Week 7: Investigating Earthquake Activity
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Using AEJEE to Analyze Earthquake Patterns
Key Investigation Questions
Introduction
Key Investigation Questions
Introduction
Launch AEJEE and Open the Earthquakes Project
Examine a Year's Worth of Earthquake Data
Examine the Distribution of Past Significant and Big Earthquakes
Compare Earthquake Distributions
Where are the Big Earthquakes Mostly Likely to Occur in the Future?
- Select convergent plate boundaries
- Set a buffer to select earthquakes from the sig_big layer that are within a specified distance
- Show the results of the spatial query
Using AEJEE to Analyze Earthquake Patterns
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Key Investigation Questions:
- How are earthquakes distributed?
- Where do really big earthquakes occur?
- How do recent quakes compare with the historical record?
Introduction
Earthquake Patterns
Earth is a dynamic planet. Its crust is continuously forming and deforming, constantly pushed and pulled as it moves. When strain that has built up over time is suddenly released, the crust shakes, and we call this movement an earthquake. Depending upon their strength and where they strike, earthquakes can inflict severe property damage and claim thousands of lives.
Launch AEJEE and Open the Earthquakes Project
- 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 will open with the Continents, US States, and Lines of Longitude and Latitude on the map.
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Examine a Year's Worth of Earthquake Data
Add earthquake data from 2009
- Click the Add Data
button. The Content Chooser window opens. - Navigate to the csv_files folder within the EarthquakesAE folder. In that folder, select the 2009EQ.shp file that was automatically created the last time you added this data as Add Event Theme data. Then click OK.
- Right-click on the PC or control-click on the Mac on the 2009EQ label in the Table of Contents. Then select Attribute Table.
- Scroll down to the bottom of the Attribute Table to find out how many earthquakes with a magnitude of 4.0 or greater occurred in the past year.
- Click the Add Data
button. The Content Chooser window opens. Navigate to the csv_files folder within the EarthquakesAE folder. In that folder, select the 2009EQ.shp file that was automatically created the last time you added this data as Add Event Theme data. Then click OK.
- Right-click on the PC or control-click on the Mac on the 2009EQ label in the Table of Contents. Then select Attribute Table.
- Scroll down to the bottom of the Attributes of 2009EQ table to find out how many earthquakes of a magnitude 4.0 or greater occurred in 2009.
- Click the Add Data
- Turn on the Plate Boundaries layer by clicking the checkbox in front of its name.
Examine the Distribution of Past Significant and Big Earthquakes
Add the significant and big earthquakes from 2150 BC to 2007 AD
- Choose View > Add Event Theme to map historical Significant and Big earthquakes using Longitude and Latitude coordinates. The Add Event Theme window opens.
- Click the Browse
button to navigate to the file named sig_big.csv. (Path: ESRI/AEJEE/Data/EarthquakesAE/csv_files). Select sig_big.csv and click Open. - Select 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.
The options in the Add Event Theme window are as follows:
- Table: ESRI/AEJEE/Data/EarthquakesAE/csv_files/sig_big.csv
- X field: Longitude
- Y field: Latitude
- Draw event using symbol with:
- Style: Circle
- Color: Blue
- Size: 5
- The Output Directory defaults to the current csv_files folder that you obtained the earthquake file from. Accept this default.
- Click OK.
Show me how
Hide
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Compare Earthquake Distributions
- Turn off the 2009EQ layer by unchecking the box next to its name. Now observe the sig_big layer. This layer maps "big" earthquakes ranging from the earliest recorded events to 2007. To learn more about this layer, open the Attribute Table to see the date range. This layer is a combination of recorded data and data based on other information, such as historical writings.
- Turn the 2009EQ and sig_big layers on and off to get a sense of how they are similar and different.
- Move the Plate Boundaries layer, to the top of the Table of Contents.
- Right-click on the PC or control-click on the Mac on Plate Boundaries in the Table of Contents. Then select Move Layer >Move to Top.
- This is what the map looks like with the plate boundary layer on top.
- Right-click on the PC or control-click on the Mac on Plate Boundaries in the Table of Contents. Then select Move Layer >Move to Top.
