The quake struck early on Wednesday at a depth of 10km, the GFZ said.
While the full extent of the devastation in Vanuatu remains unclear, Australia will be among countries deploying assistance to the earthquake-struck Pacific nation.
At lunchtime on Tuesday, a 7.3 magnitude tremor rattled nearby Port Vila for 30 seconds, causing destruction in the capital.
A building housing the United States, United Kingdom, French and New Zealand diplomatic posts was among the worst hit, with the bottom floor of the US embassy crushed by the above floors.
Remarkably, the US and other nations have reported all of their staff to be safe.
Others have not been so lucky.
"Many victims in the country, flights suspended, communications cut, no water or electricity, we are organising relief," French ambassador to Vanuatu and Solomon Islands, Jean-Baptiste Jeangene Vilmer, posted on social media.
Très fort tremblement de terre au Vanuatu, ambassade détruite (déchirée en 2, rez-de-chaussée ambassade 🇺🇸 écrasée), personnel sain et sauf mais nombreuses victimes dans le pays, vols suspendus, comm coupées, ni eau ni électricité, organisons secours 🇫🇷🇦🇺🇳🇿., num urgence à venir — Jean-Baptiste Jeangène Vilmer (@jeangene_vilmer) pic.twitter.com/IZjr2VjVGuDecember 17, 2024
In a broadcast by news outlet VBTC, caretaker Prime Minister Charlot Salwai issued a state of emergency for seven days, and instituted a curfew - except for essential services - from 6pm to 6am.
It is not yet clear how many people have been injured or lost their lives, owing to telecommunications failures after the earthquake.
Those that were able to communicate with the outside world were largely able to do so through Starlink, including journalist Dan McGarry.
"I know of one fatality according to police stationed at Port Vila Central Hospital, and I saw with my own eyes three others on gurneys ... I'm expecting the casualty figure to rise," he told AAP about three hours after the earthquake.
Mr McGarry has documented landslips around the capital, including a major blockage of a key road near the country's chief international port, in addition to destruction of buildings.
Many photos on social media show collapsed buildings, one which has crumpled cars underneath.
"People died and many more were hurt. Some have lost their home, and many will find it hard to get back to work. Repairs will likely stretch for years, as they always do in the wake of disaster," Mr McGarry posted on X.
"But people are pulling together as only Vanuatu knows how. We will get through this. We always do."
More than 80 islands make up Vanuatu, and it is also unclear how the 350,000-strong population is faring in towns and settlements outside the capital.
Australian Foreign Minister Penny Wong called the disaster a "dreadful tragedy," and with acting Pacific Minister Matt Keogh, said Australia would be rushing to its neighbour's aid.
"Australia stands with the people of Vanuatu ... we are family and we will always be there in times of need," the pair said in a statement.
"Early reports indicate that significant damage has occurred. The Australian government is preparing to deploy immediate assistance (from Wednesday), including urban search and rescue and emergency medical teams.
"We are closely monitoring the situation and stand ready to provide further assistance to the people of Vanuatu as the extent of damage becomes clear."
The Australian Government is preparing to deploy immediate assistance to Vanuatu from tomorrow, including urban search and rescue and emergency medical teams. — Senator Penny Wong (@SenatorWong) We're closely monitoring the situation and stand ready to provide further assistance to the people of Vanuatu.December 17, 2024
Mr Jeangene Vilmer said France was working with Australia and New Zealand to co-ordinate the disaster response.
The disaster has also occurred at a moment of political turmoil in the Melanesian country.
Mr Salwai dissolved parliament last month, setting the stage for a snap election on January 14, only for opposition MPs to mount a constitutional challenge to his move.
While a first case was dismissed by the Supreme Court last week, former prime minister Ishmael Kalsakau has announced they are appealing that judgment - which was due to be heard before Christmas.
with reuters
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