For the last few years, a group of international scientists has been reassessing the cause of the March 2011 tsunami that inundated the Tohoku coastline.
The common view among seismologists is that the tsunami was caused solely by the magnitude-9.0 earthquake that struck in the Pacific Ocean about 150 km off the coast of Miyagi Prefecture.
But a group of scientists led by Dave Tappin, a professor of marine geology at the British Geological Survey, believes the explanation is more complex.