The big aftershock
Sky News in Australia is reporting live the 6.0 aftershock in Christchurch.
Hopefully this will be the worst of the aftershocks. The reporter is saying you could see balconies bouncing up and down.
Talking of the quake, kudos to Phil Goff and John Key for travelling down and visiting an emergency shelter together. A very nice reminder of how those things which unite us, are more important than those we disagree on.
View Christchurch earthquake: Where the land shook in a larger map
The NZ Herald has been mapping the quakes on Google Maps. Real nice use of social media. God, you can only empathise with the locals. While logically one knows the first quake is the strongest, psychologically it must be very upsetting – especially for kids and pets.
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Tags: Christchurch, earthquake
September 8th, 2010 at 8:21 am
From Geonet
5.1
Depth 6 km
* Within 5 km of Lyttelton
* 10 km south-east of Christchurch
* 10 km north-west of Diamond Harbour
And another one just now…
September 8th, 2010 at 8:25 am
It’s almost time to put politics to one side; the only exception is the fate of the Troughmaster-General
Seriously though, this disaster cuts right across partisan politics, and it is good to see the human side of our politicians during a crisis.
September 8th, 2010 at 8:28 am
Agreed I2, hopefully they can learn from this experience and build on it, and not let it fade away like the aftershocks (eventually).
Funny, initial reports were of 6.1 but so far Geonet has only listed 5.1 this morning.
September 8th, 2010 at 8:29 am
Somewhere near Fiji got a 6.3 quake about 4 hours ago. http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_big.php
Meanwhile Christchurch waits for their 6.0+ rock and roll.
September 8th, 2010 at 8:35 am
Agreed, Key is showing true leadership.
Somehow I just cannot imagine Helen Clark ever taking the leader of the opposition with her, she would never have wanted to give them the photo opportunity.
September 8th, 2010 at 8:37 am
The psychological toll must be compounding. I feel a bit, um, lame, sitting here commenting from afar. Does the city need volunteer workers?
September 8th, 2010 at 8:38 am
Wot Fot said
September 8th, 2010 at 8:39 am
Geonet is showing a 5.1 centred _under the Port Hills_. If it weren’t so clagged in, I could look out my window and see the epicentre! We are all pretty freaked. And we have been getting after-aftershocks. Not fun. This like being _trapped_ in a funhouse ride, and not being able to get off the ride and the shocks are random and get changed.
At least most of us got some better sleep last night. Only small aftershocks. sigh.
September 8th, 2010 at 8:41 am
You guys are getting slammed.
I thought Hawkes bay was bad …. hope everyone is alright once again.
September 8th, 2010 at 8:42 am
Krazy, hard to know what to do from a distance, but possibly one option is to offer respite accommodation for those that want a break from the shake zone?
September 8th, 2010 at 8:50 am
Quite a bad aftershock this morning. I was thrown to the floor, the wife thrown sideways. I saw the doorframe and wall jolt. I feel like I’ve been overdosed on adrenaline the last few days. Up, down, up, down. Very tiring.
This is not much fun anymore.
September 8th, 2010 at 8:51 am
Must go Petey Gal as the Ute is loaded with water and food. I will venture into the unknown and drop supplies where they are needed. I hope you don’t break a fingernail typing all day! The poor kids.
September 8th, 2010 at 8:59 am
@Pete – Good idea (so long as Wellington isn’t next!) I’ll investigate.
September 8th, 2010 at 9:03 am
Rufus: Yep, good way to put it. Overdosed on adrenaline. Of course, it is a fight or flight response, but there isn’t anything we can fight, and it isn’t so easy to flee, unless we load up our wagons and head out as in days of old. (Or new, in the less developed parts of the world.)
I am SO ready for a quieter life right now.
September 8th, 2010 at 9:10 am
The psychological effects are definitely kicking in now. Sad about the media taking such delight in repeating the “scientists say” story that there is yet to be a level 6 aftershock. In my network of contacts there are several elderly folk and quite a few ladies getting seriously on edge because of that story. I am having to devote a lot of time to reassuring phone calls and trips around town because of it. At some point such media speculation ceases to be informed news and becomes irresponsible scare mongering.
September 8th, 2010 at 9:11 am
@David in Chch – If you decide on flight somewhere other than nearby email me at krazykiwi.kiwiblog@gmail.com.
September 8th, 2010 at 9:12 am
Commiserations David. Thoughts are with you.
September 8th, 2010 at 9:12 am
For the first time since Staurday, I could hear fear in my daughter’s voice when I rang her just after this morning’s jolt. She’d been pretty gung-ho up until now, but this one seemed to have thrown her. I just want to get on the next plane to Christchurch, but realise that would only benefit ME!
September 8th, 2010 at 9:12 am
Krazy Kiwi..very good of you to offer to help..Somonelse mentioned getting some people away from here for a time..It is very stressful. I just noticed domestic violence figures are up with people arguing over whether to leave their homes etc..We are fortunate in being able to sleep most of the night..those who are getting really stressed are not getting much sleep. I spoke with an elderly lady yesterday who hadn’t had any sleep at all the previous night. These people will get in a real mess if this goes on for too long.
