Page 433 - Laboratory Manual in Physical Geology

A CTIVIT Y 16.3 Locate the Epicenter of an Earthquake

Name: ______________________________________ Course/Section: ______________________ Date: ___________

A single earthquake produced the seismograms below at three different locations (Alaska, North Carolina, and Hawaii). Times
have been standardized to Charlotte, North Carolina to simplify comparison. See if you can use these seismograms and a seismic-

wave travel time curve ( FIGURE 16.5 ) to locate the epicenter of the earthquake that produced the seismograms.

Sitka

Charlotte

Honolulu

8:06 8:08 8:10 8:12 8:14 8:16 Times

A. Estimate to the nearest tenth of a minute in the seismographs above, the times that P-waves and S-waves above first arrived at
each seismic station (Sitka, Charlotte, Honolulu). Then, subtract P from S to get the S-minus-P time interval:
First P arrival First S arrival S-minus-P

Sitka, AK ____________ ___________ ____________

Charlotte, NC ____________ ___________ ____________

Honolulu, HI ____________ ____________ ____________

B. Using the S-minus-P time intervals above, and the travel time curves in FIGURE 16.5 , determine the distance from the

epicenter (in kilometers) for each seismic station.
Sitka, AK: _________ km Charlotte, NC _________ km Honolulu, HI __________ km

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