A state of emergency has been declared at a nuclear power plant but officials said there were no radiation leaks.
At least 60 people have been killed by the quake, which struck about 400km (250 miles) north-east of Tokyo.
The tremor, measured at 8.9 by the US Geological Survey, hit at 1446 local time (0546 GMT) at a depth of about 24km.
A tsunami warning was extended across the Pacific to North and South America.
Source: BBC News