So far in this course, you have practiced querying, classifying, and symbolizing data. All of these efforts helped you to sort and organize the data displayed on the map so that you could look for relationships and patterns in data. Now you will use spatial and database querying to sift out even more details about the earthquake events of 2009.

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Launch AEJEE and Open the Earthquakes Project

AEJEE_logo
  • Launch AEJEE by double-clicking its icon on your desktop or by clicking its icon in the Dock (Mac) or Launch Bar (Win).
  • Choose File > Open, navigate to ESRI/AEJEE/Data/EarthquakeAE, select the E_QuakesAE.axl file, and click Open.
  • A global map opens, showing Continents, US States, and Lines of Latitude and Longitude.




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Add Earthquake Data From 2009

If you worked through the "Introduction to Mapping Tabular Data" section, then you can use the Add Data button to bring up the previously mapped earthquake data. Otherwise, you'll need to use Add Event Theme to map the 2009 earthquakes.

Choose ONE of the following two options to add 2009 earthquake data to the map.
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    Add 2009 earthquake data as a shapefile


  • Click the Add Data button add layer button .
  • Navigate to the csv_files folder. (Path: ESRI/AEJEE/Data/EarthquakesAE/csv_files)
  • Choose the 2009EQ.shp shapefile that was automatically created and saved in the previous section.
  • Click OK.
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    Map 2009 tabular earthquake data by longitude and latitude coordinates

  • To map the 2009 earthquake events using Longitude and Latitude coordinates:

    • Choose View > Add Event Theme to open the Add Event Theme window.
    • Click the Browse browse button button and navigate to the file named 2009EQ.csv. (Path: ESRI/AEJEE/Data/EarthquakesAE/csv_files).
    • Choose the 2009EQ.csv file and click OK.
    • Choose Longitude for the X Field and Latitude for the Y Field.
    • Draw the events using symbols that are Blue Circles with a point size of 5.
    • Use the default Output Directory.
    • Click OK.

    The 2009 Earthquakes will now be displayed on the map.


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    Think Spatially about Earthquake Data

    Begin by brainstorming questions that could be asked when thinking spatially about earthquakes. Some examples of questions you might ask:

    • How many earthquakes occurred in Chile in 2009?
    • Do all earthquakes occur near plate boundaries?
    • How far is a given earthquake from a major city?
    • Do earthquakes occur more frequently near coastlines?
    • Are there more earthquakes at certain elevations?
    • Do earthquakes appear to be more common in one geographic region than another?
    • Are the deepest earthquakes more common around one type of boundary than another?
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    Carry Out a Simple Spatial Query

    On September 30, 2009 a Magnitude 7.5 earthquake struck Sumatra, Indonesia. The quake originated at a moderate depth of 81 kilometers. At the surface, over 1100 people were killed and 2650 buildings were damaged in the earthquake and subsequent landslides. Power and communications were disrupted. The earthquake was felt over a wide area and produced a small tsunami.

    Imagine that you worked for an international disaster aid organization, and wanted to quickly identify Indonesian cities that might have been close enough to the quake to need your help.

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    Select the Sumatra earthquake

    • Turn on the 2009EQ layer by clicking the checkbox next to its name. Then click on its name in the Table of Contents to make it the active layer.
    • Use a Query to locate the Sumatra earthquake:
      • Click the Query Builder button Query builder button .
      • In the query builder, set up the following equation:
        (Month = 9) and (Day =30) and (Magnitude = 7.5).
      • Click the Execute button.
      • Click the Highlight and the Zoom To buttons. (Note: If clicking the Zoom button does not zoom in on the highlighted earthquake, you will need to zoom in manually using the Zoom In tool zoom_in_tool aejee )

    1. Turn on the 2009EQ layer by clicking the checkbox next to its name. Then click on its name in the Table of Contents to make it the active layer.
    2. Use a query to locate the Sumatra earthquake:
    • Click the query builder button Query builder button .
    • In the Query Builder window, set up the following equation:
      (Month = 9) and (Day =30) and (Magnitude = 7.5).
    • Click the Execute button.

    query builder and map sumatra
  • In the Query Results list at the bottom of the Query Builder window, click to select the single found record.
  • At the bottom of the query builder window, click the Highlight and Zoom buttons.

  • sumatra_eq_zoom_aejee
  • The map will zoom to center on the highlighted Sumatran earthquake. (Note: If clicking the Zoom button does not zoom in on the highlighted earthquake, you will need to zoom in manually using the Zoom In tool zoom_in_tool aejee ).
  • Close the Query Builder window.

  • The Sumatran earthquake should be highlighted and centered on the map.

    set up buffer 1


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    Set a buffer distance

    A buffer is a zone drawn around a given map feature or features, measured in units of distance or time. A buffer can be drawn around points, lines, or polygons as well as groups of pixels in raster data. Buffering, or the process of creating a buffer, is a commonly used proximity function. Once the buffer is drawn, it defines what is inside or outside of the given space.

    Buffering involves complex mathematical computations, which can use a lot of computer processing power and time. It is best to buffer simpler shapes rather than highly complex ones, such as the Louisiana Soils or Elevation > 2km layers.


    buffer window only

    To create a set of concentric buffers around the earthquake:


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    Use the results to answer a spatial question

    Now, you'll go back to your original scenario of identifying major Indonesian cities that might be affected by the earthquake. To do this, you will add a world cities layer and use the buffer tool to select any cities within each of these radii.


