Ask Ethan: How Can We Know If North Korea Is Testing Nuclear Bombs? (Synopsis)

"In this first testing ground of the atomic bomb I have seen the most terrible and frightening desolation in four years of war. It makes a blitzed Pacific island seem like an Eden. The damage is far greater than photographs can show." -Wilfred Burchett

The news has been aflame with reports that North Korea detonated a hydrogen bomb on January 6th, greatly expanding its nuclear capabilities with their fourth nuclear test and the potential to carry out a devastating strike against either South Korea or, if they're more ambitious, the United States.

Image credit: TV screenshot of CNN’s The Situation Room, April 3, 2013.  Go to hell, CNN. Image credit: TV screenshot of CNN’s The Situation Room, April 3, 2013. Go to hell, CNN.

The physics of what a nuclear explosion actually does and how that signal propagates through the air, oceans and ground, however, can tell us whether this was truly a nuclear detonation at all, and if so, whether it was fusion or fission. From all the data we've collected, this appears to be nothing new: just a run-of-the-mill fission bomb, with the rest being a sensationalized claim.

Image credit: Alex Hutko on Twitter, via Note that the Pn and Pg labels are backwards, which I suppose is a note that only geophysicists will care about. Image credit: Alex Hutko on Twitter, via…. Note that the Pn and Pg labels are backwards, which I suppose is a note that only geophysicists will care about.

Come find out how we determined it all on this week's Ask Ethan !

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Very good. I have one question: in this

If it were, it would be by far the lowest energy, most efficient fusion reaction ever created on the planet, and done so in a way that even theorists are uncertain how it could occur.

should the word most be least?

hould the word most be least?

I wouldn´t think so.
Bigger isn´t always better. Efficient in this context would mean to be able to ignite fusion on an unprecedented low level of energy, which would be a pretty advanced and surprising thing to do.
So the fusion bomb with the smallest yield could still be the most efficient, so to speak.

@ Erik H
Turn the blocker off, enter the site, turn blocker back on immediately. After that, you should not have to go through all that again. Works for FF.

Continuing to explain and complain is also a good idea because if they change their advertising stance to one less customer unfriendly and open to subversion by criminals, most people would stop blocking ads and they would regain their expected revenue stream from their advertising, and we would get the stuff we're paying for by watching ads and everyone is happy.

*Just* blocking only means their advertising is less effective and they will go further to trying to get the adverts seen, by ANY means possible. In which case, everyone is UNhappy.

In a scenario with exclusivity deals (e.g. anything with copyright), "buying" elsewhere doesn't work, so the invisible hand can't move things to a common ground. Hence adblocking.

It would be nice if we didn't feel (and were justified in doing so) that we needed to use ad blocking.

Actually, we have evidence that NK HAS detonated a nuclear bomb.

South Korea is much closer to them, watching them intently, and they are restarting their propoganda war with their neighbours again ***because NK has detonated a nuclear bomb***,

If we were to prove no such event happened, this would make out South Korea to have lied in their motivation, and thereby their attacks, even though soft, are an unwarranted and unprovoked attack, something that the UN has sanctioned for in such volatile hotspots.

Ethan - do you think it might be possible in principle to conceal an a-bomb test behind a naturally occuring earthquake 1 or 2 Seismologal scale levels stronger? They obviously don't know when the earthquake would happen. But say, forgetting NK for the sake of this and putting someone more plausible in the frame, like the USA. It doesn't seem crazy to imagine the US has at least the resources, to situate bombs at multiple locations along fault lines...probably at the bottom of the oceans. And wire the detonation logic up with the network of seismic sensors they already have as an up and running web over a lot of the planet.
Value could feasibly be large size across a broad spectrum from testing sychnronized combinations of blasts, to gaining knowledge of other countries sensor/monitoring sophistication, to testing secret doomsday weapons. All which comes together potentially as first strike strategics, in dimensions the enemy does not suspect so cannot counter, therefore that could degrade deterrence value (by degrading the risk level of successful counter strike).
Or is it just not feasible for geologic-seismological factors? Like, trying to hide a fart with a burp.....resulting in a fart followed by a burp. No whatta mean.

