A strong 6.4 magnitude earthquake hit near the South Pacific island nation of Vanuatu on Monday but no tsunami warning was issued, the US Geological Survey said. There were no immediate reports of damage from the quake, which hit at 4:21 am (1721 GMT Sunday) at a depth of 33 kilometres (20 miles), 125 kilometres from the town of Isangel on Tanna island, USGS said.
Geoscience Australia recorded it as 6.5 magnitude at a depth of 60 kilometres. The quake was the strongest of a series of aftershocks following a 6.6 magnitude quake which hit Sunday, the latest in a series of undersea tremors near the island, which is home to an active volcano.
A powerful 7.3-magnitude earthquake struck the area on December 26, triggering a small tsunami exactly six years after giant waves killed 220,000 people around the Indian Ocean, but there were no reports of damage or casualties.
The Pacific Tsunami Warning Center said no warnings or advisories were in effect following the latest quake.
Vanuatu, which lies between Fiji and Australia and north of New Zealand, is in the "Pacific Ring of Fire" known for its seismic and volcanic activity caused by friction between moving plates in the Earth's crust.