Violent Shallow 5.8 Earthquake Damages Christchurch – updated. Significent Aftershocks Continue

Update: Another quake, at least as big as the earlier 5.8, struck the city at 3.18pm and significant aftershocks are still continuing (3.35pm) Some locals are saying the latest was a 6.4.

The USGS gave a figure of 5.8 for the 3.18 earthquake and a depth of 4.9km, located at 43.491°S, 172.844°E. That puts it on land in the west of Pigeon Bay.

Geonet later rated this as a magnitude 6.0 at a depth of 5.8 km, placing it in South New Brighton:

Reference Number	3631380 [View event in Google Maps][View Felt Reports in Google Maps]
Universal Time	December 23 2011 at 2:18
NZ Daylight Time	Friday, December 23 2011 at 3:18 pm
Latitude, Longitude	43.53°S, 172.74°E
Focal Depth	6 km
Richter magnitude	6.0
Region	Canterbury
Location	10 km east of Christchurch 10 km north of Lyttelton

See chart below for all of today’s quakes.

Trace showing the 3.19 quake

A violent 5.8 earthquake has hit Christchurch at 1.58pm today, followed by a succession of strong aftershocks. No reports of tsunami yet.

RadioNZ has reported one casualty at Eastgate shopping mall and there is liquefaction in St Albans, Wattle drive,  Bromley..

Initial photos of the quake may be found here and there have been rockfalls at Scarborough cliffs.

Christchurch airport has been evacuated, and there is an unconfirmed report that one of the buildings was damaged, some phone networks down, power out in New Brighton.

RadioNZ is saying that the force of the quake is comparable to the devastating 22 February earthquake:

Newstalk ZB reporter Elliott Smith was on the couch in his Mairehau home when it struck.

“It just came and boy, it certainly had a lot of force to it. Judging by the reaction of people, our neighbours have come over, they weren’t expecting anything like this at all,” he says.

Since the quake, Elliott Smith says there’s been several smaller aftershocks which have left people on edge… more here

Qantas flight QF45 Sydney to Christchurch has been diverted to Wellington source

more to come.

Details from Geonet

Reference Number	3631359 [View event in Google Maps] [View Felt Reports in Google Maps]
Universal Time	December 23 2011 at 0:58
NZ Daylight Time	Friday, December 23 2011 at 1:58 pm
Latitude, Longitude	43.49°S, 172.90°E
Focal Depth	8 km
Richter magnitude	5.8
Region	Canterbury
Location	20 km north-east of Lyttelton 20 km north-east of Diamond Harbour 20 km east of Christchurch

Will have been damaging in Christchurch.

5.8 earthquake and aftershocks in Christchurch 23 Dec 2011

Geonet drums. Quakes hit Christchurch 23 December 2011

Large Quake Rattles North, South Islands – Updated

Picton quake 3 Dec 2011

A large 5.7 magnitude earthquake shook the top of the South Island and lower North Island at 7.19pm today.

The epicentre was 60 km deep and felt strongly in Marlborough and Wellington. A  TVNZ report told of how highrise windows were shattered in the capital and apartments being evacuated, police said.

“there has been damage to louvres and windows broken on the Meridian Building on Custom Quay Street in central Wellington. Some of the louvres have come loose and are hanging precariously.

The Quay Apartments in Picton had to be evacuated as a hot water cylinder burst and set off the fire alarms. Two other cylinders were also damaged in the town, according to the Fire Service…”

GeoNet duty officer Dr Tony Hurst told the NZ Herald this shake was the biggest they had recorded in the area for around 20 years.  Mr Hurst also said  the depth of the earthquake, at 60km, meant there were not likely to be many aftershocks.

Aftershocks Getting Shallower

Mr Hurst has since been proven wrong and it looks like things may be hotting up in the Wellington region.

After this blog was written on 3 Dec there were two more shakes in the area. On the 8 Dec there was a  A 4.2 magnitude quake at 10.16am, 30 km deep centred 10km west of Porirua and another later in the day at 8.13pm which measured 3.1 magnitude at a depth of 10 km, centred 10km south east of Lower Hutt. For more see GeoNet.

