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Meteorological support for nuclear disarmament and weapons control

This web page continues my previous one at BOKU.

Staff: Petra Seibert, Anne Philipp
Former staff: Radek Hofman. (At BOKU): Andreas Frank, Paul Skomorowski

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Activities:

Ongoing:

  • Participation in the Working Group B of the Comprehensive Nuclear Test-Ban-Treaty Organisation / Preparatory Commission
  • Research to support source location from radionuclide measurements

Past activities:

  • Participation in source location experiments of CTBT/PrepCom International Data Centre and WMO
  • Organisation of the Kick-off workshop of the new Independent Group of Scientific Experts on the detection of clandestine nuclear-weapons-usable materials production (iGSE)

Recent conferences:

Information about nuclear events

(reverse chronological order)

April 2018: Discussion on DPRK nuclear-test moratorium

DPRK's leader Kim announced on 21 April 2018 (local time) that his country no longer needed to test nuclear weapons or long-range missiles and would close a nuclear test site (ee e.g. this NYT article). This could be understood as an announcement of a moratorium on nuclear-weapon testing. CTBTO/PrepCom Executive Secretary immediately suggested that DPRK then should join the CTBT (see CTBTO News Release).

Recently, a number of media report that North Korea's move may be caused by the DPRK test site being unusable anyway, referring to the strong aftershocks of the September 2017 test (see also information below.), see for example New York Post or The Guardian. These articles are based on a report by a Hongkong-based Chinese newspaper, saying that an article will soon come out on the testsite destruction in GRL, by a team around Lianxing Wen. Rumours are spread that even respuspended radioactive dust from the mountain's interior could threaten Chinese territory. While we don't have solid information, this at least appears to be far-fetched.

As explained on the 38North web site, even if the tunnel system used collapsed, the Punggye-ri test site has more sections, which are probably not affected. See also a follow-up article on 38N.

DPRK nuclear test of 03 September 2017

Weak seismic event on 23 September 2017 (USGS analysis of 08:29 event / L. Zerbo's twitter message with seismograms of 04:43 and 08:49 event) - considered to be a geological mass movement triggered by the large 03 Sept test. It increases again the possibility for later seeing some radionuclides at monitoring stations.
CTBT comparison of seismic signal
CTBTO/PTS Comparison of seismic signals (to scale) of all six declared DPRK nuclear tests, as observed at IMS station AS-59 Aktyubinsk, Kazakhstan.

BGR (German National Data Centre for CTBT) provides a detailed analysis (in German) with atmospheric transport modelling and a map of the CTBTO radionuclide (RN) stations.
38North analyses:
  • First analysis by 38North, 3 Sept 2017
  • Analysis of satellite imagery by 38North, 5 Sept 2017
  • Analysis by 38North, 12 Sept 2017.
    Some highlights: 250 kt yield - close to what 38 North had previously determined to be the maximum estimated containable yield for the Punggye-ri test site. - significant “cracking” (possibly extending to the surface) ... Such cracking facilitates radioactive gas seepage in other environments. It remains to be seen, however, whether or not the North Portal will ever be used for another nuclear test. There are still two unused additional tunnel complexes (served by the South and West Portals) that are also deemed potentially capable of further nuclear testing, albeit for tests having lower yields than that of the sixth test.
Articles on BBC News (read also linked articles, e.g. Kim inspects 'nuclear warhead': A picture decoded and 'Tunnel collapse' at nuclear site may provide clues, as well as original BBC Live Blog )
South Korea finds Xe-133 (0.1-1 mBq/m3): Nuclear Safety And Security Commission Press release13 Sep 2017 (PDF with detailed data)
Facts in short:
  • Signal comes from known DPRK test site, close to previous tests
  • Signal strength was about 5-10 times higher than Sept. 2016 test (which was estimated at 10-30 kt). The details of CTBTO's interactive analysis have not yet been published but there is a (re)tweet on CTBTO_alerts that says the mb is 6.07 and calculates an estimated yield of 140 kt.
  • The second seismic signal 8 min after the main one is interesting. It can indicate a cavity collapse or a mass movement on the mountain surface. Analysis of satellite imagery posted on the 38North web site reports small landslides but no collapses of cavities that deform the surface.
  • If there was a prompt release of radionuclides into the atmosphere, they will be sampled by the CTBTO station RN58 Ussurysk probably on Monday 4 Sept 2017, with the analysis being available ca 48 h later. Note that the Xe measurement at this station is not yet certified.
Conclusions:
  • Given the strength, it is reasonable to assume that the device indeed had a fusion component; however, boosted fission is more likely than a two-stage thermonuclear device.
  • The progress on weaponisation is still difficult to judge (i.e., whether the device would fit on the available missiles, and whether it would survive the re-entry phase of an ICBM).
  • The strength of the detonation means that more radionuclides were produced and that it will be more difficult to contain them, therefore the chance to see a signal in the CTBTO radionuclide network is higher this time. In addition, national verification means in form of airborne radionuclide sampling (and probably additional surface sampling) are also undertaken by some countries.
Science-oriented background links
Policy-oriented links
This time, the DPRK test deserves a different attitude - not only because of its magnitude, but also because of DPRK's progress in missile technology and last not least because of the personalities of political leaders involved. Even if the general public's attention has decreased, the risk of war has not!

