A LATTICE SOLID MODEL FOR THE NONLINEAR DYNAMICS OF EARTHQUAKES

A lattice solid model is presented that is capable of simulating the n onlinear dynamical processes (friction and fracture) associated with e arthquakes. It is based on molecular dynamics principles to model inte racting particles by numerically solving their equations of motion. Pa rticles represent indivisible units of the system such as grains and i nteractions are described through effective potential functions. In th is initial work, particles interact through radial pairwise potentials and the solid is made of particles arranged in a two-dimensional tria ngular lattice which corresponds to an isotropic elastic medium in the macroscopic limit. Simple and tractable potentials are specified to m odel brittle and ductile material. Numerical experiments of flawed bri ttle and ductile blocks subjected to uni-axial compression yield mode II fracturing behavior and characteristic stress-strain curves. In ano ther experiment involving brittle blocks with rough surfaces being dra gged past one another, stick-slip frictional behavior is observed. The se results suggest that earthquakes can be simulated using the particl e based modeling approaches even when the particles and their interact ions are highly simplified.