Professor Susumu Yasuda of Tokyo Denki University conducted a survey of the effects of liquefaction, caused by the 11 March 2011, 9.0 quake.

He looked at the Tokyo Bay area and found at least 4,200 hectares (10,378 acres) of land had suffered liquefaction.  Tokyo is 370km (230 miles) from the quake’s epicenter.

Liquefaction also destroyed residential areas built on reclaimed land in Chiba Prefecture.

Professor Yasuda says more liquefaction will occur in the future unless the underground water is removed and the ground solidified.  Left on its own the ground will take more than 100 years to stabilize.