Large Quake Hits North Island – updated

A large 6.5 magnitude quake rocked the North Island today, centred 30km west of Taupo at a depth of 150km. It follows a swarm of shallow earthquakes beneath Lake Taupo from 28-30 May.

Reference Number 3540736]
Universal Time July 5 2011 at 3:36
NZ Standard Time Tuesday, July 5 2011 at 3:36 pm
Latitude, Longitude 38.67°S, 175.75°E
Focal Depth 150 km
Richter magnitude 6.5
Region Taupo
  • 30 km west of Taupo
  • 220 km south-east of Auckland

The long rolling earthquake was felt widely felt throughout both islands of New Zealand and aftershocks are expected. Follow NZ earthquake news as it happens using the #EQNZ hashtag

The quake has been followed by an almost continuous stream of vibrations, picked up on this drum from Oturere at Mount Ngauruhoe. Note the smaller quakes hours earlier. Charts like these are bound to raise concerns that the quake may be magmatic, or volcanic, in origin

Update 7 July 2011

Two days later a large 7.6 earthquake rattled the Kermadec Islands off the NE shore of North Island, the quake was picked up on the Oturere drum. Read more here:- “Tsunami warning cancelled after large Kermadec quake

Mount Ngauruhoe

Mount Ngauruhoe is an active stratovolcano or composite cone in New Zealand, made from layers of lava and tephra. It is the youngest vent in the Tongariro volcanic complex on the Central Plateau of the North Island, and first erupted about 2,500 years ago. Although seen by most as a volcano in its own right, it is technically a secondary cone of Mount Tongariro.

The volcano lies between the active volcanoes of Mount Tongariro to the north and Mount Ruapehu to the south, to the west of the Rangipo Desert 25 kilometres to the south of the southern shore of Lake Taupo.

It has erupted 45 times in the 20th century, the last time in 1977. Learn more about the volcano, also known as Mount Doom in the Rings trilogy films, here

From the NZ Herald

GNS volcanologist Brad Scott said although the earthquake was centred near Taupo it would have been felt more strongly along the East Coast, particularly the Napier through Wellington region, because of its depth.

Today’s earthquake was fairly typical movement, he told Radio New Zealand.

“We would typically have maybe two or three events around maybe 5.5 and 6 (magnitude) at about 150-200km depth a year under the North Island. It’s slightly larger than average but it’s kind of what we really expect.”

It would generate some aftershocks “but at that depth and being smaller than the main shock they are very unlikely to be noticed”, he said…” more here

Felt in Christchurch, Palmy North and Blenheim (source)

“I don’t know exactly how long ago it was, was in last 20 or 30 minutes, we felt really really subtle light wavy movement here (south Chch) that went on and on and on, at least 30 seconds from the time we noticed it (was confirmed by light shade swinging very gently). Don’t know if it’s related though, or something else going on closer to us here.”

“I felt it here too in Chch- very gentle rolling feel that went on for quite a while and I was surprised when it didnt show up on Quakecrowe. I was upstairs at the time and heard my windchimes in the lounge rattle- always a sign that its over a 3.5. My daughter was downstairs and she didnt feel it, and I probably wouldnt have if I had been up and doing things at the time. I spose what we felt could have been a separate shake and nothing to do with the North Island one.”

“Felt in our old farmhouse in Kapiti. Really felt it and thought ‘I hope it’s not Chch again’. I’m so glad we had the house strapped to the piles it was sitting on when we moved in, can’t believe the previous owners were so lucky as one good shallow shake and the house would have shifted completely off those piles. Only took over 50 years for someone to notice it wasn’t strapped.”

“felt it quite strong in Palmy Nth. Thought must have been a decent one somewhere. Was just pleased it wasn’t Christchurch.”

“felt it in Blenheim, blamed the kids for rocking the couch until I realised they were siting still!”

One thought on “Large Quake Hits North Island – updated

  1. A robust one in the Kermadecs just hit this morning. Tidal swell expected.Seismic activity has certainly been on the increase. snip – “This follows a recent escalation of Fiji area 5+ quakes, that was already amongst a period of heightened seismic activity on the north and east Australian Plate. New Zealand geology is ultimately affected by this type of movement”

    One point of interest is the unpredictability of it all. Per Teara: “The historical record in New Zealand is rather short to be accepted as an accurate guide to the distribution of future epicentres.”

    The NE Australian plate causing all the problems, and the size of New Zealand compared to the size of the edge of that plate, can be seen here:

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