The Min of social Dev is attempting to contact 16,000 over 65′s living on their own. The people who have been getting these calls are really grateful..there are still 6/7 thousand yet to be contacted.. Some of these calls are being made from Hamilton and Invercargill. I visited a woman in a council flat yesterday..noone from the council housing office has visited or made contact as yet.
Sam Johson , law student and aspiring community board member has organized a large group of uni students to clean up various areas..he arranged this thru the council..They were out Halswell way yeaterday then planned to move to Avonside..The elderly people in Halswell said it was the first help they had rec’d and were very grateful..If you came down you could join up with this group..or contact civil defence , or Red Cross , or Sally Army , or other church groups or youth groups…Some of the students were going door to door with muffins..Many of the elderly who live alone struggle to cook for themselves at the best of times so it will be worse now..so cooking could well be helpful..There has been shortages at the supermarket..no bread , no water , now restictions on buying water , little meat yeasterday apart from pork , no hand sanitiser , very little breakfast cereal , shortage of batteries , little juice and soft drinks etc..
Just so you know we have had four significant shakes in the past hour or so…
You sound like a practical person so I hope you can find some way to help…I am sure anything you do will be greatly appreciated.
September 8th, 2010 at 9:17 am
What a most generous offer Pete.
Can I take it that you are offering dad4justice a respite break at your place?
September 8th, 2010 at 9:21 am
I really feel for the people of Canterbury – I was listening to Radio-Live last night and some very stressed lonely and sleep deprived people from Christchurch were phoning in. I think those of us outside Canterbury really have no idea how this is for the local people.
On the other side of the equation I am very impressed with the responses by the Government, Mayor Bob Parker, (whose support has shot through the roof on ipredict) and also big business (many of whom have contributed $1m each).
Phil Goff will be so pleased to be in the shadow of Prime Minister John Key – such is his desperation for media Oxygen. So far I think he has had on 7 seconds on television – so being seen with the PM will certainly lift his profile. Hell he may even rise to 3% in the polls. But so sad are the left that there was one commentator who made the comment that John Key was just down there for the photo op. – How pathetic can the left get?
September 8th, 2010 at 9:22 am
The aim is to reduce stress levels Fot.
Have a few contacts in Christchurch, will see how they feel about having a break.
Monty – your political nit picking sounds a bit pathetic too. This isn’t a political problem, it’s a people problem.
September 8th, 2010 at 9:25 am
Wonder if Jim Anderton just backs out of the mayoral race. Be obvious but very classy as well.
And why be embarrassed by an opponents landslide victory. He can’t lose face as he’ll be keeping his word.
A gesture the people could appreciate at this time.
September 8th, 2010 at 9:27 am
Can’t speak for anyone else but leaving is one thing I wouldn’t do right now.
Couldn’t think of anything worse than worrying about what’s happening in my world from where I can’t help.
This morning’s ‘quake (the first one) was the worst “aftershock” yet – spilled my coffee.
September 8th, 2010 at 9:27 am
David in Chch 8:39 am,
… some bloke on the 9 am news was saying this was a different faultline and was likely triggered due to the activity in adjacent faultlines – understandable I guess.
I wonder if the other earthquakes throughout the country in the last 30 hours were also triggered by the ongoing activity in Canterbury?
From the “latest thirty New Zealand earthquakes” page on Geonet:
Once again, prayers and thoughts to all you Cantabrians.
September 8th, 2010 at 9:28 am
How prepared are the non partisan politicians for ” the big one,the Alpine Fault”.?
They really do need to sit down together and think hard about it.
Without taking away from the disaster and stress that everyone in Chch must be feeling,the country must prepare for the inevitable.
Forget bullshit warming NZ has real problems.We are a tectonic plate boundary!
September 8th, 2010 at 9:48 am
Just in case anyone might be thinking the Big Trough meister is having any other thoughts i repeat what I posted earlier.
The man is so bloody arogant.
Anderton displays just what and ars****e he is.
Parker’s 20-hour days for ‘a personal thing’
By GLENN CONWAY – The Press
What has kept the exhausted mayor going?
“There is a really important job to do. This is a very personal thing,” he said. “It’s our city, our families, our friends, and we are all working together to do our best.”
Parker said his head was not in the right place for next week’s scheduled Press mayoral debate, which has been cancelled.
His main challenger, Jim Anderton, wanted the event to go ahead, saying he did not want to see the elections cancelled or delayed.
“I think we have to be careful not to too easily suspend democratic processes,” he said.
He was still campaigning – not to create photo opportunities but to help people with all sorts of issues, both before and after the quake.
http://www.stuff.co.nz/national/canterbury-earthquake/4105709/Parkers-20-hour-days-for-a-personal-thing
September 8th, 2010 at 9:48 am
I think it might be time for Christchurch to return a National MP if only as a vote of thanks for the care, time and money they are getting in this crisis. John Key surely is the man for the times. This disaster has brought to the fore his superb management skills. You can see the concern on his face so the human heart is there but also the effective leader. I think we are very lucky he is PM at this awful time. It doesn’t hurt that he’s from ChCh himself.
