Events such as earthquakes, explosions and releases of radionuclides produce signals and surface features that may be observed locally, nationally, regionally or globally. Such events can be located in time and space, and their characteristics can be estimated based on the data products collected. This theme covers the characterization of the source, the signals being emitted, and what these reveal about the event and its environment. Only if the source is well characterized can its associated signals and anomalies be correctly analysed and interpreted. To ensure compliance with the Treaty, it is essential to understand the full extent of signals that may be generated by a nuclear explosion, as well as to be familiar with any other seismic, acoustic, radionuclide or other signals that could be confused with those from a nuclear explosion.

The Treaty’s provision for OSI depends upon knowledge of the observables that may be expected after a nuclear test and how these could be identified as geophysical, radioactive, temperature or other anomalies or artefacts of testing. While such observations can help distinguish between inactive and active nuclear weapon test sites, the data recorded by International Monitoring System (IMS) stations also make it possible to differentiate nuclear tests from other human made or natural events, thereby serving as a unique reservoir of knowledge for better informed policy making.

One of the challenges facing an inspection team at a historic test site is the need to distinguish and identify observables generated by historic underground nuclear explosions (those conducted before the nuclear testing moratorium) and those resulting from a more recent event. Factors to consider could include recognizing features that may indicate a decommissioned and decontaminated site or those that may suggest an active or reopened site. The types of expertise and capabilities required for these purposes need to be elaborated and could become relevant in the case of any contingency operations that would call upon CTBTO technological capabilities, if requested and if approved by the States Signatories.

Theme 2. Topics

T2.1 Characterization of Treaty-Relevant Events

T2.2 Challenges of On-Site Inspection 

T2.3 Seismoacoustic Sources in Theory and Practice 

T2.4 Atmospheric and Subsurface Radionuclide Background and Dispersion

T2.5 Historical Data from Nuclear Test Monitoring

This theme focuses on the systems used for the monitoring of nuclear explosions and the processing of the recorded data. This includes advances in traditional areas such as seismic and radionuclide instrumentation, sensor networks and processing methodologies, as well as the exploration of novel methods and the adaptation and integration of methods used in other fields. Diverse sources of remotely sensed data, whether from satellites, aircraft or remotely controlled measurement platforms, may find use in nuclear explosion monitoring. OSIs pose special challenges for sensors and associated equipment, which must be capable of detecting observables related to an event that triggered an OSI, especially those related to a nuclear test.

Theme 3. Topics

T3.1 Design of Sensor Systems and Advanced Sensor Technologies

T3.2 Laboratories Including Mobile and Field Based Facilities 

T3.3 Remote Sensing, Satellite Imagery and Data Acquisition Platforms

T3.4 Augmented Reality and Fusion of Data from Different Monitoring Technologies

T3.5 Data Analysis Algorithms, Artificial Intelligence, Big Data and Deep Learning

Operation and sustainment of a global network of monitoring systems poses substantial challenges. Near real time acquisition and forwarding of continuous and segmented data from the IMS and the subsequent processing and analysis of data at the International Data Centre (IDC) also present great challenges. Strict requirements for operational data availability, quality and timeliness must be met and sustained. The results of processing and analysis raise further issues with regard to quality and timeliness. The handling of OSI data is also subject to specific requirements outlined in the Treaty and the OSI Operational Manual. In addition, the performance of the IMS and IDC critically depends on enabling technologies such as information technology and power systems.

Beyond the IMS, IDC and OSI, the full Treaty verification system also includes National Data Centres (NDCs) and the possible use of non-IMS data to supplement IMS data. NDCs provide advice to their National Authorities, which make decisions in view of a broader policy context. NDCs may have IMS data and Treaty monitoring functions integrated into national operations and procedures to enhance their performance. NDCs provide feedback to the IDC on its products and services, including the NDC analysis tools, and conduct preparedness exercises jointly with other NDCs.

Optimization of the performance of the CTBT verification system involves other factors such as: improvements to efficiency and cost effectiveness, reliability, and security. Contributions on improving performance related to the verification system are invited.

Theme 4. Topics

T4.1 Network Optimization 

T4.2 Systems Engineering 

T4.3 Enabling Technologies 

T4.4 Performance of the Full Verification System 

The CTBTO verification system exists within the broader context of international organizations, global policy making and international collaboration as well as public awareness and safety. This theme explores lessons learned from other arms control agreements and arrangements and from relationships within the broader context as they relate to the CTBT and nuclear explosion monitoring.

Advances in science and technology can drive progress in advising on policies and solutions based on data and evidence and can impact confidence building. This theme explores applications of verification technologies and identifies innovative solutions for change within the framework of the CTBT as well as other relevant agreements and arrangements.

Apart from their purpose of monitoring and detecting nuclear test explosions, IMS data and IDC products may be made available for scientific use, under confidentiality agreements, through the virtual Data Exploitation Centre (vDEC). IMS data may also be used for civil applications, such as nuclear and radiological emergency preparedness and tsunami early warning.

Ensuring that countries and institutions have a robust science‒policy interface requires the wide dissemination and appropriate communication of scientific knowledge to both decision makers and the general public. It is therefore important to raise awareness through a broad range of outreach initiatives and science communication.

Theme 5. Topics

T5.1 Science in Policy Discussions and Lessons Learned from Other Arms Control Agreements and Arrangements

T5.2 Experience with and Possible Additional Contributions to Issues of Global Concern such as Disaster Risk Mitigation, Climate Change Studies and Sustainable Development Goals

T5.3 Capacity Building, Education and Public Awareness