This draft page includes a discussion about the tsunami. I mention shortly how the earthquake led to the tsunami, then discuss the observations of the tsunami, and follow up with a short discussion about the paleotsunami research.
The M9.0 earthquake displaced the seafloor where the fault reaches the seafloor in the subduction zone trench. The deformation was resolvable with multibeam bathymetric data.
The seafloor deformation caused the overlying sea water to move upwards. The gravitational relaxation and oscillation of the water column generated the tsunami. NOAA (and others) generated some models of the sea surface height so they could estimate where there might be tsunami waves across the Pacific. As the waves propagate across the ocean, tide gages and bouys measure actual wave heights that may or may not match the model outputs. Below are some of the maps that were generated in real-time during the tsunami (and some created later).
Here are the model outputs:
Here is the NOAA source web page for a widely used map of modeled sea surface elevations:
Here is the original map as provided by NOAA:
Here are the model outputs with plots of real measurements:
Here is a “Travel Time” map for the Tohoku-Oki Tsunami: