It is early in the morning of 26 January. In the headquarters of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) in Vienna, Austria, representatives of Member States together with CTBTO experts watch a live video feed of a large conventional explosion in the Israeli desert.
The detonation was part of an international experiment organized by the CTBTO in cooperation with 21 countries from around the world. “This is a crucial test for the infrasound technology, an important component of our monitoring system,” said Tibor Tóth, Executive Secretary of the CTBTO.
Infrasound detects low frequency sound waves, inaudible to the human ear, and is used by the CTBTO to detect nuclear explosions in the atmosphere.
The International Monitoring System (IMS) consists of almost 340 installations around the world that watch over the planet to detect signs of a nuclear explosion. The 60 infrasound stations are part of that system.
The infrasound technology is relatively young. Scientific and technological attention declined after atmospheric nuclear tests were banned by the 1963 Partial Test Ban Treaty. “The CTBT and our monitoring system brought infrasound back to life,” Tóth told the gathering.
Monitoring of the blast in the Negev desert was widespread: 25 mobile infrasound sensors deployed in 15 European and Middle Eastern countries stood ready to register the sound waves emanating from the explosion. Conducted in a controlled environment, the detonation is expected to generate important ground-truth information for the calibration and fine-tuning of infrasound sensors and infrasound data processing tools.
It’s calm again in the Negev desert. The dust lifted by the blast has settled. But, the work has only just begun. International scientific experts and CTBTO specialists are now sifting through a host of data from the explosion, assessing the information and starting to plan the next steps towards completing the build-up of the IMS infrasound network.