EAS Ph.D. Defense Yanqing Su

Title: Numerical study of the dynamic processes in volcanic eruptions: Bubble dynamics and volatiles diffusion

Abstract: Volcanic eruption releases gases and aerosols (e.g., sulfur compounds) to the atmosphere, impacting climate for up to several years. While most research efforts of volcanologists to date have been devoted to unraveling the eruptive activity and formation of volcanoes, the understanding of volatiles diffusion during volcanic eruption is still preliminary, largely due to the lack of robust computational tools for magma dynamics during volcanic eruption at the necessary time and length scales. On the other hand, magmatic processes, from the production of melts in the upper mantle to their crystallization or eruption at the surface, are dominated by dynamic processes in deep Earth that are not directly observable, limiting the direct measurement of these processes through geological fieldwork. This dissertation includes three main parts: (i) a non-equilibrium bubble growth models are developed to assess the role of bubble dynamics and volatile kinetics in "excess sulfur'' problem and the implication of the volatile diffusion profile after eruptions on magma ascent history; (ii) a new bubble dynamics model that accounts for hydrodynamical interactions (deformation, coalescence) between bubbles are established; (iii) the dynamical response of saturated porous media to transient stresses is studied using the lattice Boltzmann method with four different porous media topologies. It is anticipated that the findings in this dissertation will improve physical understanding of volatile degassing, bubble dynamics, and saturated porous media in response to transient changes of stresses.

Committee:

Dr. Christian Huber, Dr. Andrew Newman, Dr. Zhigang Peng, Dr. Jingfeng Wang, and Dr. Josef Dufek.