Rock Fractures and Fluid Flow
Main research fields
We use numerical modelling to improve our understanding of the formation of various geological structures and the associated processes. More specifically we use numerical models to analyse the formation of magma chambers and associated collapse calderas, focusing on the thermal and mechanical conditions for magma-chamber development and the tectonic conditions and local stresses triggering caldera collapse. Additional processes studied numerically include the propagation paths of fluid-driven fractures such as dykes, sills, inclined sheets, and mineral veins, as well as human-made hydraulic fractures and associated fluid transport. Particular focus is on the effects of mechanical anisotropy, in particular mechanical layering and contacts between layers, on the propagation paths of fluid-driven fractures. Our models also include local stress fields associated with fault zones, fractured reservoirs, and the evolution of fault systems of sedimentary basins.
Additional modelling includes thermal models. Here the theoretical focus is on thermal aspects of magma-chamber formation and the thermal effects of intrusions on the host rock. In particular, the potential that dykes and sills have for melting the host rock. The more applied aspects of the modelling focus on the thermal effects of intrusions in sedimentary basins, particularly sills, on maturity.
The group uses both finite-element and boundary-element modelling. The main boundary element software used is BEASY. Several finite-element programs have been used, including ANSYS and ABAQUS, but in recent years the focus has been on the use of the COMSOL Multiphysics software.
Vertical and horizontal surface displacements resulting from magma-chamber roof subsidence of 100 m in a layered crust. In model A two soft (compliant) layers (blue, with a Young's modulus of 1 GPa) lie in-between stiffer layers (brown, with a Young’s modulus 40 GPa) which have the same stiffness as the rest of the crust hosting the chamber. In the lower model (B) there are three soft layers (dark blue, Young’s modulus 1 GPa), the uppermost one being the surface layer in contact with the glacier. Graphs on the right indicate the vertical and horizontal displacements in the crustal (solid) and ice (dashed) surface for each configuration. Chamber radius a is 4 km, its half-thickness b is 1 km, and the depth of its roof d below the surface of the ice is 5 km
See the following PDF file:
Surface displacements resulting from magma-chamber roof subsidence