# North Korean Nuke--Seismograph? **URL:** \ **Category:** Factual Questions\ **Created:** [October 7, 2006, 11:12pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655 "2006-10-07T23:12:14Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [October 7, 2006, 11:12pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/1 "2006-10-07T23:12:14Z")
Can we expect to be able to detect a possible North Korean nuclear test on a seismograph? What kind of Richter Scale yield will it produce? Could Kim trigger a fault in some way, to make it appear he had a nuke? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [October 8, 2006, 2:17am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/2 "2006-10-08T02:17:41Z")
[QUOTE=Bosda Di’Chi of Tricor] Could Kim trigger a fault in some way, to make it appear he had a nuke? [/QUOTE] If he could trigger an earthquake fault at will, he certainly wouldn’t need a nuclear weapon! ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [October 8, 2006, 2:23am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/3 "2006-10-08T02:23:22Z")
[QUOTE=Bosda Di’Chi of Tricor] Could Kim trigger a fault in some way, to make it appear he had a nuke? [/QUOTE] I have heard ideas batted about for that sort of thing in general. Unfortunately, it would require many of the big nukes to even hope to trigger an earthquake so we are probably in big trouble if he can pull that off. ---
**Author:** ![pesch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pesch/32/4925_2.png) [@pesch](https://boards.straightdope.com/u/pesch)\ **Post date:** [October 8, 2006, 2:45am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/4 "2006-10-08T02:45:44Z")
[According to this site that discusses India’s nuclear tests,](http://www.llnl.gov/str/Walter.html) scientists used teleseismic stations to detect and judge the strength of the explosions. Apparently, they use something called a “teleseismic signal” that’s comparable to the Richter scale. They highest they found was a 5.2 blast. The figure can vary depending not only on the number of kiloton yields (obvious), but where the test took place. Two tests, conducted in a sand dune [?] “poorly couple the explosive energy into seismic waves and thus reduce the strength of any recorded seismic signal.” ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [October 8, 2006, 3:02am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/5 "2006-10-08T03:02:56Z")
[QUOTE=Bosda Di’Chi of Tricor] Can we expect to be able to detect a possible North Korean nuclear test on a seismograph? [/QUOTE] Absolutely. A couple of good friends of mine did just that in the late 80’s as part of a U.S. Gov’t research team. That was at least one of the ways in which we and the Soviets monitored each other to make sure that we all did just as many tests as we agreed that we would do. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 8, 2006, 11:04am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/6 "2006-10-08T11:04:16Z")
No doubt we’ll have lots of “eyes in the sky” trained on NK around the time we think that they’ll set off a nuke. We’ll want to know everything we can about the nuke, so we’ll be looking to see how it’s transported, how long it takes them to set everything up, and what happens when/if it goes off. ---
**Author:** ![crowmanyclouds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crowmanyclouds/32/19884_2.png) [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)\ **Post date:** [October 8, 2006, 11:11am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/7 "2006-10-08T11:11:07Z")
[Comprehensive Nuclear-Test-Ban Treaty Organization](http://www.ctbto.org/) > [@](#): > > …the International Monitoring System (IMS) network consists of 337 monitoring facilities all over the globe, comprising seismic, infrasound, hydroacoustic and radionuclide monitoring stations… CMC fnord! ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [October 8, 2006, 11:13am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/8 "2006-10-08T11:13:56Z")
[Info about satellites](http://www.globalsecurity.org/wmd/world/israel/nuke-test.htm): > [@](#): > > In addition to the very bright optical signals, an atomic explosion also unleashes a pulse of radiation at radio wave frequencies which can be detected by EMP sensors. This electromagnetic pulse covers much of the radio wave spectrum. > > Other radiation emitted by the blast includes gamma and beta rays and neutrons, which, in the case of a sea level or low-altitude explosion, are absorbed by the atmosphere giving rise to electromagnetic radiation at frequencies extending over the entire range from radio waves to the ultraviolet. Detectors on satellites are capable of sensing at least some of these instantaneous signals, but if the radiation is missed in the first instant, then they are gone forever, traveling away from Earth at the speed of light. I presume that the EM radiation would be visible even if it were a deep ground test. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 8, 2006, 6:01pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/9 "2006-10-08T18:01:51Z")
