The post-doc position is part of the “FastSlip” project funded by the
DeepNL programme of the Dutch Research Council (NWO). You will join a multidisciplinary team of leading experts in the fields of Granular Mechanics, Earth sciences, and Tribology from the University of Twente (UT) and Utrecht University (UU).
Background and aim: The strength of geological faults drastically reduces at near-seismic slip rates, leading to large co-seismic displacements in fault zones. The observed weakening has been attributed to several multiphysical mechanisms, involving rapid frictional heating and temperature change, leading to high pore fluid pressures. While these phenomena originate at the microscale, current earthquake simulators often use continuum approaches, that typically require empirical rate and state friction models, without addressing the discontinuous, coupled multi-physical processes within the fault gouges and their coupling to fault reactivation at the larger length scales.
Accurate prediction of highly dynamic fault slip requires the development of comprehensive and experimentally validated models across different length scales: microscale, where friction between grains generates heat in fault gouges; mesoscale, featuring the fault microstructure, including pore networks that dominate the generation and dissipation of fluid overpressure; and macroscale, where thermal and stress waves attenuate and propagate across multiple faults. Based on the development of predictive models at these scales, a multiscale, multiphysical understanding of fault frictional phenomena will be obtained to help constrain estimates of hazards due to induced seismicity. In particular,
We aim to
simulate coupled thermo-hydro-mechanical processes within fault gouges to investigate loading conditions inaccessible in laboratory and
upscale their effects on fault reactivation using a concurrent
multi-scale modeling approach recently developed at the University of Twente.
Your tasks: - Extend the multi-scale methods already implemented in the open-source code Kratos Multiphysics from mechanical to coupled thermo-hydro-mechanical problems.
- Implement a thermal-hydro-mechanically coupled discrete element method (DEM) model for dynamic friction phenomena in fault gouges, in collaboration with a PhD student from the Surface Technology and Tribology group at UT.
- Couple the micro-scale (DEM) of the fault gouges and the macro-scale (FEM) models for fault reactivation within the same computational domain, in collaboration with a postdoctoral researcher at UU.
- Compare the simulation results with laboratory data from the High Pressure and Temperature Lab of UU.