DPRK nuclear test of 09 September 2016

DPRK nuclear test of 06 January 2016

CTBT Briefing
CTBTO/PTS Briefing, official photostream, CC BY 2.0

Currently available information shows that the magnitude of this test is very similar to the 2013 test (ca. 10 kt). Thus, claim of the DPRK to have tested a hydrogen bomb (fusion as the primary source of energy, typically over 1 Mt yield, rarely under 100 kt) appears to be wrong. At most, they may have tried to test a boosted fission device; it would be hard to say whether there was a significant boost effect or not.

If a prompt release of radioxenon would have occurred, it would have been measured at the Takasaki monitoring station in Japan a few days later, which did not happen. A delayed release through the access tunnel is still possible. Analyses (see below) indicate that the rock overhead of the 2016 test site was larger than 2013; a prompt release thus is quite unlikely.

BGR (CTBTO NDC Germany) information (in German, has forecast concentration maps for Xe release)
Prof. Rüdiger Frank (Univ Wien): Kaum noch Mittel gegen Nordkoreas Atomwaffenambitionen

DPRK nuclear test of 12 February 2013

Infrasound signals from the underground nuclear explosions of North Korea by Il-Young Che, Junghyun Park,Inho Kim, Tae Sung Kim and Hee-Il Lee. Geophysical Journal International, Volume 198, Issue 1, 495-503, July 2014.
Radioxenon detections in the CTBT international monitoring system likely related to the announced nuclear test in North Korea on February 12, 2013 by A. Ringbom, A. Axelsson, M. Aldener, M. Auer, T.W. Bowyer, T. Fritioff, I. Hoffman, K. Khrustalev, M. Nikkinen, V. Popov, Y. Popov, K. Ungar, G. Wotawa. Journal of Environmental Radioactivity, Volume 128, February 2014, Pages 47-63
High-precision location and yield of North Korea's 2013 nuclear test by Miao Zhang and Lianxing Wen. Geophysical Research Letters, Volume 40, Issue 12, pages 2941–2946, 28 June 2013
Analysis by U.S.-Korea Institute at the School of Advanced International Studies, John Hopkins University, Baltimore MD ("38 NORTH" website)