But it does hurt to see those beloved old buildings so battered and wrecked. It won’t look like my old hometown any more.
September 8th, 2010 at 9:49 am
Living on what could be described as the edge of the zone as well as living increasingly on the “edge”, the cumulative effect of the continual fear of what could still come is becoming far more apparent.
The media’s continued use of the prediction that the prospect of a 6+ aftershock is ‘likely’ instead of only ‘possible’ is ratcheting up anxiety levels considerably and is becoming somewhat tiresome. Will they go to another level and start speculating on the outside possibility that a shake in excess of the 7.1 is not impossible and with the potential that the long expected “major” on the main faultline could be triggered with the current activity is a real possibility.
Yes we need to be aware that this event aint over yet and we need to be vigilant but the seemingly inexhaustable thirst of the major media for headlines has gone from the reasonable to the sensational and is starting to concern this old wrinkly.
September 8th, 2010 at 9:51 am
Key’s advisors have obviously learnt lessons from New Orleans and the likely political fall out.
I agree Kowtow, it does put things in perspective – time to can ETS. Only one party has consistently campaigned against ETS. It’s time for the Nats to get real!
September 8th, 2010 at 9:54 am
Given the fragile state of humanity in Chch its time to consider actually mobilising a couple of battalions. they can be constructively useful and a visual reminder of order and authority at the same time. Make it their 20 days in place of AFE. They’ll learn more useful skills too.
Proactive is always more effective than reactive and its going to get messy there very soon if the ground doesn’t stop moving.
September 8th, 2010 at 10:01 am
I live just outside of Rolleston, about 10km from the original Epicentre. While the earthquakes are bad enough, now it is a weekday and the media all looking to sensationalise things, their incitement to vulnerable people to panic does nobody any good. They should just stick to the facts and stop trying to out scaremonger and sensationalise the other channel/newpaper/radio network.
September 8th, 2010 at 10:07 am
How prepared are the non partisan politicians for ” the big one,the Alpine Fault”.?
They really do need to sit down together and think hard about it.
They sure do.
This event in Christchurch has some of us over here on the West Coast in a state of fear. My house has been shaking from the moderate to larger after shocks, and the main quake shook the house like hell.
We have been told that our “big one” could be more than thirty times as powerful as the Christchurch quake, I just don’t think there will be anything left over here. Much of Greymouth, Hokitika, and Westport are built on the same alluvial ground that caused so many problems in Christchurch, imagine that and thirty times worse!!
My house is on 4 foot piles (for flooding) which is bad enough, but then the ground underneath is just sand with a 1m cap of light clay and river silt.
I fear that in a quake like they are predicting there is just nothing I and my neighbours can do to stop catastrophic damage.
A wake up call is a good thing most of the time, it is not so good when you realise there is little you can do to prepare.
Does anyone know anything I could do to strengthen my house against this? Any engineers out there got any ideas?
September 8th, 2010 at 10:14 am
“A wake up call is a good thing most of the time”
I think a lot of Cantabrians are getting too many wake up calls at the moment.
I’m interested to know Shunda, what magnitude quakes are you feeling on the coast?
And anyone in Christchurch – what magnitude do you feel? Over 4-ish?
I have only felt the 7.1 in Dunedin.
September 8th, 2010 at 10:15 am
I think the best thing you can do short term is be entirely prepared to live for several weeks without a house. A large tent and non-perishable supplies as well a water.
Don’t forget some form of non-electronic entertainment. Boredom is the worst danger after the shaking.
September 8th, 2010 at 10:17 am
The media’s continued use of the prediction that the prospect of a 6+ aftershock is ‘likely’ instead of only ‘possible’ is ratcheting up anxiety levels considerably and is becoming somewhat tiresome.
The reality is that it is entirely likely. The Fiordland 7.1 earthquake in 2003 had 2 aftershocks of mag 6 among many above mag 5.
If this information saves life and limb it is very important to inform people of the reality of what is going on. Anxiety is a natural and important defence mechanism, it can be used to save lives.
September 8th, 2010 at 10:21 am
Mobilize a regiment to keep law and order Murray? I don’t think that would be wise.
September 8th, 2010 at 10:23 am
This is a really good graphic that displays the main earthquake and aftershocks happening in real time.
It gives you a really good idea of what they are going through in Christchurch.
http://www.christchurchquakemap.co.nz/#
September 8th, 2010 at 10:28 am
I didn’t say law and order Banana, use them for general relief. The very presence of unforms helps maintain order.
Also I said battalions, not regiment. We only have one “regiment” as such and its all the infantry.
Woulod you rather see guys in DPM or with gang patchs walking the streets at night? We sure as hell do not have the police to do for any sustained period.
September 8th, 2010 at 10:29 am
kowtow 9:28 am,
Indeed, Kowtow – we need to face reality, not some “what if” based on bad science.
