Hauraki Gulf Quakes

Nev · Unread post by **Nev** » Sun 17/03/2013 16:07

Just felt 2 good tremors here!

David · Unread post by **David** » Sun 17/03/2013 16:08

Good shake on Motutapu Island according to Geonet. Sharp jolt felt here 4.06pm

David · Unread post by **David** » Sun 17/03/2013 16:12

Magnitude 4.0, 5km deep
http://geonet.org.nz/quakes/region/newz ... 013p203051
Hasn't been reviewed just yet though.

Nev · Unread post by **Nev** » Sun 17/03/2013 16:17

First one was just south of Little Barrier Island, but that 2nd one under Motutapu was a real doozy!

Vertigo · Unread post by **Vertigo** » Sun 17/03/2013 16:18

awesome little shake, strongest ive ever felt

jamie · Unread post by **jamie** » Sun 17/03/2013 16:21

Not a thing here on the spongy soil in the Waikato. People on hills might have been different.

ricky · Unread post by **ricky** » Sun 17/03/2013 16:22

not too sharp here but the best I've ever felt in auckland.. quite a fast shaking with the shallow depth, did knock something down in the house but cany find what it was!

David · Unread post by **David** » Sun 17/03/2013 16:25

Vertigo wrote:awesome little shake, strongest ive ever felt

Yes, strongest I have felt too. My computer monitor was shaking back and forth for a few seconds!

Manukau heads obs · Sun 17/03/2013 16:28

there is the Hunua fault line running north through Motutapu I think, yes?

ScottyD · Unread post by **ScottyD** » Sun 17/03/2013 16:29

Not the stongest I've felt, but the first one I've felt in Auckland in the 12 years I've been living here. Most unexpected.

Nev · Unread post by **Nev** » Sun 17/03/2013 16:38

I see there was another just a little further NE of Motutapu Island.

Manukau heads obs · Sun 17/03/2013 16:46

from nzherald:

The quake was centred on Motutapu Island, next to the volcanic island of Rangitoto. There are unconfirmed reports that smoke was rising from Motutapu.

that would make a good tui billboard...yeah right

http://tuibillboards.co.nz/choice/bro/481#.UUVBf1eOVUx
will be just rising low cloud, due to the very humid conditions

ScottyD · Unread post by **ScottyD** » Sun 17/03/2013 17:00

Manukau heads obs wrote:from nzherald:
The quake was centred on Motutapu Island, next to the volcanic island of Rangitoto. There are unconfirmed reports that smoke was rising from Motutapu.
that would make a good tui billboard...yeah right
will be just rising low cloud, due to the very humid conditions

I seriously can't believe that the Herald had that in their article! Great reporting.

Nev · Unread post by **Nev** » Sun 17/03/2013 17:11

Seems both quakes were now more or less under Motutapu Island:

M3.1 at 4km deep at 4:01pm
M3.9 at 6km deep at 4:05pm

jamie · Unread post by **jamie** » Sun 17/03/2013 17:20

Jeez that's shocking reporting. They probably made it up themself. 'Unconfirmed report'. So why even put it in the article.

Orion · Unread post by **Orion** » Sun 17/03/2013 17:22

Lived in Auckland for 25 years and never felt a one. Amazing times we live in.

Nev · Unread post by **Nev** » Sun 17/03/2013 17:31

Auckland's last felt quake was the 9km deep M2.9 near Mission Bay on July 1st, 2011.

Here's what I wrote at the time...

Nev wrote:While quakes are fairly unusual around the Hauraki Gulf and Akld, we do get them from time to time. The Hauraki Gulf cluster on Feb 21, 2007, including a M4.5, M3.7 and M3.8, was the last time a quake was felt by mainland Akld.

We also get the odd cluster here on Waiheke - the most recent being Oct and Dec in 2009, of which the largest was a M2.5. And before that we had cluster on Nov 29/30, 2005, with the largest being a M3.3.

David · Unread post by **David** » Mon 18/03/2013 18:39

I see there were two tiny aftershocks this afternoon, magnitudes 1.3 and 1.4

littleheaven · Unread post by **littleheaven** » Mon 18/03/2013 23:42

I skimmed through a paper called "Large Scale Faulting In The Auckland Region" last night (you can read it here http://www.iese.co.nz/LinkClick.aspx?fi ... &tabid=344) which suggested that the Drury fault carries on beneath Motutapu. In any event, the map appears to show a known fault under the island, whether it actually connects to the Drury fault or not. They also theorise about the presence of many other faults in Auckland, going by topography, borehole data, etc - and place moderate confidence on one running right across the bottom of my street. I was quite fascinated.

Manukau heads obs · Tue 19/03/2013 07:30

yeah,as I had suggested above...and its real ancient rock there on Motutapu,too, and is an extension of that found on the hunua ranges further south

littleheaven · Unread post by **littleheaven** » Tue 19/03/2013 19:24

A couple more aftershocks recorded around 11pm last night, both less than 2 on the Richter scale.

Manukau heads obs · Tue 19/03/2013 19:50

neat how even a relatively small earthquake has an aftershock sequence

littleheaven · Unread post by **littleheaven** » Mon 25/03/2013 22:50

Another one at 9.28pm this evening - a magnitude 2.0, still under Motutapu but not quite in the same location. I think I might have felt it, just the faintest little shimmy as I was sitting on the sofa around that time. Hard to tell if that was the cause, though. I'm on poles so the house shakes easily.

Manukau heads obs · Thu 11/04/2013 12:38

did you guys see this:
http://www.stuff.co.nz/national/8537487 ... blow-again

Razor · Unread post by **Razor** » Thu 11/04/2013 14:54

Manukau heads obs wrote:did you guys see this:
http://www.stuff.co.nz/national/8537487 ... blow-again

I'm not quite sure how this is 'new's I recall vulcanologist Dr Ian Smith telling us in Geology 101 lectures at Auckland Uni in the 1991 that Rangitoto quite likely reflects a new phase in the Auckland Volcanic Field with Rangi being one that can erupt more than once (and has), and is bigger than the older ones on the Auckland isthmus, etc

Probably just a new study confirming that outlook

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