Bay of Plenty Quakes

A burst of earthquake activity in the Bay of Plenty between midnight and 1 a.m. was not volcanic according to GeoNet.

Friday 7th May 2010

A burst of earthquake activity that occurred between midnight and 1 o’clock this morning showed strongly on the seismograph located at Mayor Island volcano in the Bay of Plenty.

Mayor Island drum for 7 May 2010

However, an enquiry with GeoNet shows that the quakes were actually centred 90 km north of White Island, well away from the volcanoes of White Island and Mayor Island. The five biggest events were of magnitude 3.7 to 4.3 and their seismic waveforms suggest that they were not volcanic in origin.

The quakes, which occurred at the same location over a short period of time, could be due to the same spreading process that gave rise to the Matata earthquake swarms. Over time, East Cape is very slowly moving further away from the Coromandel Peninsula creating what is known as a “spreading zone” in the Bay of Plenty and the Taupo Volcanic Zone.

[Compiled from data provided by the GeoNet project and its sponsors EQC, GNS Science and FRST.]

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