He also wouldn’t try to keep it in any way secret. The whole purpose of testing a nuke is to let everyone else know about it. If you go to the UN and _say_ “I have nukes, so you’d better be nice to me”, everyone will laugh in your face (as we’ve pretty much been doing to Kim). But if seismographs and gamma detectors and spy satellites all confirm that a nuke went off, well then, in that case the other nations are bound to take you seriously. In fact, there was a large explosion of some sort in Korea a year or two ago that showed up on seismographs around the world, but not on radiation detectors. One likely explanation is that Kim just made a big ol’ pile of TNT or the like and set it off, in an attempt to bluff that he had a nuke. I don’t think anyone fell for it, though. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 8, 2006, 6:09pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/10 "2006-10-08T18:09:28Z")
[QUOTE=Chronos] In fact, there was a large explosion of some sort in Korea a year or two ago that showed up on seismographs around the world, but not on radiation detectors. [/QUOTE] Wouldn’t a subterranean detonation look the same? I can imagine him wanting to test his first nuke in secret, in case it failed. 'Cause, you know, that would pretty embarassing for a world leader with his amount pf pride. Test it underground so you know your design works, then test another one later, very publicly. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [October 8, 2006, 8:12pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/11 "2006-10-08T20:12:04Z")
[QUOTE=Chronos] In fact, there was a large explosion of some sort in Korea a year or two ago that showed up on seismographs around the world, but not on radiation detectors. One likely explanation is that Kim just made a big ol’ pile of TNT or the like and set it off, in an attempt to bluff that he had a nuke. I don’t think anyone fell for it, though. [/QUOTE] That explosion was a train carrying [liquiefied natural gas](http://news.bbc.co.uk/2/hi/asia-pacific/3649655.stm) or some other highly explosive compound. The world press treated it as an accident and was pretty clear on what had happened and why. The seismic and spectral signatures of a nuke blast are very distinctive; likewise, different fuels burn different colors, so if any “eye in the sky” saw the blast it would be theoretically possible to figure out the chemical composition of the fuel. With sensitive enough instruments tuned to the right spectra, you might even be able to tell the difference between diesel from different refineries, or LNG from Asia vs. American LNG. It’s highly unlikely that anything other than a nuke could masquerade as a nuke. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [October 8, 2006, 11:41pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/12 "2006-10-08T23:41:33Z")
I’m not an expert, but I do know that the shockwave produced by a nuke is sharper, more intense than that produced by chemical explosions; even if the test ( or fake ) is deep underground, it might be possible to tell the difference. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [October 9, 2006, 3:46am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/13 "2006-10-09T03:46:48Z")
> [@](#): > > South Korean intelligence officials said a **seismic wave of magnitude-3.58** had been detected in North Hamkyung province, according to Yonhap. It said the test was conducted at 10:36 a.m. (9:36 p.m. EDT Sunday) in Hwaderi near Kilju city on the northeast coast, citing defense officials. [North Korea says nuclear test successful](http://news.yahoo.com/s/ap/20061009/ap_on_re_as/koreas_nuclear_93) ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [October 9, 2006, 3:58am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/14 "2006-10-09T03:58:29Z")
I came in here to say that one way they help determine whether a seismic signal is an earthquake or a nuclear test is that the latter are invariably exactly on the hour or half-hour. However I see it’s gone ahead and happened at 10:36; so much for that theory. But that kind of trivia seems insignificant now. I feel sick to my stomach. ---
**Author:** ![asterion](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@asterion](https://boards.straightdope.com/u/asterion)\ **Post date:** [October 9, 2006, 4:13am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/15 "2006-10-09T04:13:43Z")
I’m hearing it claimed that the size of the shock detected in South Korea would mean that, if North Korea was hoping for a 400 kiloton yield, they were short of that. I know there’s been 60 years of nuclear technology development, but considering that the first weapons designed were 1/20th that power, how the heck could they get 400 kilotons out of a first design of their own, assuming no help from a current nuclear power? ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [October 9, 2006, 4:34am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/16 "2006-10-09T04:34:32Z")
