tsunami, scientists are trying to understand what exactly triggered such enormous waves professor stephan grille have been looking for clues under the sea and could have found the answer. waves of more than 20 meters hit the coast of iwate prefecture less than one hour after the earthquake. the professor's team studied the seabed 190 kilometers northeast of the quake focus. they noted it had changed shape after the disaster. researchers believe a landslide may have occurred under the sea immediately after the tremor. the landslide triggered a series of waves that came on top of the original tsunami. the team says the results of its simulations concur with the actual height of the waves that hit japan's pacific coast. >> if we can confirm this and we're running additional simulations to verify that this is really what happened, then it means a lot for tsunami hazard assessment, for risk mitigation, for the future. >> the researchers say they want to work with japanese counterparts to inspect the site of the landslide. >>> people in northeastern japan are reminded daily of what they lost on march