By Chris Mannering (not verified) on 10 Jan 2016 #permalink

Seismologists are pretty good at locating an epicenter, even of such small quakes. And they do have different results depending on where they are, and some can't happen in some places. So if you see a quake that occurs at subduction plates happen in NK where there is no subduction at the low depth the test is at, it's not *proof* of a bomb test, but it's a heavy argument.

> Forbes serving malware yet again this week

What part of "Capitalist Tool" isn't clear?

If they don't own your computer yet, they're not doing their job.

By Hank Roberts (not verified) on 10 Jan 2016 #permalink

I did graduate work in the seventies looking at seismograms from earthquakes and nukes. I could tell which from just a glance of the seismogram. There are several giveaways: (1) Shallow depth. (2) The bomb gives of its energy in a fraction of a second, and unless a lot of prestressed rock if cracked its a pressure wave, without shear waves at the source. Reflections off rock layers and the surface do mix P and S waves together, but these are time delayed after the initial pulse. An earthquake of any size ruptures many kilometers of fault, so the source waves are distributed in both space and time, and mostly S-waves.

Chris @8. In theory you could probably do it. But if you didn't get a near simultaneous earthquake of sufficient magnitude
the gig would be up. The odds of pulling it off would be against you.

By Omega Centauri (not verified) on 10 Jan 2016 #permalink

There are multiple sorts of bombs.

The simplest uses a spherical implosion of a spherical Plutonium pit. With greater confidence in the quality of the spherically symmetric shockwave a hollow sphere can perform better, and fusion fuel can be placed in the hollow. The fusion doesn't just add energy, but it creates high energy neutrons which greatly increase the amount of fissionable bomb material which actually fissions. These high energy neutrons can also fission U-238, so yield can be increased by making the bomb casing out of Natural or depleted Uranium. Any of these fusion enhanced designs would have much greater than 10KT yield.

A true H bomb has a secondary fission/fusion bomb which is
compressed by the original explosion, and which can be many times larger in size. In military applications using a Uranium casing to take advantage of the high energy neutrons, and the lions share (over 80%) of the net bomb energy actually comes from fission.

The Tsar Bomba, was designed for even higher yield (100MT) than the test bomb, Sakharov convinced the Russians to omit the casing, because the resulting fallout would have been far worse had the full design weapon been used.

By Omega Centauri (not verified) on 10 Jan 2016 #permalink

You convinced me.

By Chris Mannering (not verified) on 10 Jan 2016 #permalink

how much atmospheric a-bomb testing took place, do you know? a few hundred bombs worth of yield I imagine. Doesn't appear to have done much long term harm for testing on that sort of scale (scale was set with naked guessing so almost certainly accurate) Are you familiar with the controversy about the risk radiation poses at low dosages (< 200 millisieverts )

Background radiation was 400 millisieverts per hour at peak spots, yesterday, according to Google. Something like 167 times the annual human dose on average. Seems high

By Chris Mannering (not verified) on 10 Jan 2016 #permalink

I know practically know nothing about forbes, but it's probably one of only two titles I could count on demand upon the finger (TIME).
I'm ordinary for most things I reckon; I reckon Time & Forbes are two of the most ubiquitously known, most worldwide prestigious...reasonably I guess by corollary given world we're in, most purified biggest bunch of scumbags all the way through. But I digress.
When Ethan announced the opportunity handed to him by, not Forbes, they are incidental - but the legacy of himself, all the traits that it takes to pioneer a blog single-handedly raising it to a commercial standard - which no other science blog comes not close to, and maintain it there for years.

So he has this opportunity from a world renowned online chapter of a famous printed-magaizine. And with both hands and throwing every last lump of unmmfff he's currently got

And clearly gone way out of his way, to maintain for as long as he can, a stable platform synthetically elongating his readership environment so they experience no pressure and may continue as they are.

I reckon that's up to 50% his workload again for doing, and maintaining expensive little frozen capsule whore along the lines of that. Could be wrong, but how wrong is it even possible to be' it ain't free.

Yet this malware thing. It's at really gratuitous levels in the comments. People are throwing in, on comment threads where it's almost impossible that they did not see the way it was plastered over the thread already. And for the most not even their first regurgitation. Far from for the most part I should say.

