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Nuclear Test Ban Treaty Monitoring

In 1996, the UN member states drafted an agreement banning nuclear tests. An International Monitoring System (IMS) coordinated in Vienna was established to control adherence to this agreement. The IMS monitors seismological, hydroacoustic, radionuclide and infrasound data and associated communications, supported by the Technical Secretariat's International Data Centre (IDC).

The SED contributes by providing data recorded by a purpose-built seismic station near Davos which, for example, recorded ground shaking 12 minutes after the nuclear test conducted in North Korea in January 2016.

Explore the International Monitoring System (IMS) by clicking on the interactive CTBTO map.

The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO), was set up by the State Signatories to the Treaty on 19 November 1996 and carries out the preparatory work needed to ensure the Treaty's effective implementation.

A global verification regime has been established to monitor compliance with the Comprehensive Nuclear Test Ban Treaty (CTBT). The verification regime consists of the following elements:

  • International Monitoring System (IMS)
  • International Data Centre
  • Consultation and clarification process
  • Global communication infrastructure
  • On-site inspections
  • Confidence-building measures.

The Preparatory Commission has two subsidiary bodies: Working Group A (WG A) on administrative and budgetary matters and Working Group B (WG B) on verification issues, as well as an Advisory Group on financial, budgetary and associated administrative issues. The Working Groups submit proposals and recommendations for consideration and adoption by the Preparatory Commission at its plenary sessions.

See the interactive CTBT map to find out which countries have already ratified the treaty.

The verification work carried out by the Swiss Seismological Service is based on tasks jointly assigned to us by the Swiss Federal Department of the Interior and the Department of Foreign Affairs. Our role in fulfilling these tasks entails:

  • very reliably operation of the seismic auxiliary station DAVOX, using regularly calibrated instruments;
  • providing high-quality data through the AutoDRM interface when requested by the IDC and documenting performance by taking appropriate measurements;
  • automatically monitoring the health of our data archive and alerting the seismologist on duty to any failures;
  • providing expertise and first-hand information to Swiss government authorities and representing Switzerland at scientific and technical meetings of the State Signatories to do with the establishment and implementation of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO);
  • maintaining contact with other National Data Centres (NDCs) and the IDC to cooperate in areas such as common scientific projects, knowledge transfers and task sharing.

Main Activities at the Swiss National Data Centre (NDC)

The main seismic verification activities at the Swiss National Data Centre are quality control and applied research into improved data exchange features, discriminating earthquakes from explosions, and studying the consequences of using different geographical coordinate systems.

We also represent Switzerland at meetings of Working Group B at the Vienna International Centre.

Switzerland's Participation in the Group of Scientific Experts (GSE)

From 1989 to 1996 Switzerland participated in the work of the Group of Scientific Experts (GSE) and was a member of several working groups (it still is a member of the Group of Scientific Experts' Technical Test Three (GSETT-3) Working Group on Planning).

The Conference on Disarmament tasked the GSE with developing a system to detect and identify seismic events. An experimental system of this kind has been in operation since 1 January 1995 (GSETT-3). During 1996 the GSETT-3 network was gradually modified and integrated into the IMS network set-up. Since 1990, the GSE has developed a comprehensive set of data exchange formats that are also widely used for other seismological purposes.

Between 1 January 1995 and 31 May 1996, Switzerland's three-component station APL Alpnach was part of the GSETT-3's auxiliary network. During 1995, the IDC retrieved a total of 9,372 digital waveforms (seismograms) from the Swiss station using the e-mail-based data transfer system AutoDRM. From mid-April 1996 to mid-February 2002 the designated auxiliary IMS station near Davos (code: DAVOX) was part of the GSETT-3 network. Since 2003, the new certified DAVOX station has been part of the IMS.

The CTBTO's seismic network consists of 170 seismometers in 76 countries. Around the clock, 50 of these seismometers feed information on seismic events (earthquakes or explosions) to the data centre in Vienna. The Swiss Seismological Service (SED) oversees one of these seismometers, the DAVOX station.

The video explains how the CTBTO's seismic monitoring system works.

Verification means confirming whether or not something is true. Where major tremors are concerned, verification entails experts telling the authorities and general public whether detected phenomena are of natural origin or were caused by a nuclear explosion. Seismic verification thus involves differentiating between an earthquake and a nuclear explosion (typically an underground nuclear explosion) based on signals measured using a seismometer.

Construction of the DAVOX Station

January 2002 Building permit application for Dischmatal and Strelapass
March 2002 Decision in favour of the site in Dischmatal
April 2002 Building permit issued
June 2002 Construction work begins: concrete vault, pile foundation, telephone line
July 2002 Installation of technical devices; start of operation and data transmission to the SED in Zurich
August 2002 Installation of the satellite link to Vienna
Sept. 2002 CTBTO computer starts up and transmits data to Vienna
July 2003 Configuration of the last devices completed

Certification and Inauguration of the DAVOX Station

Inspectors from the CTBTO visited DAVOX on 14 and 15 July 2003 to verify the station's technical compliance with the Station Operations Manual (CTBT/WGB/TL-11/21, 9 January 2003).

On 22 August 2003, the DAVOX station was certified as the ninth of 120 auxiliary seismic stations comprising the International monitoring system (IMS). DAVOX was integrated into the IDC's operational network on 23 September 2003 and officially inaugurated on 2 October 2003.

