Theme 2: Events and their characterization

Theme 2: Events and their characterization

Events such as earthquakes, explosions or radionuclide releases produce signals and surface features that may be observed locally, regionally or globally. The 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 way that nuclear explosions generate the full variety of signals, as well as being familiar with any other seismic, acoustic or radionuclide signals that could be confused with those of a nuclear explosion.

The Treaty’s provision for on-site inspections depends on a priori knowledge of the observables (telltale signs) that can be expected after a nuclear test and how these might be identified as, inter alia, geophysical, radioactive, temperature or other anomalies or testing artefacts. The increasing database of recorded events and historical observables also establishes an asset for research on a wide range of scientific applications.


  • T2.1 On-Site Inspection: Integrated Field Exercise 2014 (IFE14)
    Implementation of OSI techniques in IFE14; IFE14 results, evaluation and lessons learned

  • T2.2 Treaty-Relevant Events
    Case studies of nuclear test explosions; explosion-like natural events; radionuclide source terms

  • T2.3 Seismoacoustic Sources in Theory and Practice
    Seismoacoustic sources in the solid Earth, oceans and atmosphere; source characterization including location; data intensive methods for characterizing events; source discrimination

  • T2.4 Atmospheric Background of Radioxenon
    Monitoring and mitigation of noble gas releases from medical isotope production; characterization of xenon background using observations and atmospheric transport modelling