    Movie Icon

    Before going on, you'll need to clean house a little:

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    Carry Out a Containment Query

    A containment query finds all the features within a given boundary, such as all of the Tamarix plants in the State of Arizona or all of the lakes in Canada.

    How would you select all the earthquakes in a given country? For example, say you wanted to find all the earthquakes in Chile.

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    Locate and select Chile

    You'll use the Find tool to locate and highlight Chile.



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    Set a buffer to select all the earthquakes within Chile

    Now you will use the Buffer buffer tool icon tool to select the 2009 earthquakes that occurred in (or very near to) Chile:

    1. Click the Buffer tool buffer tool icon to open the Buffer window.
    2. In the Buffer window, set the Buffer Distance to 1 and the Units to Miles.
    3. Check Use the Buffer to select features from this layer option and choose 2009EQ from the list of layers.
    4. Click the Apply button. The 2009 earthquakes that occurred in or within 1 mile of Chile will now be highlighted on your map.
    5. Close the Buffer window.

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    Show the results of the spatial query

    1. Right-click (Win) or control-click (Mac) the 2009EQ layer and open the layer's Attribute Table. Scroll down the attribute table. The selected records are highlighted in blue. How many records were selected?

    2. Right-click (Win) or control-click (Mac) any of the field names of the attribute table and choose Sort Selected Data to Top from the contextual menu. The earthquake records from Chile will be moved to the top of the table.
    Movie Icon

    Time to do housecleaning again before the final spatial query:



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    Carry Out a Proximity Query

    Proximity is how close one object is to another object. In this case you will learn how to find all the earthquakes that are within a set distance of a given type of plate boundary.

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    Select features of interest (transform boundaries)

    1. Click and drag the 2009EQ layer below the Plate Boundaries layer in the Table of Contents.
    2. Turn on and make the Plate Boundary layer active.
    3. Click the Query Builder button. Set up a database query to select the Transform boundaries.
      (MARGIN_TYP = 'Transform' )

    4. Close the Query Builder window.

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    Set the buffer distance to select earthquakes that are within a specified distance

    1. Click the Buffer button buffer tool icon to open the Buffer window.
    2. In the Buffer window, set the Buffer Distance to 50 and the Buffer Units to Miles.
    3. Turn on the Use buffer to select features from this layer option, using the 2009EQ layer.
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    Show the results of the spatial query

    1. Right-click (Win) or control-click (Mac) the 2009EQ layer and open the layer's Attribute Table. Scroll down the attribute table. The selected records are highlighted in blue. How many records were selected?

    2. Right-click (Win) or control-click (Mac) any of the field names of the attribute table and choose Sort Selected Data to Top from the contextual menu. The records for earthquakes within 50 miles of a transform boundary will be moved to the top of the table.

    Movie Icon

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    Create and Explore More Spatial Queries

    Practice spatial queries using combinations of select features, buffering, and database queries
    Try the following:
    1. Use the earthquakes layer and the Latitude and Longitude lines on the map to answer the question:
      Find all the earthquakes in the Northern Hemisphere.
    2. Use the earthquakes layer and a database query to answer the question:
      Find all the earthquakes of a Magnitude greater than 7.
    3. Use the earthquakes layer and a database query to answer the question:
      Find all the deep earthquakes.
    4. Use the earthquakes layer and the plate boundaries layer to answer the question:
      How many earthquakes are there at each of the boundary types?
    5. Use the earthquakes layer and the cities layer to answer the question:
      How many National Capital cities were within 20 miles of an earthquake in 2009?

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    Build Your Own Spatial Query and Take a Screenshot

    Set up and execute a spatial query of interest to you. Use the data in the project folder or add another "add event theme dataset" from the folder provided and use the new layers to complete a spatial query. Add other layers of interest to your map and symbolize the layers.

    Take a screenshot. Post this screenshot along with a description of the layers you used and the query you made. This is the screenshot that is needed for your required weekly activity.

    The EarthquakeAE folder includes many datasets to explore that don't follow the seismology theme. Here are just a few of the possible combinations there are many more!


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    Explore More If You Have Time

    Take the time to read more about the additional event theme data sets on the website links where they were downloaded from. The following PDF contains more information (Acrobat (PDF) PRIVATE FILE 48kB Mar25 10) and links to the data sets.

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    Resources


    Sumatra Earthquake Information

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    Movies on this Page

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    How to download movies

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    Flash Video Versions

    Download these versions to play on your computer. You'll need an appropriate movie player to view the file, such as Flash Player, Real Player (Mac / Win), or Adobe Media Player.

    Movie Icon Performing a Spatial Query in AEJEE

    Movie Icon Performing a Containment Query in AEJEE

    Movie Icon Performing a Proximity Query in AEJEE

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    iPod Versions

    Download these version to play on your iPod or iPhone.

    Movie Icon Performing a Spatial Query in AEJEE

    Movie Icon Performing a Containment Query in AEJEE

    Movie Icon Performing a Proximity Query in AEJEE


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