A magnitude-7.2 earthquake struck north-eastern Japan on Saturday and authorities have issued a tsunami warning for the prefecture of Miyagi.
The first tsunami wave has already swept ashore in Miyagi, according to broadcaster NHK.
There were no immediate reports of casualties or damage to property. The quake also shook buildings in Tokyo.
The seismic centre of the quake that rattled the region at 6:09 pm (0909 GMT) was off Miyagi, said the Japan Meteorological Agency.