Project institution: University of Glasgow
Project supervisor(s): Dr Antoniette Greta Grima (University of Glasgow) and Dr Tobias Keller (University of Glasgow)
Overview and Background
Overview: This PhD studentship focuses on developing GPU-accelerated models of subduction dynamics and surface evolution with fluid release, volatile transport and melt dynamics with implications for volcanic hazard and critical resource formation potential. Subduction processes, fluid release and flow, and the resulting surface response of our planet operate across different scales, spanning from grain size to regional scale dynamics and span across quasi-instantaneous timescales to millions of years. This is a stand-alone project which will contribute one component of a multi-scale framework of independent projects using advanced GPU-based techniques to investigate the influence of fluid on subduction and surface processes. In this project, you will focus on the interaction between fluid transport and topographic evolution on the continental overriding plate at subduction zones with implications for magmatic eruption location, landform deformation preceding volcanic unrest and continental break-up.
Your work will include software development, integrating and interpreting field and experimental data sets, attending regular seminars, collaborating within a research team, and receiving training through ExaGEO workshops.
Background: Subducting slab transport altered near-surface rocks into the Earth’s mantle, introducing volatiles that sustain the deep water and carbon cycles and are crucial in generating melt and magmatic processes. Subduction links shallow and deep Earth systems, maintains conditions essential for a habitable planet (e.g., Tian et al., 2019) and at shallow depths has a critical influence on mineral resource emplacement.
Furthermore, the volatiles and fluids carried by the subducting slab influence subduction style, weaken and fracture the overriding plate, induce fluid release from the slab and into the mantle wedge, and control the location, timing, composition, and volume of arc magmatism (Nakao et al., 2016). These processes in turn govern volcanic hazards and the formation of critical metal deposits (Faccenda, 2014). Despite the key role of fluids in subduction zones, fluid release and the mechanisms controlling volatile and melt dynamics, and reactive fluid transport in subduction dynamics remain poorly understood. This project will utilise high-resolution, GPU-accelerated simulations to investigate the interaction between fluid and subduction dynamics and their expression at the Earth’s surface.
Methodology and Objectives
Modelling subduction processes is a complex scientific and computational challenge, especially when coupled with free surface deformation and fluid release and transport. This complexity stems from the interplay of multi-scale, multi-component, and multi-phase processes with feedback operating across varying timescales and rheologies. To tackle these challenges, this project employs a multiscale modelling approach that integrates small-scale reactive fluid transport and lithospheric dynamics with large-scale 2D and 3D subduction models incorporating free surface evolution.
The candidate will develop new computational tools in Julia and Python, leveraging GPU architectures and Exascale computing to couple advanced, high-resolution 2D and 3D subduction simulations with ultra-high-resolution crustal-scale models. These simulations will bridge processes operating over regional scales, and geological timescales with grain boundary-scale dynamics occurring over short timescales. Traditional CPU-based systems are insufficient for such a computationally intensive approach. GPUs enable the parallel processing necessary for adaptive mesh refinement (AMR), ensuring high resolution where intricate interactions such as those between fluid phases, rock deformation, and thermal processes occur. By utilizing Exascale capabilities, this project will be the first to dynamically couple multi-scale subduction models, capturing fine-scale details to inform system-scale dynamics while maintaining computational efficiency for large-scale simulations.
This project is part of a broader suite investigating subduction dynamics (e.g., slab-fluid interactions, fluid-fracture transport in the overriding plate). However, it stands alone in its focus on how subduction-driven reactive flow and fluid presence influence the rheology of the continental overriding plate, guide melt focusing, and shape the topographic evolution of continents.
The project begins with two introductory “teaser” projects designed to familiarise the candidate with key techniques and datasets, followed by a tailored research focus.
Teaser Project 1: GPU-Optimized Two-Phase Flow Model
Develop a GPU-optimized two-phase flow model in Julia to simulate fluid migration and solid matrix interactions in subduction zones, based on Keller & Suckale (2019). This model will leverage Exascale GPU computing to handle large, high-resolution grids and complex boundary conditions efficiently. Accelerated computation will enable parameter sweeps and real-time analysis of melt presence, mobility, and deformation patterns.
The GPU-based approach will significantly reduce simulation times, allowing systematic validation against benchmarks while exploring key parameters such as fluid mobility and viscosity contrasts. By linking microscale fluid behaviour to macroscale tectonic processes, this model will advance understanding of how subduction-driven fluid dynamics influence seismicity, magmatism, basin formation and mantle convection.
Teaser Project 2: Multiphase Thermo-Mechanical Subduction Processes
Model thermo-mechanical subduction processes in 2D and 3D Cartesian geometries using ASPECT, an open-source finite element software (Heister et al., 2017). This project will incorporate visco-plastic rheology and free surface boundary conditions to simulate time-dependent thermal structures and topographic evolution. It builds on the methods of Douglas et al. (2024), parameterizing slab dehydration via phase diagrams coupled with reactive transport processes.
This teaser project will extend ASPECT’s capabilities by developing GPU-accelerated solvers for finite element assembly and solution, enhancing resolution, AMR, and computational speed. These advancements enable multi-scale simulations to capture small-scale features such as fluid migration pathways and their impact on the rheology of the overriding plate and surface deformation. This real-time coupling of fluid dynamics and deformation is critical for exploring how subduction related stresses are influenced by dynamic fluid transport to shape topography
References and Further Reading
- Faccenda, M. (2014). Water in the slab: A trilogy. Tectonophysics, 614, 1–30 (click here)
- Heister, T., Dannberg, J., Gassmöller, R., & Bangerth, W. (2017). High accuracy mantle convection simulation through modern numerical methods – II: Realistic models and problems. Geophysical Journal International, 210(2), 833–851 (click here)
- Keller, T. and Suckale, J., 2019. A continuum model of multi-phase reactive transport in igneous systems. Geophysical Journal International, 219(1), pp.185-222
- Nakao, A., Iwamori, H., & Nakakuki, T. (2016). Effects of water transportation on subduction dynamics: Roles of viscosity and density reduction. Earth and Planetary Science Letters, 454, 178–191 (click here)
