International Monitoring of Nuclear Test Technologies In Use

1. International Monitoring of Nuclear Test Technologies In Use • Legal basis of the international monitoring of nuclear test • Technologies used illustrated with some recent observations • Present status of the international network

2. Mecanical signature • (Pressure wave : Seismic, Infrasound and Hydroacoustic) Wave choc 55% debris 20% N, γ, β, neutrino 10% • Radioactive signature • (Aerosols, Gaz) X Ray 70% Thermal production 35% • Thermal signature (Heat flow) NUCLEAR TEST IMMEDIATE SIGNATURES Breakdown of energy released during a nuclear test

3. THE LEGAL BASIS OF THE INTERNATIONAL TREATY On 10 September 1996, adoption by the United Nations General Assembly in New York of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) which prohibits all nuclear test explosions. The treaty is intended to implement a global verification regime to monitor compliance with its provisions. The regime comprise a global network of monitoring stations (the International Monitoring System), an International Data Centre in Vienna, a consultation and clarification process, On-site Inspections, and confidence-building measures. It will enter into force when among others, the 44 states with nuclear capacity will have ratified.To date 34 states have ratified but China, North Korea, India, Pakistan and USA have still to do so. The States Parties establish an Organization (CTBTO) to achieve the object and purpose of the Treaty. A Provisional Technical Secretariat is responsible for • supervising and coordinating the operation of the International Monitoring System (IMS); • Operating the International Data Centre (IDC); • Routinely receiving, processing, analysing and reporting on IMS data; • Providing technical assistance for the installation and operation of monitoring stations

4. INTERNATIONAL MONITORING SYSTEM A network of globally-distributed sensors will be installed in 321 monitoring stations located at 260 facilities in over 80 countries worldwide that will provide monitoring coverage of all the continent, oceans and atmosphere. It utilizes four technologies: • Seismic (underground seismic waves) • Infrasound (atmospheric sound waves) • Hydroacoustic (underwater seismic waves) • Radionuclide (radioactive isotopes) The data from the stations flow via a global communications network into the International Data Center in Vienna where analysts receive, analyze, and archive the data. Data can be provided electronically to States Signatories.

5. SEISMIC MONITORING STATION The seismic technology consists in measuring the movement of ground surface and allows the detection of underground and underwater explosion as well as atmospheric ones close to the ground surface. • Sensor type: Seismometer • Station type :Three component and mininetwork • Three component passband: 0.5-16 Hz and 0.02-1 Hz. • 50 primary seismic stations will send continuous data and 120 auxiliary seismic stations sending waveform segments. • 35 primary and 99 auxillary seismic stations are installed and 74% and 59% are already certified.

6. SEISMIC MONITORING STATION IDC Reviewed Event Bulletin: 1 January to 31 July 2007: 17,987 events Source: CTBTO-R. Pearce/L. Zerbo

7. SEISMIC MONITORING STATION Seismograms recorded at Station PS31 (Wonju, Republic of Korea) Nuclear test Earthquake

8. INFRASOUND MONITORING STATION The infrasound technology consists in measuring the variation of atmospheric pressure and allows the detection of low frequency signals such as those of atmospheric explosion as well as underground and underwater ones close to the surface. Noise Filtering System detector • 60 infrasound arrays will send continuous data, • 38 stations are installed and 62% are already certified.

9. Air input Wave Front detector Velocity Direction Pressure Captor Infrasound Station 30 cm Air inlet INFRASOUND MONITORING STATION • Sensor type: Microbarometer with passband: 0.02 - 4 Hz • 4 element arrays • Triangle with a component at the centre. 1.5 0 -1 Distance (km) -1.5 0 1.5 Distance (km) 1 station = 4 elements sensor + noise filtering system

10. INFRASOUND MONITORING STATION Source: CTBTO-F. Guendel

11. HYDROACOUSTIC MONITORING STATION The hydroacoustic technology consists in measuring the variation of pressure wave and allows the detection of underwater explosion as well as atmospheric and underground ones close to the surface. • Hydrophone with passband of 1 – 100 Hz • 6 hydroacoustic arrays will send continuous data and 5 "T-Phase" stations which are seismic stations on coasts which are used to detect hydroacoustic signals • 11 hydroacoustic and T phase stations are installed and 91% are already certified.

12. HYDROACOUSTIC MONITORING STATION The hydroacoustic station at Diego Garcia recorded the Tsunami Waveform at frequencies of about 0.002 to 0.01 Hz even though the site was not significantly impacted by the Tsunami. Water depth is 1500 m. Source: CTBTO-F. Guendel

13. HYDROACOUSTIC MONITORING STATION Source: W.A. Watkins et al. , 2004, Deep Sea Research

14. RADIONUCLIDE STATIONS (PARTICULATES) The radionuclide technology consists in collecting aerosols and gaz samples for measuring the variation of their radioactivity. This technology is the only one that can prove that the explosion detected by the others technologies is nuclear. • Filter : collection efficiency 80% for particulates below diameter of 2 µm • Station type : 500 m3/hour during 24 hours • 80 radionuclide stations • 58 stations are installed and 58% are already certified. Credit photo: CTBTO

15. RADIONUCLIDE STATIONS (PARTICULATES) • Gamma spectrometry • Detector: HP Ge relative efficiency above 40 % • Baseline sensitivity 30 µBq.m-3 for 40Ba • 9 of 16 radionuclide measurement laboratories are already certified. Credit photo: Dase & CTBTO

16. RADIONUCLIDE STATIONS (PARTICULATES)

17. NOX49 SEX63 CAX16 RUX61 MNX45 CAX05 CAX17 DEX33 CNX20 USX75 JPX38 CNX22 PAX50 AUX09 FRX27 ARX01 NZX46 ARIX SAUNA SPALAX RADIONUCLIDE STATIONS (GAZ – XENON) • Station type : 0.4 m3/h over 24 hours max • Measurement type: Beta-gamma coincidence or HR Gamma spectrometry • 133Xe (and 135Xe) activity concentration above 1 mBq.m-3 for a 10 m3 sample. • 40 noble gaz stations • 14 stations are already installed.

18. RADIONUCLIDE STATIONS (GAZ – XENON) Source: CTBTO-Saey

19. SUMMARY The Comprehensive Test Ban Treaty Organization (CTBTO) is putting into place an International Monitoring System (IMS) of 321 stations of which 248 are already installed. A private network composed of frame relay and satellite links called the Global Communications Infrastructure (GCI) conveys the data measurement to a center in Vienna-Austria. Once the IMS is completed, the International Data Centre (IDC) will collect and archive over 1,500 channels of data from the IMS stations, comprising a daily volume of up to 10 Gbytes. The IDC will serve as the primary central repository of all data from the IMS sensors. Although the implementation rate of the network now stands at 80%, it’s efficiency was demonstrated by the detection of the nuclear test in North Korea and as for seismic data, countries are already using them for their national early warning tsunami centers.