Japan quake death toll rises to 90, XInhua reported according to NHK.
The Japan Meteorological Agency (JMA) has upgraded the magnitude of the earthquake from 7.9 to 8.4 and later revised it up to 8.8.
The U.S. Geological Survey reported the earthquake at 8.9 on the Richter scale.
The epicenter the quake, which occurred at 2:46 p.m.(0546 GMT), was located some 130 km east of the Miyagi Prefecture at a depth of 24.4 km under the sea, said the JMA.
After the great quake occurred, all cabinet ministers were summoned to the prime minister's office and a crisis management team were set up there.
In Tokyo and surrounding areas, up to 4 million homes suffered a power cut.
And Tokyo metropolitan expressways as well as Tokyo subways and suburban rail services were also closed following the quake. But no big collapses were reported in Tokyo expressways.
In Miyagi Prefecture, Sendai airport was closed. A major power outage and gas leaks were reported in a number of areas in Sendai city, capital of the prefecture.
Meanwhile, numerous people were injured, local media reported, citing Miyagi prefecture police.
In Iwate Prefecture, a four-meter-high tsunami was observed and dozens of cars and buildings were washed away.
In Fukushima Prefecture, two nuclear plants on Pacific coast were automatically shut down.
The quake affected the nation's key transportation systems, including Narita airport, which were closed for safety checks of its runways.
