Global fast-traveling tsunamis driven by atmospheric Lamb waves on the 2022 Tonga eruption

On 15 January 2022, the Hunga Tonga-Hunga Ha'apai volcano erupted, producing tsunamis worldwide including first waves which arrived more than 2 hours earlier than what is expected for conventional tsunamis. We investigated the generation and propagation mechanisms of the tsunami "forerunner," and our simulation found that fast-moving atmospheric Lamb waves drove the leading sea height rise whereas the scattering of the leading waves related to bathymetric variations in the Pacific Ocean produced subsequent long-lasting tsunamis. Tsunamis arriving later than the conventionally expected travel time are composed of various waves generated from both moving and static sources, which makes the tsunami, due to this…