Our Work

Verification Regime

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits all nuclear explosions, whether they are conducted for military or non-military purposes, no matter how high or low their yield. To monitor compliance, its unique verification regime is designed to detect any nuclear explosion conducted anywhere – underground, under water or in the atmosphere.

International Monitoring System

The International Monitoring System (IMS) is a unique global network that, when complete, will consist of 321 monitoring stations and 16 laboratories hosted by 89 countries around the globe. Around 90 percent of these 337 facilities are already up and running, providing a steady flow of real-time data.

Monitoring Technologies

The IMS uses four complementary verification methods – seismic, hydroacoustic, infrasound and radionuclide – using the latest available technology.

Station Profiles

Find details on the location and status of all 337 International Monitoring System stations and laboratories worldwide.

International Data Centre

Data are at the core of the CTBT’s verification efforts. Located in the CTBTO’s headquarters in Vienna, the International Data Centre (IDC) collects, processes and analyses monitoring data from more than 300 IMS facilities and distributes them to Member States in both raw and analysed form.

On-Site Inspection

On-site inspection (OSI) is the final component of the CTBT verification regime. Once the Treaty enters into force, Member States will be able to request an inspection to gather further evidence on the ground if the global monitoring system detects a possible nuclear explosion.

Detecting Nuclear Tests

The CTBT’s International Monitoring System has already proved its effectiveness, detecting all six declared nuclear tests conducted between 2006 and 2017.

Civil and Scientific Applications

Beyond its core purpose of detecting nuclear explosions, the International Monitoring System produces a treasure trove of data that can be put to wider civil and scientific use, from helping to save lives in a tsunami or tracking fallout from a nuclear accident to expanding our knowledge of the Earth and the natural world.

CTBTO TeST Centre

The CTBTO Technology Support and Training Centre (TeST Centre) is a multipurpose hub for equipment storage, maintenance and testing as well as training, supporting the build-up and sustainment of the verification regime and providing the Provisional Technical Secretariat (PTS) with the operational capability and readiness required for entry into force.