A shallow 6.9-magnitude earthquake hit off the coast of the South Pacific island of Vanuatu late on Thursday, the US Geological Survey said, but there was no tsunami warning.
There were no immediate reports of casualties or damage.
The quake struck at a depth of 10 kilometres, around 122 kilometres west of the capital Port Vila.
The Hawaii-based Pacific Tsunami Warning Centre issued an information bulletin but no alert, saying “no destructive widespread tsunami threat exists based on historical earthquake and tsunami data”.
The earthquake hit shortly after midnight (local time), USGS said.
