Audible and infrasonic waves generated during the 2022 Hunga eruption: Observations from across Aotearoa New Zealand

Abstract

The 15 January 2022 eruption of Hunga volcano (Kingdom of Tonga) featured one of the most powerful blasts in recent history, generating atmospheric acoustic phenomena observed around the world. Here we examine seismo-acoustic data of the eruption from across Aotearoa New Zealand, host of the densest network of seismo-acoustic sensors in the south-west Pacific. We find clear evidence for two wavepackets of audible acoustics generated by the eruption propagating north-to-south across Aotearoa New Zealand. Celerities estimated from manually picked arrival times indicate that each wavepacket was likely induced by nonlinear phenomena during the passage of Lamb and Pekeris waves, the latter an atmospheric resonance mode not observed prior to the eruption of Hunga volcano. We also highlight results from array processing across a large scale acoustic network, where we successfully detect and estimate backazimuths for coherent low frequency acoustic waves across a maximum aperture of 11 km. The observations presented here provide a new dataset for developing novel techniques for modelling and monitoring of rare atmospheric acoustic phenomena.