Major Quake, Vanuatu

A major undersea earthquake struck near Vanuatu overnight, generating a small tsunami wave.

Sunday 26th December 2010

A magnitude 7.3 earthquake struck 145 km west of Isangel on the island of Tanna, Vanuatu (195 km north of Tadine in the Loyalty Islands, 230 km south of Port Vila, Efate, Vanuatu) at 2:17 this morning, New Zealand Daylight Time. The quake was 12 km deep, according to the U.S. Geological Survey.

Geoscience Australia reports the quake as magnitude 7.6 at a depth of 11 km. It estimates that the quake would have caused damage within 180 km of the epicentre, and would have been felt up to 2300 km away.

The Pacific Tsunami Warning Centre issued three bulletins for this event. Initially reporting the quake as magnitude 7.6 at 2:26 NZDT, it had revised the magnitude to 7.3 in its final bulletin issued at 3:45 a.m. NZDT. By this time a wave gauge at Vanuatu had reported an increase in sea level of 15 cm. Tsunami warnings were issued for Vanuatu, New Caledonia and Fiji but these were cancelled in the 3:45 a.m. bulletin.

New Zealand’s Ministry of Civil Defence and Emergency Management issued one bulletin for this event. Issued at 2:55 a.m. its advisory stated there was no threat to New Zealand.

Twelve aftershocks with magnitudes between 5.0 and 5.6 have struck the Vanuatu region since the main event.

[Compiled from data supplied by the U.S. Geological Survey and its contributing agencies, the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre, and Geoscience Australia.]

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