So far more than 2,000 nuclear tests have been conducted worldwide. The table below shows which countries have carried out nuclear explosions in the atmosphere, underground or underwater.

Country Number of tests Type
China

21

24

atmospheric nuclear explosions

underground nuclear explosions

France

45

153

atmospheric nuclear explosions

underground nuclear explosions

India 3

underground nuclear explosions

North Korea 5

underground nuclear explosions

Pakistan 2

underground nuclear explosions

Soviet Union

213

503

2

atmospheric nuclear explosions

underground nuclear explosions

underwater nuclear explosions

United Kingdom

21

24

atmospheric nuclear explosions

underground nuclear explosions

USA

216

818

5

atmospheric nuclear explosions

underground nuclear explosions

underwater nuclear explosions

Unknown 1  

Click on the image to find out where on the interactive CTBTO map which kinds of nuclear explosions have taken place.

Nuclear Tests Year Treaties

9 September: North Korea conducts an underground nuclear test

2016  

6 January: North Korea conducts an underground nuclear test

2016  
  2014 Signature and ratification by 44 nuclear states is required for the Treaty to enter into force. So far 41 of these States have signed and 36 have ratified it.
12 February: North Korea conducts an underground nuclear test 2013  
25 May: North Korea conducts an underground nuclear test 2009  
  2008 20 May: 178 of 193 States have signed the CTBT and 144 States have ratified it
  2007 31 December: 244 out of 321 IMS stations have been built and 214 have been certified. Ten out of 16 radionuclide laboratories have been certified.
9 October: North Korea conducts a nuclear test at its Punggye-ri site 2006 31 December: 244 out of 321 IMS stations had been built and 184 have been certified. Nine out of 16 radionuclide laboratories have been certified.
10 February: North Korea announces it has nuclear weapons 2005 31 December: 219 out of 321 IMS stations have been built and 156 have been certified. Six out of 16 radionuclide laboratories have been certified.
  2004 31 December: 204 out of 321 IMS stations have been built and 109 have been certified. Five out of 16 radionuclide laboratories have been certified.
  2003

31 December: 150 out of 321 IMS stations have been built and 83 have been certified. Three out of 16 radionuclide laboratories had been certified.

22 August: Switzerland's DAVOX station is certified as the ninth of 120 auxiliary seismic stations comprising the International Monitoring System (IMS).

30 April: Mauritania becomes the 100th country to ratify the Comprehensive Nuclear Test Ban Treaty (CTBT).

India conducts a series of 5 nuclear explosions on 11 and 13 May, at Pokaran in the Rajasthan Desert.

Pakistan conducts a series of 6 nuclear explosions on 28 and 30 May in Beluchistan.

1998  
France and China conduct their last nuclear explosive tests 1996

African Nuclear-Weapon-Free Zone Treaty, ANWFZ (Treaty of Pelindaba).

24 September: the Comprehensive Nuclear Test Ban Treaty (CTBT: Treaty text, CTBTO) is opened for signature in New York; 71 States, including the five nuclear-weapon States, sign the Treaty that day.

  1995 Southeast Asia Nuclear-Weapon-Free Zone Treaty (Treaty of Bangkok)
The United States conduct its last nuclear explosive test 1992  
The United Kingdom conducts its last nuclear explosive test 1991  
The Soviet Union conducts its last nuclear explosive test 1990  
  1985 South Pacific Nuclear Free Zone Treaty, SPNFZ (Treaty of Rarotonga)
  1976 The United States and the Soviet Union sign the Treaty on Underground Nuclear Explosions for Peaceful Purposes (Peaceful Nuclear Explosions Treaty, PNE), limiting the yield of individual nuclear explosions conducted outside nuclear weapon test sites to 150 kilotons
India conducts a nuclear explosion 'for peaceful purposes' at Pokaran in the Rajasthan Desert 1974 The United States and the Soviet Union sign the Treaty on the Limitation of Underground Nuclear Weapon Tests (Threshold Test-Ban Treaty, TTBT), limiting the yield of such tests to 150 kilotons
  1968 Treaty of the Non-Proliferation of Nuclear Weapons (NPT), obliging non-nuclear-weapon State Parties not to possess, manufacture or acquire nuclear weapons or other nuclear explosive devices, and obliging nuclear weapon State Parties not to transfer to any recipient whatsoever nuclear weapons or other nuclear explosive devices and committing them to the goal of nuclear disarmament
  1967 Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlateloco)
China conducts its first nuclear explosive test at Lop Nor, Xinjiang 1964  
  1963 On 5 August, the Partial Test Ban Treaty (PTBT) banning nuclear explosions in the atmosphere, outer space and underwater, but not underground, is signed by the United Kingdom, the Soviet Union and the United States
France conducts its first nuclear explosive test near Reggane in the Sahara Desert 1960  
  1959 Antarctic Treaty, providing for the demilitarisation and denuclearisation of the Antarctic continent
The United Kingdom conducts its first nuclear explosive test at the Monte Bello Islands off the Australian coast 1952  
The Soviet Union conducts its first nuclear explosive test near Semipalatinsk in Kazakhstan 1949  

On 16 July, the United States conducts the first nuclear explosive test at Alamogordo, New Mexico.

In August, two atom bombs are exploded over Hiroshima and Nagasaki, Japan.

1945