Numerical simulations reveal the dynamics of the most intense eruption of Hunga Tonga in January 2022

Abstract A violent undersea explosive eruption occurred at Hunga Tonga–Hunga Ha’apai volcano on 15 January 2022, generating an eruption cloud more intense than any previously observed. We performed numerical simulations of eruption cloud dynamics using a 3D fluid-dynamic model and an ensemble-based tephra dispersal inversion model to reconstruct the eruption’s climactic phase and compare it with available observations. Our results reveal that during this phase, 190–1500 Tg of seawater interacted with magma, producing a mass flow rate of the eruptive magmatic mixture of 3.2–6.3 × 10⁹ kg s −1 , which is several times more intense than the 1991 Pinatubo eruption. Moreover, we show that the eruption cloud, which injected approximately 1 Tg of volcanic ash and 0.1 Tg of seawater into the mesosphere, was in a state of thermal disequilibrium with the surrounding environment. The eruption injected 0.3–11 Tg sulfur dioxide into the atmosphere. These results suggest that a substantial amount of magmatic material, water vapor, and sulfur dioxide was injected into the stratosphere and mesosphere during this eruption, which could have a significant impact on the global climate several years after the eruption. Our work also shows the importance of high-resolution simulations in capturing the complex dynamics of eruption plumes generated by undersea volcanic eruptions, leading to more accurate predictions of eruption impacts.