Hard News: What Now?
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We have a garden but due to flooding digging a long-drop was impossible (a week post-quake and we still hit water a spade-length below ground). The nearest public park (across two busy roads) has worse drainage than our garden does so would have been a poor choice for a shared dunny. Buying a chemical toilet meant we were able to actually live in our house (and I am staggeringly aware of the privilege that allowed us to drive to a shop and buy the thing).
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Isabel Hitchings, in reply to
Steven The number of things which I disapprove of in general life that have been godsends in the current circumstances is mind-boggling and a little humbling - from paper plates to federated farmers!
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DeepRed: From your link: "Henry Ford thought of cars as tools for liberating humanity from the wretchedness of cities" . Yes, they were a means to get OUT of them so that you could visit the countryside.
For any Engineers out there: If a building is built to survive a 7 earthquake, does that mean that it should then be removed and a new one put up? How reliable is post reinforcing of an already damaged building that has done what it was designed to do????
Which reminds me. I was concerned at Phil Parkes comment at the Blend where he claimed that it was not the old buildings that killed people. When the raw facts of "death per building" are considered is true. But the old buildings do not have the people density of the new ones. Then, once the new ones with their open plan offices pancake....
I gather he was using this as an argument to consider saving the heritage buildings. Build new, better and safer buildings.
Re Japan: What has impressed me with the hand held footage of the insides of buildings especially is the lack of ceilings and floors crashing down around ears. Those buildings have withstood horrendous shaking and I suspect heritage buildings would truly be dust along with practically all of the city if this has occurred in Chch or Wgtn. There is a lesson there
Finally. Anyone for Nuclear power in Aotearoa??? We would have ended up the long white shroud after an event like that.
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Andre Alessi, in reply to
Finally. Anyone for Nuclear power in Aotearoa??? We would have ended up the long white shroud after an event like that.
After a 9.0 earthquake here, there wouldn't be enough infrastracture (or people) to worry about any sort of nuclear event. You can't plan for something this massive, any more than you can plan for massive meteorite strikes in urban areas, etc These events don't say anything about the safety of nuclear power in non-exceptional situations.
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Rich Lock, in reply to
After a 9.0 earthquake here, there wouldn't be enough infrastracture (or people) to worry about any sort of nuclear event.
Depends what you mean by 'here', though, surely? A 9.0 quake in the SI woudn't necessarily bring Auckland to a standstill, same as Tokyo is still more or less functioning, but battered.
But any reactor near the epicentre would certainly be worrying me, same as those ones in Japan are.
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Matthew Poole, in reply to
These events don’t say anything about the safety of nuclear power in non-exceptional situations.
No, they don't. But a seismically-active country such as NZ needs to be cognisant of the risks associated with nuclear power coupled with being earthquake-prone. All the more so when NZ has no real need for nuclear power, in the presence of ample opportunity for hydro, tidal, wind and geothermal generation.
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BenWilson, in reply to
Steven The number of things which I disapprove of in general life that have been godsends in the current circumstances is mind-boggling and a little humbling - from paper plates to federated farmers!
Word. Life isn't meant to be a survival situation. But when it is, you're seldom too concerned about the greater impact of something that is saving your life. I don't generally much admire SUVs in cities, but I imagine they're currently gold down there.
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Fooman, in reply to
Re Japan: What has impressed me with the hand held footage of the insides of buildings especially is the lack of ceilings and floors crashing down around ears. Those buildings have withstood horrendous shaking and I suspect heritage buildings would truly be dust along with practically all of the city if this has occurred in Chch or Wgtn. There is a lesson there
Peak ground accelerations in Japan were much lower than in central/east/south Christchurch from the Feb 22 quake. The Japan quake was spread over a much wider area due to the comparative sizes of the two quakes. Shaking was longer in Japan. Infrastructure density in Japan is also likely to affect perception of (earthquake) related damage (no oil refineries in the south island!).
Compare Japan with Feb 22 Christchurch and Sept 4 Christchurch.
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Possibly also worth noting that it appears to have been the Tsunami that screwed the reactors, rather than the 'quake itself.
The reactors shut down due to the 'quake, and stopped generating electricity. So far so good. Normally they would use the external electrical supply to power cooling and control systems, but due to major damage to the power grid, that wasn't available as a power source. The emergency diesel generators started correctly, but were damaged by flooding from the tsunami that followed - the wave overtopped the seawall and flooded them.
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Finally. Anyone for Nuclear power in Aotearoa??? We would have ended up the long white shroud after an event like that.
I'm not against them on principle. If they're on the East Coast, even if there was a leak, the likely fallout is going to be heading out across thousands of miles of Pacific Ocean.
Also, as in Japan, the nuke plant is the least of their worries, really. In fact, I think being downhill from a hydro dam could be more devastating.
All the more so when NZ has no real need for nuclear power, in the presence of ample opportunity for hydro, tidal, wind and geothermal generation.
More to the point.