For more about earthquake risks in Wellington please follow this link

Picton quake was felt over a large area

Government Buildings Closed

Recently a number of government buildings have been closed after they were found to be below present day earthquake standards. According to an article in Stuff around 40 schools in Wellington alone are on the suspect list

Tremors are rippling through the public sector as more government buildings are closed and vacated following alarming seismic risk reports.

An Inland Revenue processing centre in Upper Hutt housing hundreds of staff is to be closed for a month and six court buildings – three in the lower North Island – will be closed for up to a year.

Both the Justice Ministry and Inland Revenue yesterday reassured staff their jobs were safe, saying they would continue to be paid while earthquake strengthening work was completed.

Hundreds of government buildings are being assessed to determine the level of risk and whether they need to be vacated and earthquake strengthened.

Forty schools in Wellington city are deemed potentially earthquake-prone or are under investigation by the council…” more here

Twitter

Twitters users were quick to take to the net with their accounts of the quake.  The hashtag to follow for all things earthquake related in NZ is #eqnz

Aftershock Predictions Held Back From Public

The NZ Herald reporting on the Christchurch earthquake inquiry have said that GNS scientists held back from making predictions about another powerful aftershock  following the Boxing Day 2011 quake.

“Government earthquake experts held back forecasts of a massive aftershock for Christchurch following the magnitude 4.9 Boxing Day jolt because they didn’t want to alarm the already traumatised population.”

GNS scientist Dr Kelvin Berryman admitted under cross examination that

“information was withheld from the public, on advice from social scientists scared for the beleaguered city’s collective mental health.”

The Herald reports that Christchurch lawyer Marcus Elliott said that after the 22 February 6.3 magnitude aftershock which killed 182 people, GNS made public statements warning of the possibility of an aftershock of one order of magnitude less.

He then asked the panel of four scientists if they considered issuing the same warning after the December 26 shake.

Mr Elliott asked: “If someone had come to GNS after Boxing Day and said, `we want to give people the Christchurch a people of understanding if this one less magnitude earthquake occurred under the city’, could GNS have calculated the likely ground forces and given people an understanding of what they might expect?”

The panel confirmed they could provide such information.

But GNS Scientist Dr Terry Webb said the idea of a issuing a warning was thought to be”unhelpful”.

Dr Webb admitted: “In the first couple of weeks (after the Boxing Day shake), social science advice was basically that we’ve got a traumatised population and what can you do to help them cope best, and that really was to get them coping with aftershocks.

“They had a need and a right to know, and that’s why we readily talked about the possibility of a six, so that certainly wasn’t hidden.

“But what was thought of as unhelpful at the time, was talking about the possibility of an event bigger than Darfield (magnitude 7.1 on September 4) itself, in terms of magnitude.” … you can find the entire Herald report here

However, if you look back to this news report from January you’ll see that there is no mention of the possibility of a magnitude 6 aftershock, people were being told to expect tremors of up to magnitude 5 every month to six weeks.

“Flurry of aftershocks hits nerves” 21/01/2011

Christchurch has been rattled by its 10th aftershock in 24 hours after a magnitude 4.4 quake struck this morning…

…GNS Science seismologist John Ristau warned people to expect aftershocks of up to magnitude 5.0 every month to six weeks.

He said aftershocks could go on for “months, a year or maybe even over a year”.

The report goes on to talk about the psychological effect the quakes were having and the high degree of anxiety some people were experiencing. This had been heightened by the Boxing Day quake.

But as the New Year holiday season drew to a close and people started going back to work fears began to grow. A month and a day before the 22 February quake people were voicing their concerns about returning to workplaces and entering high-rise buildings:

“The general manager of counselling and trauma support organisation Employee Assistance Programmes Services, Rod Berry, said some people were still apprehensive about returning to their workplace.

“There are some people naturally nervous about going into any buildings at the moment, particularly high-rise buildings,” he said.

The ACC will pay for counselling only if a a person is physically injured in the quake or can show a mental injury arose from the physical injury.

A Canterbury District Health Board anxiety disorders unit spokesman said there had not been a noticeable increase in referrals.”

