Dispersion of Lamb Waves From the 2022 Hunga Tonga–Hunga Ha'apai Volcanic Eruption Reveals Coupling Between Lower and Upper Atmospheric Layers

Abstract

Atmospheric Lamb waveforms are useful for reconstructing large air events, but the propagation of Lamb waves is significantly affected by varying atmospheric conditions. The detailed dispersion of Lamb waves remains vague due to lack of data, but also to simplifications inherent in existing models. Here, we investigate the pressure perturbations induced by the 2022 Hunga-Tonga eruption at both global and regional barometric arrays. After correction of the influence of wind and temperature, the group velocity dispersion curves, measured by tracking energy arrival times across different frequencies, show a decreasing trend with frequency which is superimposed by two low-velocity bands. Regarding the synthetic results, we interpret these low-velocity bands as the coupling effect between Lamb waves in the lower atmosphere and gravity or acoustic waves in the upper atmosphere, offering profound understandings of surface-to-space observations for hazard management and mitigation after extreme atmospheric events.