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Fooman: Some people think it is the ground acceleration is the big killer. Far from it. It is the surface and low frequency waves and how long they persist that send the parapets and buildings into oscillations. Not being in Chch but I suspect witness accounts would say that the collapsing did not occur in the first second or so of the quake but seconds later.
I think the peak accelerations would be a pretty good measure of how close you were. The top at the Heathcote School was 2.2g vertical. But it was so short that the buillding do not have the opportunity to be chucked up.
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While any meltdown in a nuclear reactor is a very serious problem, I would be surprised if there is any loss of life or health effects from the incidents being reported from nuclear stations in the area. I wish I could say the same about oil.
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Fooman, in reply to
Hi Ross,
NZS3404 (Steel Structures Standard), in discussing seismic loading do take that point:
"The design earthquake forces are derived from the 450 year return period damped uniform spectra...these spectra are indicative of the likely recurrence of the peak acceleration response..."
with the cavets of:
"a) The level of sustained shaking likely to cause damage within a building is approximately 60% of recorded peak response...
b) [experience] show that buildings perform better than can be predicted by calculation using simplified analysis..."
This suggests to me, that the current standards base seismic loadings on PGA. I recall, (admittedly with some levels of vagueness) that NZ4203 (loadings standard) loads are derived from the expected accelerations and the building mass. There are design details in 3404 to ensure a ductile response of the building if design loads are exceeded, or to make the response fully elastic, as well as appropriate damping response (types of connections etc).
So I would say the current building codes use PGA as the basis for loading in seismic design, but accommodate the duration and excitation response of the structure in the design. I guess Bill Robinson or Chris Gadd at RSL would be one to ask with regards to this.
Not being in Chch but I suspect witness accounts would say that the collapsing did not occur in the first second or so of the quake but seconds later.
Did peak acceleration occur in the first second? And if the initial response of the structure was inelastic (e.g. bending or initiating fractures) in that first second, that doesn't necessarily mean it has fallen down, but just severely weakened - and susceptible to smaller loads (further shaking and aftershocks). It is hard to say.
The top at the Heathcote School was 2.2g vertical. But it was so short that the buillding do not have the opportunity to be chucked up.
That doesn't mean it wasn't significantly loaded - the building could have been a light, flexible, well damped design (i.e. wooden frame building like most schools I know of).
But anyway, metaphorically, the gist of my initial post was to point out that the Japanese hurricane did not necessarily have stronger winds than the Chch tornado...
Cheers,
FM -
Good news steel structure story of a different sort.
Leaweld Perimeter Solutions is one of the companies undertaking preliminary work in Christchurch, having just signed a contract to supply 17km of 1.8m-high security fencing to be be erected around damaged buildings.
Leaweld managing director Steve Evans said the scale of damage to buildings in Christchurch was so great there wasn't enough security fencing anywhere in the country to meet the city's needs and the Christchurch City Council had been looking at importing 19 container loads of security fencing from Australia to fill the gap.
However, Evans realised if several local firms pooled their resources they could make the fencing in this country at a lower cost than the imported option.
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Talks with various suppliers revealed other businesses were prepared to pull out all the stops if it meant assisting with the Christchurch recovery effort.
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Russell Brown, in reply to
I think the peak accelerations would be a pretty good measure of how close you were. The top at the Heathcote School was 2.2g vertical. But it was so short that the buillding do not have the opportunity to be chucked up.
How much does peak acceleration have to do with the nature of the shallow soil? Heathcote Primary is on shifting soil, it seems. David Haywood in Avonside wrote about his PC slamming into the wall next to his head and "shattering into parts". It sounded really violent.
OTOH, none of the first-person accounts or videos of the Japanese quake seem to show anything like that. It just went on for ages.
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Rich Lock, in reply to
I'm not against them on principle. If they're on the East Coast, even if there was a leak, the likely fallout is going to be heading out across thousands of miles of Pacific Ocean.
You're relying awfully heavily on something you can't even begin to control for disaster limitation, though. There are parts of Scotland which, even 25 years after Chernobyl, can't be used to graze sheep intended for market. And Scotland is an awful long way downwind from your plume source.
What if the wind happens to be blowing in the wrong direction?
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BenWilson, in reply to
What if the wind happens to be blowing in the wrong direction?
Then there would be fallout, and bad consequences. It's not 100% safe, of course. But you do need to compare it to other power generation sources over the years to really see how important that is. There are disaster cases in most power generation sources.
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Matthew Poole, in reply to
There are disaster cases in most power generation sources.
Yes, there are. NZ has been quite fortunate in having had none of significance.
That said, one needs to consider the worst-case scenario when looking at these things. The worst that can go wrong with hydro is a catastrophic dam failure, but water goes away and structures can then be rebuilt immediately the ground dries out. Except for people in the immediate downstream, there's time to give a warning to evacuate. With thermal, you can potentially have a dust/gas explosion, which could level a moderate distance around the plant but then the damage is done. Geothermal, the same.
