A powerful 7.3-magnitude earthquake struck off the western Pacific nation of Vanuatu on Sunday, triggering a small tsunami exactly six years after giant waves killed 220,000 people around the Indian Ocean.
The Hawaii-based Pacific Tsunami Warning Center said that the shallow quake generated a tsunami, but it cancelled a regional warning after the wave measured only 15 centimetres (six inches) higher than normal in Vanuatu.
"Sea level readings confirm that a tsunami was generated," the centre said in its bulletin.
"This tsunami may have been destructive along coastlines of the region near the earthquake epicentre," it said, but cancelled the warning when no destructive wave hit.
The quake struck at 12:16 am on Sunday (1316 GMT Saturday), and the initial tsunami warning covered Vanuatu, Fiji and the French Pacific territory of New Caledonia. There were no reports of damage or casualties.
Jackie Philip, a member of staff at the Melanesian Port Vila Hotel in the Vanuatu capital, said the hotel was busy with late-night Christmas revellers when the quake struck.
"Some of us, we ran outside and stood and watched the sea for a few minutes but nothing happened. There is no damage and no injuries," he said, adding that no tsunami warning had been given on local radio.
A receptionist at Port Vila's Grand Hotel called it a "small" earthquake, adding that calls to the meteorological office went unanswered. Staff at the nearby Island Magic Hotel also said there had been no local tsunami warning.
"We haven't had any notification of a tsunami," a worker said. "We definitely felt the earthquake but we are notified if there's actually a tsunami."
Meteorological and disaster management officials were not available for comment when contacted.
The US Geological Survey said that the quake was just 12.3 kilometres (7.6 miles) deep, and its epicentre was 145 kilometres (90 miles) west of Isangel, on the island of Tanna - home to an active volcano - in the Vanuatu archipelago.
The USGS revised its initial readings for the magnitude and distances involved, after first recording the quake at 7.6.
At least a dozen aftershocks of magnitude 5.0 or greater hit the area after the main tremor, according to USGS, including a powerful 6.2-magnitude shock some 12 hours after the initial quake.
Vanuatu, which lies between Fiji and Australia and north of New Zealand, is part of the "Pacific Ring of Fire" - an ocean-wide area alive with seismic and volcanic activity caused by the grinding of enormous tectonic plates.
Sunday's quake came on the sixth anniversary of one of the worst natural disasters of modern times, when a huge tsunami triggered by an undersea quake off Indonesia killed more than 220,000 people around the Indian Ocean.
After the disaster, which came with little or no warning for millions of coastal residents, regional governments deployed a string of monitoring buoys in the Indian and Pacific Oceans to keep track of any abnormal waves.
In August, a 7.5-magnitude earthquake off Vanuatu generated a small tsunami and sent thousands of frightened people running for the hills.
In September last year, Samoa in the Pacific suffered its worst natural disaster when three rapid-fire quakes of up to 8.1 magnitude unleashed waves as high as 15 metres (50 feet) that flattened villages and tourist resorts.
The seismic catastrophe claimed 143 lives in Samoa, 34 in the US-administered territory of American Samoa and another nine in Tonga.
Vanuatu lies between Australia and Fiji and has a population of 220,000 scattered across several islands including Tanna, south of Port Vila, where the fiery Yasur volcano is a major tourist draw.