The devastating tsunami that struck Japan last March killed more than 15,000 people, disrupted power and services across the country and crippled the Fukushima Dai-ichi nuclear power plant. The massive waves were triggered by a 9.0-magnitude earthquake that gave the sea floor a huge shove toward Honshu, Japan's largest island.
But exactly how much the earth moved in the quake has been unclear — until now.
A new look at the sea floor before and after the 2011 Tohoku earthquake reveals massive shifts in the ocean crust. Energy from the uplifted sea floor — which was thrust 164 feet (50 meters) horizontally and 33 feet (10 meters) vertically — triggered the immense tsunami waves that struck the coast of Japan.
Massive Sea-floor Shove Triggered Japan's Tsunami