I know this has really got us here in Wellington thinking seriously about how we would be copying if/when we get a sizeable earthquake here.
It’s times like these I really appreciate having faith in Christ:
Psa 120:1 In my distress I cried unto the LORD, and he heard me.
September 8th, 2010 at 10:39 am
What rank would the CO hold, 2+ battalions would be a binary regiment wouldn’t it? Anywho not going to argue about the designation so i will concede.
NZDF could use it’s logistics branch well enough if they aren’t getting basics into effected areas but i don’t see why the police can’t “Deputize” the locals and send the thugs packing.
September 8th, 2010 at 10:40 am
Bad news Kris, I’ve already had three people tell me the quakes were caused by Gorebul warming.
And this is in a university, god knows what the great unwashed are thinking. Ask swiftman, his brrain seems pretty fucked up so he may have an insight.
September 8th, 2010 at 10:50 am
“… it must be very upsetting – especially for kids and pets.”
LOL the cats have just come back inside, soaking wet from the rain, some 5 hours after the big shake this morning. My wife has only just finished putting out the line of fire in the carpet that they left on the way to the cat door!
September 8th, 2010 at 11:03 am
First of all, as a geoscientist, I can tell you that antropogenic climate change (the correct term) is completely separate and totally unrelated. Whoever said that has shit for brains.
I can also tell you, standing in the doorway on Saturday morning as the building shook and bucked and rolled, that I thought it was likely the Big One we had been expecting – either the Hope Fault (about every 90 to 150 years, and last time in 1888 knocked the top off the Chch Cathedral) or the Alpine Fault (about every 300 years, but the number depends on the intervals and long term or more recent (i.e. last 1,000 years or so), and last was 1717). When I heard it was a previously unknown fault, my first thought was “Oh fuck! We are still due!” We do NOT yet know if this event has released some of the stress, and eased the danger due to the Hope or Alpine Faults, or has simply transferred the stress towards them, thus increasing the danger. That needs much more data acquisition and data analysis.
What is interesting is that the aftershocks seem to be all over the place. The one this morning – under the Port Hills?? Shit. It means that it is causing some of the neighbouring structures to release energy too. Almost like a domino effect. (NOTE: Almost!! Please do NOT misconstrue. I am attempting an analogy that is imperfect. OK, end of qualifying statement.
)
Anyway, I live in the central city, but I might just take up the offer of a bed in the suburbs. I am becoming more and more on my own inside the cordon as more and more of my neighbours get the fuck out.
Pardon my language, but given the circumstance, I hope you will understand and sympathise.
And sunda: Get an engineer to look at how best to anchor your house. It will DEFINITELY come off the piles when (not if) the big one really does hit. Wooden framed houses tend to ride earthquakes out well because the wood flexes and takes up the strain better than, say, brick. The major damage here has been to brick buildings.
Oh, and brick chimneys are ESPECIALLY vulnerable and susceptible to collapse in an earthquake.
September 8th, 2010 at 11:20 am
Fuck Phil Goff.
That is all.
September 8th, 2010 at 11:57 am
Im sure glad its only the left politicising this disaster……… eh Ben and Monty
September 8th, 2010 at 12:07 pm
I think the accepted wisdom is that if you have a main fault rupture of M7, you’ll get
(a) one aftershock of M6
(b) ten aftershocks of M5
(c) one hundred aftershocks of M4
(d) one thousand aftershocks of M3
etc
September 8th, 2010 at 12:16 pm
It’s a general rule-of-thumb sort of guide, but every event behaves in its own way. It also has the underlying assumption that no other structures are triggered, and this morning’s 5.1 event suggests to me that that may be the case. So complicates things.
September 8th, 2010 at 12:23 pm
David –
What do you reckon about the Hawkes Bay quake the other day? The pundits the news people found seem to think there is no connection; the civil engineer in me tends to suspect that if you relieve a large amount of stress somewhere it’s not inconceivable that there’s a buildup somewhere else in the structure. Your thoughts on this?
September 8th, 2010 at 12:28 pm
….and a couple of wee creaks in Cook Strait shortly after? All conjecture, I know, but interesting.
September 8th, 2010 at 12:46 pm
The 8.2 quake (1855,Cook Straight) raised Wellington airport and turned Miramar island (was it called this?) into Miramar peninsular. Another descent quake and the Wellington airport extension conundrum will be solved: It’ll be longer north and south!
September 8th, 2010 at 1:12 pm
RRM: My gut reaction is that there is no connection. They are different structures. That said, we have seen in the past elsewhere in the world events triggering other events on nearby faults. However, the character of the event can be analysed to tell whether it is triggered or not, but that is something for future analysis.
Keep in mind that there are lots of magnitude 5 events worldwide every week.
Sorry for the delay in posting. I am trying to get a response from some structural engineers about the adjoining building here in the Chch CBD. It has some big cracks that weren’t there yesterday.
September 8th, 2010 at 1:29 pm
Shunda – if you are living in a 1960s+ conventional timber-framed house with tin roofing and lightweight wall cladding (e.g. weatherboards or polystyrene) and no tall brick chimney, then you’re is as good a position as anyone realistically can be.
