Dr David Wallis will deliver the ESE Departmental Seminar on Thursday the 5th of December 2024: “Transient creep of olivine in postseismic deformation and glacial isostatic adjustment”
Join us in room G41 – RSM Building – on Thursday 5 December 2024 at 12h15.
Abstract
Geodynamic processes operating over human timescales, such as postseismic deformation and anthropogenic glacial isostatic adjustment, involve flow of the upper mantle under changing stress conditions. Modelling this flow is central to assessments of fault-zone behaviour over the seismic cycle and the response of ice sheets to changing boundary conditions. However, during this nonsteady-state deformation, the viscosity of mantle rocks evolves with strain and our understanding of this transient creep is still in its infancy. I will outline the case for developing more robust models of transient creep based on microphysical processes operating in mantle rocks, present recent advances in modelling transient dislocation creep of olivine, and explore the implications of the latest model for postseismic deformation and glacial isostatic adjustment. Notably, viscosity evolution predicted by the latest model is more pronounced and complex than classical formulations, highlighting the need for a new generation of large-scale geodynamic models.
About the speaker
I am a structural geologist interested in the rheological and macroscopic tectonic impacts of micro-scale rock deformation mechanisms. Currently I am working on application of Electron-Backscatter-Diffraction-based (EBSD-based) methods to questions of rock rheology during deformation in the upper mantle and in crustal shear zones. More generally my research interests include crustal evolution and deformation during orogeny and interpretation of fault zone behaviour from deformation microstructures. I completed my PhD at the University of Leeds in 2010 and undertook a postdoc at the University of Oxford. I was an Assistant Professor at Utrecht University until 2020 and am currently an University Assistant Professor and UKRI Future Leaders Fellow at the University of Cambridge.