# 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:** 12\ **Page:** 2
**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, 5:55am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/21 "2006-10-09T05:55:51Z")
[QUOTE=alphaboi867] 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. [/QUOTE] Jesus, is that all? That’s a surprise, at least to me. ---
**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 9, 2006, 6:00am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/22 "2006-10-09T06:00:15Z")
> [@](#): > > It’s highly unlikely that anything other than a nuke could masquerade as a nuke. I agree entirely, and I didn’t mean to imply otherwise. But a lunatic like Kim-Jong Il might have try it, anyway, if he didn’t have an actual nuke. I stopped following that other story before it came out that it was a train carrying LNG, though… Thanks for that information. As for the current news… Well, it might well be the real thing, but I’m still going to wait for confirmation. Not that there’s anything I could do about it one way or the other, of course. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 9, 2006, 6:06am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/23 "2006-10-09T06:06:08Z")
[QUOTE=Airman Doors, USAF] Jesus, is that all? That’s a surprise, at least to me. [/QUOTE] IIRC, it’s actually not easy to make a **low** yield weapon, because of critical mass needs. ISTR that the Fat Man and Little Boy were as small as we could make them (and even then it was difficult to get them inside the bombers) and the Davy Crockett was a technological marvel for being so small. Setting off a tiny nuke _ **may** _, I repeat _ **may** _, indicate a greater level of technical ability than it might at first seem. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 9, 2006, 7:49am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/24 "2006-10-09T07:49:41Z")
[QUOTE=Squink] [North Korea says nuclear test successful](http://news.yahoo.com/s/ap/20061009/ap_on_re_as/koreas_nuclear_93) [/QUOTE] [Conflicting accounts of how big the “quake” was.](http://www.newscientisttech.com/article/dn10251) > [@](#): > > Officials in South Korea said an explosion had been detected in the north of its neighbour’s territory, which **measured 3.5 on the Richter scale**. The US Geological Survey also detected the explosion, giving its **magnitude as 4.2, equivalent** to a “light” earthquake. IIRC, the Richter scale is one of those where going up a level means something like an exponential increase. ---
**Author:** ![Achren](https://avatars.discourse-cdn.com/v4/letter/a/898d66/32.png) [@Achren](https://boards.straightdope.com/u/Achren)\ **Post date:** [October 9, 2006, 7:52am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/25 "2006-10-09T07:52:43Z")
[This](http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/INCN_24hr.html) was linked at Slashdot. I’ve no idea how to read it/its accuracy/if the site is actually USGS. Any informed opinions would be very welcome. ---
**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, 8:12am UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/26 "2006-10-09T08:12:07Z")
[Here’s the USGS page on the quake](http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/ustqab.php) **4.2.** They frequently adjust the intensity by a tenth or two over the course of a day as more stations report in. ---
**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 9, 2006, 12:18pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/27 "2006-10-09T12:18:33Z")
Well, now we know. Unfortunately, that **isn’t** “half the battle”. The battle may just be begining… ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [October 9, 2006, 3:00pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/28 "2006-10-09T15:00:43Z")
> [@](#): > > South Korea’s saying the blast was equal to 550 tons of TNT, just over half a kiloton. How can we tell the difference between a 500 ton underground nuke and an underground explosion of 500 tons of ordinary TNT? ---
**Author:** ![Wallenstein](https://avatars.discourse-cdn.com/v4/letter/w/b5a626/32.png) [@Wallenstein](https://boards.straightdope.com/u/Wallenstein)\ **Post date:** [October 9, 2006, 3:12pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/29 "2006-10-09T15:12:10Z")
[QUOTE=Patty O’Furniture] How can we tell the difference between a 500 ton underground nuke and an underground explosion of 500 tons of ordinary TNT? [/QUOTE] I would presume the “shape” of the explosion would produce a different seismic intensity graph? No idea of the details, but I imagine that TNT explodes at a different rate than a nuke… and takes a different length of time? ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 9, 2006, 3:18pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/30 "2006-10-09T15:18:13Z")
[QUOTE=alphaboi867] 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. [/QUOTE] [Russia puts the yield as high as 15 kt.](http://news.bbc.co.uk/1/hi/world/asia-pacific/6033457.stm) > [@](#): > > Russia said it was between five and 15 kilotons. The 1945 Hiroshima bomb was 12.5-15 kilotons. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [October 9, 2006, 5:19pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/31 "2006-10-09T17:19:22Z")
This article [from Lawrence Livermore Labs](http://www.llnl.gov/str/Walter.html) discusses how to detect nuclear explosions via seismic monitoring. ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [October 9, 2006, 5:50pm UTC](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655/32 "2006-10-09T17:50:20Z")
France is agreeing with SK on the size of the bomb, so it might well be a fizzle. [Previous page](https://boards.straightdope.com/t/north-korean-nuke-seismograph/375655.md?page=1)