So...what's the deal brought into play for Ethan? You're acting as if he's a big fish over at Forbes. LIke the advertising strategy of Forbes is in his gift to say. It's obvious he's at the fragile beginning of professional relations with Jupiter Forbes. Obvious that everyone is clear on that. So what that means for what you are doing, is you are pressuring him to complain to Forbes about Forbes.

He might have already done it. I get no such problem and haven't throughout. It could all you need is a few IT tips. But if you've had him do that piece for you, for you, inconvenienced by pop-ups all the time, having to move your middle finger of your over burdened wank hand over the touch then make it click for pesky popuos to go away.

Then you've probably damaged his career. Because, oh yeah, he can complain to Jupiter forbes. And their response will with brevity to geeky Forbes, cut the pop-ups viewed so dismally over at Bang, his amazing readership VIP.

And it won't cost him anything today. And if he's lucky, only with luck, will he get off doing that more or less scott free. Even if he hasn't said anything, your gratuitous malware - forbes anxiety porn will have been picked up and unappreciated. unappreciative of ethan, not you.

It's really mean and selfish. You're a bunch of tossers really aren't you.

By Chris Mannering (not verified) on 10 Jan 2016 #permalink

how much atmospheric a-bomb testing took place, do you know? a few hundred bombs worth of yield I imagine.

Counting bombs is probably not a good way to do it, because the yield of various tests differed by three orders of magnitude (10s of kt's to 10s of Mt's). In terms of explosive power and radiation produced, probably only the top 10 or 20 detonations contributed 90% of the yield.

Wikipedia says that at its peak in the early 60s, atmospheric tests contributed about 7% of the total background radiation absorbed by people (its about 0.23% now). Not hugely significant but not insignificant for people who lived through the 40s-60s, either.

Doesn’t appear to have done much long term harm for testing on that sort of scale (scale was set with naked guessing so almost certainly accurate)

Well we can argue about what counts as unacceptable harm until the cows come home. Everyone has a different tolerance for what sort of additional cancer risk they will accept from various sources, and usually, the selection isn't rational because people have social reasons for preferring one equivalent cancer risk over another (example: I get more pleasure over a 0.01% increase in cancer risk from eating peanut butter than I do a 0.01% increase risk from DOD testing its new design).

However, on a different note, I think it's important to point out that the global harm from tests very likely underpredicts the global harm from an attack of equivalent kilotonnage or megatonnage. That's because attacks on populated areas are likely to produce far more dust, soot, etc. than atmospheric tests did. We saw this on a small scale in the Iraq War 1 (after Saddam invaded Kuwait); when he retreated, he lit a lot of oil wells on fire, and they produced such a significant atmospheric change that IIRC it created a detectable albeit small and short-duration change in global temperature. A nuclear attack on a city would do the same thing, only much worse. A multi-warhead exchange - even in a local war such as India-Pakiistan - would likely have multi-year global climate consequences, in addition to the radioactive fallout issues.

Which is a long-winded way of saying that the relatively tame effects of 1950s-60s testing should not make us blasé about the potential impact of nuclear weapons on the environment.

I typically don't read the comments and had honestly never seen the Forbes issue mentioned. I had just seen a story on the malware problem and was asking a sincere question. I'm not savvy enough to know whether it's something I should be concerned with or not. So far it sounds like the advice is either subscribe or don't read the article, but I haven't looked back at past discussions. If those are my choices that's fair. This was new to me and I was just looking for guidance. Sorry if this is some ongoing controversy.

By Erik Henry (not verified) on 11 Jan 2016 #permalink

Erik Henry - the easiest way to read without ads/malware is
1. Wait 5 days after Ethan publishes the article, then
2. Read it on Medium, which is ad-free.

Most of Ethan's articles are not so time-sensitive that waiting 5 days will ruin anything. You just have to get over the psychological hump of waiting.

Thanks, Eric. I hadn't appreciated that they eventually still show up on Medium. Yeah, often he's talking of things with time scales of millions or billions of years--so I can probably wait five days.

By Erik Henry (not verified) on 11 Jan 2016 #permalink

No problemo. People like you (and I) are the reason I've also suggesed to Ethan that he add a link to the Medium article at the end of every Synopsis, with the date it will become active in the text to let people know when it will be available.