Key events
Gavin Blair
20 earthquakes of magnitude 4 or stronger have struck off the coast of Ishikawa and neighbouring Niigata prefectures between 4.06pm and 5.29pm local time.
The strongest earthquake now estimated at magnitude 7.5.
Blackouts and burst water mains have been reported in towns in the affected area, while major roads are being closed due to cracks and other damage.