In general, conventional light timber framed house construction performs very well in earthquakes.
What kills buildings in earthquakes is their own weight, plus not being tied together sufficiently into a single unit.
This is why so many of the photos of CHCH destruction show old brick buildings. Bricks are very heavy, not very strong, and not really joined together in any meaningful way. When the shaking starts they tend to get thrown off. Modern houses with brick veneers are better because there is a timber wall under there with a large number of ties attaching the bricks to the wall.
The few photos I have seen so far of destroyed modern houses in Canterbury, have all been ones where the ground underneath the house has liquefied into waves and mounds, and no building is going to fare well if that happens. But the majority of them that were subjected to shaking only seem to have ridden it out pretty well, with mainly just contents damage.
September 8th, 2010 at 1:31 pm
krazykiwi 12:46 pm,
The 8.2 quake (1855,Cook Straight) raised Wellington airport and turned Miramar island (was it called this?)
I think it was called “Mirimar Swamp”
– well the lower bits were swamp-like, anyway.
September 8th, 2010 at 1:43 pm
@Kris K – Yup. There are parts of the Miramar basin that are A+ liquifaction candidates in a big shake.
September 8th, 2010 at 1:45 pm
The emotion vultures are flocking into Christchurch and the Government has kicked in to help them.
Didn’t the Israeli Army do a study on war trauma which showed the best response to shock is to carry on, normalise things as quickly as possible?
The counsellor types smell emotional carrion in Christchurch – that is folk who can be kept wallowing in their fear and shock until it’s permanently ingrained. Grief, trauma, counsellors, specialists, even “therapists” are in one of the great bullshit games of the times.
They better not bring trauma counselling into Christchurch schools without parents’ consent.
Good piece by Stephen Franks in his blog:
The Franks blog:
http://www.stephenfranks.co.nz/
The Govt provides top up fuel for the counselling mob:
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10671923
September 8th, 2010 at 1:51 pm
I see a very interesting insurance debate springing up because of the quake, some issues will need to be addressed. The government will have to walk a very fine tightrope on this one.
Meanwhile there is a large exercise here this weekend, the big blow out. This is to remind people that our mountain ( Taranaki) is only sleeping. After Saturdays quake interest has increased greatly in the up coming exercise, a very good thing indeed.
To those effected by the quake, can’t offer much in the way of practical help, not sure you would have much use for a cow but the wife and I have agreed to make a generous donation. Best wishes to all and hope things turn out well for you all.
September 8th, 2010 at 2:07 pm
Side Show Bob at 1.51.
As a Christchurcher, thank for your kind thoughts and planned generosity.
I don’t need any help, but plenty of others do.
September 8th, 2010 at 2:15 pm
David, you might be able to answer a question for me.
How will a force 8 in the alpine fault compare to what we have just experienced in Christchurch?
Sure, the alpine one will be a lot bigger in magnitude. But it might also be a lot deeper and further away. Since the Christchurch quake was close to the city and shallow, could it be that the effects on Christchurch were greater than what the alpine quake will be?
September 8th, 2010 at 2:20 pm
I really feel for you all in Christchurch. I’m keeping in touch with a number of friends who have young children and they are finding it very hard. The children seem to get some sleep but the adults are getting seriously sleep deprived with worry, fear etc.
To get a feel for the unrelenting nature of the aftershocks check out this site. http://www.christchurchquakemap.co.nz/
I too feel I can’t do a lot from a distance however there will be opportunities. I’m working with one of our local schools to effectively adopt a school near Kaiapoi – we’re fundraising, completing art work etc for the kids down there, collecting items etc for them and are liaising with the leadership of that school so that we can put an even on for them (when they have a safe location for school, the kids are back, etc etc). I have suggested to others that they too can adopt a school, a kindy, a branch of a voluntary group or similar. Morale and knowing they aren’t alone will help – as will the cash!
September 8th, 2010 at 2:22 pm
whirikiwis business 9:25 AM. I doubt it.
cheers
David Prosser
September 8th, 2010 at 2:26 pm
We need to remember that the Richter scale is logarithmic.
So an earthquake rating 7.0 is ten times more “powerful” than one rated “6.0″.
I get the feeling that some people think a 5.0 rated aftershock is about 2/3ds the power of the original one of 7.1.
But here is the reality.
Aftershock of 5 say 1000 units of terror. Aftershock of 6.0. 10,000 units of terror. Original Shock of 7.0 equals 100,000 units of terror.
In other words the aftershock of 5 has 100th the power of the original.
that is why no one feels aftershocks of 3. They are tiny and only detectable by instruments.
On the other hand a repeat of the 1857 quake of 8.0 would by 1,000,000 units of terror. Ten times more powerful than Christchurch.
September 8th, 2010 at 2:36 pm
When the quake hit on Saturday morning, I thought it was the Big One, either the Hope Fault or the Alpine Fault. In hindsight, I realise that we will feel an Alpine Fault event as longer period shaking, and for longer. So we would likely fare better than this one, because this one was (1) big, (2) close AND (3) shallow. That is the worst possible combination, and we in a sense have had the best possible outcome from that. Lots of damage but no fatalities. That is remarkable!
