​After several years and attempts to establish an International Monitoring System (IMS) infrasound station in the Azores Islands, located in the middle of the North-Atlantic Ocean, the cooperation between the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), the Azores Government, the Centre of Volcanology and Geological Risks Assessment (CVARG) of the University of Azores and the Santa Cruz da Graciosa Municipality, led to the construction, installation and certification of the IS42 station (I42PT) during the year 2010. CVARG assures the management, operation and maintenance of the station, on the behalf of the International Monitoring System (IMS).

Installed in a heavily forested area in the middle of the Island, the array is composed by eight elements and one central recording facility (CRF), where the data are collected before being transmitted via the GCI interface to Vienna. Each array element has 230V independent power supply from the public grid and all the elements are linked to the CRF via optical fibre, in order to guarantee reliability, robustness and high performance, as already evidenced by the high data availability (around 100%) and detections recorded since the time of its certification.

Located in the North Atlantic, IS42 covers a key position for CTBTO monitoring purposes and will offer also the opportunity to study a number of natural events, like volcanic and seismic activity, as well as weather perturbations crossing the Atlantic Ocean. This will set the ground not only for a complementary use of infrasound data by CVARG (tasked by the Azores Regional Government to monitor local volcanic and seismic activity), but also for a number of interactions with other infrasound research groups across Europe and beyond, as already started with the Department of Earth Sciences, University of Florence, in the study of the detections of the 2011 eruptive activity of the Etna Volcano, in Italy, already presented in previous communications and still in progress.