Seismograph Distance and Accuracy
Country: United States
Why can an earthquake be measured more accurately
with a seismograph that is farther away from the epicenter? For
example, the San Francisco Earthquake was measured with a
seismograph in Japan!
To find the epicenter of an earthquake, a process called
triangulation is used. Three seismographs are used and the time of
detection for each allows for the location of the epicenter. Any
geometry textbook should tell you the math behind
triangulation. Triangulation is also used in cell phones so that
you get reception from the cell tower that you are closest to and/or
have the strongest signal from.
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Update: June 2012