Events such as earthquakes, explosions and releases of radionuclides produce signals and surface features that may be observed locally, regionally or globally. Such events can be located in time and space, and their characteristics can be estimated from the data that are 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 analyzed and interpreted. To ensure compliance with the Treaty, it is essential to understand the full range of signals that may be generated by a nuclear explosion that occurs in any medium, 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 on-site inspections depends upon knowledge of the observables that might be expected after a nuclear test and how these could be detected and assessed as geophysical, radioactive, temperature or other anomalies or artefacts of testing at the surface, or above or below the surface. The methods allowed for in on-site-inspection under the Treaty may cover up to 1,000 square kilometres, and studies of the signatures that might be observable can assist in on-site inspection design.

Data observed from past nuclear test explosions include a diversity of historical records, many of which are not easily available to researchers, and which need digitising, reformatting, and the reconstruction of metadata such as calibration parameters. The possibility that such records may become degraded, lost or discarded gives rise to an urgent need to safeguard such legacy data. Moreover, observations from the aftermath of nuclear test explosions shed light on the physical and radiological characteristics that are the subject of on-site inspections.

Topics:

2.1 Treaty-Relevant Events
2.2 Characterization of Events Through On-Site Inspection
2.3 Seismoacoustic Sources in Theory and Practice
2.4 Atmospheric Background of Radioxenon
2.5 Historical Data from Nuclear Test Monitoring

This Theme focuses on the sensors used for nuclear explosion monitoring, and 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 exploration of novel methods, and the adaptation and integration of methods used in other fields, such as satellite photography. Diverse sources of remotely sensed data, whether from satellites, aircraft or unmanned aerial vehicles, may find use in nuclear explosion monitoring.

On-site inspection poses special challenges for sensors and associated equipment which must be capable of detecting observables related to an event that triggered the on-site inspection, especially those related to a nuclear test.

Topics:

3.1 Design of Sensor Systems and Advanced Sensor Technologies
3.2 Laboratories Including Mobile and Field-Based Facilities
3.3 Remote Sensing, Satellite Imagery and Data Acquisition Platforms
3.4 Geophysical Methods Applied to On-Site Inspection
3.5 Data Processing and Interpretation
3.6 Fusion of Data from Different Monitoring Technologies
3.7 Algorithms

Sustained operation of a globally distributed network of sensors poses substantial logistical challenges and the need for a rational approach to life-cycle management. Near-real-time acquisition and forwarding of continuous and segmented data from the global International Monitoring System, and its subsequent processing and analysis at the CTBTO’s International Data Centre also pose great challenges. Strict specifications for data availability, quality and timeliness must be achieved and sustained, while the results of processing and analysis pose further issues of quality and timeliness. Special demands are placed upon the handling of OSI data, which will be governed by many requirements outlined in the Treaty and the on-site inspection Operational Manual. Also relevant is the integration of IMS data and Treaty monitoring into national operations and procedures.

The optimization of performance has many facets, and contributions are invited on any subject that impinges on the efficiency, quality, timeliness, reliability and cost-effectiveness of the verification process.

Topics:

4.1 Performance Optimization and Systems Engineering
4.2 Operations Research and Systems Analysis
4.3 Logistics and Lifecycle Management
4.4 Quality Management and Business Process Optimization in an Operational Environment
4.5 Network Optimization and Error Analysis

The CTBTO verification system exists within the broader context of international organizations, global policy making, international collaboration and citizen awareness. This Theme explores these relationships as they impinge upon the CTBT and explosion monitoring data.

Topics:

5.1 Science in Support of Global Policy Decisions
5.2 Science in Support of International Treaties and Sustainable Development Goals
5.3 Comparative Roles of Global Verification and On-Site Verification
5.4 Capacity Building, Education and Public Awareness