Tohoku University Professor, Toru Matsuzawa, says the biggest earthquake we should expect is magnitude 10.  This is based on the Earth’s size and known faults (which have been increasing).

Last year japan suffered a magnitude 9 quake.  In 1960 Chile got hit by a magnitude 9.5 quake.  A magnitude 10 earthquake will be 32 times more powerful than a magnitude 9!

Toru Matsuzawa says a magnitude 10 tembler would happen if an 8,800 kilometers (5,468 miles) fault line around the northern Pacific Rim shifted 20 meters (65.6 feet).  It would shake the earth for 20 minutes to an hour, and create tsunamis that last for days.

He says he is only warning people so they can prepare for the worst case scenario, after all, the people of Japan had always been told by officials that the strongest quake they could expect was magnitude 8, with three meter high tsunamis, and look what happened on 11 March 2011.