CSDMS 2014 annual meeting - Uncertainty and Sensitivity in Surface Dynamics Modeling

Unifying Tectonics and Surface Processes in Geodynamics

Peter Koons

University of Maine, United States
Phaedra Upton GNS Science New Zealand
Sam Roy University of Maine United States

In formulating tectono-geomorphic models of landscape evolution, Earth is typically divided into two domains; the surface domain in which “geomorphic” processes are solved for and a tectonic domain of earth deformation driven generally by differential plate movements. Here we present a single mechanical framework, Failure Earth Response Model (FERM), that unifies the physical description of dynamics within and between the two domains. FERM is constructed on the two, basic assumptions about the three-dimensional stress state and rheological memory: I) Material displacement, whether tectonic or geomorphic in origin, at or below Earth’s surface, is driven by local forces overcoming local resistance, and II) Large displacements, whether tectonic or geomorphic in origin, irreversibly alter Earth material properties enhancing a long term strain memory mapped into the topography. In addition to the gathering of stresses arising from far field tectonic processes, topographic relief, and the inertial surface processes into a single stress state for every point, the FERM formulation allows explicit consideration of the contributions to the evolving landscape of pore pressure fluctuations, seismic accelerations, and fault damage. Incorporation of these in the FERM model significantly influences the tempo of landscape evolution and leads to highly heterogeneous and anisotropic stress and strength patterns, largely predictable from knowledge of mantle kinematics. The resulting unified description permits exploration of surface-tectonic interactions from outcrop to orogen scales and allows elucidation of the high fidelity orogenic strain and climate memory contained in topography.

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Of interest for:
  • Terrestrial Working Group
  • Geodynamics Focus Research Group