HR: 0800h
AN: T51B-0545    [Abstracts]
TI: 4-D Subduction Models Incorporating an Upper Plate
AU: Stegman, D
EM: dave.stegman@sci.monash.edu
AF: School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia
AU: * Capitanio, F A
EM: fabio.capitanio@sci.monash.edu
AF: School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia
AU: Moresi, L
EM: Louis.Moresi@sci.monash.edu
AF: School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia
AU: Mueller, D
EM: dietmar@geosci.usyd.edu.au
AF: EarthByte Group, School of Geoscience, University of Sydney, Sydney, NSW 2006, Australia
AU: Clark, S
EM: stuart@simula.no
AF: Simula Research Laboratory, Marine Linges v 17, Formebu, Lysaker, 1325, Norway
AB: Thus far, relatively simplistic models of free subduction have been employed in which the trench and plate kinematics are emergent features completely driven by the negative buoyancy of the slab. This has allowed us to build a fundamental understanding of subduction processes such as the kinematics of subduction zones, the strength of slabs, and mantle flow-plate coupling. Additionaly, these efforts have helped to develop appreciable insight into subduction processes when considering the energetics of subduction, in particular how energy is dissipated in various parts of the system such as generating mantle flow and bending the plate. We are now in a position to build upon this knowledge and shift our focus towards the dynamic controls of deformation in the upper plate (vertical motions, extension, shortening, and dynamic topography). Here, the state of stress in the overriding plate is the product of the delicate balance of large tectonic forces in a highly-coupled system, and must therefore include all components of the system: the subducting plate, the overriding plate, and the underlying mantle flow which couples everything together. We will present some initial results of the fully dynamic 3-D models of free subduction which incorporate an overriding plate and systematically investigate how variations in the style and strength of subduction are expressed by the tectonics of the overriding plate. Deformation is driven in the overriding plate by the forces generated from the subducting plate and the type of boundary condition on the non-subducting side of the overriding plate (either fixed or free). Ultimately, these new models will help to address a range of issues: how the overriding plate influences the plate and trench kinematics; the formation and evolution of back-arc basins; the variation of tractions on the base of the overriding plate; the nature of forces which drive plates; and the dynamics controls on seismic coupling at the plate boundary.
DE: 1031 Subduction zone processes (3060, 3613, 8170, 8413)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting