The USGS Earthquakes Hazards Program keeps a great site that shows, among other things, the location of most recent earthquakes on the globe.  Your task here is to create a new map using ArcView to locate the most recent worldwide earthquakes.  There are several steps to this task.

Important Note: This exercise assumes you have some basic ArcView skills. The activity below was written for ArcView 3.3 - your challenge this year is to do the activity using ArcMap.

1.    Start ArcView.  Add a world map (O:\student apps\geo_data\world\cntry94...) to a View and for the time being make all the countries "clear".

2.    Go to the USGS page that indicates the most recent earthquakes on a world wide basis.  Click on M5+ Earthquake list just below the map. Study the data that is included in the table.

3.    Enter the 20 most recent earthquakes into a new table in ArcView. (Watch out for the aftershocks, we do not want more than two earthquakes in the same place)  Follow these steps:

• From the Project Window, highlight Tables and then choose New.  In the New Table window select the appropriate drive and directory to save your work.  Call the table newquakes.  Click OK.
• Your new (blank) table will appear.   Notice the .dbf extension.  Doesn't look like much now.  You have to add the fields (or columns) for the data and then the records (or rows) of actual data. The Asteroid assignment explains how to enter data into an ArcView table.
• Go the web page again and make note of the number and names of columns or fields.  You are only going to use three of these: Latitude, Longitude and Magnitude.

Now you can set up the table so you can enter some data.  Under Edit choose Add Field.  The Field Definition box appears.  In the Name row type Latitude.  Change the Type to Number and set the Width to 6.  Set the decimals to 2.  Hit OK and this field is added to your table.  Easy, eh?  Now repeat these steps for the other fields.
• Now you can add the rows or, more properly, the records for the table with their data.

Important Note: Be sure you use negative numbers for longitude.  Longitude is measured east and west of the Prime Meridian but ArcView doesn't recognize east and west so we use negative numbers for west.  The same is true for south latitude.

• Under Edit choose Add Record and then choose the Edit button in the bottom row of buttons.  Enter the data for the first earthquake, pressing the Tab key to move across the table. Important Note: When you get to the last field, hit Enter.

Choose Add Record again and a new row appears in the table.  Repeat these steps exactly, making sure to hit Enter at the end of each record.  Continue until you have entered all the earthquake data.
• When you are finished choose Stop Editing under Table and in the Save Edits? box that appears choose Yes.  Note how the names of the fields change to italics.

4.    Map this data.  Note that your table is a .dbf file and as such it can't be mapped directly in ArcView.  You have to do a couple of steps first.

• With the View as the active window, choose View on the menu at the top and then choose Add Event Theme.
• Specify the table you just created.
• Set X to Longitude and Y to Latitude.
• Hit OK and the theme will be added to the table of contents of the View.  Turn it on and, voila, there are the earthquakes!

5.    Modify the theme by using Graduated Symbol in the Legend Editor to indicate the magnitude of the earthquake.

6.    Add the data from O drive to map the earthquakes of 1996 (O:\Student Apps\Geo_Data\ArcCanada3\Disk3\World\Shp\quakes96.shp).  Add as well the plate boundary theme (Plat_Pol) and the major world cities theme (w_cities).  Arrange the table of contents of the View so that the country theme is on top (and it should be clear).

7.    Answer these questions:

1.    Describe the location of the most recent earthquakes.  Is there any discernible pattern?
2.    What sorts of plate boundaries are the quakes associated with: divergent or convergent?
3.    How do the more recent earthquakes compare with those from 1996?
4.    Are there any major populations centres that appear to be threatened?

8.   Create a Layout that includes only the countries and the most recent earthquakes. Make it look good!

An added Feature: Chose 5 of the recent earthquakes that occurred near populated centers (ie. not those out in the oceans). Create a 1000km buffer around the quake(s) and use ArcView to determine the number of major cities within the buffers as well as the total population of these cities. (use w_cities.shp).

Hint: How to Buffers: Tools - Customize - Commands - Tools - drag the Buffer Wizard to the top - Select your 5 quakes using the Select Features button in the Tools Menu (use the Shift key to select multiples) and then click on the Buffer Wizard button - follow the Wizard and input the necessary information. Please make sure to send your Buffer to your H drive.
Hint: How to select the cities within the buffer:  Selection - Select by Location - Read carefully and fill in the necessary windows.
Hint: How to determine population: Right click on the cities layer in the table of contents - Selection - Create Layer from Selected Features - Right click on this new layer - Open Attribute Table - Right click on Population in the chart and then select Statistics and there is your answer!

Add the number of cities in the buffer and their total population in a text window on the map.

What we want on the Final map:

1. The countries of the  world
2. The Plate Boundaries
3. The Recent Earthquakes - Graduated Symbols
4. The Buffers of the Selected Earthquakes
5. The cities selected by the Buffer
6. A Text box stating the number of cities and their total population.
7. The answers to the above 4 questions (see #7 above) on a separate piece of paper.
Do not include the 1996 quakes or the w_cities theme.

Good Luck!

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