Japan's meteorological agency has reported that the quake struck at local time of 2.46 pm, some 80 miles off the country's east coast and at a depth of around eight kilometers at an original intensity of 7.9 which was later upgraded.
The agency has also mentioned the possibility of a tsunami following the undersea earthquake. The Pacific Tsunami Warning Centre said top-level evacuation alerts for the entire Japanese coast, Russia and the Mariana Islands.
Further details are awaited.