May 2010 radionuclide detections over East Asia

The Great 2010 DPRK Nuclear Test Debate Continues: Imagery Evidence Inconclusive, by Joel S. Wit and Sun Young Ahn, published by 38North, 28 April 2015
The Great 2010 DPRK Nuclear Test Debate, by Jeffrey Lewis, published by 38North, 28 April 2015 / 1 May 2015
Seismological evidence for a low-yield nuclear test on 12 May 2010 in North Korea, by M. Zhang and L. Wen. Seismol. Res. Lett., 86(1), doi: 10.1785/02201401170, 2015.
Reinforced evidence of a low-yield nuclear test in North Korea on 11 May 2010 by Lars-Erik De Geer. Journal of Radioanalytical and Nuclear Chemistry, December 2013, Volume 298, Issue 3, pp 2075-2083
140La/140Ba ratio dating of a nuclear release. by Sakari Ihantola, Harri Toivonen, Mikael Moring. Journal of Radioanalytical and Nuclear Chemistry November 2013, Volume 298, Issue 2, pp 1283-1291
Low-Yield Nuclear Testing by North Korea in May 2010: Assessing the Evidence with Atmospheric Transport Models and Xenon Activity Calculations by Christopher M. Wright. Science & Global Security: The Technical Basis for Arms Control, Disarmament, and Nonproliferation Initiatives Volume 21, Issue 1, 2013, DOI:10.1080/08929882.2013.754310
Meteorological analysis of the detection of xenon and barium/lanthanum isotopes in May 2010 in Eastern Asia. by Gerhard Wotawa. Journal of Radioanalytical and Nuclear Chemistry, 296, Issue 1, April 2013.
Radionuclide Evidence for Low-Yield Nuclear Testing in North Korea in April/May 2010 by Lars-Erik De Geer. Science & Global Security: The Technical Basis for Arms Control, Disarmament, and Nonproliferation Initiatives, Volume 20, Issue 1, 2012

DPRK nuclear test of 25 May 2009

Contemplating a third nuclear test in North Korea by Frank V. Pabian and Siegfried S. Hecker, Bulletin of the Atomic Scientists, 08/06/2012 - 13:55 (online). Has discussion of 2006 and 2009 tests and their location.

Detailed news with technical information on the CTBT public website

DPRK nuclear test of 09 October 2006

A Technical Analysis of North Korea's Oct. 9 Nuclear Test by Richard L. Garwin and Frank N. von Hippel
A long distance measurement of radioxenon in Yellowknife, Canada, in late October 2006 by Saey, P. R. J., M. Bean, A. Becker, J. Coyne, R. d'Amours, L.-E. De Geer, R. Hogue, T. J. Stocki, R. K. Ungar, and G. Wotawa, Geophys. Res. Lett. (2007), 34, L20802, doi:10.1029/2007GL030611.
Atmospheric Transport Modeling and Data Fusion in Support of Comprehensive Nuclear-Test-Ban Treaty Verification by Wotawa, G. and A. Becker, Contribution to the The 29th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, Denver, Colorado (Sept. 2007). Contains measurements and atmospheric transport calculations indicating the nuclear nature of the DPRK test.
Paul R.J. Saey, Andreas Becker and Gerhard Wotowa: North Korea: a real test for the CTBT verification system? Part II: noble gas observations CTBTO Spectrum, 10, 20-21

Publications:

Petra Seibert and Paul Skomoroswki (2009), Source Location for the CTBTO-WMO Exercise 2008, Oral presentation at EGU General Assembly 2009. (pdf, 3.5 MB)

A. Becker, G. Wotawa, L.E. de Geer, P. Seibert, R.R. Draxler, C. Sloan, R. D' Amour, M. Hort, H. Glaab, P.Heinrich, Y. Grillon, V. Shershakov, K. Katayama, Y. Zhang, P. Stewart, M. Hirtl, M. Jean, P. Chen (2007): Global backtracking of anthropogenic radionuclides by means of a receptor oriented ensemble dispersion modelling system in support of nuclear-test-ban treaty verification. Atmos. Environ., 41 (21), 4520-4534 ([Fulltext for Elsevier subscribers] )

Wotawa, G., Lars-Erik DeGeer, Philippe Denier, Martin Kalinowski, Harri Toivonen, Real D'Amours, Franco Desiato, Jean-Pierre Issartel, Matthias Langer Petra Seibert, Andreas Frank, Craig Sloan and Hiromi Yamazawa (2003): Atmospheric transport modelling in support of CTBT verification -- Overview and basic concepts. Atmos. Environ., 37 (18), 2529-2537.

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