Where are the Big Earthquakes Mostly Likely to Occur in the Future?
As you discovered, most "big" earthquakes are concentrated at convergent plate boundaries. It is possible to characterize a risk zone using a GIS. For example, through querying and buffering, we can find out how many magnitude 7.0 or greater earthquakes have occurred within a specified distance of a plate boundary.
- Turn off the 2009EQ earthquakes layer, but make sure the sig_big earthquake layer is on.
Select convergent plate boundaries
- Select the convergent plate boundaries by querying the Plate Boundaries layer for Margin type.
- Click on the the Plate Boundaries layer to make it active.
- Then click the Query Builder
button. Type the following expression into the input box: (MARGIN_TYP = 'Convergent').
- Click Execute.
- Here is what the map looks like with the convergent plate boundaries highlighted.
- Click on the the Plate Boundaries layer to make it active.
Set a buffer to select earthquakes from the sig_big layer that are within a specified distance
- Click the Buffer
button and in the Buffer window that opens, set the Buffer Distance to 100 and the Buffer Units to Miles. Check "Use buffer to select features from this layer" and select the sig_big layer. Then click Apply and click OK.
- Click the Buffer button and in the Buffer window that opens, set the Buffer Distance to 100 and the Buffer Units to Miles. Check "Use buffer to select features from this layer" and select the sig_big layer. Then click Apply and click OK.
- This is what the map looks like with a 100 mile buffer set around the convergent plate boundaries and with the intersecting earthquakes highlighted as well.
- Click the Buffer button and in the Buffer window that opens, set the Buffer Distance to 100 and the Buffer Units to Miles. Check "Use buffer to select features from this layer" and select the sig_big layer. Then click Apply and click OK.
Show the results of the spatial query
- Open the Attribute Table of the sig_big layer to find out how many earthquakes were selected.
- Make sig_big the active layer by clicking once on its name in the Table of Contents. Right-click on the PC or control-click on the Mac on Sig_big and then select Attribute Table.
- Scroll the Attributes of sig_big to view the selected records.
- Make sig_big the active layer by clicking once on its name in the Table of Contents. Right-click on the PC or control-click on the Mac on Sig_big and then select Attribute Table.
What percentage of big earthquakes occur within 100 miles of a convergent plate boundary?
- Click the Clear All Selections
button. Repeat the query and set the buffer again, but change the Buffer Distance to 200 miles.
- Click the Clear All Selections
button.
How does the 2010 Earthquake Pattern Stack Up?
- Click the Add Data
button. Navigate to the world cities layer, cities.shp in the EarthquakesAE data folder. Click OK.
- Choose Add Event Theme to add the 2010 Earthquake data. Repeat the instructions from above. This time when importing, change the symbol to another color of your choice, such as Orange or Cyan.
- Compare 2010 earthquakes to 2009 and historical earthquakes.
Thought Question: Observe the 2010 layer, does there seem to be a continuation of the historical pattern? Where might more earthquakes be due to happen in 2010?
Select the Chilean earthquake
- Make the 2010 quakes layer the active layer. Use a database query to find the earthquake that occurred in Chile.
- M 8.8
- 2010 2- 27 06:34:14 UTC
- Depth 35km
Discover how far this earthquake was from a major city
How would you discover the distance that this earthquake was from a major city?
- Now that this earthquake is selected, zoom in on it. Use the identify tool
and click on the cities to learn their names. - You can also use the map tips
tool to quickly find the cities names by hovering over them.
Click on the map tips button, set the map tips to select to CITY_NAME from the cities shapefile.
Show me the result
- Use the measure
tool to measure to selected cities from the earthquake.
Use the procedure above to investigate the Haitian earthquake.
- M 7.0
- 2010 – 01-12 21:53:10 UTC
- Depth 13km
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Explore More if you have Time
- Review the slide show: Haiti Chile Slides.pdf (Acrobat (PDF) 23MB Mar24 10) (link) to learn more about these two Earthquakes and why one was so much more destructive than the other.
- Add other data from the EarthquakesAE folder, such as world volcanoes, tectonic plates or faults. Also included in the folder is world elevation and world topography.tif. Discover other stories you could tell with these pieces of data.