Tsunami Revelations: Scientists Discover that the Japanese Tidal Wave Was a 'Merged Tsunami' — the First Ever Observed

The tsunami that tore through northern Japan on March 11 was catastrophically strong. The waves—triggered by a 9.0 earthquake—swamped coastal towns, destroyed homes and offices and led to the deaths of nearly 16,000 people. (For a chilling look at the devastation, check out these photos by the Japanese photographer Kishin Shinoyama.) The tsunami also led to a meltdown at the Fukushima Dai-ichi nuclear plant, resulting in the worst atomic accident since Chernobyl—with long-term effects that are still up for debate.

Obviously the sheer power of the quake helps explain why the tsunami was so devastating—but that's not the only reason. Scientists from NASA and Ohio State University now say that the waves were actually a "merged tsunami," and that the phenomenon doubled the power of the disaster.

Satellites from NASA and European agencies show at least two wave fronts created by the quake—not just one as you might expect from a single quake. Those wave fronts merged to form a single, double-high wave out to sea. As it traveled towards land, ocean ridges and undersea mountains pushed the wave fronts together, keeping the tsunami stable even as it hurtled towards the coast.      Full Read