Presented at the International Seminar

1. Presented at the International Seminar “Non-compliance with disarmament and non-proliferation agreements: lessons learnt and ways forward” Geneva Centre for Security Policy (GCSP), Geneva, 20 April 2007 Centre d’Etudes de Securite Internationale et de Maitrise des armements (CESIM) Dr. Lassina Zerbo Director, International Data Centre (IDC) Division Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization Provisional Technical Secretariat Vienna International Centre P.O. Box 1200 A-1400 Vienna, AUSTRIA Lassina.Zerbo@ctbto.org The Capacity of the CTBTO PrepCom to Monitor Compliance with a Comprehensive Test-Ban Treaty Provisional Technical Secretariat

2. Outline • Introduction to the Verification System, the International Monitoring System (IMS), the Global Communications Interface (GCI) and the International Data Centre (IDC) • Current status of the Treaty and its verification system • The effectiveness of the verification system―present and future • The 9 Oct 2006 event in DPRK • Seismological observations • Potentially relevant radioactive noble gas observations • Conclusions • Conclusions Provisional Technical Secretariat

3. Underwater Tests • Hydroacoustic Waves • Possible Seismic/Infrasonic Coupling • Probable Radionuclide Release Radionuclide Noble Gas Network Hydroacoustic Network • Atmospheric Tests • Infrasound waves • Possible Seismic/Hydroacoustic Coupling • Radionuclide Release • Underground Tests • Seismic Waves • Possible Infrasonic/Hydroacoustic Coupling • Probable Radionuclide Release Radionuclide Particulate Network Infrasound Network Radionuclide Laboratories Auxiliary Seismic Network Primary Seismic Network Not Started Under Construction Completed/Transmitting Certified CTBT Bans Nuclear Test Explosions in all Environments Provisional Technical Secretariat

4. International Monitoring System 321 stations: seismic, hydroacoustic, infrasound, radionuclide International Data Centre collect, analyse, distribute data & products On-Site Inspection prepare for conduct of on-site inspection Components of the Verification Regime Provisional Technical Secretariat

5. Data from Remote Station, to Vienna, to State Signatory Provisional Technical Secretariat

6. PTS: IDC Division Mission Statement Receive, collect, automatically process, interactively analyse, report on, and archive data from IMS facilities Provide technical assistance Progressively enhance its technical capabilities Provide standard IDC productsobjectively Provisional Technical Secretariat

7. Current status of the Verification System • The Treaty has not yet entered into force • The IMS network of stations is not yet complete • The IDC processing and analysis systems are still being built up • IDC automatic and reviewed ‘Products’ have been issued routinely on a test basis under ‘Provisional Operations’ since February 2000 • Includes daily bulletins of seismoacoustic events and particulate radionuclide observations • Schedules are more ‘relaxed’ than envisaged after entry into force • All IMS data and IDC products are available to authorized users of all States Signatories • Continuous IMS data received in IDC Provisional Operations is available to States in near-real-time Provisional Technical Secretariat

8. ~175,000 Events Located by PTS 21 February 2000 to 1 April 2007 ~25,000 events/year Provisional Technical Secretariat

9. Status of the International Monitoring System at the beginning of 2007 IMS stations in IDC Provisional Operations and contributing to IDC Products: • Primary Seismic: 68% of 50 • Auxiliary seismic: 50% of 120 • Hydroacoustic: 82% of 11 • Infrasound: 58% of 60 • Radionuclide particulate: 55% of 80 • Radionuclide noble gas: None • about 15 stations operating in experimental mode Provisional Technical Secretariat

10. Effectiveness of the Verification System • Notional design goals, sometimes referred to* for the IMS, are not a guide to the actual capability of the network, either now or after its completion * for example: “the ability to detect an event with mb 4.0”; “the ability to detect 1kiloton TNT-equivalent explosion fully-coupled in hard rock” etc. • “Threshold monitoring” studies show that the current IMS seismic network has a capability below mb 4.0 in most land areas of the world, even with the current network • Actual threshold depends crucially upon the station network, geographic location and prevailing worldwide earthquake activity • Consider 9 October 2006 as an example... Provisional Technical Secretariat

11. Threshold monitoring for 9 Oct 2006 01:00-02:00UT Note: Inclusion of a missing station in the threshold monitoring calculations improves the threshold in the Australian region Provisional Technical Secretariat

12. DPRK 9 Oct 2006 event—Context • After Entry into Force (EIF) of the Treaty, the International Data Centre (IDC) will issue processed technical data (“standard products”) “without prejudice to final judgements with regard to the nature of any event, which shall remain the responsibility of States Parties”CTBT Protocol Part I paragraph 18 • The IDC’s role will be to provide data and products to assist Member States to make their judgements • The 9 October 2006 DPRK event provided an unplanned test of many aspects of the emerging CTBT verification system • Less than 60% of the 321 stations of its International Monitoring System (IMS) were in the IDC Operational system • No stations from the Radioactive Noble Gas network were in IDC Operations • The IDC processing software and procedures are still under development • The (Provisional) Technical Secretariat was in ‘Provisional Operations’ mode, with no non-business day working and a ‘relaxed’ schedule for operational activities Provisional Technical Secretariat

