A Unification of Earthquake Cycle and Structural Evolution Models for Thrust Faults

Abstract:

Geodetic observations of interseismic deformation near dip-slip faults may be used to estimate slip rates on both isolated structures and across geometrically complex thrust systems. Interpreting these kinematic measurements requires integrating the effects of interseismic elastic strain accumulation from quasi-static earthquake cycle models. While a kinematically consistent theory for planar thick-skinned models has been widely applied the theory for thin-skinned models has remained less satisfactory due to an inadequate treatment of vertical velocities. Here we develop a kinematically consistent model of horizontal and vertical interseismic deformation in thin-skinned thrust systems including non-planar faults. The key aspect of this model is the integration of kinematic structural evolution models with elastic deformation models. Predictions include localized interseismic hanging wall uplift as well as smoothly varying horizontal and vertical velocities. Additionally, this model implies slightly modified patterns of elastic coseismic deformation in the hanging wall including coseismic folding. The interseismic deformation model described here provides a step toward more unified interpretation of both decadal-scale geodetic observations and long-term tectonic uplift.