Speaker
Description
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was adopted by the United Nations General Assembly on 10 September 1996 to prohibit nuclear explosions. Twenty-five years later, the CTBT enjoys near universality, however it has not yet entered into force. In the meantime, the Preparatory Commission (PrepCom) for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is responsible for promoting the CTBT and establishing a verification regime to ensure compliance with the CTBT. The International Data Centre (IDC) of the CTBTO PrepCom receives and processes in near real-time data from the International Monitoring System (IMS), a globally distributed network of seismic, hydroacoustic, infrasound and radionuclide stations. Once completed, the IMS network will comprise 337 facilities including 60 infrasound stations. As of mid-2022, 53 have been installed and are sending data to the IDC. The infrasound stations are arrays of measurement systems are sensitive to low-frequency [0.02 – 4 Hz] acoustic pressure variations in the atmosphere. Once received, stored and referenced in IDC database, the station data are automatically processed. This action then leads to the network processing stage to constructs seismic, hydro-acoustic and infrasound events reported in IDC products, such as final waveform product the Reviewed Event Bulletin (REB). During provisional operations, the target timeline for REB publication is within 10 days of real time.
For infrasound technology, specialized software has been developed for every IDC processing stage, which allow to detect infrasound signals, categorize and identify relevant detections, form automatic events and perform interactive review analysis. Since 2010, tens of thousands of waveform events containing infrasound associations appear in IDC bulletins. This demonstrates the sensitivity of the IMS infrasound component and IDC ability to monitor the infrasound activity at the global scale. The unique information gathered by the IMS systems have been widely used for civil and scientific studies and related to atmospheric impacts of NEO such as the Chelyabinsk meteor in February 2013, the Bering Sea fireball on 18 December 2018 or the atmospheric airburst over the Southern Atlantic Ocean on 7 February 2022. Other significant events registered with infrasound technology are powerful volcanic eruptions, controlled explosions, or announced underground nuclear tests. Infrasound technology remains an active research field on atmospheric dynamics, on characterizing the infrasound global wavefield, or on gravity waves study that could lead to deriving a space and time varying gravity wave climatology.
