Phew. No tsunami after giant earthquake.

A giant earthquake of magnitude 7.8 to 8.1 struck the Tonga Islands and triggered tsunami warnings. From Reuters:

Islands from New Zealand to Fiji were immediately warned of a possible tsunami following reports of a powerful underwater tremor, whose force is classified as "great" by the US Geological Survey.

The tremor's epicentre was 95 miles south of Tonga's Neiafu island, and 1,340 miles northeast of Auckland, striking at 4.26am local time (1626 BST). If the quake has triggered a tsunami, early predictions suggest that the waves would reach Auckland at 7.21am (1921BST).

So far, there are no reports of any tsunami. From smh.com.au:

"It was the biggest quake we've ever felt," a Tongan police officer told Sky News, adding that it "lasted about one minute and 30 seconds".

Police had no immediate reports of damage or tsunami in the capital Nuku'alofa.

A witness on the island, however, said the electricity grid had gone down in the aftermath of the quake.

Television reports said the quake was felt in several islands around Tonga.

New Zealand, one of the countries that was given the tsunami warning initially, was later given the all clear but officials there are still preparing for a possible tsunami. From TV NZ:

A tsunami warning was initially issued for Fiji, Tonga and New Zealand but that has since been amended.

It's still not known if a tsunami has been generated, but warnings are still in place for Tonga, Niue, American Samoa, Samoa, Wallis Futuna and Fiji.

There were initial fears that any tsunami created by the quake would strike Gisborne after 6am.

Thankfully, fears of a tsunami hitting the Pacific coast is now over. The Pacific Tsunami Warning Center who issued the initial warnings, have now cancelled them. From the Pacific Tsunami Warning Center Bulletin:

SEA LEVEL READINGS INDICATE A TSUNAMI WAS GENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONG COASTS NEAR THE EARTHQUAKE EPICENTER. FOR THOSE AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS. AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES.

NO TSUNAMI THREAT EXISTS FOR OTHER COASTAL AREAS IN THE PACIFIC ALTHOUGH SOME OTHER AREAS MAY EXPERIENCE SMALL SEA LEVEL CHANGES. THE TSUNAMI WARNING IS CANCELLED.