Photo courtesy of Reuters
Aid agencies are voicing concern for the Asia Pacific region as tsunami warnings are issued.
The Red Cross and Red Crescent Societies have said that waves reaching more than one metre high could wash right over some islands in the Pacific.
Al Jazeera's Harry Fawcett, reporting from Kuala Lumpur, the Malaysian capital, said the potential effects of this "could spread very rapidly over the next few hours".
Some of the nations for which the US Pacific Tsunami Warning Centre has issued alerts for includes: Russia, Taiwan, the Philippines, Indonesia, Papua New Guinea, Australia, New Zealand, Fiji, Mexico, Guatemala, El Salvador, Costa Rica, Nicaragua, Panama, Honduras, Chile, Ecuador, Colombia, Peru and Canada.
However not all of those nations are issuing their own alerts. The Tsunami Warning Centre of Australia has denied a threat to the country, and in New Zealand, which was recently hit by a devastating earthquake, Civil Defence has not issued its own warning, saying it was assessing the threat.
Tsunami warnings are being issued around the Pacific, from the coast of Russia and Hawaii to Australia and New Zealand.
In Taiwan, the coast guard has been evacuating its east coast with waves 50cm high expected to reach the island later in the day. Hawaii has been making similar moves, with tsunami waves expected to hit within the next three hours.
Google has launched an online service for people to post and search for information about victims: http://japan.person-finder.appspot.com
Friday's massive earthquake is Japan's biggest ever and the seventh largest on record, according to data from the US Geological Survey.
Those others include the 9.1 magnitude earthquake that struck Indonesia on December 26, 2004 which left more than 220,000 people dead.
The biggest earthquake on record was a 9.5 one off the coast of Chile in May 1960, that killed around 1,600 people.