Timelines of data processing and analysis

Timelines of data processing
and analysis

The time elapsing from the occurrence of an event to its detection and analysis is crucial when seeking clarity on a suspicious event. The Treaty does not define timelines for the analysis process and the resulting bulletins. These details are included in the relevant documentation on the functioning of the IDC and relate to timelines applicable after the Treaty’s entry into force.

The time elapsing from the occurrence of an event to its
detection and analysis is crucial when seeking clarity on a
suspicious event.

As explained above, the results of the automatic processing of waveform data, i.e. seismic, hydroacoustic and infrasound data, are listed in successive event lists, the Standard Event Lists (SEL). The envisaged time lines for these event lists to be produced after an event occurred are about one hour for SEL1, four hours for SEL2 and six hours for SEL3.

The interactive review of events listed in SEL3 will be completed within the following two days and resulting events will be listed in the Reviewed Event Bulletin (REB). The automatic process to screen out natural events listed in the REB will take little more than one hour and the results will be published in the Standard Screened Event Bulletin (SSEB).

Following entry into force of the CTBT, all relevant information
on a suspicious event will be available to Member States two
days after an event occurred.

Thus, two days after a suspicious event, Member States will have at their disposal comprehensive information consisting of processing and analysis results based on data from the IMS waveform networks.

As the Treaty has not yet entered into force, the monitoring, processing and analysis of data does not proceed according to envisaged time lines. Currently, SEL1, SEL2 and SEL 3 are available two, six and twelve hours respectively after an event occurred. The interactive review of waveform data and initial automatic analysis can take up to ten days, with the ensuing automatic event screening process being completed a few hours later.

The CTBTO provided Member States with relevant waveform
processing and analysis results only two days after the
announced nuclear test in the Democratic People’s Republic
of Korea on 9 October 2006.

The CTBTO strives to advance the automatic processing and interactive analysis processes so that they meet the requirements under the Treaty.  Following the announcement by the Democratic People’s Republic of Korea on 9 October 2006 that it had conducted a nuclear test, the IDC applied the time lines as foreseen under the Treaty and issued the REB for the day of the event just two days later.

There are major differences in the way waveform data and radionuclide data are processed and analysed in the IDC.  The interpretation of any IMS radionuclide observation depends crucially upon prevailing global wind patterns. They determine how radionuclide particles or noble gases migrate from source to detecting station. The dispersion of radioactive particles and noble gas generated by an event can take days or even weeks before reaching a monitoring station, long after the waveform data for the same event have been analysed.

Timelines for radionuclide analysis depend on the dispersion
of radionuclides by wind and weather. Analysis results will be
available three days after sample collection.

Following the arrival of radionuclides at a monitoring station, radionuclide data sampling, measurement, data transmission to IDC and data processing take a minimum of two days, resulting in the Automatic Radionuclide Report (ARR). The Reviewed Radionuclide Report (RRR) is the result of an interactive review of radionuclide data and will be available approximately three days after the sample collection started.

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Atmospheric transport modelling and data fusion