A powerful 6.9-magnitude earthquake struck off Vanuatu Sunday, but a tsunami threat passed with no immediate reports of major damage along the coasts of the Pacific archipelago.

The quake, initially reported as 7.2 magnitude, struck at a depth of 35 kilometers (22 miles), 81 kilometers north-northwest of the town of Port Olry on Espiritu Santo island in Vanuatu at 0823 GMT, the United States Geological Survey said.

A powerful 7.3-magnitude earthquake struck off Vanuatu in the Pacific Ocean on Wednesday, but no tsunami threat was detected and no damage reported, seismologists said.

The quake hit at a depth of 131 kilometers (81 miles) about 335 kilometers from the capital Port Vila, the United States Geological Survey said.

Residents in storm wrecked areas of Micronesia appealed for help Thursday as a clean up began on the worst affected islands after Super Typhoon Maysak swept through the region on its way towards the Philippines.

"We can do with all the help we can get," Courtney Stinnett at the Truk Stop Hotel dive shop on the main island of Weno in Chuuk state told Agence France Presse.

The death toll from Vanuatu's devastating cyclone was revised down to 11 on Monday, according to the United Nations which also said contributions to the South Pacific nation's recovery have topped US$10 million. 

The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) had on the weekend put the number of fatalities at 16, but its latest update noted that the Vanuatu government had advised the number was 11.

More than half of the South Pacific island nation Vanuatu's population has been affected by Cyclone Pam, the U.N. said Saturday as the death toll rose to 16.

Severe Tropical Cyclone Pam barreled into the archipelago a week ago, bringing sustained winds of some 250 kilometers (155 miles) per hour which devastated entire communities.

Vanuatu has hit out at aid groups swarming the cyclone-ravaged Pacific nation over a lack of coordination, which it said cost precious time getting help to those in need, while warning food will run out in a week.

Relief agencies have been battling logistical challenges in the sprawling archipelago with a lack of landing strips and deep water ports hampering their efforts to reach distant islands and get a better grip on the full scale of the disaster.

Northeastern Australia battened down Thursday in preparation for a strong cyclone forecast to hit coastal areas north of Cairns, one of the gateways to the Great Barrier Reef.

Tropical Cyclone Nathan, currently a category three storm, was tracking back towards the Cooktown area, some 260 kilometers (160 miles) from popular tourist destination Cairns, having first threatened the coast last week before moving out to sea.

Aid began arriving in some of cyclone-hit Vanuatu's worst affected islands Wednesday but others remain isolated, with flights over the Pacific nation showing desperate villagers spelling out the letter "H" for help.

Relief agencies are battling logistical challenges in the sprawling archipelago with a lack of landing strips and deep water ports hampering their efforts to reach distant islands and get a better grip on the full scale of the disaster.

Aid began arriving in some of cyclone-hit Vanuatu's worst affected islands Wednesday but others remain isolated, with flights over the Pacific nation showing desperate villagers spelling out the letter "H" for help.

Relief agencies are battling logistical challenges in the sprawling archipelago with a lack of landing strips and deep water ports hampering their efforts to reach distant islands and get a better grip on the full scale of the disaster.

The death toll from Cyclone Pam has been revised from 24 to 11 in Vanuatu, the U.N. said, with storm damage still limiting access to affected areas.

The U.N. lowered its earlier toll, citing figures from the Pacific nation's disaster office.