Field Theory: Japan moves
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I was trying to work out the chances of dying in a natural disaster, as opposed to any other means. Less than 1000 NZ inhabitants have died in all such disasters since colonisation (including Napier, Christchurch, Marlborough 1855, Wairarapa 1848). If you assume maybe 5 million total deaths since then, then that's a 1:5000 chance of dying in such a disaster. Even if you assume that modern average disasters will be more lethal than historic ones (due to increased population density) then 1:1000 would be an outer estimate of one's likely demise involving earthquake, volcano or storm.
So ignoring the news is a perfectly sane thing to do. Of course, disaster readiness is a harmless and enjoyable hobby, but I wouldn't be worried about missing tsunami warnings because I don't sleep with radios tuned to all available channels and some sort of Twitter-driven alarm clock.
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Caught between falling rocks and a wet place. Earthquake + Tsunami is a pretty shitty combo, bottom line is ... coastal people are screwed. How do you flee when the roads are fucked/blocked? How do you hear you need to if the mobile net is blocked?
I guess flick straight to radio, and just hope they have time to get an alert out. But even then, if you don't have a high point nearby, what can you do? If an earthquake big enough to swamp Rosebank peninsular hit (would need to be HUGE), it's about 3 km to my nearest hill, along only one road, along which about 10,000 live/work/go to school.
That's the horrible thing about tsunamis - they get into every nook and cranny. You're not getting away by hiding under a table. Which suggests to me why so few "on the ground" movies came out from Japan. They're all dead, or they were far too busy surviving to get their cameras out.
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And also related to statistics:
The accepted model amongst most health physicists is the linear no-threshold response model discussed in this article.
That posits that any increase in radiation will cause an increase in cancers. “Background” radiation causes cancers – it isn’t safe, it’s just unavoidable. One particle track going through a cell nucleus, if unrepaired, will give you cancer. And whether that track hits a nucleus and whether a body repairs it is down to chance -so the more particles, the more cancers result.
Gofman reckoned on a figure of 475,000 additional cancers from Chernobyl. It’s hard to say if he’s right, because you can’t tell whether a cancer is an additional one from man-made radiation exposure, or a “natural” one.
So even if there are zero acute deaths from Fukushima, that doesn’t mean that a bunch of people aren’t going to die, even without knowing what caused their death.
[The nuclear industry is keen on an alternative model, radiation hormesis, which suggests that low doses are harmless/beneficial. Evidence for this has been somewhat lacking, although it has the force of convenience on its side]
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Sacha, in reply to
it has the force of convenience on its side
Strikes me as a very useful analytical phrase...
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Bart Janssen, in reply to
Gofman reckoned on a figure of 475,000 additional cancers from Chernobyl.
Which is fun to say because it's impossible to prove or disprove since most cancers go unnoticed.
The problem with low dose radiation exposure is we just don't know how humans respond. One thing we do know is that the simple linear model from high dose to low dose is wrong, if it was right we would lots and lots more dead radiation industry workers and we don't. But it is also the most conservative assumption and hence is the best assumption to use when setting safety standards.
The nuclear industry is keen on an alternative model ...
Nah it's most of the scientific community that are keen on an alternative model, because the data says the linear model is wrong. Exactly what is the right model is up for more question mostly because doing the experiments is frowned upon.
Based on what I know, my guess is that there is a certain level of DNA damage that does no harm at all, it gets repaired and replaced just fine without anyone noticing. That makes the low dose end of the curve result in much lower death rates than expected. I don't know if you need some damage to be healthy but it wouldn't surprise me, biology is weird like that. I wouldn't base safety standards on that because there is no reason to take the risk.
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Given 10 units of radiation will cause some form of "damage".
10 units of radiation dumped on one person is 10 times worse (for that person) than 1 unit dumped on 10 people. The chances are that one of those 10 will still likely get hit with the "damage".
It seems to be that the total dose is related to the total number of people "damaged". Spread the dose out and it becomes a hell of a lot harder to pick the losers.
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Islander, in reply to
“bottom line is…coastal people are screwed”
Depends on what generates the tsunami: one of the larger ones to roll over Big O was apparently a ‘slump’ tsunami, triggered by a big earthquake much further south. There are quite massive trenches off the coast of Big O, and when a side of one them slumps, a large tsunami results (this is what happened in Papua Niu Guinea in much more recent times.) We have no way of anticipating one of those except the usual “if it’s a largish localish earthquake, get away from the beach"-
we __can__react less generally when the earthquake triggering a tsunami is outside of ANZ (see earlier post) because we do get warning of those, and some of us are owls (um, so to speak!)The CHCH earthquakes were a hideous problem for CHCH but dont trigger tsunami this side of the hill (nor would large earthquakes elsewhere in ANZ.)
