A powerful magnitude 7.6 earthquake and multiple aftershocks have struck off the coast of New Caledonia in the Loyalty Islands.
The first quake, which struck about 3.30pm AEDT, appears to have been shallow — at just 10km beneath the Earth’s surface.
At least five aftershocks also hit, ranging in magnitude from 5.6 to 6.0, within about 90 minutes.
The Pacific Tsunami Warning Centre immediately issued a warning that hazardous tsunami waves could possibly affect locations up to 1000km away — including New Caledonia and Vanuatu – and that tsunami waves had been observed.
The PTWC had said tsunami waves of between one and three metres were possible, while waves of up to one metre were possible in Fiji, but there were no initial reports of destructive waves or major damage.
The first tsunami wave reading in New Caledonia was just 38cm but in its official warning the PWTC noted: “A tsunami is a series of waves and the time between waves can be five minutes to one hour.”
Authorities in the French South Pacific territory urged people to move to locations more than 300 metres distant from the shore, and if possible, to sites higher than 12 metres above sea level.
“We have set off the alarm on the exterior of New Caledonia but we don’t have any immediate assessment of potential damage,” said a spokeswoman for the Directorate for Civil Protection and Risk Management.
Residents also received text messages directing them to go to refuges.
But people in New Caledonia and nearby Vanuatu said they did not feel the quake, and tsunami warning sirens were not immediately activated in Vanuatu.
Judith Rostain, a freelance journalist based in New Caledonia’s capital Noumea, said there was no damage to the city and that the threat of a tsunami appeared to have passed. She said the situation remained unclear on the east coast and scattered outer islands.
Dan McGarry, the media director at the Vanuatu Daily Post, said he heard only of three small wave surges hitting the southern island of Aneityum. He said the waves traveled only about two metres beyond the normal tidal waves, and that everybody was fine on the island.
McGarry said he felt the quake where he is based in Vanuatu’s capital, Port Vila, as a mild shaking.
“We get a lot of earthquakes every year,” he said. “The tsunami warning was what was different this time, though.”
The warning center said there was no threat to Hawaii.
— EMSC (@LastQuake)
There is no tsunami threat to New Zealand following the 7.6M SOUTHEAST OF LOYALTY ISLANDS earthquake.— MCDEM (@NZcivildefence)
According to the US Geological Survey, the quake struck about 168 kilometres east of Tadine in New Caledonia at a shallow depth of 10 kilometers. Earthquakes are generally more destructive when the epicentre is near the surface.
An automated assessment of the threat posed by the quake, generated by the US Geological Service, placed the prospect of economic loss and fatality as very low.
A spokesman for French mining and metals group Eramet , which operates the Doniambo nickel plant in the main harbour of Noumea, said it had enacted its tsunami alert process.
“The procedure is to ask people who work near the sea to move higher up,” he said, adding that he had felt the quake, describing it a strong but not long- lasting shaking.
New Caledonia sits on the Pacific “Ring of Fire,” the arc of seismic faults around the Pacific Ocean where most of the world’s earthquakes and volcanic activity occur.