The understanding of processes happening in active shallow magma reservoirs is fundamental for monitoring volcanic activity and forecasting possible hazards. Furthermore, the understanding of the evolution of heat transfer in a cooling reservoir helps the identification of possible remnant hot areas that can be used for the production of geothermal energy. Due to inaccessibility and complexity of these processes, numerical models are at the foreground for the study of magma migration through the Earth´s crust and thus for the evolution of magmatic reservoirs.
The aim of this project is to investigate how magma flows and transfers heat while accumulating into a growing reservoir surrounded by a deforming elastic solid (the host-rock). In particular, the attention is focused on the effects of the solid deformation on the flow pattern and on the importance of magma viscosity in driving magma ascent, flow dynamics, and heat transfer.
Sub-solidus deformation of solidified magma observed from relict magma reservoirs indicates strong dynamic interaction between magma inflow and crystallization, reservoir growth, and host-rock deformation during reservoir emplacement. The project addresses this interplay through FEM models built in Comsol Multiphysics version 5.2a. To account for the processes observed in nature, the numerical models include fluid-structure interaction, change of phase (due to crystallization of the magma), and strong dependency on the temperature of magma properties such as viscosity and density. The models allow us to study the dynamic flow patterns in space and time of a magma having physical properties that change during cooling. Such models quickly acquire complexity and require more computational efforts when fluid-structure interaction is considered together with a strong temperature dependence of magma viscosity that produces high viscosity contrasts and broad viscosity ranges. This makes computations on computer clusters necessary.
Results will provide hints about how the magma flows, convects, sinks, and accumulates while cooling during the injection in the reservoir. This allows the investigation of the dynamics, extent, and causes of fluid instabilities in the reservoir that could be related to volcanic hazards and/or homogenization processes. Results will also provide hints about where the heat is transferred during the expansion, formation, and cooling of a magma reservoir, expanding our knowledge about the localization of heat useful for the production of geothermal energy.