A LATTICE SOLID MODEL FOR THE NONLINEAR DYNAMICS OF EARTHQUAKES

Abstract

A lattice solid model is presented that is capable of simulating the nonlinear dynamical processes (friction and fracture) associated with earthquakes. It is based on molecular dynamics principles to model interacting particles by numerically solving their equations of motion. Particles represent indivisible units of the system such as grains and interactions are described through effective potential functions. In this initial work, particles interact through radial pairwise potentials and the solid is made of particles arranged in a two–dimensional triangular lattice which corresponds to an isotropic elastic medium in the macroscopic limit. Simple and tractable potentials are specified to model brittle and ductile material. Numerical experiments of flawed brittle and ductile blocks subjected to uni–axial compression yield mode II fracturing behavior and characteristic stress–strain curves. In another experiment involving brittle blocks with rough surfaces being dragged past one another, stick–slip frictional behavior is observed. These results suggest that earthquakes can be simulated using the particle based modeling approaches even when the particles and their interactions are highly simplified.