Week 7: Investigating Earthquake Activity

top of page

Getting to Know Spatial Querying in ARCGIS

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.

top of page

Launch ARCGIS and Open the Earthquakes Project

• Launch ARCGIS by double-clicking its icon on your desktop or by clicking its icon in on the Launch Bar.
• Choose File > Open, navigate to C:/eyesinthesky2/week7/EarthquakeAM, select the EarthquakeAM.mxd file, and click Open.
• A global map opens, showing Continents, US States, and Lines of Latitude and Longitude.

top of page

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 XY Data to map the 2009 earthquakes.

Choose ONE of the following two options to add 2009 earthquake data to the map.

1. top of page

   Add 2009 earthquake data as a shapefile

• Click the Add Data button .
• Navigate to the csv_files folder. (Path: C:/eyesinthesky2/week7/EarthquakesAM/csv_files)
• Choose the 2009EQ.shp shapefile that was automatically created and saved in the previous section.
• Click OK.

Show me the shapefile and map

Hide

top of page

Map 2009 tabular earthquake data by longitude and latitude coordinates

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

• Choose Tools > Add XY Data to open the Add XY Data window.
• Click the Browse button and navigate to the file named 2009EQ.csv. (Path: C:/eyesinthesky2/week7/EarthquakesAM/csv_files).
• Choose the 2009EQ.csv file and click OK.
• Choose Longitude for the X Field and Latitude for the Y Field.
• Click OK.

Show me how

Hide

1. Select Tools > Add XY Data.
   
2. The data file is in the csv_files folder within the EarthquakeAM data folder. Click the Browse button.
   
3. Navigate to the csv_files folder within the EarthquakeAM data folder.
   
4. Choose the file named 2009EQ.csv. Click Add.
   
5. In the Add XY Data window, define the coordinates.
   

• Table: C:/eyesinthesky2/week7/EarthquakesAM/csv_files/2009EQ.csv
• X field: Longitude
• Y field: Latitude
• Click OK.
• Click OK on the Table Does Not Have Object ID popup window.

top of page

Convert XY Data to Shapefile

To get full functionality from your XY points, it is necessary to convert your XY point (event) layers to shapefiles. It is a simple two step process.

• Right click on the 2009EQ.csv Events layer. Click on Data > Export Data.
  
• Navigate to project folder and click OK.
  
• Click Yes to add the 2009EQ.shp to your Table of Contents.
  
• Right click on 2009EQ.csv Events and click on Remove.
  

The 2009 Earthquakes will now be displayed on the map.

top of page

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?

top of page

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.

top of page

Select the Sumatra earthquake

• Turn on the 2009EQ layer.
• Use a Query to locate the Sumatra earthquake:
• Click the Selection > Select by Attributes menu.
• In the Select by Attributes window, set up the following equation:
  (Magnitude = 7.5) and (Month = 9) and (Day =30).
• Click the Apply button. Move the Select by Attributes window aside and adjust your query as necessary if you don't get the desired results.
• Right click the 2009EQ layer, Selected and then Zoom to Selected options in the context menus.

The map will zoom to center on the highlighted Sumatra earthquake.

top of page

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 menu option to select any cities within different distances of the Sumatra earthquake.

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

• Close the Attribute Table, and the Select by Location windows.
• Click the Selection > Clear Selected Features menu option to clear all selections in both the 2009EQ and cities layers.
• Click the Zoom to Full Extent button to show the entire map again.

top of page

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.

top of page

Locate and select Chile

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

• Click the Find tool to open the Find window.
• In the In field choose Countries and enter Chile in the Find field.
• Click the Find button. One record (Chile) should now appear in the Find Results box.
• At the bottom of the Find window, right click Chile and Select and Zoom To. The map should zoom to Chile, which should be highlighted blue.

top of page

Set a buffer to select all the earthquakes within Chile

Now you will use the Select by Location menu option to select the 2009 earthquakes that occurred in (or very near to) Chile:

1. Click the Selection > Select by Location menu option to open the Select by Location window.
2. In the Select by Location window, select the options to query "2009EQ" "Within a Distance of" "Countries". Put a check in the Use Selected Features box. (This will use the selected country of Chile in this query) Check the box to Apply a Buffer to Features in Countries option. Fill in Buffer Distance box to 1 and the Buffer Units to Miles.
3. Click the Apply button. The 2009 earthquakes that occurred in or within 1 mile of Chile will now be highlighted on your map.
Show me the map
Hide



4. Close the Select by Location window.

top of page

Show the results of the spatial query

1. Right-click the 2009EQ layer and open the layer's Attribute Table. Look down at the bottom of the attribute table. The selected records are highlighted in blue. How many records were selected?
Show me the result
Hide
Result: 190 earthquakes are selected. (Hint: Look at the bottom of the attribute table window for the total number of records selected.)




2. Click on the Selected button at the bottom of the attribute table. Only the earthquake records from Chile will be displayed in the table.
Show me the attribute table
Hide
The 2009EQ attribute table sorted with the selected records grouped at the top.

