On March 11, 2011 at 2:45 p.m. local time, a 9.0 magnitude earthquake occurred 81 miles 130 km off the east coast of Sendai, Honshu, Japan, triggering a massive tsunami. A tsunami is a series of ocean waves generated by sudden displacements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. The tsunami wave may come gently ashore or may increase in height to become a fast moving wall of turbulent water several meters high. Forecasted wave heights in Japan were up to 66 ft 20 m and there were many reports of tsunami waves three stories high in parts of Japan. Across the Pacific Ocean, many countries issued evacuations along the coasts because of the predicted tsunami waves. Propagation of the tsunami was computed with the NOAA forecast method using the MOST Method of Splitting Tsunami model with the tsunami source inferred from DART data. Approximately 25 minutes after the earthquake, the tsunami was first recorded by one of the DART buoys. Each yellow dot represents one these DART buoys for measuring intensity and wave height.