If the scientists had provided the information and predictions, which they told the inquiry that had at their disposal,  could more lives have been spared on 22 February?

Would people have still occupied damaged buildings if they were fully aware that a magnitude 6 quake was likely to strike at any time?

Canterbury Shaken By Strong Quake

View Larger Map

The Canterbury region of New Zealand was shaken by a strong 5.5 magnitude earthquake this evening.

Data from Geonet place the epicentre 20km east of Christchurch at a depth of only 12km.

The quake was later classified as a new event by the Earthquake Commission for insurance purposes, fresh claims may be made for damage. This was the largest quake quake to hit the city since a 6.3 magnitude on 13 June.

Reactions to the insurance annoucement were predictably skeptical:

Anon chch – “whats the bloody use in claiming when the insurance companies are not stepping up to fix the houses. Save tax payers money and make the insurance’s step up for once. Enough has been paid out by the Eqc, still waiting a year down the road to get house fixed and thats in green zone. if the damage is made worse its down to insurance for failing to fix in the first place.”

Anon -  “what a f..king joke now we will have to waiting another 12 months to have our places looked at”

beattie8 – “yet another claim for insurance companys? maybe they should hire more staff and get the claims from a year ago sorted first. slack as”

“Shit that was big”

People in the area were shocked by the power of the quake and were quick to take to the internet and talk on Trademe.

• “phones are out”
• “Harewood was big and rumbling”
• “Has to be a 5……right??? really bad here in Redwood”
• “Good one here in Leithfield too…. not nice!”
• “shakey shakey here in Timaru as well!!”
• “GEONET’s DOWN not a good sign – must have been over 5 then – not down but REAL GLITCHY”
• “Felt that in Methven too. Usually has to be a big one over your way for us to feel it.”
• “felt long out here (Doyleston) started out like Feb, was waiting for it to grow…”
• “I must admit that I got off of my chair in readiness for a increase in the intensity, it started off like the 7.1 did last year”
• “reminded everyone to make sure their touches are at the ready just in case, bit of a rough couple of days”
• “We rockn out west.”
• “Looks like it was centered somewhere in the sea off of Godley Heads”
• “It was a big one in Bromley & a few more of the block’s in the house came loose with it,if we get any more like that I wont have any left.We keep putting them back in but I think it’s a waste of time. A lot of thing’s fell out of the cupboard’s as well.”

Reference Number	3591999
Universal Time	October 9 2011 at 7:34
NZ Daylight Time	Sunday, October 9 2011 at 8:34 pm
Latitude, Longitude	43.58°S, 172.82°E
Focal Depth	12 km
Richter magnitude	5.5
Region	Canterbury
Location	10 km north-east of Diamond Harbour 10 km east of Lyttelton 20 km east of Christchurch

As yet we’ve not heard of any structural damage or liquefaction, daylight may bring some news.

Large Kermadec Quake

6.1 Kermadec quake was picked up over much of NZ

There has been a 6.1 magnitude quake south of the Kermadec Islands this evening, details from USGS are as follows

Magnitude	6.1
Date-Time	Friday, October 07, 2011 at 08:58:29 UTC Friday, October 07, 2011 at 08:58:29 PM at epicenter Time of Earthquake in other Time Zones
Location	32.389°S, 178.902°W
Depth	40 km (24.9 miles)
Region	SOUTH OF THE KERMADEC ISLANDS
Distances	106 km (65 miles) S of L’Esperance Rock, Kermadec Islands 359 km (223 miles) SSW of Raoul Island, Kermadec Islands 762 km (473 miles) NE of Auckland, New Zealand 1136 km (705 miles) NNE of WELLINGTON, New Zealand
Location Uncertainty	horizontal +/- 15.2 km (9.4 miles); depth +/- 6.2 km (3.9 miles)
Parameters	NST=398, Nph=432, Dmin=360.7 km, Rmss=1.12 sec, Gp= 29°, M-type=”moment” magnitude from initial P wave (tsuboi method) (Mi/Mwp), Version=B
Source	Magnitude: USGS NEIC (WDCS-D) Location: USGS NEIC (WDCS-D)
Event ID	usc00065x2