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.
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