Earthquake activity in the South Pacific

Since the eruption at Raoul Island last Friday, the area between Vanuatu and Tonga has experienced 11 earthquakes of magnitudes between 4.2 and 5.9 at varying depths and locations according to data provided by the US Geological Survey.

The earthquakes are occurring in an area known as the Fiji Microplates where a southward projection of the Pacific Plate and a northward projection of the Australian Plate are moving apart.

The earthquakes are scattered across the area at depths ranging from very shallow to very deep and, as yet, show no clear pattern of activity.

Four of the earthquakes ranging in magnitude from 4.2 to 5.9 have occurred at depths between 10 km and 560 km near Vanuatu. An isolated magnitude 5.4 event 36 km deep has occurred east of Noumea to the southeast of the Loyalty Islands.

Three earthquakes ranging in magnitude between 4.9 and 5.6 have occurred at depths ranging from 10 km to 590 km east of Fiji.

Four earthquakes ranging in magnitude between 4.3 and 5.2 have occurred at depths between 100 km and 520 km southwest of Tonga.

The area has experienced bursts of activity in recent months, including a magnitude 6.5 quake southwest of Tonga on February 26th and a magnitude 7.1 east of Fiji on January 2nd. Both earthquakes were over 500 km in depth and had associated activity.

The implication of this activity is not yet clear but, with the recent eruption further south at Raoul Island, this is an area to watch.

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