Island Watch: Fiji and Tonga

Earthquake activity near Fiji and Tonga has increased again during the past week.

The activity occurred simultaneously in both regions, commencing with a magnitude 4.9 event near Tonga and a magnitude 5.1 quake near Fiji on November 25th, New Zealand time. Both earthquakes were shallow, at a depth of 10 km.

During the week, 12 earthquakes have been recorded with 5 occurring near Tonga and 7 near Fiji. Magnitudes have ranged between 4.6 and 6.0 with only three of the events at shallow depths (less than 40 km) and 8 striking at depths over 100 km.

Activity has been reported elsewhere on the southern part of the Pacific Plate. Several earthquakes were felt in New Zealand, a pair of quakes were reported in the Kermadec Islands, and a pair of shallow quakes struck the Easter Island region.

On December 1st, a magnitude 6.2 earthquake was reported at a depth of 10 km on the Pacific-Antarctic Ridge. This ridge lies along the boundary where the Pacific and Antarctic tectonic plates are moving apart.

[Compiled from data supplied by the US Geological Survey and its contributing agencies.]

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