In this multi-part activity, students study seismograms from 3 different seismic stations recording the magnitude 9.0 Sumatra earthquake of December 26th, 2004. By comparing the arrival times of the P and S waves on each seismogram, students determine the distance from the epicenter to each station. Using that data, they can accurately map the location of the epicenter and the precise time of the earthquake. After locating the epicenter, students calculate the position of the tsunami generated by the quake at one hour intervals. From those determinations, predictions are made about how much time people had before the tsunami crashed onto their shores. Finally, students investigate some of the ways people can lessen the impact of the next great tsunami.