It has been 50 years since an equivalent 5.1 magnitude earthquake hit the fault line near Te Aroha, Waikato, that shook 20,000 people this morning - including as far away as Auckland.
GNS seismologist, Dr Jen Andrews, has described the 5.1 magnitude quake that hit 5km south of Te Aroha, at a depth of 7km, at 5.30am as “quite uncommon”.
Reports of the shaking rushed in online early this morning from Kiwis as far apart as Tauranga, Hamilton, Cambridge and Pukekohe.
A subsequent 3.9 tremor rocked Waikato and Bay of Plenty at 11.29am today as an aftershock to the 5.1 Te Aroha quake.
“It isn’t an area where we see a lot of earthquakes but it is part of the Hauraki Rift,” Andrews said.
“It’s near the Kerepehi Fault so it is a known and mapped fault, and we have had activity in the past that we’ve recorded, but it isn’t a particularly active area.”
Andrews provided some context on how rare it was for moderate to large quakes to hit the Kerepehi Fault that produced the Firth of Thames and the Hauraki Plains.
“I can give you some numbers. So we’ve only had five earthquakes larger than magnitude 3 in this region in the last 10 years,” Andrews said.
“So it’s quite uncommon. But there was a 4.9 magnitude back in 1972. So we do have these magnitude 5-ish earthquakes happening. Pretty rare.”
Andrews clarified that other quakes that have affected New Zealand’s North Island in recent months - a 4.1 magnitude quake in South Taranaki on December 26 and a 5.7 magnitude quake south-west of Taupō on November 30 - were not connected to this morning’s Te Aroha rumble.
“There was a 3.9 foreshock, to the Te Aroha quake, on the 29th December - so that would be to the 5.1 that we had this morning,” Andrews said.
“So those are connected but for everything else in the wider New Zealand Pacific area, not connected. It’s just a very active area.”
Speaking to the Herald earlier this morning, Andrews predicted a possible aftershock like the 3.9 magnitude tremor that hit Waikato and Bay of Plenty at 11.29am today.
“The most likely scenario is they’ll be a few aftershocks and those tapering off with time. There is a small possibility that we would see a larger earthquake following the 5.1, but the likelihood of that is low and it would decrease very rapidly with time from the earthquake.”
Andrews said if another moderate to large quake like today’s 5.1 magnitude is going to happen it will be in the coming days, or not at all.
There have now been seven aftershocks of 2.6 magnitude or greater since the initial jolt at 5.30am today.
Tauranga resident Gary told Newstalk ZB said it carried on rolling for about 20 seconds.
Colleen Firth also felt the quake in Katikati.
“I was asleep, and I woke up to the whole house shaking.”
She says it was noisy, and lasted for about a minute.
A Pāpāmoa resident said she felt the quake at 5.49am and the whole house shook.
Other people took to social media and Shelley Wood said “yes felt bed shaking!” while Marama Mateparae said “yes - woke me up”.
Northern fire communications said it had not received any reports of significant damage or calls for assistance following the strong quake.
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