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Name: Mary
Status: Educator
Grade: 9-12
Location: NV
Country: United States
Date: 


Question:
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!



Replies:
Mary,

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.

Matt Voss



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