Particle Methods in Tectonic Modelling

October 27, 2003

Hans F. SchwaigerSean Willett

University of Washington

Title

Dis-continuum Modelling in Geodynamics

Analogue/Sandbox models

Discrete Element Modelling (DEM)

Smooth Particle Hydrodynamics (SPH)

Outline

Fluid/Solid interaction withBrittle deformation

Wu, et. al., 1998Bertotti, et. al., 2000

Analogue/Sandbox Models

Simulates Mohr-Coulomb behaviour

Difficult to adjust model parameters

Bonini and Sani., 2002Persson and Sokoutis., 2002

Discrete Element Modelling

Simulates granular material

Forces are transmitted through contacts with neighbouring particles

Accommodates large strain on discrete structures

DEM applied to lithospheric processes

Burbidge, 2000

Saltzer, et. al., 1992

Accretionarywedges

Extensionalfaulting

Smooth Particle Hydrodynamics

Grid-Free Lagrangian Method

Solves Continuum Equations

Can handle an arbitrary

constitutive law (in principle)

Bonnet, 1999

SPH Formulations of Field Equations

Model testing

1-D Thermal 1-D Mechanical

Couette Flow Poisouille Flow

Heat Flow

Model testing

2-D Mechanical

Monaghan, 1994

Inviscid Dam Burst

Adding Viscosity

Low Viscosity

Adding Viscosity

Medium Viscosity

Adding Viscosity

High Viscosity

Folding of viscous layers

Accretionary Wedges

Low Viscosity

Medium Viscosity

Accretionary Wedges

High Viscosity

Future work

Add energy equation (2/3-D Heat flow, heat sources)

Add non-linear stress in momentum equation

Add erosion

Parallelize code (necessary for 3-D)