Seminář – Irene Bianchi: Seismoacoustic Monitoring within the CTBTO Verification Regime

Irene Bianchi – Engineering and Development Section, International Monitoring System Division, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna, Austria

The Comprehensive Nuclear‑Test‑Ban Treaty Organization (CTBTO) maintains a global verification regime designed to detect nuclear test explosions through a multilayered integration of seismic, hydroacoustic, infrasound, and radionuclide technologies. Central to this regime is the International Monitoring System (IMS), a 337‑facility global network that, once completed, will include 50 primary and 120 auxiliary seismic stations, alongside 11 hydroacoustic and 60 infrasound stations, enabling robust seismoacoustic signal detection and characterization.

Seismoacoustic monitoring plays a critical role in nuclear‑explosion verification by tracing the propagation of seismic waves in Earth’s crust and acoustic waves in the oceans and atmosphere. Nuclear explosions generate distinctive energy signatures that couple across solid earth, water, and air, enabling multimodal detection using the IMS sensor architecture. The CTBTO’s scientific capabilities support continuous global surveillance and enable differentiation between nuclear tests and natural phenomena such as earthquakes or volcanic activity. These technologies underpin transparency and confidence‑building measures across the international security landscape.

Current research efforts within the CTBTO verification community focus on enhancing signal detection thresholds, refining event classification algorithms, and exploiting synergies between seismic and acoustic datasets. Seismoacoustic observations also offer valuable civil and scientific applications, including earthquake characterization, tsunami warning, and the detection of atmospheric perturbations.

The CTBTO Preparatory Commission operates the IMS and its International Data Centre (IDC) in a provisional but fully functional mode. This sustained operational readiness ensures that seismoacoustic monitoring capabilities remain globally accessible to Member States, researchers, and the wider scientific community.

The talk will give a general introduction to the CTBTO and its organizational structure. It will then proceed to focus on the International Monitoring System (IMS), outlining its four monitoring technologies, the global network, and the activities undertaken by the IMS Division to build, operate, and maintain this infrastructure. The talk will also address several components relevant to the verification regime, including examples related to global velocity models, detection algorithms, and seismic source characterization.

The views expressed in this abstract are those of the author and do not necessarily reflect the views of the CTBTO preparatory Commission.

Maintenance work at the seismic station GEYT, Alibeck, Turkmenistan.