Japan earthquake: Thousands in shelters overnight after tsunami warnings
BBC
Four people are confirmed to have been killed, the Kyodo news agency reports, and dozens of others have been injured.
An unknown number of people are trapped beneath the rubble of collapsed buildings in several towns.
The 7.6-magnitude quake struck at around 16:10 local time (07:10 GMT) on Monday. Tsunami warnings were issued and later downgraded.
About 60 tremors have been recorded following the initial quake.
A snowboarder on holiday in Japan's Hakuba Alps said his entire hotel room shook. Speaking to Reuters, Baldwin Chia said he was concerned about avalanches but hadn't received reports of any taking place.
He said it was common to hear about earthquakes in Japan, but "you wouldn't expect to actually experience one".