In this activity, you will determine the location of an earthquake's epicenter and estimate its Richter magnitude. You will be working with seismograms, which are the records of earthquake waves.

In order to accurately record earthquake waves at a seismic station at least three seismographs are needed: one each for E-W, N-S, and vertical motion.
By examining seismograms at 3 different recording stations, it is possible to "triangulate " the epicenter of an earthquake.