Owen – you are talking about the Richter scale, which is a measure of the energy released by the earthquake. For how it feels, we often refer to the Modified Mercalli scale, and for that the 5.1 this morning, which was located _under the Port Hills_ thus inside the city limits and was also shallow (6 km), would have felt almost as strong as the original event.
In fact, I live in the CBD (but after this morning I may accept a friend’s generous offer of their spare bed), and there is additional damage readily visibly now that wasn’t there yesterday.
September 8th, 2010 at 2:37 pm
Sorry Owen, a 1.0 difference in the Richter scale is 32 times in terms of amount of energy released.
So a 7.1 quake is 32 times stronger than a 6.1.
Also the depth and distance make a huge difference to whether it can be felt or not.
September 8th, 2010 at 2:47 pm
I knew it wasn’t simple – the house of someone I know was undamaged on Saturday but damaged this morning – but it’s more complicated than I thought.
The moment magnitude scale (MMS) has superceded the Richter scale. As with the Richter scale, an increase of 1 step on this logarithmic scale corresponds to a 101.5 ≈ 32 times increase in the amount of energy released, and an increase of 2 steps corresponds to a 103 = 1000 times increase in energy.
The Richter scale was not useful above about 6.8, the MMS is not good below 3.5.
Magnitude scales differ from earthquake intensity, which is the perceptible moving, shaking, and local damages experienced during a quake. The shaking intensity at a given spot depends on many factors, such as soil types, soil sublayers, depth, type of displacement, and range from the epicenter (not counting the complications of building engineering and architectural factors). Rather, they are used to estimate only the total energy released by the quake.
http://en.wikipedia.org/wiki/Moment_magnitude_scale
From the earthquake effects table on http://en.wikipedia.org/wiki/Richter_magnitude_scale
0-4.9 Light – Noticeable shaking of indoor items, rattling noises. Significant damage unlikely.
5.0-5.9 Moderate – Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings.
6.0-6.9 Strong – Can be destructive in areas up to about 160 kilometres (100 mi) across in populated areas.
7.0-7.9 Major – Can cause serious damage over larger areas.
September 8th, 2010 at 2:55 pm
Yes, but PG, it also depends on how close and how shallow. Thus a magnitude 8+ on the Alpine Fault may not feel as bad to Christchurch, because it would be deeper and further away (as tknorriss noted above). This 7.1 event is actually best compared to the Haiti event, which was shallow and close to Port au Prince (although there is a fault closer to Port au Prince that could also fail in the near future – shudder to think of the implications for that).
Also the 5.1 this morning felt almost as bad as the 7.1 because it was SO close. If the weather had been clear, I could have looked at the epicentre out my apartment window.
For comparison, the 7.1 was about 40 km from Chch, and 10 km down. The 5.1 this morning was, based on triangulation by Geonet, _under the Port Hills_, and was only 6 km down. Many people are reporting that they felt a vertical “jump”, i.e. the initial motion, quite strongly. That for me was the last straw. I am getting out of the CBD.
September 8th, 2010 at 2:55 pm
David in Chch 2:36 pm,
I have always thought the Richter magnitude was largely useless when wanting to know the impact on the surface – especially in relation to manmade dwellings and personal risk.
Why is it we never hear mention of the Modified Mercalli scale? I assume this is a surface measurement.
And is there a crude way of translating a Richter magnitude at a given depth into an equivalent surface magnitude (Modified Mercalli scale?)?
No doubt strata and soil type come into it as well.
September 8th, 2010 at 3:02 pm
If you look at the Geonet site, they have a tab that says something like “Shaking maps” which are in essence a graphical version of the MMS.
It’s a useful site. I use it regularly.
September 8th, 2010 at 3:05 pm
On and yes, soil has a BIG effect. Just look at Avonside and Bexley – soft river and estuary sediments.
September 8th, 2010 at 3:07 pm
Regardless of what qualitative scale you want to measure the earthquakes with, the practicality remains that earthquakes and hurt feelings don’t kill people, collapsing buildings do.
There is some excitement about the main Saturday morning event in engineering circles, because word on the street is the main 7.1 earthquake produced ground shaking in CHCH that was right up at pretty much 100% of the acceleration spectra used in current structural design. And yet no big high-rise buildings have collapsed. Pretty good results. The university research labs do amazing work but there aren’t a lot of opportunities to verify the theory with full-scale testing of real buildings.
September 8th, 2010 at 3:08 pm
David Prosser
Whereas Parker has performed well in the last few days, his performance over the last 3 year is substandard.
As Anderton has also done well over the last few days (that is he did not pretend to be a mayor in waiting and kept things orderly by allowing Parker to do his job) I expect he will make an adequate Mayor for the next 3 years (which is more than I can credit Parker).
