Major Quake, Fiji

A major undersea earthquake of seventh magnitude struck Fiji just before midnight New Zealand time.

Tuesday 10th October 2009

A very deep magnitude 7.2 earthquake struck mid-way between Fiji’s two main islands of Viti Levu and Vanua Levu at 11:45 p.m. New Zealand Daylight Time on Monday night. The quake, which was 585 km deep, was centred 100 km north of the Fijian capital Suva, 135 km south-west of Lambasa, Vanua Levu.

The Pacific Tsunami Warning Centre issued two bulletins for the event. The first bulletin, issued at 1154 p.m. NZDT, reported the quake at magnitude 6.8 at a depth of 586 km, and advised that a destructive tsunami was not expected; based on historical data. The second bulletin, issued 14 minutes later, revised the magnitude to 7.1 at the shallower depth of 565 km and confirmed that a destructive tsunami was not generated because of the depth of the event.

Geoscience Australia reports the quake at magnitude 6.8 at a depth of 600 km. They estimate the tremor would have caused damage within 80 km of the epicentre, and would have been felt up to 1,000 km away.

New Zealand’s GeoNet also reports the quake at magnitude 6.8, at a depth of 574 km. By 8 o’clock this morning, no reports of shaking from the event had been reported from New Zealand. The epicentre is 2205 km north of Auckland, and GeoNet’s tsunami gauges showed no significant sea level variations by 8 a.m.

Two aftershocks of magnitude 4.9 and 4.5 were reported at 2:20 a.m. and 2:55 a.m. Only one felt report for the main event had been lodged with the U.S. Geological Survey by 9 o’clock this morning.

[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, the GeoNet project and its sponsors EQC, GNS Science and FRST, and Geoscience Australia.]

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