Investigating the impact of atmospheric conditions, ash aggregation and turbulence on volcanic cloud spreading and particle settling
Riccardo Simionato 1, 2, Jonathan Lemus 1, 2, Christophe Coreixas 2, 3, Jonas Latt 2 and Costanza Bonadonna 1
Affiliations: 1 Department of Earth Sciences, University of Geneva, Genève, Switzerland 2 Computer Science Department, University of Geneva, Carouge, Switzerland 3 Institute of Advanced Study, BNU-HKBU United International College, Zhuhai, China
Presentation type: Talk
Presentation time: Thursday 08:45 - 09:00, Room S160
Programme No: 3.12.2
Abstract
Explosive volcanic eruptions release large volumes of tephra into the atmosphere, where it is dispersed by wind and deposited on the ground. The dispersal and sedimentation of tephra are influenced by key processes such as ash aggregation, volcanic cloud turbulence, and shear at the cloud base. Additionally, tephra interacts with atmospheric conditions (e.g., wind, temperature, humidity, and atmospheric turbulence), leading to complex dynamics. To better understand these processes, we employ advanced numerical modelling techniques. Specifically, we implement a 3D model in Palabos (Parallel Lattice Boltzmann Solver) that combines the lattice Boltzmann method (LBM) for fluid dynamics with a low-diffusive finite difference scheme (WENO) to solve advection-diffusion equations. This hybrid approach is further fed by field observations and laboratory experiments, offering a detailed perspective on cloud-atmosphere interactions. We use the 2010 Eyjafjallajökull eruption (Iceland) as case study where different sedimentation processes have been observed. Our preliminary results show that the mixing induced by the turbulence allow particles to reach the ground earlier than in a simpler shear-only scenario. By combining these methodologies, our study intends to enhance the accuracy of models predicting ash dispersion and sedimentation, ultimately improving hazard assessments related to volcanic eruptions.