All of those things can go wrong, and have overseas, but there is no long-term environmental "scorched earth" that irretrievably lays waste to potentially large swathes of the country. An accident at a nuclear plant at one end of NZ, with the wind blowing the fallout along the country, could render nearly the entire nation uninhabitable.ETA: And NZ does have all those other options, plus solar, wind and tidal, all of which have proven to be remarkably safe. Nuclear for NZ is not, unlike Japan, an option that must be considered in the absence of much credible alternative.
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Craig Ranapia, in reply to
What if the wind happens to be blowing in the wrong direction?
If I stand at my front door and look north, I can see two petrol stations and an awful lot of light industrial buildings and big box retail. None of which I'd like to be downwind of if they were uncontrollably ablaze after an 8.9 magnitude quake.
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Matthew Poole, in reply to
If I stand at my front door and look north, I can see two petrol stations and an awful lot of light industrial buildings and big box retail. None of which I’d like to be downwind of if they were uncontrollably ablaze after an 8.9 magnitude quake.
When was the last time any of the above laid semi-permanent waste to an area? Petrol stations burn, industrial burns, life goes on. Look at Southdown Freezing Works, which burned several times, caused a lot of aggravation for the locals when it did, but once the fire was out it was all done. The hazard was gone.
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Yes, there are. NZ has been quite fortunate in having had none of significance.
Well, we had a pretty bad one last year in the extraction of coal, most of which is for power plants, I presume.
An accident at a nuclear plant at one end of NZ, with the wind blowing the fallout along the country, could render nearly the entire nation uninhabitable.
Yes, if a very poorly designed plant had the biggest nuclear disaster in human history, and the wind conditions were exactly right, that could happen. And I would be opposed to the construction of such a plant.
Chernobyl was a long time ago, and the technology has improved massively since then, and they were well behind anyway, the Soviet Union virtually bankrupt and totally deaf to the objections of the populace and quite possibly the scientists setting the plant up.
The way they're designed now, they could actually have a core meltdown, and not release harmful levels of radiation. The plant would be fucked, is all.
But we don't need it, so the whole thing is moot. We get enough rain and wind. Personally, I'd like to see more wind power, it's something that can be done in small increments, and it couples nicely with hydro, because the excess generation that wind produces at times can be stored by pumping water back into the dams.
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Matthew Poole, in reply to
Well, we had a pretty bad one last year in the extraction of coal, most of which is for power plants, I presume.
You presume wrong. The coal from Pike River is mostly used for making steel.
And even if it was used for power generation, that's not a power generation accident. That's like saying that someone drowning in a hydro dam is a power generation accident.Yes, if a very poorly designed plant had the biggest nuclear disaster in human history
It wouldn't need to be as big as Chernobyl for that to happen. Scotland is a hell of a lot further away from Chernobyl than Bluff is from Cape Reinga.
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Matthew Poole, in reply to
The way they’re designed now, they could actually have a core meltdown, and not release harmful levels of radiation. The plant would be fucked, is all.
And this has been tested? No, didn't think so.
Theory is great, in theory. In practice, we haven't got a snowball's chance in hell of predicting and controlling all the possible ways that Mother Nature can fuck with our best-laid plans. -
Nuclear power is not a viable option for his country even just on economic grounds - we simply don't have the scale of industry or population to justify building a nuclear capability. It's really expensive regardless of the poisonous and persistent safety and pollution issues.
Seems to be touching some political memories for NZ's left. but is a distraction from other goings-on that actually do have real consequences here. Like rebuilding Christchurch - and the sneaky things that will be slipped in on that pretext. Nuclear power is not one of them.
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BenWilson, in reply to
That's like saying that someone drowning in a hydro dam is a power generation accident.
I would say that, if it happened. And I wouldn't see it as sufficient reason to not have hydro, although they should probably look at ways to prevent the same accident happening again.
It wouldn't need to be as big as Chernobyl for that to happen. Scotland is a hell of a lot further away from Chernobyl than Bluff is from Cape Reinga.
Scotland is not uninhabitable. It produces a lot of food. You have massively overprojected the destruction that the Chernobyl accident wreaked.
And this has been tested? No, didn't think so.
As far as I know, yes, it's been tested. They know how hot it gets in a melting core, and they make and test the containment to that.
Theory is great, in theory.
It's not just theory. There are a lot of existing nuclear reactors, this technology has been around for a long time, has been tested for a long time, has improved all through that time. Every step along the way with the theory they do tests and experiments over and over again with massive amounts of care and attention.
In practice, we haven't got a snowball's chance in hell of predicting and controlling all the possible ways that Mother Nature can fuck with our best-laid plans.
No, but we can predict the likely ones. In the end our entire planet could be wiped out by a large asteroid, sure, but I'm not wasting much time worrying about it. I'm definitely not going to worry about whether nuclear plants might be ruptured in that event.
What's happened in Japan has been a real testament to the modern design of nuclear plants, in fact. There has been no dangerous leak, despite the fact that it was hit by massive earthquake AND a massive tsunami. However, the tsunami itself has had a catastrophic death toll. That's been a considerably more important factor in disaster planning than any worrying about the nuclear plant.
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