Northern Japan lies on a southward projection of the North American Plate and, off its east coast, the Pacific Plate is subducting beneath it; friction along this subduction zone pulls down the edge of the North American Plate and, eventually, the Plate rebounds, triggering an earthquake and lifting the overlying ocean.
Today's massive quake, the most powerful in Japan's recorded history, measured 8.9 on the Richter scale and sent a wall of water across the northeast coast of that island nation. While most destructive close to the earthquake, the tsunami will propagate in all directions, affecting islands and coastlines along and across the Pacific. The axis of maximum energy is projected to pass through Hawaii and toward South America but tsunami warnings have been posted from Alaska to New Zealand, including much of the U.S. West Coast.
Widespread destruction and numerous deaths will surely be reported in Japan and the effects of this powerful earthquake will no doubt produce emotional, physical and economic damage across the globe. In this respect, the tsunami will spread well beyond the Pacific Basin.
