Auckland Earthquake

2.9 earthquake shook Auckland

A shallow earthquake, centred east of Mission Bay,  rocked Auckland at 9:09 this evening and was widely felt around the city. It was reported as a Moment Magnitude 8 (heavily damaging) at Ponsonby, there were 25 reports of MM5 and 2123 reports of MM4.

Learn more about the MM scale here. Geonet reported the quake as follows,

Reference Number 3538900
Universal Time July 1 2011 at 9:09
NZ Standard Time Friday, July 1 2011 at 9:09 pm
Latitude, Longitude 36.84°S, 174.84°E
Focal Depth 9 km
Richter magnitude 2.9
Region Auckland
  • 10 km east of Auckland

Active Faults around Auckland

Contrary to popular belief Auckland does have some active faults, see map below (source)

Auckland faults

But the major hazard in Auckland is believed to be from volcanic activity, rather than earthquakes. Auckland sits on a recently active volcanic zone.

Much of Auckland is built on a recently active volcanic field. There are about 50 volcanoes between Manukau Harbour and Rangitoto Island. Some are familiar hills with large craters like Rangitoto, Mt Eden, and One Tree Hill. Some like Albert Park and Mount Smart have been quarried away, and others like Panmure Basin and Orakei Basin have always been large craters. Scientists do not expect these existing volcanoes to erupt again.

The lack of surface activity in Auckland leads to the false impression that the field is extinct. The hot spot of molten rock deep below the city remains active and it will almost certainly send up more magma some time in the future. Where and when that eruption will take place is unknown.

Even a small, brief eruption would have a major impact on Auckland. The level of destruction and disruption would depend on the size and location of the eruption, type of activity, warning time, wind direction, and preparedness. Seismic activity is monitored around Auckland to provide early warning of renewed volcanic activity.” read more on the ARC’s website here

The quake very quickly became a hot topic for discussion on the TradeMe forum, affecting many people who’d left Christchurch to escape the quakes

Ribena1: “Didn’t feel minor to me, geez I just about threw up, after dealing with them in Ch-Ch I thought Auckland didn’t get them :(“

Southern-belle: “Remuera, just moved from CHCH to get away from them

rtm3: “House was shaking in Takapuna – big bang

rattie-77: “jeepers any little rumble my heart is racing, dam i heart so goes out to the CHCH peeps get have those everyday **BIG HUGS CHCH**”

Cate11: “we are in Beachhaven, I did not notice it but my daughter came into the room waving her arms about (she is not talking as part of the 40 hour famine) and typed on the computer that her room shook. The dog has been pacing the house like crazy too.”

denismore: “Yes felt it, just a sharp jolt in Birkenhead.”

windsinger: “Bit too close to Rangitoto that one. Could be that Taniwha getting a bit upset. Auckland is built on 49 volcanoes so we don’t really want to have any thanks.”

tofumnky: “I felt it here at Birkenhead. It was like someone push against the house.”

mairangi: “I did feel something I am on Mairangi Bay beach. No shake but I heard the roof go bang. We have people staying with us from christchurch with a new baby. Shes up here for a break.”

jhan: “We’re in Mt Wellington and we’ve been keeping our boots beside the bed for about a month now, it seems prudent somehow. We are not scared of earthquakes, (except the big ones), but the pacific ring of fire is quite active right now.

nzrys: “Heard a tiny rumble then the whole house shook and it felt like a car had hit the house. We are in Narrowneck Beach Devonport. My first earthquake!