Time to do housecleaning again before the final spatial query:

• Close the Attribute Table, and the Select by Location windows.
• Click the Selection > Clear Selected Features menu option to clear all selections in both the 2009EQ and cities layers.
• Turn off the Cities layer.
• Click the Zoom to Full Extent button to view the entire map.

top of page

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.

top of page

Select features of interest (transform boundaries)

1. Click and drag the 2009 EQ layer below the bounds(Plate Boundaries) layer in the Table of Contents.
2. Turn on the bounds layer.
3. Click the Selection> Select by Attributes menu option. Set up a database query to select the Transform boundaries.
   (MARGIN_TYP = 'Transform' )
Show me the Query Builder window and results of the query.
Hide



4. Close the Select by Attributes window.

top of page

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

1. Click the Select > Select by Location button menu option to open the Select by Location window.
2. In the Select by Location window, select the options to query "2009EQ" "Within a Distance of" "bounds". Put a check in the Use Selected Features box. (This will use the selected transform plate boundaries (bounds) in this query) Check the box to Apply a Buffer to Features in bounds option. Fill in Buffer Distance box to 50 and the Buffer Units to Miles.
3. Click the Apply button. The 2009 earthquakes that occurred in or within 50 miles of transform plate boundaries will now be highlighted on your map.
Show me the Select by Location window and results
Hide

top of page

Show the results of the spatial query

1. Right-click the 2009EQ layer and open the layer's Attribute Table. Look down at the bottom of the Attribute Table. The selected records are highlighted in blue. How many records were selected?
Show me the result
Hide
Result: 658 earthquakes were within 50 miles of a Transform boundary. (Hint: Look at the bottom of the attribute table window for the total number of records selected.)




2. Click on the Selected button at the bottom of the attribute table. Only the records for earthquakes within 50 miles of a transform boundary will be displayed in the table.
Show me the attribute table
Hide
The 2009EQ attribute table with only the selected records displayed.

top of page

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.
   Show me the query steps
   Hide
   1. Use the Select feature tool to drag a rectangular selection around the Northern Hemisphere. The Northern hemisphere will be highlighted blue.
   2. Click the Selection > Select by Location menu option, set the buffer distance to 1 mile, and use the buffer to select the 2009 earthquakes from within this containment.
   3. Open the earthquakes Attribute Table. We got 4227 earthquakes selected, but your number may vary depending on where you defined 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.
   Show me the query steps
   Hide
   1. Click the Selection > Select by Attributes menu option to open the Select by Attributes window.
   2. Set up the following query statement: (Magnitude >= 7.0 ).
   3. Click the Apply button.
   4. Open the earthquakes Attribute Table. We got 17 earthquakes of magnitude 7 or higher.
   
   
3. Use the earthquakes layer and a database query to answer the question:
   Find all the deep earthquakes.
   Show me the query steps
   Hide
   1. Click the Selection > Select by Attributes menu option to open the Select by Attributes window.
   2. Set up the following query statement: (Depth > 400 ).
   3. Click the Apply button.
   4. Open the earthquakes Attribute Table. We got 234 earthquakes deeper than 400 km.
   
   
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?
Show me the query steps
Hide
1. Repeat the given in the example above, but change the initial data base query to (MARGIN_TYP = 'Convergent' ) and (MARGIN_TYP = 'Divergent').
2. Result: 2708 earthquakes were within 50 miles of a Convergent boundary; 902 earthquakes within 50 miles of a Divergent boundary; and 657 earthquakes within 50 miles of a Transform boundary.



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?
Show me the query steps
Hide
1. Add the Cities layer from the EarthquakesAM folder.
2. Open the Attribute Table, take a look at the Status Field.
3. Set up and execute the database query ((STATUS = 'National and provincial capital') or (STATUS = 'National capital')). Recall that in queries, "or" is more inclusive than "and", so both of these types will be selected. Result: 214 cities are selected in this query.
4. Click the Select > Select by Location menu option, set the buffer distance to 20 miles. Use the buffer to select features from the 2009EQ layer.
5. 32 earthquakes are selected — pretty impressive.

top of page

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 EarthquakeAM 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!

• Hummingbird Migration and temperature patterns.
• Tornado touchdowns and US States.
• World Glaciers and Elevation.
• World Volcanoes and Faults
• Groundwater temperature and US Thermal Springs

top of page

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) 48kB Mar25 10) and links to the data sets.

top of page

Resources

Sumatra Earthquake Information
top of page

Movies on this Page

top of page

How to download movies

• Click the link to go to the SERC media library listing for the movie. The record will open in a new window.
• On the SERC media library page, right-click (Win) or control-click (Mac) the link (below the movie on the Flash version pages) to download the movie file to your hard drive.
Show me where to look for the download link
Hide
Look below the movie window for the file download link.

top of page

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.

Performing a Spatial Query in ArcGIS

Performing a Containment Query in ArcGIS

Performing a Proximity Query in ArcGIS

top of page

iPod Versions

Download these version to play on your iPod or iPhone.

Performing a Spatial Query in ArcGIS

Performing a Containment Query in ArcGIS

Performing a Proximity Query in ArcGIS