Atmosphere-solid earth coupling signals generated by the 15 January 2022 Hunga-Tonga eruption

The January 15th 2022 eruption of the Hunga-Tonga volcano was associated to one of the highest energy volcanic explosions of the past few decades. Here we present a compilation of data from global seismic networks to explore three main topics: the time evolution of the eruption, the propagation of the atmospheric waves around the Earth and the low-frequency, long-lasting seismic signals worldwide after the main event. We find that the eruption started around 04:00, included two large explosions at 05:30 and 08:25 and produced atmospheric waves which circled the Earth more than two times during a time span of 3.5 days and were detected seismically. We also identify very low frequency signals, detected over several hours, which we interpret as resulting from the excitation of Earth normal modes. To our knowledge, there are no previous examples of atmospheric-solid Earth coupling over such a long time interval and only two examples of normal mode excitation following volcanic eruptions.