The top image is a wave height model of the Pacific in the wake of the tsunami triggered by today’s 8.9 magnitude earthquake off Japan. The waves are tallest near the earthquake epicenter and lessen with increasing distance, growing taller in coastal zones (but also decreasing in size with distance). Tsunami waves extend through the entire water column to the ocean floor, unlike surface waves, so the faster the seafloor bathymetry changes from deep to shallow areas (second image shows 3D bathymetry offshore of Japan), the taller the waves could become. The epicenter of this event was relatively close to shore, ultimately reducing the amount of water displaced, but still affecting much of the Pacific.
You can see NOAA’s animation of the tsunami propagation below:
Update: For a narrated version of the NOAA animation, you can go here.
Images from the NOAA Environmental Visualization Laboratory (NOAA and NOAA Center for Tsunami Research). See here and here for more information about how they were created and for some of the physics behind tsunamis. Video from Youtube user ExWeather with NOAA data.
h/t pourmecoffee on Twitter for the NOAA images