[QUOTE=asterion] I’m hearing it claimed that the size of the shock detected in South Korea would mean that, if North Korea was hoping for a 400 kiloton yield, they were short of that. I know there’s been 60 years of nuclear technology development, but considering that the first weapons designed were 1/20th that power, how the heck could they get 400 kilotons out of a first design of their own, assuming no help from a current nuclear power? [/QUOTE] Once you’re in the 400 kiloton ballpark, you’re basically at the maximum yield for a fission weapn. I think that would be _highly_ unlikely, especially for the ‘Beloved Leader’ who would not want to squander so much of his fissile material on one mere test blast. And, there’s no way he and his fellow loonies could have developed an H-bomb (i.e. a fusion bomb). Even with all the scientific and financial resources of the US and the USSR, it took them basically a decade to make the transition from fission to fusion. [This chart](http://en.wikipedia.org/wiki/Image:US_nuclear_weapons_yield-to-weight_comparison.svg), from Wiki, shows comparative yields of fission and fusion weapons. ---
**Author:** ![Airman\_Doors\_USAF](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Airman\_Doors\_USAF](https://boards.straightdope.com/u/Airman_Doors_USAF)\ **Post date:** [October 9, 2006, 4:53am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/17 "2006-10-09T04:53:11Z")
[QUOTE=asterion] I’m hearing it claimed that the size of the shock detected in South Korea would mean that, if North Korea was hoping for a 400 kiloton yield, they were short of that. I know there’s been 60 years of nuclear technology development, but considering that the first weapons designed were 1/20th that power, how the heck could they get 400 kilotons out of a first design of their own, assuming no help from a current nuclear power? [/QUOTE] Physics are physics. Once something is known it is a (relatively) simple thing for skilled people to emulate it. Of course, for a first test it would be extremely unlikely that they could get 400 kilotons, but I feel safe in saying that the yield was much higher than the Hiroshima/Nagasaki bombs. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [October 9, 2006, 5:27am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/18 "2006-10-09T05:27:37Z")
[QUOTE=Airman Doors, USAF] . . . I feel safe in saying that the yield was much higher than the Hiroshima/Nagasaki bombs. [/QUOTE] Just curious, but why do think so? AFAIK, which I’ll be the first to admit ain’t much, test blasts are, by and large, rather small yields. The reason for this is that much, perhaps all, of the purpose of the test is to check to see if the basic mechanisms are working. So long as they are, it’s virtually irrelevant whether the bomb has a 10 or 200 kt yield. In fact, in order to conserve the precious uranium or plutonium, and to minimize unwanted radiation and fallout (with the former are real consideration for a state like North Korea), it actually makes more sense to have small test blasts. ---
**Author:** ![alphaboi867](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alphaboi867/32/3898_2.png) [@alphaboi867](https://boards.straightdope.com/u/alphaboi867)\ **Post date:** [October 9, 2006, 5:50am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/19 "2006-10-09T05:50:51Z")
[QUOTE=Airman Doors, USAF] Physics are physics. Once something is known it is a (relatively) simple thing for skilled people to emulate it. Of course, for a first test it would be extremely unlikely that they could get 400 kilotons, but I feel safe in saying that the yield was much higher than the Hiroshima/Nagasaki bombs. [/QUOTE] South Korea’s saying the blast was equal to 550 tons of TNT, just over half a kiloton. Much weaker than Fat Man and Little Boy. ---
**Author:** ![Airman\_Doors\_USAF](https://avatars.discourse-cdn.com/v4/letter/a/e36b37/32.png) [@Airman\_Doors\_USAF](https://boards.straightdope.com/u/Airman_Doors_USAF)\ **Post date:** [October 9, 2006, 5:54am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/20 "2006-10-09T05:54:26Z")
[QUOTE=KarlGauss] Just curious, but why do think so? AFAIK, which I’ll be the first to admit ain’t much, test blasts are, by and large, rather small yields. The reason for this is that much, perhaps all, of the purpose of the test is to check to see if the basic mechanisms are working. So long as they are, it’s virtually irrelevant whether the bomb has a 10 or 200 kt yield. In fact, in order to conserve the precious uranium or plutonium, and to minimize unwanted radiation and fallout (with the former are real consideration for a state like North Korea), it actually makes more sense to have small test blasts. [/QUOTE] That’s true, but remember that North Korea relies on the propaganda value of things. If they can demonstrate that they have a big bomb this early in the game that makes their _fait accompli_ all the more impressive. Think about it. In the history of nukes the size of the bomb has (until recently) been the driving force. It’s like people who are afraid of a big gun because it’s big, not realizing that smaller guns will kill you just as dead. Of course, I’m just speculating here. I’m sure we’ll get word one way or the other sooner or later. [Next page](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655.md?page=2)