Activity Purpose:

How frequently do large earthquakes occur?

Materials:

USGS Real Time Earthquake Data List
Ruler
Graph
Crayons, markers, or color pencils
Calculator
Tally Sheet

Procedure:
 

1.  Internet specialist will print out USGS Real Time Data Earthquake list, tally sheet, and graph paper.
2.  Give your graph a title:  "How Often Does a Large Earthquake Occur?"
3.  Label the horizontal axis "Magnitude".
4.  Label each line on the Magnitude axis 0 to 9.
5.  Label the vertical axis "Number of earthquakes".
6.  Next to each line on the vertical axis, label 0 to 18.
7.  On the USGS Real Time Data Earthquake List find the column labeled mag  (magnitude).
8.  Round the magnitude to the nearest whole number.
9.  Count the number of earthquakes having a magnitude of 1.  Record it on your tally sheet.
10.  Follow the same procedure for magnitudes of 2 through 9.
11..  Create a bar graph on graph paper to illustrate the information you gathered from your tally sheet.
12.  On the horizontal axis line label the following next to each line:

Great = 8 and higher
Major = 7- 7.9
Strong =  6-6.9
Moderate = 5-5.9
Light =  4 -4.9
Minor =  3-3.9
Very Minor = 0.1-3.0

Draw Conclusions:
 

1.  Which magnitude occurred most often?
2.  Did you find that any magnitude did not occur at all?
3.  What was the difference in the number of earthquakes having a magnitude of 3 and 5?
4.  How many earthquakes occurred each day?
5.  Find the average number of earthquakes occurring during these 3 days.
6.  Using this information, can you estimate the number of earthquakes occurring in    1 month?    1  year?    10 years?
     (Note:  Calculators may be used to answer this question.)