When did Tohoku earthquake happen?

The magnitude 9.0 earthquake off the shore of Japan occurred at 2:46 p.m. (local time) on March 11, 2011. The U.S. Geological Survey agency said this was the biggest quake to hit Japan since record-keeping began in the late 1800s and one of the biggest ever recorded in the world.

A timeline of events on March 11 and following days can be found here. More details of the 2011 Tōhoku earthquake can be found here.