September 8th, 2010 at 3:18 pm
Excellent initiative Jadis. We’re doing our bit as a business as well – this week and next we’ll be donating a percentage of our retail take to the local council’s appeal for Christchurch which is being held next week. We’re looking at other responses as well.
September 8th, 2010 at 3:20 pm
David, if there were to be another BIG earthquake soon (say, in the next five years), would we see the same liquefaction? My lay understanding is that it was caused basically by water being squeezed out of the ground below the city. So if the water is now mostly gone, then it seems to me that it should take a while to build up again..?
September 8th, 2010 at 3:22 pm
Um. I_the_R: To me, a Chch resident and voter, Anderton has been conspicuous in his absence. I saw either in the city or on camera in the city, the other Chch MPs. And frankly, I cannot imagine how the superannuitant Anderton would have coped with this. Before the event, I was not supportive of EITHER of the candidates. I am less uncommitted now.
September 8th, 2010 at 3:25 pm
Repton: Yes it get’s squeezed, but the paths followed will be different, water will re-infiltrate over time, etc. etc. etc. So I would expect different levels and patterns of liquefaction, but it could certainly still occur. I am glad now that I didn’t buy that house in New Brighton!
September 8th, 2010 at 3:36 pm
David in Chch 3:25 pm
… it is indeed a wise man who builds his house upon the rock.
September 8th, 2010 at 3:39 pm
Hmmm an interesting issue… say New Brighton is now deemed unsuitable for residential housing, would the council/govt relocate the affected households and give them a new piece of land somewhere? Or are the house owners stuffed and forced to buy another section somewhere to rebuild, after all EQC & insurance companies only pay out the house but not the the land, right?
September 8th, 2010 at 3:41 pm
@ Inky_the_Red – the best thing that Jim Anderton could do now would be to withdraw his nomination for mayor, and announce that he intends to focus his efforts on supporting his constituents in Wigram. He would thus be spared an embarassing loss, and could retire gracefully at the 2011 election as he has previously announced.
September 8th, 2010 at 3:50 pm
“The Government has set aside $2.4 million for trauma counselling for Christchurch earthquake victims, Social Welfare Minister Paula Bennett says. ”
This is bloody madness!, more of my tax payer dollars being wasted.
There has been an earthquake, deal with it and get on with the rest of your life, all this bloody hand holding and tax payer funded encouragement of the victim mentality is not going to get us anywhere.
September 8th, 2010 at 3:52 pm
Except, KK, good friends of mine have their house up on the hills – almost directly where the epicentre has been located.
September 8th, 2010 at 3:58 pm
A good geological explanation in Tectonics of the M7 earthquake near Christchurch
Trauma counselling might seem like madness to you Fot, but there may be people affected in Christchurch who are grateful for some help.
September 8th, 2010 at 4:02 pm
A question re mortgages for Christchurch people can’t work as a result of the earthquake – why not a peep out of the banks? Even the mention of, say, a 3-week mortgage repayment holiday would be a hell of a big stress reliever for people down there. Or that they will at least be understanding and try to find a solution if people fall behind as a result of the disaster.
The banks’ profit is healthy enough for them to be decent at a time like this. Besides, think of the good publicity.
Failing that, the funding windfall for counsellors would possibly be better applied to alleviating the cause of some of the stress rather than to something as unproven as counselling. (I’m assuming here they’d employ counsellors rather than suitably qualified psychologists – not enough of those to go round).
September 8th, 2010 at 4:09 pm
Apparently all you have to do is speak to your bank rep, who of course will be feeling as traumatised as you. That’s my plan at least.
I also think that’s part of the reason behind the wage support plan announced yesterday.
September 8th, 2010 at 4:40 pm
The “Wage Support Plan” is lovely for those folks on a permanent contract of some sort.
However I know a number of people who work more than 1 job, all on a “as needed” basis – ie. 0 hr contracts. They’re trying to ride out this recession, working as many jobs, any jobs they can, to make their 40-50 hrs a week. Now they have no work at all.
For these folks I know, no work = no pay. WINZ can’t help them, since they’re technically not unemployed, they’re just not getting any hours in the foreseeable future.
September 8th, 2010 at 4:51 pm
I tried to avoid getting into all the technicalities but just convey a simple truth to those people (like the young woman at the check out this morning) who thought that a 5 Richter scale earthquake was almost as “strong” as a 7.0 R.
Of course all those other factors come into account and the M scale is more related to feelings. Hence I used a common English language word in quotes “powerful”.
Normally, when people ask you the time, there is no need to give them the workings of the watch.
the Richter scale may have been “superseded” but it is still the scale normally quoted in news broadcasts etc.
September 8th, 2010 at 4:58 pm
I have always thought the Richter magnitude was largely useless when wanting to know the impact on the surface – especially in relation to manmade dwellings and personal risk.
Why is it we never hear mention of the Modified Mercalli scale? I assume this is a surface measurement.
And is there a crude way of translating a Richter magnitude at a given depth into an equivalent surface magnitude (Modified Mercalli scale?)?
