This demonstration of earthquake location uses triangulation on a globe. It requires seismograms and travel-time curves (the site explains where to obtain these), string, and a globe. Since P waves travel faster than S waves, the time difference between the arrival of the P wave and the arrival of the S wave depends on the distance the waves traveled from the source (earthquake) to the station (seismograph). Students will measure the time difference between the P and S wave arrival using a seismogram. Then they will use the travel-time curves to find the distance that corresponds to this time difference. Next, students will measure this distance on the globe using the string and locate the earthquake using the distances from three stations.