Performance variability of the Hydroacoustic and Infrasound IMS stations

Seismic, hydroacoustic, infrasound, and radionuclide are the four complementary monitoring technologies of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). The International Monitoring System (IMS) of the CTBTO consists of, when complete, 50 primary and 120 auxiliary seismic stations, 11 hydroacoustic stations, 60 infrasound stations, 80 radionuclide stations and 16 radionuclide laboratories. Hydroacoustic and Infrasound stations of IMS are designed to detect events of any kind in and underwater, and in the atmosphere respectively. Hydroacoustic stations have been in operation since 1999; 11 stations, of which 6 hydrophones and 5 T-phase, have been sending data since the completion of the network in 2016. Infrasound data was introduced to routine data analysis in 2010 after improvements in automatic processing to reduce the number of false detections. Currently, 54 (out of 60) infrasound stations are being processed. Both hydroacoustic and infrasound technologies have had significant contributions to detecting and to improving event location at the International Data Centre (IDC). This presentation assesses the data quality and performance of the hydroacoustic and infrasound stations in the data analysis aspect. We focus on signal and event detection rate and in turn the contribution of the data from hydroacoustic and infrasound stations to the data analysis. We show how the station performance changes temporally and discuss the results.