Name_____________________
Date_________________
Per___________
Task: Your task is to use earthquake data to map a possible fault line and then evaluate
the risk of damage from earthquakes near this fault line.
Materials:
• Seismograms showing the arrival of p- and s-waves at 3 different locations from 3
different earthquakes
• Location map for this exercise
• Colored pencils
• Drawing compass
• Ruler
• Calculator
Background:
To establish the risk for an earthquake, geologists first collect seismic data from many
locations to find the centers for earthquake activity. When the data is plotted on a map,
they can locate the point on the Earth’s surface above the earthquake which is called the
earthquake epicenter. Mapped patterns of earthquake date accumulated over time may
reveal fault lines hidden over time by other geologic processes.
Procedure:
1) On the Seismic Data Sheet, use the edge of a piece of paper and measure the distance
between the P-wave and the S-wave arrival times.
2) Use the time scale at the bottom of the page to determine the difference in arrival
times in seconds. (In all but one case, the number should be a decimal less than 1)
3) Divide the difference in arrival times by 0.15 sec/km. (This is the difference in the
velocity of the two waves). Your answer will be in km.
4) Using the distance scale at the bottom of the map to measure, open the compass to the
distance obtained in step #3.