However, any movement of the Alpine fault constitutes a possible tsunami hazard. All of us who live here (or in other beach settlements in South Westland) are well aware of the potential danger – but we love living by the sea… -
Depends on what generates the tsunami
I won't be quibbling about what generated it until after I've got everyone to higher ground.
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Islander, in reply to
Here, with 2 kinds of tsunami, you have chances of getting people to higher ground: with the 3rd kind (slump) not so much...
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I'm told by one of my geology PhD acquaintances studying the area that there's also a trench off Kaikoura which could spark a similar no-warning tsunami on this coast.
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Call me reckless, but I find it really difficult to work up any real concern over a tsunami affecting me directly. Killed in traffic seems more likely. Or attacked by Mothra.
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but you could be called fucking stupid.
The dismissive tone indicates that perhaps 2/7 days of sanity is better for the soul than a lifetime of paranoia.
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Islander, in reply to
Yep. Except I'm told by the local occaisionally resident expert that the Kaikoura trench is based in different rock/sedimentary material than the Big O ones.
Martin Lindberg - I rather suspect you dont live on the Coast - or any coast.
chris/bloodsplat -???????
(Never run soul/pyschic/spirit stuff past me thank you. It just does not compute.) -
<takes note>
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Islander, in reply to
Thanks!
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I DO note that last week NIWA announced that they were about to do a hydrographic survey and small seismic type survey of the area north of Banks Peninsula looking for faults. .....the area between the Kaikoura trench and Sumner......the seismic survey will only penetrate about 1.5km into the sediment.
I wonder why the quakes stopped just at the coast.........fascinating...
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Islander, in reply to
My seisimological mates will be back here in Big O in May – I’ll ask ’em Ross Mason
(part of their kaupapa, Welsh & French as they are, and having more than a couple of real doctorates- is explanation! Especially for local people!) -
Rich Lock, in reply to
Um... okay. Had we done that here (and our distance from the estuary is measured in metres, not kms) it'd have been about the dumbest thing we could have done. Those "nearest hills" were in the process of falling on Redcliffs and Sumner. And we'd have been running from a tsunami that wasn't coming - for lack of information, leaving a safe place for a dangerous place.
Also, you might want to check whether your screaming and fleeing neighbours are big fans of Ken Ring's.
My Hobson's choice is to risk the rocks, or risk the waves. Watching footage of the Tsunami in Japan has given me a nasty case of the heebie-jeebies, so my personal choice is to risk the rocks. Each to their own, I guess.
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Bart Janssen, in reply to
10 units of radiation dumped on one person is 10 times worse (for that person) than 1 unit dumped on 10 people. The chances are that one of those 10 will still likely get hit with the “damage”.
That's exactly the problem. 10 units is not 10 times worse than 1 unit. 1 Unit does less than one tenth of the damage. It's not linear and the reasons get complicated. But the upshot is 10 people with 1 unit each will likely suffer no damage whereas one person with 10 units would.
The unit of measure does measure how much energy is deposited in a body and that part is linear but it doesn't measure how the body responds to damage and that part is highly variable.
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Rich of Observationz, in reply to
You say that like it's accepted truth.
The International Committee On Radiation Protection, who are the international authority on this, disagree:
while existence of a low-dose threshold does not seem to be unlikely for radiation-related cancers of certain tissues, the evidence does not favour the existence of a universal threshold. The LNT hypothesis, combined with an uncertain DDREF for extrapolation from high doses, remains a prudent basis for radiation protection at low doses and low dose rates.
So do the New Zealand National Radiation Laboratory, incidentally.
But maybe we should abandon these international bodies and have safe radiation levels decided by a vote on slashdot.
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Bart Janssen, in reply to
remains a prudent basis
Which I agree with entirely. The linear model is used for all safety limits because it's the most conservative model. We know it's not right but because we have nowhere near enough data from experiments to define the "real" model we use the conservative linear assumption.
So yes it is an accepted truth that low dose radiation does less damage than you would expect AND everyone uses the linear model for safety.
Note they don't disagree with me
existence of a low-dose threshold does not seem to be unlikely
it's just that if you are dealing with safety then you err on the side of the conservative model.
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Here is a good example of radiation dose by numbers; Yonks ago, some silly bugger discovered XRays. Then someone noticed that if a certain salt was put in the Xray it glowed. The Fluoroscope was invented. Then an even silly bugger developed it into a device to check the fit of shoes. The silly buggers were heros at the time BTW. They had no idea what slow death machine they had invented. It took a little while, like when Edison discovered one of his workers had developed radiation sickness and he gave up working on them.
But the upshot was, the more shoes you checked the more you were likely to get hit with radiation sickness. It was quite the fashion to just cruise the shops to see your bones. Note they were only outlawed in GB in the 70s!!!!! Is you Mum a Pom and did she take you down to the shoe shop?
The problem was - and still is - noone knows how much will do you in. As Bart suggests, it is totally dependent of physiology and luck. The bad type if you are shit out of it.
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xkcd has this radiation dose chart which might be useful.
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