KEY POINTS:
A tsunami warning has been issued for the north-west of Japan after a quake measuring 7 on the Richter scale at 2.39pm NZT.
The Japanese public broadcaster NHK said the quake registered 4 on a Japanese scale of 7.
The website weather.org said the an after-shock measuring 5.3 struck minutes later at a depth of 135km of the coast of Honshu.
- NZ HERALD STAFF
