NASA and Ohio State University researchers have discovered the major tsunami generated by the March 2011 Tohoku-Oki quake centered off northeastern Japan was a long-hypothesized "merging tsunami." The tsunami doubled in intensity over rugged ocean ridges, amplifying its destructive power at landfall.
Data from NASA and European radar satellites captured at least two wave fronts that day. The fronts merged to form a single, double-high wave far out at sea. This wave was capable of traveling long distances without losing power. Ocean ridges and undersea mountain chains pushed the waves together along certain directions from the tsunami's origin.
The discovery helps explain how tsunamis can cross ocean basins to cause massive destruction at some locations while leaving others unscathed. The data raise hope that scientists may be able to improve tsunami forecasts. (read more)