Discrete Element Method (DEM) Numerical Modeling of Mechanical Controls on Emergent Normal Fault Systems in Extensional Environments
Author
Portnoy, Samantha ElisabethIssue Date
2021Keywords
discrete element methodextensional tectonics
geomechanics
geophysics
numerical modeling
structural geology
Advisor
Hughes, Amanda N.
Metadata
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
A wide range of normal faulting styles accommodate strain in extensional tectonic settings, yet the mechanical reasons for this variability remain unresolved. The ability to more confidently interpret these structures in natural systems has critical importance to subsurface applications in seismic hazard assessment, energy and mineral resources, and regional tectonic analyses. The relative importance of material strength parameters, boundary conditions, and layer thicknesses in the formation of end-member structural styles in extensional systems can be characterized through discrete element method (DEM) numerical modeling. Results from two-dimensional DEM experiments demonstrate that realistic structures can be modeled with this approach without predefining the locations or geometries of the faults in the models. Because of this, these models can be used to evaluate the role of overburden thickness, basal layer thickness, basal layer dip, and relative material strength in controlling the style of upper crustal structural evolution within extensional systems. This study varies these parameter inputs within a model setup that permits emergent growth of structures without prescribing fault planes in order to quantitatively identify the range of conditions under which different structural styles evolve. The structural styles associated with a weak basal layer underlying a clastic overburden sequence deforming under variable geometric configurations are assessed and interrogated for their stress and strain evolution. Defining the necessary conditions for formation of different styles of normal fault systems provides a fundamental understanding of the processes governing structural growth and can significantly improve interpretations and predictions related to structural geometries within passive margins.Type
textElectronic Thesis
Degree Name
M.S.Degree Level
mastersDegree Program
Graduate CollegeGeosciences