Record-breaking ocean drilling reveals why Japan's 2011 tsunami was so deadly

Scientists have uncovered a hidden weakness beneath the Pacific Ocean that helps explain why Japan’s catastrophic 2011 earthquake and tsunami became so devastating. By drilling deeper into the seafloor than ever before, researchers discovered a thin, slippery layer of ancient clay that allowed the massive rupture to race all the way to the ocean floor, triggering enormous seafloor movement and a powerful tsunami.