This window shows the construction of actual seismograms, the records of passing earthquake waves, at three different seismic stations from the world-wide network. For example, as the red P waves arrive at each of the selected stations, whose locations are shown on the lower windows, they register on the seismogram of the upper window. The sounds you hear are generated by speeding up the seismic waves 16000 times so that they become audible. Note that the farther a station is from the earthquake epicenter, the longer the seismic waves take to arrive.
