A 6.4 earthquake struck Vanuatu but there was no immediate tsunami warning or reports of casualties.
The US Geological Survey said the quake struck just after 6 o'clock yesterday evening, and was 320 kilometres north of the capital Port Vila,
The quake was registered at a depth of 35 kilometres.
Two aftershocks with magnitudes of 5.4 and 5.3 struck roughly the same spot in the next half hour.
The Pacific Tsunami Warning Centre in Hawaii did not issue a tsunami alert for the region.