“The Honshu tsunami was generated by a Mw 8.9 earthquake (38.322°N, 142.369°E ), at 05:46 UTC, 130 km (80 miles) E of Sendai, Honshu, Japan (according to the USGS). In approximately 25 minutes, the tsunami was first recorded at DART® buoy 21418. Forecast results shown below were created with the NOAA forecast method using MOST model with the tsunami source inferred from DART® data.” (Source)
Much more information about this tsunami is available by the NOAA Center for Tsunami Research.