Atmospheric Lamb wave inversion from the 2022 Hunga Tonga–Hunga Ha’apai eruption for tsunami prediction

Abstract The 2022 Hunga Tonga–Hunga Ha’apai eruption generated atmospheric Lamb waves that were recorded by barometric pressure sensors at meteorological stations around the world. This type of atmospheric pressure wave can efficiently generate tsunamis when propagating over the deep ocean. In this study we estimate an eruption source model by inversion of Lamb waveforms recorded at weather stations in the Southwest Pacific and Japan. The observed Lamb waves suggest that the apparent speed of the wave slows from 325 m/s within 2000 km from the source to 317 m/s around New Zealand, and to 288 m/s around Japan. This wave speed data is essential for the source inversion. Overall, inversion for the source time function suggests that the total duration of the generative explosions is about 30 min, with a main explosion at around 4:15–4:20 UTC. This study also shows that the source model can be used to accurately predict the tsunami at offshore tsunami gauges both in the Southwest Pacific and Japan.