Viscoelastic Movies
Bridget Smith and David Sandwell
in preparation, 2004
Here we present a 3D simulation of the earthquake cycle that includes
multiple fault elements and explores postseismic deformation for
intermediate time scales following an earthquake. The basic model
consists of a fault system of three independent segments, A, B, and C,
that are imbedded in a 50 km thick elastic plate that is loaded by 40
mm/yr of relative plate motion. Between earthquakes, the middle fault
segment, B, is locked from the surface to a depth of 25 km, below which
deep, secular slip occurs. The two adjacent fault segments, A and C,
are allowed to slip completely to the surface with no locking,
simulating uniform fault creep.


In this model, we assume that the
fault system is a mature one (geologically evolved), where t = 0 years
represents the time of model initiation assuming a full secular plate
step is already in place. This model spans 300+ years, where the first
100 years include secular tectonic loading and 4 m of slip will
accumulate on the locked segment. At t = 100 years, we simulate an
earthquake by initiating coseismic shallow slip (depths < 25 km) on
segment B. Following this event, postseismic deformation due to
viscoelastic relaxation will occur. We capture singleyear snapshots at
5year increments for both 3D velocity and Coulomb stress. Alternative
velocity models for H= 25km and 100km (d=25km) are also shown below.
Coulomb stress models show the postseismic stress response both with
and without secular accumulation following the event. 
