Geoff FordenThe Second North Korean Nuclear Test

North Korea announced today that they have conducted test of a test of a nuclear weapon. Coming on the heals of their failed satellite launch attempt April 5th, the DPRK made sure to point out in their announcement that this one had a higher yield than their last test. Estimates first varied on the yield of that test but Western analysts generally settled on a value of about ½ kiloton. The North’s announcement today seems to concede that the first test had problems:

The current nuclear test was safely conducted on a new higher level in terms of its explosive power and technology of its control and the results of the test helped satisfactorily settle the scientific and technological problems arising in further increasing the power of nuclear weapons and steadily developing nuclear technology.

No word yet of independent assessments of the test’s yield or even that it took place. Watch this space for further information and analysis as it becomes available.

Update (7:50am): 20 kilotons certainly seems to say that they went with the “safest” weapon design possible to ensure that they got a good bang.

Update (11 am): 2009 test appears to be in roughly the same location as the 2006 test. (Remember there are errors associated with both these positions; the largest being associated with first location for the latest test.)

click on the image for a larger version

(For some reason, GoogleEarth seems to have presented the titles of the two sites reversed: the new location is actually to the West of the 2006 location. However, the kmz file below IS correct.)

Click here for a GoogleEarth file with the two locations as of today, 25 May 2009.

Update (11:10 am): Two great posts by Josh on totalwonkerr discussing this issue of the test yield:

Here We Go Again?

Lankov Times The Market

We all knew we needed the TOTALWONKERR back; glad to see that it has happened at any level!


  1. Jan

    The German news magazine Der Spiegel reports on its website: “a short time after [the detonation] a missile was allegedly launched.” link

    What a weekend…

  2. FOARP (History)

    Russians first to confirm, they say 20 Kilotons!

    Will be interested to see if this figure is as equally at variance with those of other agencies as the last one was.

  3. FOARP (History)

    Hang on, Itar-Tass may have it at around 20 KTons, but RIA Novostii and Interfax both have it at 10-20. Seems there’s some wires crossed/conservative estimating somewhere:

    “The special control service of the Defense Ministry of the Russian Federation registered an underground nuclear explosion equivalent to 10-20 kilotons in the territory of the DPRK at 04:54:41 a.m. (Moscow time) (0054 GMT) on May 25,”

    Okay, let’s have a sweep-stake, everyone take a half-kiloton increment. Grab them whilst they’re (radioactively) hot! I’m taking 6.5 KTons – so far Russia has over-estimated pretty much everything that North Korea does.

  4. Jan

    Apparently Yonhap News is the source for the information about the missile launch (link):

    A source, who declined to be named, said North Korea coupled the detonation with a test of a short-range missile from a coastal base where the communist regime conducted its April 5 rocket launch.

    They also quote Russian media about the yield:

    Russia said the “nuclear explosion” appears to have had a force of up to 20 kilotons, according to its state media.

    Hmm, cannot find anything on the English itar-tass website about that.

  5. Guy de Loimbard (History)

    On his blog, the French defense journalist Jean-Dominique Merchet cites “Russian sources” estimating the yield to 20kt.

    Not sure that’s exactly what you mean by “independent” assessment, though…

  6. Major Lemon (History)

    “The force of the nuclear blast was 10 to 20 kilotons, Russian Defense Ministry spokesman Alexander Drobyshevsky told the state-run RIA-Novosti news agency.” This was reported in the Jerusalem Post.

  7. FOARP (History)

    @Jan – Translation is often delayed as it is written first in Russian and then handed on to the translators, and then often subsequently edited to make it readable.

    The Chinese government also “firmly condemns” the test:

  8. FOARP (History)

    Oh, and KCNA are now on Twitter, give them a follow for the sheer weirdness of it:

    Hell, do you think I should DM them to ask Kim “the Il-est” Jong-Il to cool it with the nukes? I mean, all this radiation stuff this is, like, so totally harshing my mellow

  9. Allen Thomson (History)

    The USGS earthquake site says,

    Magnitude 4.7

    * Monday, May 25, 2009 at 00:54:43 UTC

    Location 41.331°N, 129.011°E

    Depth 0 km (~0 mile) set by location program

    Region NORTH KOREA

    Location Uncertainty horizontal +/- 5.3 km (3.3 miles); depth fixed by location program

    Parameters NST= 76, Nph= 76, Dmin=474.4 km, Rmss=0.8 sec, Gp= 68°,
    M-type=body wave magnitude (Mb), Version=8

    Source * USGS NEIC (WDCS-D)

    Event ID us2009hbaf

  10. Jochen Schischka (History)

    Isn’t this some sort of recognizable pattern: first a failed Taepodong-test, then a (failed?) nuclear test – this is 2006 all over again!

    But the North Koreans apparently learn from their failed tests (something that i personally would associate with a real development program), since both 2009 tests (missile and bomb) obviously worked better than their 2006-counterparts…

    Considering the 20kt-figure: i’d suggest that this one is possibly some sort of snapshot by the Russians – a yield of “up to 20kt” would be a typical figure for a unboosted (fission-only) implosion-type nuclear device…and at the same time, lower actual yields like 1kt or 5kt (indicating perhaps a “fizzle”) are not excluded. What do you all make of the purported Richter-value of 4.5 (measured somewhere in South Korea)? I’m looking forward to the findings of a more thorough analysis.

  11. Tim


    The best place to look for confirmation of these things is the USGS website which is updated in real time:

    Is magnitude 4.7 consistent with 20kt?

  12. Andrew Higgins (History)

    The U.S. Geological Survey has it as a M4.7 event:

    Compared to the 9 Oct 2006 event, which was a M4.3 event:

    This would imply (all else being equal) that the yield of several times that of the 2006 test.

  13. mike (History)

    US Geo has estimated a 4.7 ‘quake’ there, what would that be consistent with?

    link data

    Also, shouldn’t the story headline read “Wonk Special Alert!”

  14. Fred Reinheimer (History)

    “North Korea announced today that they have conducted test of a test of a nuclear weapon.”
    “Test of a test”? Hungh?

  15. Maggie Leber (History)

    This test of course does not “Come on the heals of their failed satellite launch attempt”. It comes on the heels of it. 🙂

  16. Martin Senn (History)

    What about the missile launch? According to REUTERS ( , the DPRK launched a surface to air missile with a range of 130km. Do you think it actually was a surface-to-surface missile (KN-02 type)? Why would they test a SAM after the nuclear test?

  17. Bart

    Maggie Leber: always first with the non sequitur.

  18. Arash Chavoshi (History)

    i cant wait for my country (iran) to get nuclear weapons…this just made me unbearably jealous

    the yeild on this test is a major improvement on the previous one