The problem is the M Mercalli scale is just a measure of relative effects of an earthquake in any given location, it is not a measure of the overall energy released. The Richter scale is also largely obsolete and though it is still used by the media what they are actually quoting is the moment magnitude scale.
September 8th, 2010 at 5:11 pm
Interesting point on NOT PC.
Finally, the view has already been advanced that the building regulations enforced by local government played a major part in their being no loss of life. Those advancing this view have overlooked something altogether too obvious to mention, but I will. Contrary to this simplistic view, the buildings that have collapsed in the inner city were virtually all the very listed and historically protected buildings the council insisted must be preserved. These were buildings that, without the intervention of the council, would in most cases been replaced long ago with something much safer. Only timing and luck has spared the council of direct responsibility for the death of their constituents.
September 8th, 2010 at 5:19 pm
How will a force 8 in the alpine fault compare to what we have just experienced in Christchurch?
Sure, the alpine one will be a lot bigger in magnitude. But it might also be a lot deeper and further away. Since the Christchurch quake was close to the city and shallow, could it be that the effects on Christchurch were greater than what the alpine quake will be?
The Alpine fault quake will definitely be classified as shallow, the tectonics of the area make that pretty certain.
It will be a lot further away from Christchurch, but being possibly 32 times bigger the effects will still be significant. But the 7.1 was just so close to Christchurch that it could quite possibly be a more destructive event than a theoretical mag 8 on the Alpine fault. The effects of the Murchison 7.8 earthquake on Christchurch in 1929 would be a good case study, though the Alpine fault rupture will still be a bit bigger.
Another consideration is on which part of the Alpine fault the rupture occurs, if it happens near Haast for example it may not be as bad for Christchuch as if it happened behind Hokitika.
September 8th, 2010 at 5:27 pm
Well, all this has not been upsetting for me, and while I may change my middle name to ‘Stoic’ obviously others are very nervous, and I think some more effort needs to go into making clear that instances of moving earth will reduce in frequency and power over time.
Mind you, the front of my house did not fall off, an event which might have given me a new perspective, especially from the loo.
September 8th, 2010 at 5:36 pm
There is no guarantee what size “the big one” will be – could be 7.5, 8.0. 8.5, whatever. Could be multiples of different sizes, in different places, different depths, domino. Nothing we can do but be as prepared as possible without being paranoid, and wait and see.
It could be a short wait or a long wait too, no way of knowing. May not be in our life times.
Look on the bright side – it may raise the South Island enough to compensate for sea rises
September 8th, 2010 at 6:44 pm
To bite.. or not to bite. Nope – I’ll let it go.
September 8th, 2010 at 7:28 pm
Does anybody know who to contact to help out in Christchurch? I am thinking of rounding up a few guys and heading over the hill, we will need help on our side at some stage, so it only seems fair.
September 8th, 2010 at 7:37 pm
Shunda barunda (1,317) Says:
September 8th, 2010 at 7:28 pm
Does anybody know who to contact to help out in Christchurch? I am thinking of rounding up a few guys and heading over the hill, we will need help on our side at some stage, so it only seems fair.
******************
I hear that what they want is money, for the mayoral relief fund.
September 8th, 2010 at 8:00 pm
Shunda..the council . civil defence , Red Cross , any of the churches..maybe Age concern or Grey power..many of the elderly are really sleep deprived and stressed..some are very lonely..could do with help with food , shopping , boiling water..
As a resident , I am just managing my own household , keeping in touch with friends , neighbours , elderly etc…I think people living on thier own are really struggling with the fear..also foreigners who have never been in an earthquake before.
Homes which were ok after Sat are now damaged today after the serious aftershock..generally we are all trying to keep in close touch with one another. Good on you for wanting to help.
September 8th, 2010 at 9:25 pm
We have so much work to do Farrar,
and so much confidence to rebuild,
one thing I can tell you is that Parker will not be building stainless steel living cages in Central Christchurch, Henderson facades,
September 8th, 2010 at 10:37 pm
“LOL the cats have just come back inside, soaking wet from the rain, some 5 hours after the big shake this morning. My wife has only just finished putting out the line of fire in the carpet that they left on the way to the cat door!”
Lol, did they bang their heads at the opening.
September 9th, 2010 at 6:41 am
It gets worse.
Last months weather stats.
This weather event is a reflection on Tauranga’s retention of its title as sunniest and wettest main centre.
The mean temperature was 11.2C – above average by 0.9C, with 452 sunshine hours. Rainfall in Tauranga totalled 528mm during winter an ‘above normal’ amount of 144 per cent.
Christchurch had the most miserable winter of the main centres weather wise with a mean temperature of 6.6C and 304 sunshine hours, although it was less wet with 247mm of rain.
I should point out that fir the first 6 months of this year we had no rain of any consequence so a bit this last month helps the average.
September 9th, 2010 at 12:25 pm
The aftershocks are tiring. It frays the temper and leaves one feeling in a state of suspension – there’s no point trying to fix cracked plaster that shocks keep cracking.
And ones equilibrium is off center – every vibration of a couch or building feels like an earthquake that gnaws at trust in the world.