Wellington - A tsunami began travelling across the Pacific on Thursday towards New Zealand and Tonga after a powerful 7.7-magnitude undersea earthquake, the Pacific Tsunami Warning Centre said.
Tsunami waves were measured off Raoul Island, one of New Zealand's Kermadec Islands, up to a height of 84cm above normal sea level, the centre said.
“Sea level readings confirm that a tsunami was generated,” the centre said. “This tsunami may have been destructive along coastlines of the region near the earthquake epicentre.”
The tsunami could reach Tonga by 20h17 GMT and the eastern coast of New Zealand by 20h52 GMT, the centre added, advising that if there were no damaging waves for two hours after the initial warning, local authorities could assume the threat had passed.
The earthquake struck at 19h03 GMT on Wednesday at a depth of just one kilometre, the United States Geological Survey (USGS) said.
Its epicentre was 160km east of Raoul Island and 914km from the Tongan capital, Nuku'alofa.
USGS revised the quake's magnitude slightly downward from an earlier reading of 7.8. - Sapa-AFP