13. Map showing the 13 IMS seismic stations used in the automatic location (SEL1) made available within 2 hours • The event was recorded at IMS stations throughout the world (SEL1 = Standard Event List 1) Provisional Technical Secretariat

14. Map of the 22 IMS seismic stations used in the reviewed location (REB) issued two days after 9 Oct (REB = Reviewed Event Bulletin, issued after review by analysts) Provisional Technical Secretariat

15. Map showing the IDC automatic and reviewed locations with their uncertainties • In red: the automatic location (SEL1) with its uncertainty ellipse (2,389 sq km) • In blue: the analyst reviewed location (REB) with its uncertainty ellipse (880 sq km) • 1,000 sq km is the maximum area allowed for an On-Site Inspection under the Treaty • These results can be exactly reproduced by States Parties using the processing software provided by IDC > 100km < Provisional Technical Secretariat

16. Daily concentration of radioactive Xenon recorded at the IMS noble gas station at Yellowknife, Canada • Peaks are observed on 21 October and 25-26 October Provisional Technical Secretariat

17. For each location, the emission of Xenon-133 that would be necessary at 00:00-03:00UT on 9 Oct to create the 21 October peak at Yellowknife (“backtracking”) CRL CAX16 MNX45 Event RUX58 • Uncoloured regions could not have given rise to the peak in the indicated period • Korean peninsula is one region which could have, with a plausible concentration • IDC based its ATM on data comprising 6 million weather observations per day • ATM crucial in the interpretation of observations at IMS radionuclide stations ATM animation Provisional Technical Secretariat

18. Exclusions of Possible Source Locations Regions in which an emission at some time during the period 11 – 23 October could have generated the signal at Yellowknife during the time period of the second peak (23 – 25 October) Uncoloured regions, which include CRL, could not have generated this signal ATM animation CRL Yellowknife (CAX16) DPRK Provisional Technical Secretariat

19. Predicted Xenon-133 signal at Yellowknife from a release at the time and place of the 9 October event (lower graph), compared with observations • The two are similar, supporting the hypothesis of a release on 9 Oct in the DPRK region Provisional Technical Secretariat

20. Predicted radioxenon signal from the 9 October hypothesis at Yellowknife and at other IMS stations not yet operating as analyzed by IDC forward ATM (click here) • If RUX58 had been operating, then a signal 100 times that observed at Yellowknife would have been detected within three days, based upon the hypothesis of a release in the DPRK • Additional IMS noble gas stations will greatly enhance the IMS verification system Provisional Technical Secretariat

21. DPRK event 9 Oct 2006―Conclusions • This DPRK event demonstrated that PTS can receive and review data to timelines envisaged after EIF • The event was well recorded at IMS seismic stations throughout the world • A good event location was made available to States automatically within 2 hours in “Standard Event List 1” • The “Reviewed Event Bulletin” issued within two days after the 9 October has corroborated and improved the location • The location uncertainty was less than the maximum uncertainty allowed for an On Site Inspection under the Treaty (1,000 sq km) • Using PTS atmospheric transport modelling, radioactive noble gas observations at Yellowknife, Canada, were shown to be consistent with a hypothesised release of radioactive Xenon at the time and location of the DPRK event • Other known sources of man-made radionuclides could be excluded • Modelling showed that additional IMS noble gas stations will greatly improve our ability to record radioactive Xenon from a release at this location in the future • All this bodes well for the future effectiveness of the verification system Provisional Technical Secretariat

22. Conclusions • The DPRK event has demonstrated the feasibility of the initial goal of PTS—to build up a viable verification system • The event has shown that a smooth transition to Entry-into-Force is feasible with the current state of IMS deployment • but much work is still needed to provide full treaty-compliant functionality • and the Treaty does not provide means to forewarn of any impending violation • Experience has highlighted the importance of the radioactive noble gas network (not yet many stations installed, and none in Provisional IDC Operations) • The Preparatory Commission has taken steps to place more emphasis on this • Progressive lowering of the detection threshold as the IMS evolves will further increase confidence in its verification capability • The recording of very small signals at some IMS stations, together with large geographic variation in the propagation of seismic signals, make it impossible to give a threshold below which a violator would be confident of non-detection • The DPRK event has highlighted the relevance of OSI as a component of the verification regime, and the need to advance its readiness towards that of the IMS Provisional Technical Secretariat

23. Thank you! Provisional Technical Secretariat