Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.652086
Title: Controls on fault network evolution and population statistics : insights from field studies and numerical modelling
Author: Hardacre, Kathryn M.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2000
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Abstract:
This is the first study in which the effects of initial conditions (e.g. rheology and material properties), boundary conditions and fault growth properties on fault size scaling are explicitly considered. I use a 2D finite element code to generate kilometre-scale, conjugate, normal faults in cross-section under a range of boundary conditions. The deforming material is modelled with a strain-softening, non-healing, Von Mises rheology with Gaussian heterogeneity in yield strength distributed randomly throughout the mesh. Faults are not defined a priori. Consequently the evolution of geologically realistic structures in the model can be attributed to the physical principles involved, not to a pre-defined geometry. Numerical modelling results indicate that initial conditions and boundary conditions control which growth processes dominate at a particular place and time. Thus, they are also control fault size scaling. Both power law and non-power law distribution types emerged spontaneously, and the power law distributions showed a range of values of c between 0.53 and 1.27. In each simulation, the exponent c of the fault size cumulative frequency distribution was observed to decrease with increasing extension; partly due to coalescence, but also because larger faults grew disproportionately faster than smaller ones. The dependence of c on total strain was weak and easily masked by other contributing factors. The exponent c systematically decreased as heterogeneity decreased and strength loss on failure increased. Most significantly, simulations with statistically identical material properties but different random heterogeneity in space gave power law distributions with as much variation in c as was observed in experiments with different material properties and different total strains. This result implies that extrapolating information about fault size scaling from one area to an adjacent area is inadvisable, even if the regions have the same lithologies and tectonic histories.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.652086  DOI: Not available
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