Series of Earthquakes Near North Island

A series of 4th magnitude earthquakes occurred under and north of the North Island last weekend according to data released by the US Geological Survey.

The earthquakes occurred at very shallow and deep levels as the Pacific and Australian tectonic plates reacted to pressures caused by their continuing collision.

The sequence of six earthquakes began on the evening of Friday April 21st and ended on the afternoon of Sunday 23rd.

The earthquakes, with reference to NZ Standard Time, were:
21st at 6:09 p.m. mag 4.1, 202 km deep, 20 km SSW of Rotorua
22nd at 2:46 p.m. mag 4.2, 5 km deep, 175 km NNE of Rotorua
22nd at 8:17 p.m. mag 4.3, 140 km deep, 110 km SSE of New Plymouth
23rd at 5:21 a.m. mag 4.1, 250 km deep, 90 km N of Rotorua
23rd at 6:30 a.m. mag 4.1, 9 km deep, 65 km ENE of Rotorua (felt)
23rd at 3:18 p.m. mag 4.1, 5 km deep, 170 km NNE of Rotorua

The earthquake of Sunday 23rd at 6:30 a.m. was reported on the Geonet website with reports that it was felt in Edgecumbe, Whakatane and throughout the central Bay of Plenty area.

The quakes follow several weeks of earthquakes further north on the plate boundary and are probably a reaction to the change in stress in the two tectonic plates. The deep earthquakes occurred in the Pacific Plate which is sliding under (subducting) the Australian Plate along a line from New Zealand, through the Kermadecs to Tonga.

The shallow earthquakes occurred in the overlying Australian Plate and indicate either accumulation or release of tension from the collision of the two plates.

One Response to “Series of Earthquakes Near North Island”

  1. Chris says:

    I shall keep an eye on your site – good info here. Would even seem to be a little more informative than the geonet website (sadly).

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