According to NOAA: 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(R) buoy 21418. Forecast results shown below were created with the NOAA forecast method using MOST model with the tsunami source inferred from DART(R) data. The graphics display forecast results, showing qualitative and quantitative information about the tsunami, including tsunami wave interaction with ocean floor bathymetric features, and neighboring coastlines. Tsunami model amplitude information is shown color-coded according the scale bar. Model amplitudes calculated with the MOST forecast model. Filled colors show maximum computed tsunami amplitude in cm during 24 hours of wave propagation. Black contours show computed tsunami arrival time.
Additional information at NOAA