It is theoretically possible that the world could see a quake with a magnitude of around 10, a researcher at Tohoku University told the government's Coordinating Committee for Earthquake Prediction, Japan.
The energy of such an earthquake would be 30 times greater than the magnitude 9.0 quake that hit the northeast on March 11, 2011.
"The estimate does not mean that a magnitude 10 quake will inevitably happen," said Toru Matsuzawa, a professor at the university's Research Center for Prediction of Earthquakes and Volcanic Eruptions. "If it happens, it would take place around once every 10,000 years."
A magnitude 10.0 quake could occur if the combined 3,000 km of faults from the Japan Trench to the Kuril-Kamchatka Trench move by 60 meters, Matsuzawa said.
No magnitude 10 earthquake has ever been observed. The most powerful quake ever recorded was a magnitude 9.5 temblor in Chile in 1960.
A magnitude 10 quake would likely cause ground motions for up to an hour, with tsunami hitting while the shaking was still going on, according to the research. Tsunami would continue for several days, causing damage to several Pacific Rim nations.