Ocean researchers say the March 11 earthquake off the coast of north east Honshu, believe the quake was more powerful than 9.0.

The Japan Agency for Marine-Earth Science and Technology, studied the sea floor at the epicenter of the March 11 quake, using a deep sea research vessel named “Kairei”.  They determined that the sea floor rose 7 meters (23 feet), and moved 50 meters (164 feet).

The scientists say that the earthquake had to be more powerful than 9.0, in order to raise the sea floor 23 feet.