Department of Earth Science |Northeastern Illinois University

ESCI 121
Fall 2007

Homework Assignment #4 (Due at class time, Monday, March 12, 2007)                                                                        Dr. Sanders

Earthquake Focus Maps

In this assignment, you will use the resources of the US Geological Survey to plot a color map showing the foci of recent earthquakes in a specific area.  You will write a brief (one page or less) report on your findings, addressing specific questions.

Assigned areas:

We will research the areas that we've studied earlier this semester, plus a few new areas.  Each student is assigned an area, as follows:
Class member
Study Area
San Francisco, California
Yellowstone National Park
Border of India and Nepal
New Zealand
The Red Sea
Lake Tanganyika
Aleutian Islands
Jakarta, Indonesia
Azore Islands
Galapagos Islands
Southern Illinois/Missouri
The Indian Ocean

Central America
Puerto Rico, Dominican Republic, and Haiti

Finding Information:

Go to the Earth Science Department home page and click "Links to More Earth Science Sites". 

At the top left, click “Earthquake Watch!”

In the blue boxes at left, click “Earthquake Search”

Under "Select the Search Area", select "Rectangular Area". 

Select “Generate Map”

Scroll down, and enter the latitude and longitude of the rectangle you have chosen.  NOTE:  If you are working in the western hemisphere, longitudes have to be entered as negative numbers!  If you are working in the southern hemisphere, latitudes have to be entered as negative numbers!

Click “Submit Search”

Wait for a minute or two; it takes awhile.  Eventually a map of earthquake foci will appear.

Check the map and see if it shows what you wanted it to.  To enlarge or reduce the area, go back one page, and enter new latitude/longitude coordinates.  Check again to be sure the area shows what you wanted it to.  Spend some time here, tweaking your coordinates to produce the best possible map.  In some cases, you might decide to print two maps to show clearly what you want. 

Print out TWO COPIES of the map (and this is important...) in color!!!!!!!!   This is important!  Print two copies in color!!!!!!!!  Seriously, the two copies of the map must be in color!!!!!  

On the two color copies of the map, write in large letters what the name of the mapped area is (e.g., Japan, Hawaii, etc.).

Writing your report:

    Format:  Your report must be typed in 12-point font or larger.  No particular line spacing is required, however, there is a one page limit.
    Writing: Your report must be written in complete sentences. 
    No plagiarism: The report must be written by you, in your own words.  You will not receive credit for material written by others!  Do not copy and paste information from web pages or any other source; write in your own words to show your own understanding of the material.  Be aware of the NEIU policy on academic misconduct.

Your report should include the following information, in this order (use this numbering in your answers):

1.  Give the name and location of your earthquake area, including the latitude and longitude coordinates you used to produce your map.. 

2.  Briefly describe the distribution of earthquake foci that you see on the map.  For example, do you see randomly scattered earthquakes, or do they follow a pattern of some sort? 

3.  Examine the focal depths of the earthquakes in your area.  How deep are the deepest?  If you have more than one color of dots indicating depth, do the colors follow some sort of pattern?  Explain.

4.  What is the plate tectonic environment of your area?  (For example, is your area situated on or near a plate boundary?  In the middle of a plate, with no boundaries nearby?  If near a boundary, what type of boundary is it?  What type(s) of plates are involved--continental or oceanic?)  Maps from the plate tectonic exercise are available in this on-line version; also see p. 224-225 in your text and the big sea floor map in the classroom.

5.  Explain why you think the earthquakes on your map show the distribution that they do (both in terms of their locations and their depths).

6. Print out the world map that appears at this link.  Plot your study area on the map.

Put your name on all four pages.  Staple your write-up to the world map, but leave the two copies of the earthquake focus map separate.  All four pages are due at class time; late homework will not be accepted.

Department of Earth Science | Northeastern Illinois University

© 2007 Laura L. Sanders.  Last updated March 5, 2007.