Question: the great east japan earthquake struck japan on
Answer: 1 ( M ) undersea megathrust earthquake off the coast of Japan that occurred at 14 : 46 JST ( 05 : 46 UTC ) on Friday 11 March 2011 , with the epicentre approximately 70 kilometres ( 43 mi ) east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 29 km ( 18 mi ) .