CTBTO International Data Centre analysis of the Hunga Tonga–Hunga Haʻapai eruption

Almost 20 years ago, the first infrasound event built only from infrasound arrivals was reported in the Reviewed Event Bulletin (REB) of the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). Over the last 25 years, 53 infrasound stations from the International Monitoring System (IMS) have been installed and are transmitting data to the IDC for the purpose of detecting any nuclear explosions in the atmosphere. The infrasound component of the IMS daily registers infragenic signals originating from various sources such as volcanic eruptions, earthquakes, microbaroms, meteorite entering the atmosphere or explosions. The IDC routinely and automatically processes infrasound data with the objective to detect and locate events then reviewed by interactive analysis.

As the IDC advances its methods and continuously improves its automatic system for the infrasound technology, several events received global interest from the scientific community and the public. On 15 February 2013 the Chelyabinsk meteor entered the atmosphere over Ural region (Russian Federation) and generated infrasound waves that were recorded by 20 of the 42 infrasound IMS stations operating at the time. Almost 9 years later, on 15 January 2022 the Hunga Tonga–Hunga Haʻapai eruption reached a climax around 04:15 UTC, which generated acoustic waves circumnavigating the Earth for several days. In addition to seismic and hydro-acoustic recordings, all 53 IMS infrasound stations registered signals from this eruption. This event is the largest ever recorded by the infrasound component of the IMS network.