Viscoelastic deformation for a clustered earthquake cycle

The clustering of earthquakes in time on the same fault affects the rate and pattern of interseismic deformation. We develop a simple analytic viscoelastic model of the surface velocity field through a clustered earthquake cycle by superposing the velocities of individual earthquake cycles of constant period but varying phase. Velocity profiles prior to and after an earthquake show a wider range of behavior than they do for earthquake cycles with constant repeat times. These new types of behavior provide possible explanations for discrepancies between geologic estimates of long-term fault slip rates and slip rate estimates from geodetic data.