Two adjacent segments of the Chile margin exhibit significant
differences in earthquake magnitude and rupture extents during the 1960
Valdivia and 2010 Maule earthquakes. We use the Discrete Element Method
to simulate the upper plate as having an inner and outer wedge defined
by different frictional domains along the decollement. We find that
outer wedge width strongly influences coseismic slip distributions. We
use the published peak slip magnitudes to pick best fit slip
distributions and compare our models to geophysical constraints on outer
wedge widths for the margins. We obtain reasonable fits to published
slip distributions for the 2010 Maule rupture. Our best-fit slip
distribution for the 1960 Valdivia earthquake suggests that peak slip
occurred close to the trench, differing from published models but being
supported by new seismic interpretations along this margin. Finally, we
also demonstrate that frictional conditions beneath the outer wedge can
affect the coseismic slip distributions.