Discrete element numerical modelling of the evolution of fault systems in 3D
Abstract
The stages in the development of normal fault systems, from initiation through localisation to maturity, are well established from the study of ancient fault systems. However, there are many aspects of fault system evolution that are not yet understood and are not easily addressed using geological data alone. For example, there is significant current debate on the strains at which the lengths of faults are established. An approach that can improve the understanding of fault growth is appropriately scaled numerical modelling that complements geological data and analysis.
We use the Particle Flow Code in three dimensions which implements Distinct Element Method (DEM) for circular particles. Particles interact via a linear force-displacement law. Cohesion is modelled by adding linear elastic bonds to particle-particle contacts. These bonds break if either critical normal or shear strength is exceeded, thus creating a fracture surface within the rock volume. Model boundaries are represented by rigid and frictionless walls enclosing the modelled volume vertically and at the ends, with periodic lateral boundaries. Extension is replicated by slowly moving the end walls away from the centre while maintaining a constant confining pressure. The DEM models are capable of replicating many aspects of real systems including fault nucleation, propagation, interaction and linkage that emerge in response to local heterogeneities and stress variations. The model results are used to examine the strains at which growing faults establish their lengths and interact with one another and the variation of this strain under different boundary conditions and properties of the faulted volume.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T32A..05A
- Keywords:
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- 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS