Department
of Earth Science |
Northeastern
Illinois University
INTRODUCTION
TO EARTH SCIENCE
ESCI
121
Spring
2007
Daily Objectives
#14 (March
7, 2007)
Dr. Sanders
By the end
of
today’s class, you should be able to do the
following:
* Sketch a diagram
illustrating the meaning of the terms epicenter and focus
(also called hypocenter) as they apply to
earthquakes.
* Describe P-waves and S-waves: their motion, velocity, arrival times,
and ability to travel through liquids.
* Explain why P- and S-waves reach seismometers at different times, and
tell how the time difference helps us learn how far away an earthquake
occurred.
* Tell why it is necessary to have seismograms for an earthquake from
at least three different locations before we can locate an earthquake
epicenter.
* Examining seismograms from three monitoring stations for the December
26, 2004 Indonesian earthquake, for each monitoring station, calculate
the P-S time difference, find the distance of the epicenter from the
station, and plot the distances on a map to locate the epicenter.
* Explain what is expected of you in Homework
#4, due on Monday.
© 2007 Laura L. Sanders. Last updated
March 7, 2007.